MICREL MIC3000_07

MIC3000
Micrel
MIC3000
FOM Management IC
General Description
Features
The MIC3000 enables the implementation of sophisticated,
hot-pluggable fiber optic transceivers with intelligent laser
control and Digital Diagnostic Monitoring Interface per SFF8472. It essentially integrates all non-datapath functions of an
SFP transceiver into a tiny 4mm x 4mm MLF® package. It also
works well as a microcontroller peripheral in transponders or
10Gbps transceivers.
A highly configurable automatic power control (APC) circuit
controls laser bias. Bias and modulation are temperature
compensated using dual DACs, an on-chip temperature
sensor, and NVRAM look-up tables. A programmable internal feedback resistor provides unprecedented dynamic range
for APC. Controlled laser turn-on facilitates hot-plugging.
An analog-to-digital converter converts the measured temperature, voltage, bias current, transmit power, and received
power from analog-to-digital. Each parameter is compared
against user-programmed warning and alarm thresholds.
Analog comparators and DACs provide high-speed monitoring of received power and critical laser operating parameters.
An interrupt output, power-on hour meter, and data-ready bits
add user friendliness beyond SFF-8472. The interrupt output
and data-ready bits reduce overhead in the host system. The
power-on hour meter logs operating hours using an internal
real-time clock and stores the result in NVRAM.
Communication with the MIC3000 is via an industry standard
2-wire serial interface. Nonvolatile memory is provided for
serial ID, configuration, and separate OEM and user
scratchpad spaces. Two-level password protection guards
against data corruption.
•
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APC or constant-current laser bias
Supports multiple laser types and bias circuit topologies
Drives external low-cost BJT for laser bias
Integrated digital temperature sensor
Temperature compensation of modulation, bias, and
fault levels via NVRAM look-up tables
Direct interface to SY88932, SY88982, SY89307 and
other drivers
NVRAM to support GBIC/SFP serial ID function
User writable EEPROM scratchpad
Diagnostic monitoring interface per SFF-8472
– Monitors and reports critical parameters:
temperature, bias current, TX and RX optical power,
and supply voltage
– S/W control and monitoring of TXFAULT, RXLOS,
RATESELECT, and TXDISABLE
– External calibration
Power-on hour meter
Interrupt capability
Extensive test and calibration features
2-wire I2C compatible serial interface
SFP MSA and SFF-8472 compliant
3.0V to 3.6V power supply range
5V-tolerant I/O
4mm x 4mm 24-pin MLF® package
•
•
•
•
•
•
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Applications
•
•
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SFF/SFP optical transceivers
SONET/SDH transceivers and transponders
Fibre channel transceivers
10Gbps transceivers
Free space optical communications
Proprietary optical links
Ordering Information
Part Number
Junction Temp. Range
Package
MIC3000BML
–45°C to +105°C
24-pin MLF™
MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2004
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M9999-101204
MIC3000
Micrel
Contents
General Description ................................................................................................................................................................................ 1
Features .................................................................................................................................................................................................... 1
Applications ............................................................................................................................................................................................. 1
Ordering Information .............................................................................................................................................................................. 1
Pin Configuration .................................................................................................................................................................................... 5
24-Lead MLF™ ......................................................................................................................................................................................... 5
Pin Descriptions ................................................................................................................................................................................. 5-6
Absolute Maximum Ratings ................................................................................................................................................................... 7
Operating Ratings ................................................................................................................................................................................... 7
Electrical Characteristics ................................................................................................................................................................. 7-11
Timing Diagram ..................................................................................................................................................................................... 11
Serial Interface Timing .......................................................................................................................................................................... 11
Address Map .......................................................................................................................................................................................... 12
Table 1. MIC3000 Address Map, Serial address = A0h ..................................................................................................................... 12
Table 2. MIC3000 Address Map, Serial Address = A2h ..................................................................................................................... 12
Table 3. Temperature Compensation Tables, Serial Address = A4h ................................................................................................. 13
Table 4. OEM Configuration Registers, Serial Address = A6h ........................................................................................................... 13
Block Diagram ....................................................................................................................................................................................... 14
Figure 1. MIC3000 Block Diagram ...................................................................................................................................................... 14
Analog-to-Digital Converter/Signal Monitoring ................................................................................................................................. 14
Figure 2. Analog-to-Digital Converter Block Diagram ......................................................................................................................... 15
Table 5. A/D Input Signal Ranges and Resolutions ........................................................................................................................... 15
Table 6. VAUX Input Signal Ranges and Resolutions ........................................................................................................................ 15
External Calibration .............................................................................................................................................................................. 16
Voltage .................................................................................................................................................................................................... 16
Temperature ........................................................................................................................................................................................... 16
Bias Current ........................................................................................................................................................................................... 16
TX Power ................................................................................................................................................................................................ 16
RX Power ................................................................................................................................................................................................ 16
Laser Diode Bias Control ..................................................................................................................................................................... 17
Figure 3. MIC3000 APC and Modulation Control Block Diagram ...................................................................................................... 17
Figure 4. Programmable Feedback Resistor ...................................................................................................................................... 17
Laser Modulation Control ..................................................................................................................................................................... 17
Figure 5. Transmitter Configurations Supported by MIC3000 ..................................................................................................... 17
Figure 6. VMOD Configured as Voltage Output with Gain ........................................................................................................... 18
Power ON and Laser Start-Up .............................................................................................................................................................. 19
Table 8. Shutdown State of SHDN vs. Configuration Bits .................................................................................................................. 19
Figure 7. MIC3000 Power-On Timing (OE=1) .................................................................................................................................... 19
Table 9. Shutdown State of VBIAS vs. Configuration Bits ................................................................................................................. 19
Table 10. Shutdown state of VMOD vs. Configuration bits ................................................................................................................ 19
Fault Comparators ................................................................................................................................................................................ 20
Figure 8. Fault Comparator Logic ....................................................................................................................................................... 20
Duty-Cycle Limiting ............................................................................................................................................................................... 20
Temperature Measurement .................................................................................................................................................................. 20
Diode Faults ........................................................................................................................................................................................... 20
Figure 9. Saturation Detector .............................................................................................................................................................. 21
Figure 10. RXLOS Comparator Logic ................................................................................................................................................. 21
Temperature Compensation ................................................................................................................................................................ 21
Table 11. Temperature Compensation Look-up Tables, Serial Address I2CADR + 4h .................................................................... 22
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Table 12. APC Temperature Compensation Look-Up Table, Serial Address I2CADR+4h ............................................................... 23
Table 13. VMOD Temperature- Compensation Look-Up Table, Serial Address I2CADR+4h .......................................................... 23
Table 14. IBIAS Comparator Temperature Compensation Look-up Table, Serial Address I2CADR+4h ......................................... 23
Table 15. Bias Current High Alarm Temperature Compensation Table, Serial Address I2CADR+4h .............................................. 23
Table 16. Range of Temperature Compensation Tables vs. LUTOFF .............................................................................................. 24
Figure 11. Examples of LUTOFF Operation ....................................................................................................................................... 24
Figure 12. Temperature Compensation Examples ............................................................................................................................. 25
Alarms and Warning Flags ................................................................................................................................................................... 26
Table 17. MIC3000 Events ................................................................................................................................................................. 26
Control and Status I/O .......................................................................................................................................................................... 26
Figure 13. Control and Status I/O Logic .............................................................................................................................................. 27
System Timing ....................................................................................................................................................................................... 27
Figure 14. Transmitter ON-OFF Timing .............................................................................................................................................. 27
Figure 15. Initialization Timing with TXDISABLE Asserted ................................................................................................................ 27
Figure 16. Initialization Timing, TXDISABLE Not Asserted ................................................................................................................ 28
Figure 17. Loss-of-Signal (LOS) Timing ............................................................................................................................................. 28
Figure 18. Transmit Fault Timing ........................................................................................................................................................ 28
Figure 19. Successfully Clearing a Fault Condition ............................................................................................................................ 29
Figure 20. Unsuccessful Attempt to Clear a Fault .............................................................................................................................. 29
Warm Resets .......................................................................................................................................................................................... 30
Power-On Hour Meter ........................................................................................................................................................................... 30
Table 18. Power-On Hour Meter Result Format ................................................................................................................................. 30
Test and Calibration Features ............................................................................................................................................................. 30
Table 19. Test and Diagnostic Features ............................................................................................................................................. 30
Serial Port Operation ............................................................................................................................................................................ 31
Figure 21. Write Byte Protocol ............................................................................................................................................................ 31
Figure 22. Read Byte Protocol ............................................................................................................................................................ 31
Figure 23. Read_Word Protocol .......................................................................................................................................................... 31
Page Writes ............................................................................................................................................................................................ 31
Figure 24. Four-Byte Page_Write Protocol ......................................................................................................................................... 32
Acknowledge Polling ............................................................................................................................................................................ 32
Write Protection and Data Security ..................................................................................................................................................... 32
User Password ....................................................................................................................................................................................... 32
Detailed Register Descriptions ............................................................................................................................................................ 33
Alarm Threshold Registers .................................................................................................................................................................. 33
Warning Threshold Registers .............................................................................................................................................................. 38
ADC Result Registers ........................................................................................................................................................................... 44
Alarm Flags ............................................................................................................................................................................................ 47
Warning Flags ........................................................................................................................................................................................ 48
Applications Information ...................................................................................................................................................................... 61
Controlling Laser Diode Bias ............................................................................................................................................................... 61
Figure 25. Example APC Circuit for Common-Cathode TOSA .......................................................................................................... 61
Figure 26. Example APC Circuit for Common Anode TOSA .............................................................................................................. 61
Choosing CCOMP ................................................................................................................................................................................. 62
Figure 27. Slew Rate vs. CCOMP Value ............................................................................................................................................ 62
Figure 28. Open Loop Unity-Gain Bandwidth vs. CCOMP ................................................................................................................. 62
Table 20. Typical Values for CCOMP ................................................................................................................................................. 62
Measuring Laser Bias Current ............................................................................................................................................................. 62
Interfacing To Laser Drivers ................................................................................................................................................................ 63
SY88912 3.3V 3.2Gbps SONET/SDH Laser Driver ............................................................................................................................. 63
Figure 29. Controlling the SY88912 Modulation Current .................................................................................................................... 63
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Table 21. Control Range of SY88912 Modulation Control Circuit ...................................................................................................... 63
SY88932 3.3V 3.2Gbps SONET/SDH Laser Driver ............................................................................................................................. 63
Figure 30. Controlling the SY88932 Modulation Current .................................................................................................................... 63
SY89307 5.0V/ 3.3V 2.5Gbps VCSEL Driver ....................................................................................................................................... 64
Figure 31. Controlling the SY89307 Modulation Current .................................................................................................................... 64
Laser Drivers Programmed via a Sink Current .................................................................................................................................. 64
Figure 32. Controlling the Modulation Current via a Sink Current ...................................................................................................... 64
Drivers With Monitor Outputs .............................................................................................................................................................. 64
Shutdown Output .................................................................................................................................................................................. 64
Figure 33. Redundant Switch Circuits ................................................................................................................................................. 65
Temperature Sensing ............................................................................................................................................................................ 65
Table 23. Contributors to Self-Heating ................................................................................................................................................ 65
Remote Sensing .................................................................................................................................................................................... 65
Table 22. Transistors Suitable for Use as Remote Diodes ................................................................................................................ 65
Minimizing Errors .................................................................................................................................................................................. 65
Self-Heating ............................................................................................................................................................................................ 65
Series Resistance with External Temperature Sensor ..................................................................................................................... 66
XPN Filter Capacitor Selection ............................................................................................................................................................ 66
XPN Layout Considerations ................................................................................................................................................................. 66
Figure 34. Guard Traces and Kelvin Return for Remote Thermal Diode ........................................................................................... 66
Layout Considerations ......................................................................................................................................................................... 66
Small Form-Factor Pluggable (SFP) Transceivers ............................................................................................................................ 66
Figure 35. Typical SFP Control and Status I/O Signal Routing (not to scale) ................................................................................... 66
Power Supplies ...................................................................................................................................................................................... 67
Figure 36. Power Supply Routing and Bypassing .............................................................................................................................. 67
Using The MIC3000 In a 5V System .................................................................................................................................................... 67
Package Information ............................................................................................................................................................................. 68
24-Pin MLF® (ML) ................................................................................................................................................................................ 68
M9999-101204
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MIC3000
Micrel
RXLOS
RSOUT
COMP
VBIAS
VMOD–
VMOD+
Pin Configuration
24 23 22 21 20 19
VDDD
2
17
NC
GNDA
3
16
GNDD
VDDA
4
15
RSIN
VILD–
5
14
VIN
VILD+
6
13
CLK
DATA
9 10 11 12
TXDISABLE
8
TXFAULT
7
XPN
18
VMPD
VRX
1
SHDN
FB
24-Pin MLF®
Pin Descriptions
Pin Number
Pin Name
1
FB
Analog Input. Feedback voltage for the APC loop op-amp . Polarity and
scale are programmable via the APC configuration bits. Connect to VBIAS if
APC is not used.
2
VMPD
Analog Input. Multiplexed A/D converter input for monitoring transmitted
optical power via a monitor photodiode. In most applications, VMPD will be
connected directly to FB. The input range is 0 - VREF or 0 - VREF/4 depending on the setting of the APC configuration bits.
3
GNDA
Ground return for analog functions.
4
VDDA
Power supply input for analog functions.
5
VILD–
Analog Input. Reference terminal for the multiplexed pseudo-differential A/D
converter inputs for monitoring laser bias current via a sense resistor (VILD+
is the sensing input). Tie to VDD or GND to reference the voltage sensed on
VILD+ to VDD or GND respectively. Limited common-mode voltage range,
see “Applications Information” section for more details.
6
VILD+
Analog Input. Multiplexed A/D input for monitoring laser bias current via a
sense resistor (signal input); accommodates inputs referenced to VDD or
GND (see pin 5 description). Limited common-mode voltage range, see
“Applications Information” section for more details.
7
SHDN
Digital output; Programmable polarity. Asserted at the detection of a fault
condition that can be used to activate a second series transistor in the laser
current path, enhancing protection against single-point failures.
8
VRX
Analog Input. Multiplexed A/D converter input for monitoring received optical
power. The input range is 0 to VREF.
9
XPN
Analog Input/Output. Optional connection to an external PN junction for
sensing temperature at a remote location. The Zone bit in OEMCFG1
determines whether temperature is measured using the on-chip sensor or
the remote PN junction.
10
TXFAULT
October 2004
Pin Function
Digital Output; Open-Drain. A high level indicates a hardware fault impeding
transmitter operation. The state of this input is always reflected in the TXFLT
bit.
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Pin Descriptions
Pin Number
Pin Name
11
TXDISABLE
12
DATA
13
CLK
Digital Input; Serial bit clock input.
14
VIN
If bit 4 (IE) in USRCTL register is set to 0 (default), this pin is configured as
analog input. If IE bit is set to 1, this pin is configured as open-drain output.
Analog Input: Multiplexed A/D input for monitoring supply voltage. 0V to
5.5V input range.
Open-drain output: outputs the internally generated interrupt signal /INT.
15
RSIN
Digital Input; Rate select input; ORed with rate select bit to determine the
state of the RSOUT pin. The state of this pin is always reflected in the RSEL
bit.
16
GNDD
Ground return for digital functions.
17
NC
18
VDDD
Power supply input for digital functions.
19
RXLOS
Digital Output; Active-High/Open-Drain. Indicates the loss of the received
signal as indicated by a level of received optical power below the programmed RXLOS comparator threshold; may be wire-ORed with external
signals. Low indicates normal operation. The LOS bit reflects the state of
RXLOS whether driven by the MIC3000 or an external circuit.
20
RSOUT
Digital Output. Open-Drain. This output is controlled by the SRSEL bit ORed
with RSIN input and is open drain only.
21
COMP
Analog Output, compensation terminal. Connect a capacitor between this pin
and GNDA or VDDA with appropriate value to tune the APC loop time
constant to a desirable value.
22
VBIAS
Analog Output. Buffered DAC output capable of sourcing or sinking up to
10mA under control of the APC function to drive an external transistor for
laser diode D.C. bias. The output and feedback polarity are programmable to
accommodate either a NPN or an PNP transistor to drive a common anode
or common-cathode laser diode.
23
VMOD–
Analog Input. Inverting terminal of VMOD buffer op-amp. Connect to VMOD+
(gain = 1) or feedback resistors network to set a different gain
24
VMOD+
Analog Output. Buffered DAC output to set the modulation current on the
laser driver IC. Operates with either a 0– VREF or a (VDD–VREF) – VDD
output swing so as to generate either a ground-referenced or a VDD referenced programmed voltage. A simple external circuit can be used to
generate a programmable current for those drivers that require a current
rather than a voltage input. See “Applications Information” section for more
details.
M9999-101204
Pin Function
Digital Input; Active High. The transmitter is disabled when this line is high or
the STXDIS bit is set. The state of this input is always reflected in the TXDIS
bit.
Digital I/O; Open-drain. Bi-directional serial data input/output.
No connection. This pin is used for test purposes and must be left unconnected.
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October 2004
MIC3000
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Absolute Maximum Ratings(1)
Operating Ratings(2)
Power Supply Voltage, VDD .................................................. +3.8V
Voltage on CLK, DATA, TXFAULT, VIN, RXLOS,
DISABLE, RSIN ....................................... –0.3V to +6.0V
Voltage On Any Other Pin .................... –0.3V to VDD+0.3V
Power Dissipation, TA = 85°C ...................................... 1.5W
Junction Temperature (TJ) ......................................... 150°C
Storage Temperature (TS) ........................ –65°C to +150°C
ESD Ratings(3)
Human Body Model ................................................... 2kV
Machine Model ......................................................... 300V
Soldering (20sec) ....................................................... 260ºC
Power Supply Voltage, VDDA/VDDD .................. +3.0V to +3.6V
Ambient Temperature Range (TA) ............ –40°C to +105°C
Package Thermal Resistance
MLF® (θJA) .......................................................... 43°C/W
Electrical Characteristics
For typical values, TA = 25°C, VDDA = VDDD = +3.3V, unless otherwise noted.
- 3.6V, T(min) - TA - T(max)(8)
Symbol
Parameter
Condition
Supply Current
Bold values are guaranteed for +3.0V - (VDDA = VDDD)
Min
Typ
Max
Units
CLK = DATA = VDDD = VDDA;TXDISABLE low;
all DACs at full-scale; all A/D inputs at
full-scale; all other pins open.
2.3
3.5
mA
CLK = DATA = VDDD = VDDA; TXDISABLE high;
FLTDAC at full-scale; all A/D inputs at
full-scale; all other pins open.
2.3
3.5
mA
2.9
2.98
V
Power Supply
IDD
VPOR
Power-on Reset Voltage
All registers reset to default values;
A/D conversions initiated.
VUVLO
Under-Voltage Lockout Threshold
Note 5
VHYST
Power-on Reset Hysteresis Voltage
tPOR
Power-on Reset Time
VREF
Reference Voltage
∆VREF/∆VDDA
Voltage Reference Line Regulation
VDD >
2.6
VPOR(4)
1.210
2.73
V
170
mV
50
µs
1.225
1.240
1.7
V
mV/V
Temperature-to-Digital Converter Characteristics
Local Temperature Measurement Error
Remote Temperature Measurement
Error
tCONV
Conversion Time
tSAMPLE
Sample Period
–40°C - TA - +105°C(6)
–40°C - TA - +105°C(6)
±1
±3
°C
±1
±3
°C
60
ms
100
ms
400
µA
Note 4
Remote Temperature Input, XPN
IF
Current to External Diode(4)
XPN at high level, clamped to 0.6V.
XPN at low level, clamped to 0.6V.
October 2004
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7
12
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MIC3000
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Electrical Characteristics
Symbol
Parameter
Condition
Min
Voltage-to-Digital Converter Characteristics (VRX, VAUX, VBIAS, VMPD, VILD+/–)
Voltage Measurement Error
–40°C - TA - +105°C(6)
Typ
Max
Units
±1
±2.0
% fs
tCONV
Conversion Time
Note 4
10
ms
tSAMPLE
Sample Period
Note 4
100
ms
5.5
V
Voltage Input, VIN (Pin 14 used as an ADC Input)
VIN
Input Voltage Range
ILEAK
Input Current
CIN
Input Capacitance
–0.3 - VDD - 3.6V
VIN = VDD or GND; VAUX = VIN
GNDA
Digital-to-Voltage Converter Characteristics (VMOD, VBIAS)
Accuracy
–40°C - TA - +105°C(6)
tCONV
Conversion Time
Note 4
DNL
Differential Non-linearity Error
Note 4
IIN–
–
VILD Input Current
+–
–
VILD | = 0.3V
pF
±1
0
–
VILD referred to VDDA
VILD– referred to GND
Input Capacitance
APC Op Amp, FB, VBIAS, COMP
GBW
Gain Bandwidth Product
TCVOS
Input Offset Voltage Temperature
Coefficient(4)
VOUT
Output Voltage Swing
ISC
Output Short-Circuit Current
tSC
Short Circuit Withstand Time
PSRR
Power Supply Rejection Ratio
AMIN
10
VILD+ Input Current
| VILD
CIN
µA
±0.5
Bias Current Sense Inputs, VILD+, VILD–
VILD
Differential Input Signal Range,
| VILD+ – VILD– |
IIN+
55
CCOMP = 20pF; Gain = 1
IOUT = 10mA, SRCE bit = 1
GNDA
IOUT = -10mA, SRCE bit = 0
VDDA–1.25
2.0
% fs
20
ms
±1
LSB
VREF/4
mV
±1
µA
+150
µA
–150
µA
10
pF
1
MHz
1
µV/°C
1.25
VDDA
55
V
V
mA
TJ - 150°C(4)
sec
CCOMP = 20pF; Gain = 1, to GND
55
CCOMP = 20pF; Gain = 1, to VDD
40
dB
Minimum Stable Gain
CCOMP = 20pF, Note 4
∆V/∆t
Slew Rate
CCOMP = 20pF; Gain = 1
3
V/µs
∆RFB
Internal Feedback Resistor Tolerance
±20
%
∆RFB/∆t
Internal Feedback Resistor
Temperature Coefficient
25
ppm/C
CIN
Pin Capacitance
10
pF
M9999-101204
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V/V
October 2004
MIC3000
Micrel
Electrical Characteristics
Symbol
Parameter
VMOD Buffer Op-Amp, VMOD+, VMOD–
GBW
Gain Bandwidth
TCVOS
Input Offset Voltage Temperature
Coefficient
IBIAS
VMOD – Input Current
VOUT
Output Voltage Swing
ISC
Output Short-Circuit Current
Condition
Min
CCOMP = 20pF; Gain = 1
Typ
Units
1
MHz
1
µV/°C
±0.1
IOUT = ±1mA
Max
GNDA+75
±1
µA
VDDA–75
mV
35
mA
150°C(4)
tSC
Short Circuit Withstand Time
TJ -
PSRR
Power Supply Rejection Ratio
CCOMP = 20pF; Gain = 1, to GND
65
dB
CCOMP = 20pF; Gain = 1, to VDD
44
dB
AMIN
Minimum Stable Gain
CCOMP = 20pF
∆V/∆T
Slew Rate
CCOMP = 20pF; Gain = 1
CIN
Pin Capacitance
sec
1
V/V
1
V/µs
10
pF
Control and Status I/O, TXDISABLE, TXFAULT, RSIN, RSOUT, SHDN, RXLOS, /INT
VIL
Low Input Voltage
0.8
VIH
High Input Voltage
VOL
Low Output Voltage
IOL - 3mA
0.3
V
VOH
High Output Voltage
(applies to SHDN only)
IOH - 3mA
VDDD–0.3
V
ILEAK
Input Current
±1
µA
CIN
Input Capacitance
2.0
Note 4
VRX
Input Signal Range
CIN
Input Capacitance
ILEAK
Input Current
V
10
Transmit Optical Power Input, VMPD
VIN
Input Voltage Range
V
pF
GNDA
VDDA
V
BIASREF=0
0
VREF
V
BIASREF=1
VDDA–VREF
VDDA
V
Note 4
10
pF
±1
µA
GNDA
VDDA
V
0
VREF
V
Received Optical Power Input, VRX, RXPOT
Input Voltage Range
VRX
Valid Input Signal Range
(ADC Input Range)
CIN
Input Capacitance
ILEAK
Input Current
October 2004
Note 4
Note 4
10
pF
±1
9
µA
M9999-101204
MIC3000
Micrel
Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
Control and Status I/O Timing, TXFAULT, TXDISABLE, RSIN, RSOUT, and RXLOS
tOFF
TXDISABLE Assert Time
From input asserted to optical output at
10% of nominal, CCOMP = 10nF.
10
µs
tON
TXDISABLE De-assert Time
From input de-asserted to optical output
at 90% of nominal, CCOMP = 10nF.
1
ms
tINIT
Initialization Time
From power on or transmitter enabled to
optical output at 90% of nominal and
TX_FAULT de-asserted.(4)
300
ms
tINIT2
Power-on Initialization Time
From power on to APC loop enabled.
200
ms
tFAULT
TXFAULT Assert Time
From fault condition to TXFAULT
assertion.(4)
95
µs
tRESET
Fault Reset Time
Length of time TXDISABLE must be
asserted to reset fault condition.
tLOSS_ON
RXLOS Assert Time
From loss of signal to RXLOS asserted.
95
µs
tLOSS_OFF
RXLOS De-assert Time
From signal acquisition to LOS
de-asserted.
100
µs
tDATA
Analog Parameter Data Ready
From power on to valid analog parameter
data available.(4)
400
ms
tPROP_IN
TXFAULT, TXDISABLE, RXLOS,
RSIN Input Propagation Time
Time from input change to corresponding
internal register bit set or cleared.(4)
1
µs
tPROP_OUT
TXFAULT, RSOUT, /INT Output
Propagation Time
From an internal register bit set or cleared
to corresponding output change.(4)
1
µs
0.525
ms
+3
%F.S.
µs
10
Fault Comparators
φFLTTMR
Fault Suppression Timer Clock
Period
Note 4
0.475
Accuracy
0.5
-3
µs
tREJECT
Glitch Rejection
Maximum length pulse that will not cause
output to change state.(4)
VSAT
Saturation Detection Threshold
High level
95
%VDDA
Low level
5
%VDDA
4.5
Power-On Hour Meter
Timebase Accuracy
Resolution
0°C - TA - +70°C(4)
+5
–5
%
–40°C - TA - +105°C
+10
–10
%
Note 4
10
hours
Non-Volatile (FLASH) Memory
tWR
Write Cycle Time(8)
From STOP of a one to four-byte write
transaction.(4)
Data Retention
Endurance
M9999-101204
Minimum Permitted Number Write
Cycles
10
13
ms
100
years
10,000
cycles
October 2004
MIC3000
Micrel
Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
IOL = 3mA
0.4
V
IOL = 6mA
0.6
V
0.8
V
Serial Data I/O Pin, DATA
VOL
Low Output Voltage
VIL
Low Input Voltage
VIH
High Input Voltage
ILEAK
Input Current
CIN
Input Capacitance
2.1
V
±1
Note 4
10
µA
pF
Serial Clock Input, CLK
VIL
Low Input Voltage
2.7V - VDD - 3.6V
VIH
High Input Voltage
2.7V - VDD - 3.6V
ILEAK
Input Current
CIN
Input Capacitance
Serial Interface
0.8
2.1
V
±1
Note 4
V
10
µA
pF
Timing(4)
t1
CLK (clock) Period
2.5
µs
t2
Data in Setup Time to CLK High
100
ns
t3
Data Out Stable After CLK Low
300
ns
t4
DATA Low Setup Time to CLK Low
Start Condition
100
ns
t5
DATA High Hold Time After CLK High Stop Condition
100
ns
tDATA
Data Ready Time
From power on to completion of one set of
ADC conversions; analog data available via
serial interface.
tTO
BUS Timeout
CLK Low
25
30
400
ms
35
ms
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. Guaranteed by design and/or testing of related parameters. Not 100% tested in production.
5. The MIC3000 will attempt to enter its shutdown state when VDD falls below VUVLO. This operation requires time to complete. If the supply voltage falls
too rapidly, the operation may not be completed.
6. Does not include quantization error.
7. Final test on outgoing product is performed at TA = +25°C.
8. The MIC3000 will not respond to serial bus transactions during an EEPROM write-cycle. The host will receive a NACK during tWR.
Timing Diagram
t1
CLK
t4
t5
t2
DATA
(Input)
t3
DATA
(Output)
Serial Interface Timing
October 2004
11
M9999-101204
MIC3000
Micrel
Address Map
Address(s)
Field Size (Bytes)
Name
0 - 95
96
Serial ID defined by
SEP MSA
96 - 127
32
Vendor Specific
128 - 255
128
Reserved
Description
G-P NVRAM; R/W under valid OEM password.
Vendor specific EEPROM
Reserved for future use. G-P NVRAM; R/W under valid OEM
password.
Table 1. MIC3000 Address Map, Serial address = A0h
Address
HEX
DEC
Field Size
(Bytes)
Name
00–27
0–39
40
Alarm and Warning Thresholds
28–37
40–55
16
Reserved
38–5B
56 –91
36
Calibration Constants
5C–5E
92–94
3
Reserved
Reserved – do not write; reads undefined.
5F
95
1
Checksum
G-P NVRAM; writeable using OEM p/w; read-only otherwise.
60–69
96–105
10
Analog Data
6A–6D
106–109
4
Reserved
6E
110
1
Control/Status bits
6F
111
1
Reserved
70–71
112–113
2
Alarm Flags
72–73
114–115
2
Reserved
74–75
116–117
2
Warning Flags
76–77
118–119
2
Reserved
Reserved – do not write; reads undefined.
78–7B
120–123
4
OEMPW
OEM password entry field.
7C–7F
124–127
4
Vendor Specific
Vendor specific. Reserved–do not write; reads undefined.
80–F7
128–247
120
User Scratchpad
User writable EEPROM. G-P NVRAM; R/W using any valid
password.
F8–F9
248–249
2
Reserved
FA
250
1
USRPWSET
FB
251
1
USRPW
FC–FD
252–253
2
POH
FE
254
1
Data Ready Flags
FF
255
1
User Control
Description
High/low limits for warning and alarms; write-able using OEM p/w;
read-only otherwise.
Reserved – do not write; reads undefined.
Numerical constants for external calibration; writeable using OEM
p/w; read-only otherwise.
Real time analog parameter data.
Reserved for future definition of digitized analog input– do not write;
reads undefined.
Control and status bits.
Reserved – do not write; reads undefined.
Alarm status bits; read-only.
Reserved–do not write; reads undefined.
Warning status bits; read-only.
Reserved – do not write; reads undefined.
User password setting; read/write using any p/w; returns zero
otherwise.
Entry field for user password.
Power-on hour meter result; read-only.
Data ready bits for each measured parameter; read-only.
End-user control and status bits.
Table 2. MIC3000 Address Map, Serial Address = A2h
M9999-101204
12
October 2004
MIC3000
Micrel
Address(s)
HEX
DEC
Field Size
(Bytes)
Name
00–3F
0–63
64
APCLUTn
A.P.C. temperature compensation L.U.T.
40–7F
64–127
64
MODLUTn
VMOD temperature compensation L.U.T.
80–BF
128–191
64
IFLTLUT
Bias current fault threshold temperature compensation L.U.T.
C0–FF
192–255
64
EOLLUTn
Bias current high alarm threshold temperature compensation L.U.T.
Description
Table 3. Temperature Compensation Tables, Serial Address = A4h
Address
HEX
DEC
Field Size
(Bytes)
Name
00
0
1
OEMCFG0
Control/status bits
01
1
1
OEMCFG1
Control/status bits
02
2
1
OEMCFG2
Control/status bits
03
3
1
APCSET0
APC setpoint 0
04
4
1
APCSET1
APC setpoint 1
05
5
1
APCSET2
APC setpoint 2
06
6
1
MODSET
Nominal modulation DAC setpoint
07
7
1
IBFLT
08
8
1
TXPFLT
TX power fault threshold
09
9
1
LOSFLT
RX LOS fault-comparator threshold
0A
10
1
FLTTMR
Fault comparator masking interval timer setting
0B
11
1
FLTMSK
Fault source mask bits
0C–0F
12–15
4
OEMPWSET
10
16
1
OEMCAL0
OEM calibration register 0
11
17
1
OEMCAL1
OEM calibration register 1
12
18
1
LUTINDX
Look-up table index read-back
13
19
1
RESERVED
14
20
1
APCDAC
Reads back current APC DAC setting
15
21
1
MODDAC
Reads back current modulation DAC setting
16
22
1
OEMREAD
Reads back OEM calibration data
17–1F
23–31
6
RESERVED
Reserved - do not write; reads undefined
20–27
32–39
8
POHDATA
28–7D
40–125
85
RESERVED
7E–FD
126–253
128
SCRATCH
FE
254
1
MFG_ID
Manufacturer identification (Micrel = 42)
FF
255
1
DEV_ID
Device and die revision
Description
Bias current fault-comparator threshold
Password for access to OEM areas
Reserved - do not write; reads undefined
Power-on hour meter scratchpad
Reserved–do not write; reads undefined
OEM scratchpad area
Table 4. OEM Configuration Registers, Serial Address = A6h
October 2004
13
M9999-101204
MIC3000
Micrel
Block Diagram
MIC3000
TXFAULT
TXDISABLE
APC
RSIN
VBIAS
COMP
RSOUT
FB
STATEMACHINES
RXLOS
INT
MODULATION
CONTROL
TIMING
VMOD+
CLOCK
I2C
VMOD–
DATA
MEMORY
ARBITRATION
FAULT DETECTION
LASER
CONTROL
A-D CONVERTER
&
SIGNAL
CONDITIONING
SHDN
VILD+
NVRAM
REGISTERS
SERIAL ID
SCRATCH
LUTs
VILD–
VMPD
VIN
VRX
POWER-ON
HOUR METER
CLOCK
&
POR
TEMP
SENSOR
XPN
Figure 1. MIC3000 Block Diagram
Analog-to-Digital Converter/Signal Monitoring
A block diagram of the monitoring circuit is shown below.
Each of the five analog parameters monitored by the MIC3000
are sampled in sequence. All five parameters are sampled
and the results updated within the tCONV internal given in the
“Electrical Characteristics” section. In OEM Mode, the channel that is normally used to measure VIN may be assigned to
M9999-101204
measure the level of the VDDA pin or one of five other nodes.
This provides a kind of analog loopback for debug and test
purposes. The VAUX bits in OEMCFG0 control which voltage
source is being sampled. The various VAUX channels are
level-shifted differently depending on the signal source, resulting in different LSB values and signal ranges. See Table
5.
14
October 2004
MIC3000
Micrel
VIN
VDDA
VMOD
7-CH
MUX
VBIAS
APCDAC
MODDAC
FLTDAC
VAUX[2:1]
VMPD
5-CH
MUX
VRX
VILD+
VILD–
TEMP
SENSOR
SIGMA-DELTA ADC
TEMP
SENSOR
Figure 2. Analog-to-Digital Converter Block Diagram
Channel
ADC Resolution
(bits)
TEMP
Input Range (V)
LSB(1)
8
N/A
1°C
VAUX
8
See Table 6
VMPD
8
VILD
VRX
Conditions
GAIN = 0; BIASREF = 0
GNDA – VREF
GAIN = 0; BIASREF = 1
VDDA – (VDDA – VREF)
GAIN = 1; BIASREF = 0
GNDA – VREF/4
GAIN = 1; BIASREF = 1
VDDA – (VDDA – VREF/4)
VILD– = VDDA
VDDA – (VDDA – VREF)
VILD– = GNDA
GNDA – VREF
n/a
0 – VREF
8
8
4.77mV
1.17mV
4.77mV
4.77mV
Table 5. A/D Input Signal Ranges and Resolutions
Note:
1. Assumes typical VREF value of 1.22V.
Channel
VAUX[2:0]
Input Range (V)
LSB(1) (mV)
VIN
000 = 00h
0V to 5.5V
25.6mV
VDDA
001 = 01h
0V to 5.5V
25.6mV
VBIAS
010 = 02h
0V to 5.5V
25.6mV
VMOD
011 = 03h
0V to 5.5V
25.6mV
APCDAC
100 = 04h
0V to VREF
4.77mV
MODDAC
101 = 05h
0V to VREF
4.77mV
FLTDAC
110 = 06h
0V to VREF
4.77mV
Table 6. VAUX Input Signal Ranges and Resolutions
Note:
1. Assumes typical VREF value of 1.22V.
October 2004
15
M9999-101204
MIC3000
Micrel
Per SFF-8472, the value of the bias current LSB is 2µA. The
conversion factor, “slope”, needed is therefore:
External Calibration
The MIC3000 is designed to support the implementation of an
optical transceiver employing external calibration, as described by SFF-8472, Digital Monitoring Interface specifications. The voltage and temperature values returned by the
MIC3000’s A/D converter are internally calibrated. The binary
values of TEMPh:TEMPl and VOLTh:VOLTl are in the format
called for by SFF-8472 under Internal Calibration. However,
since the other parameters are not internally calibrated, an
MIC3000-based transceiver must be labeled as externally
calibrated.
SFF-8472 calls for a set of calibration constants to be stored
by the transceiver OEM at specific non-volatile memory
locations, refer to SFF-8472 specifications for memory map
of calibration coefficient. The MIC3000 provides the nonvolatile memory required for the storage of these constants.
The Digital Diagnostic Monitoring Interface specification
should be consulted for full details. Slopes and offsets are
stored for use with voltage, temperature, bias current, and
transmitted power measurements. Coefficients for a fourthorder polynomial are provided for use with received power
measurements. The host system can retrieve these constants and use them to process the measured data. Since
voltage and temperature require no calibration, the corresponding slopes should generally be set to unity and the
offsets to zero.
Slope =
1191.4µA
2µA × R SENSE
= 595.7 ÷ R SENSE
The tolerance of the sense resistor directly impacts the
accuracy of the bias current measurement. It is recommended that the sense resistor chosen maintain accuracy of
1% or better. The offset correction, if needed, can be determined by shutting down the laser, i.e., asserting TXDISABLE,
and measuring the bias current. Any non-zero result gives the
offset required. The offset will be equal and opposite to the
result of the “zero current” measurement.
TX Power
Transmit power is sensed via an external sense resistor as a
voltage appearing at VMPD. It is assumed that this voltage is
generated by a sense resistor carrying the monitor photodiode current. In most applications, the signal at VMPD will be
feedback voltage on FB. The VMPD voltage may be measured relative to GND or VDDA depending on the setting of the
BIASREF bit in OEMCFG1. The value returned by the A/D is
therefore a voltage analogous to transmit power. The binary
value in TXOPh (TXOPl is always zero) is related to transmit
power by:
⎛ TXOPh ⎞
⎛ TXOPh ⎞
K × VREF⎜
⎟
⎟ K × (1220mV)⎜
⎝ 255 ⎠
⎝ 255 ⎠
PTX (mW) =
=
RSENSE
RSENSE
Voltage
The voltage values returned by the MIC3000’s A/D converter
are internally calibrated. The binary values of VOLTh:VOLTl
are in the format called for by SFF-8472 under Internal
Calibration. Since VINh:VINl requires no processing, the
corresponding slope should be set to unity and the offset to
zero.
=
K × 4.75656 × TXOPh
mW
RSENSE
(3)
The temperature values returned by the MIC3000’s A/D
converter are internally calibrated. The binary values of
TEMPh:TEMPl are in the format called for by SFF-8472
under Internal Calibration. Since TEMPh:TEMPl requires no
processing, the corresponding slope should be set to unity
and the offset to zero.
For a given implementation, the value of RSENSE is known. It
is either the value of the external resistor or the chosen value
of RFB used in the application. The constant, K, will likely
have to be determined through experimentation or closedloop calibration, as it depends on the monitoring photodiode
responsivity and coupling efficiency.
It should be noted that the APC circuit acts to hold the
transmitted power constant. The value of transmit power
reported by the circuit should only vary by a small amount as
long as APC is functioning correctly.
Bias Current
RX Power
Bias current is sensed via an external sense resistor as a
voltage appearing at VILD+ and VILD-. The value returned by
the A/D is therefore a voltage analogous to bias current. Bias
current, IBIAS, is simply VVILD/RSENSE. The binary value in
IBIASh (IBIASl is always zero) is related to bias current by:
Received power is sensed as a voltage appearing at VRX. It
is assumed that this voltage is generated by a sense resistor
carrying the receiver photodiode current. The value returned
by the A/D is therefore a voltage analogous to received
power. The binary value in RXOPh (RXOPl is always zero) is
related to received power by:
Temperature
IBIAS =
⎛ IBIASh ⎞
(0.300V)⎜
⎟
⎝ 255 ⎠
PRX (mW ) = K × VREF ×
(1)
R SENSE
0.300V
300mV
1191.4
µA
Amps =
mA =
255 × RSENSE
255 × RSENSE
RSENSE
(2)
M9999-101204
255
= K × 1220mV ×
RXOPh
255
mW (4)
For a given implementation, the constant, K, will likely have
to be determined through experimentation or closed-loop
calibration, as it depends on the gain and efficiencies of the
components upstream. In SFF-8472 implementations, the
external calibration constants can describe up to a fourthorder polynomial in case K is nonlinear.
The value of the least significant bit (LSB) of IBIASh is
given by:
LSB(IBIASh) =
RXOPh
16
October 2004
MIC3000
Micrel
Laser Diode Bias Control
The MIC3000 can be configured to generate a constant bias
current using electrical feedback, or regulate average transmitted optical power using a feedback signal from a monitor
photodiode, see Figure 3. An operational amplifier is used to
control laser bias current via the VBIAS output. The VBIAS pin
can drive a maximum of ±10mA. An external bipolar transistor
provides current gain. The polarity of the op amp’s output is
programmable BIASREF in OEMCFG1 in order to accommodate either NPN or PNP transistors that drive common anode
and common cathode laser, respectively. Additionally, the
polarity of the feedback signal is programmable for use with
either common-emitter or emitter-follower transistor circuits.
Furthermore, the reference level for the APC circuit is selectable to accommodate electrical, i.e., current feedback, or
optical feedback via a monitor photodiode. Finally, any one of
seven different internal feedback resistors can be selected.
This internal resistor can be used alone or in parallel with an
external resistor. This wide range of adjustability (50:1)
accommodates a wide range of photodiode current, i.e, wide
range of transmitter output power. The APC operating point
can be kept near the mid-scale value of the APC DAC,
insuring maximum SNR, maximum effective resolution for
digital diagnostics, and the widest possible DAC adjustment
range for temperature compensation, etc. See Figure 4.
The APCCAL bit in OEMCAL0 is used to turn the APC
function on and off. It will be turned off in the MIC3000’s
default state as shipped from the factory. When APC is on,
the value in the selected APCSETx register is added to the
signed value taken from the APC look-up table and loaded
into the VBIAS DAC. When APC is off, the VBIAS DAC may be
written directly via the VBIAS register, bypassing the look-up
table entirely. This provides direct control of the laser diode
bias during setup and calibration. In either case, the VBIAS
DAC setting is reported in the APCDAC register. The APCCFG
bits determine the DACs response to higher or lower numeric
values.
APC Op-Amp
FB
R7
R6
R5
51.2k 25.6k 12.8k
RFB[2:0]
R4
6.4k
R3
3.2k
R2
1.6k
R1
0.8k
VDD
7
BIASREF
Figure 4. Programmable Feedback Resistor
Laser Modulation Control
As shown in Figure 3, a temperature-compensated DAC is
provided to set and control the laser modulation current via an
external laser driver circuit. MODREF in OEMCFG0 selects
whether the VMOD DAC output swings up from ground or
down from VDD. If the laser driver requires a voltage input to
set the modulation current, the MIC3000’s VMOD output can
drive it directly. If a current input is required, a fixed resistor
can be used between the driver and the VMOD output. Several
different configurations are possible, as shown in Figure 6.
When APC is on, i.e., the APCCAL bit in OEMCAL0 is set to
0, the value corresponding to the current temperature is taken
from the MODLUT look-up table, added to MODSET, and
loaded into the VMOD DAC. When APC is off, the value in
VMOD is loaded directly into the VMOD DAC, bypassing the
look-up table entirely. This provides for direct modulation
control for setup and calibration. The MODREF bit determines the DACs response to higher or lower numeric values.
VDD
VOUT
DAC
VBIAS
VDD-OUT
GAIN
APC
Look-Up
Table
COMP
INV
FB
Common-cathode with Common-anode with
monitor photodiode
monitor photodiode
APCSET
RFB[2:0]
Temp
Sensor
VDD
VDD
BIASREF
VOUT
VMOD
Look-Up
Table
DAC
VMOD
VDD-OUT
MODSET
MODREF
VMOD–
Common-anode
Figure 5. Transmitter Configurations
Supported by MIC3000
Figure 3. MIC3000 APC and Modulation Control
Block Diagram
October 2004
Common-cathode
17
M9999-101204
MIC3000
Micrel
VMOD Configured As Buffered Voltage Output
VOUT
DAC
VMOD
VDD-OUT
MODREF
VMOD–
Output Swing = 0 to VREF or VDDA to (VDDA–VREF)
VMOD Configured As Voltage Output with Gain
VOUT
DAC
VMOD
VDD-OUT
MODREF
R1+R2
Gain = A =
R2
Output Swing = 0 to (VREF×A)
R1
VMOD–
R2
Figure 6. VMOD Configured as Voltage Output with Gain
M9999-101204
18
October 2004
MIC3000
Micrel
Power ON and Laser Start-Up
When power is applied, the MIC3000 initializes its internal
registers and state machine. This process takes tPOR, about
50µs. Following tPOR, analog-to-digital conversions begin,
serial communication is possible, and the POR bit and data
ready bits may be polled. The first set of analog data will be
available tCONV after tPOR. MIC3000s are shipped from the
factory with the output enable bit, OE, set to zero, off. The
MIC3000’s power-up default state, therefore, is APC off,
VBIAS, VMOD, and SHDN outputs disabled. VBIAS, VMOD, and
SHDN will be floating (high impedance) and the laser diode,
if connected, will be off. Once the device is incorporated into
a transceiver and properly configured, the shutdown states of
SHDN, VBIAS and VMOD will be determined by the state of the
APC configuration and OE bits. Table 8, Table 9, and Table
10 illustrate the shutdown states of the various laser control
outputs versus the control bits.
Configuration Bits
OE
INV
BIASREF
VBIAS
0
Don’t Care
Don’t Care
Hi-Z
1
Don’t Care
0
³GND
1
Don’t Care
1
³V DD
Table 9. Shutdown State of VBIAS vs.
Configuration Bits
Configuration Bits
SPOL
SHDN
0
Don’t Care
Hi-Z
1
0
³GND
1
1
³V DD
VMOD Shutdown State
OE
MODREF
VMOD
0
Don’t Care
Hi-Z
1
0
³GND
1
1
³V DD
Table 10. Shutdown state of VMOD vs.
Configuration bits
Shutdown State
OE
VBIAS Shutdown
State
Configuration Bits
In order to facilitate hot-plugging, the laser diode is not turned
on until tINIT2 after power-on. Following tINIT2, and assuming
TXDISABLE is not asserted, the DACs will be loaded with
their initial values. Since tCONV is much less than tINIT2, the
first set of analog data, including temperature, is available at
tINIT2. Temperature compensation will be applied to the DAC
values if enabled. APC will begin if OE is asserted. (If the
output enable bit, OE, is not set, the VMOD, VBIAS, and SHDN
outputs will float indefinitely.) Figure 7 shows the power-up
timing of the MIC3000. If TXDISABLE is asserted at powerup, the VMOD and VBIAS outputs will stay in their shutdown
states following MIC3000 initialization. A/D conversions will
begin, but the laser will remain off.
Table 8. Shutdown State of SHDN vs.
Configuration Bits
tINIT
VDD
VPOR
tINIT
tPOR
tCONV
TXFAULT
VDD
VPOR
tPOR
tCONV
TXFAULT
TXDISABLE
TXDISABLE
SHDN
(1)
SHDN
(1)
/DATA_READY
/DATA_READY
|VMOD|
|VMOD|
|VBIAS|
|VBIAS|
90% nominal output
TX Output
(2)
tON
TX Output
(b) MIC3000 Power-On, TXDISABLE Asserted
(a) MIC3000 Power-On, TXDISABLE not Asserted
Notes:
Figure 7. MIC3000 Power-On Timing (OE=1)
1. Polarity programmable; active-high shown.
2. Determined by loop response, e.g., CCOMP.
October 2004
19
M9999-101204
MIC3000
Micrel
nal device may drive RXLOS. The state of the RXLOS pin is
reported in the CNTRL register regardless of whether it is
driven by the internal comparator or by an external device. A
programmable digital-to-analog converter provides the comparator reference voltages for monitoring received signal
strength, transmit power, and bias current. Glitches less than
4µs (typical) in length are rejected by the fault comparators.
Since laser bias current varies greatly with temperature,
there is a temperature compensation look-up table for the
bias current fault DAC value.
When a fault condition is detected, the laser will be immediately shutdown and TXFAULT will be asserted. The VMOD,
VBIAS, and SHDN (if enabled) outputs will be driven to their
shutdown state according to the state of the configuration
bits. The shutdown states of VMOD, VBIAS, and SHDN versus
the configuration bit settings are shown in Table 8, Table 9,
and Table 10.
Duty-Cycle Limiting
When a fault occurs and TXFAULT is asserted, an internal
timer starts. Operation cannot resume until this timer expires.
This limits the duty-cycle that can be achieved while a fault
condition is present, preventing the host from causing an eyeunsafe condition by continually cycling the laser on and off.
Given that the fault comparator propagation delay is 95µs
and the restart delay is 200ms, the maximum duty-cycle that
can theoretically be achieved in the presence of a persistent
fault is on the order of 0.095/200ms ♠ 0.0475% (0.095s is the
maximum fault comparator propagation delay; 200ms is the
typical reset delay interval).
If a fault occurs and the host toggles TXDISABLE within
200ms, the MIC3000 will wait until the interval expires before
restarting the laser. If the restart delay has expired, i.e., it has
been at least 200ms since the last occurrence of a fault, then
the MIC3000 will begin the restart sequence immediately.
The operation of this timer is transparent to the host and does
not require any special action. The system will still meet the
300ms startup requirement called for in specifications such
as the SFP MSA. If the host toggles TXDISABLE more than
once during the 200ms interval, the timing remains the same.
The laser is restarted after the expiration of the 200ms timer.
Temperature Measurement
The temperature-to-digital converter for both internal and
external temperature data is built around a switched current
source and an eight-bit analog-to-digital converter. The temperature is calculated by measuring the forward voltage of a
diode junction at two different bias current levels. An internal
multiplexer directs the current source’s output to either an
internal or external diode junction. The value of the ZONE bit
in OEMCFG1 determines whether readings are taken from
the on-chip sensor or from the XPN input. The external PN
junction may be embedded in an integrated circuit, or it may
be a diode-connected discrete transistor. This data is also
used as the input to the temperature compensation look-up
tables. Each time temperature is sampled and an updated
value acquired, new corrective values for IMOD and the APC
setpoint are read from the corresponding tables, added to the
set values, and transferred to DACs.
Fault Comparators
In addition to detecting and reporting the events specified in
SFF-8472, the MIC3000 also monitors five fault conditions:
inadequate supply voltage, thermal diode faults, excessive
bias current, excessive transmit power, and APC op-amp
saturation. Comparators monitor these parameters in order
to respond quickly to fault conditions that could indicate link
failure or safety issues, see Figure 8. When a fault is detected,
the laser is shut down and TXFAULT is asserted. Each fault
source may be independently disabled using the FLTMSK
register. FLTMSK is non-volatile, allowing faults to be masked
only during calibration and testing or permanently.
VDDA
Saturation Detector
95% VDDA
5% VDDA
tFLTTMR
VCOMP
IBFLT
COUNTER
FLTTMR
TXFAULT pin
FLTDAC
VILD
VUVLO
/LASER_SHUTDOWN
TXFLT bit
VDD
TXPFLT
FLTDAC
VMPD
DIODE_FAULT
Figure 8. Fault Comparator Logic
Thermal diode faults are detected within the temperature
measurement subsystem when an out-of-range signal is
detected. A window comparator circuit monitors the voltage
on the compensation capacitor to detect APC op-amp saturation (Figure 9). Op-amp saturation indicates that some fault
has occurred in the control loop such as loss of feedback. The
saturation detector is blanked for a time, tFLTTMR, following
laser turn-on since the compensation voltage will essentially
be zero at turn-on. The FLTTMR interval is programmable
from 0.5ms to 127ms (typical) in increments of 0.5ms
(φFLTTMR). Note that a saturation comparator cannot be relied
upon to meet certain eye-safety standards that require 100µs
response times. This is because the operation of a saturation
detector is limited by the loop bandwidth, i.e., the choice of
CCOMP. Even if the comparator itself was very fast, it would
be subject to the limited slew-rate of the APC op-amp. Only
the other fault comparator channels will meet <100µs timing
requirements.
A similar comparator circuit monitors received signal strength
and asserts RXLOS when loss-of-signal is detected (Figure
10). RXLOS will be asserted when and if VRX drops below the
level programmed in LOSFLT. The loss-of-signal comparator
may be disabled completely by setting the LOSDIS bit in
OEMCFG3. Once the LOS comparator is disabled, an exterM9999-101204
20
October 2004
MIC3000
Micrel
VDDA
Saturation Detector
95% VDDA
5% VDDA
SATURATION_FAULT
tFLTTMR
VCOMP
COUNTER
FLTTMR
Figure 9. Saturation Detector
CNTRL
LOS
OEMCFG3
LOS
DIS
VDDA
RXLOS
VRX
LOSFLT
FLTDAC
Figure 10. RXLOS Comparator Logic
Diode Faults
The MIC3000 is designed to respond in a failsafe manner to
hardware faults in the temperature sensing circuitry. If the
connection to the sensing diode is lost or the sense line is
shorted to VDD or ground, the temperature data reported by
the A/D converter will be forced to its full-scale value (+127°C).
The diode fault flag, DFLT, will be set in OEMCFG1, TXFAULT
will be asserted, and the high temperature alarm and warning
flags will be set. The reported temperature will remain +127°C
until the fault condition is cleared. Diode faults may be reset
by toggling TXDISABLE, as with any other fault. Diode faults
will not be detected at power up until the first A/D conversion
cycle is completed. Diode faults are not reported while
TXDISABLE is asserted.
Temperature Compensation
Since the performance characteristics of laser diodes and
photodiodes change with operating temperature, the MIC3000
provides a facility for temperature compensation of the A.P.C.
loop setpoint, laser modulation current, bias current fault
comparator threshold, and bias current high alarm flag threshold. Temperature compensation is performed using a look-up
table (LUT) that stores values corresponding to each measured temperature over a 128°C span. Four identical tables
reside at serial address A4h as summarized in Table 11. The
range of temperatures spanned by the tables is programOctober 2004
mable via the LUTOFF register. Each table entry is a signed
twos complement number that is used as an offset to the
parameter being compensated. The default value of all table
entries is zero, giving a flat response.
The A/D converter reports a new temperature sample each
tCONV. This occurs at roughly 10Hz. To prevent temperature
oscillation due to thermal or electrical noise, sixteen successive temperature samples are averaged together and used to
index the LUTs. Temperature compensation results are
therefore updated at 16∞tCONV intervals, or about 1.6 seconds. This can be expressed as shown in Equation5.
TCOMPm =
Tn + Tn +1 + Tn + 2 + • • •Tn +15
16
(5)
Each time an updated average value is acquired, a new offset
value for the APC setpoint is read from the corresponding
look-up table (see Table 12) and transferred to the APC
circuitry. This is illustrated in Equation 6. In a same way, new
offset values are taken from similar look-up tables (see Table
13 and Table 14), added to the nominal values and transferred into the modulation and fault comparator DACs. The
bias current high alarm threshold, is compensated using a
fourth look-up table (see Table 15). This compensation
happens internally and does not affect any host-accessible
registers.
21
M9999-101204
MIC3000
APCSETm
APCSETm
APCSETm
Micrel
results in a table index beyond the midpoint of the next entry
in either direction. There is therefore 2 to 3°C of hysteresis on
temperature compensation changes. The table index will
never oscillate due to quantization noise as the hysteresis is
much larger than ±1¦2 LSB.
= APCSETx + APCLUT(TCOMPm )
Table _ min ≤ TCOMPm ≤ Table _ max
= APCSETx + APCLUT(max)
TCOMP > Table _ max
(6)
= APCSETx + APCLUT(min)
TCOMP < Table _ min
If the measured temperature is greater than the maximum
table value, the highest value in each table is used. If the
measured temperature is less than the minimum, the minimum value is used. Hysteresis is employed to further enhance noise immunity and prevent oscillation about a table
threshold. Each table entry spans two degrees C. The table
index will not change unless the new temperature average
M9999-101204
Byte Addresses
Function
00h–3Fh
APC Look-up Table
40h–7Fh
IMOD Look-up Table
80h–BFh
IFLT Look-up Table
C0h–FFh
Bias High Alarm Look-up Table
Table 11. Temperature Compensation Look-up Tables,
Serial Address I2CADR + 4h
22
October 2004
MIC3000
Micrel
Register Address
Table Offset
Temperature
Offset (°C)
Register Address
Table Offset
Temperature
Offset (°C)
00 h
0
0
80 h
0
0
1
01h
1
2
02h
2
4
1
81h
1
2
82h
2
4
3
3
5
5
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
3Eh
62
124
BEh
62
124
125
3Fh
63
125
126
BFh
63
127
127
Table 12. APC Temperature Compensation Look-Up
Table, Serial Address I2CADR+4h
Register Address
40 h
41h
Table Offset
0
1
Table 14. IBIAS Comparator Temperature
Compensation Look-up Table, Serial Address
I2CADR+4h
Temperature
Offset (°C)
0
Register Address
Table Offset
Temperature
Offset (°C)
1
CO h
0
0
1
2
C1h
3
42h
2
·
·
·
·
·
·
·
·
·
7Eh
62
63
2
3
C2h
2
4
5
124
·
·
·
·
·
·
·
·
·
125
FEh
62
124
125
126
FFh
127
63
126
127
Table 13. VMOD Temperature- Compensation Look-Up
Table, Serial Address I2CADR+4h
October 2004
1
4
5
7Fh
126
Table 15. Bias Current High Alarm Temperature
Compensation Table, Serial Address I2CADR+4h
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M9999-101204
MIC3000
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The LUTOFF register determines the range of measured
temperatures that are actually spanned by the tables. The
temperature span of the tables versus the value of LUTOFF
is given in Table 16.
LUTOFF
Temperature Span
tCOMP(min) – tCOMP(max)
00h
0°C to +127°C
01h
–2°C to +125°C
02h
–4°C to +123°C
·
·
·
·
·
·
0Fh
–30°C to +97°C
INDEX =
TAVG(n)
2
+ LUTOFF
(7)
where TAVG(n) is the current average temperature; and
TABLE _ ADDRESS = INDEX + BASE _ ADDRESS
where BASE_ADDRESS is the physical base address of
each table, i.e., 00h, 40h, 80h, or C0h (all tables reside in the
I2CADR+4 page of memory).
At any given time, the current table index can be read in the
LUTINDX register.
Figures 11 and 12 illustrate the operation of the temperature
compensation tables.
Figure 11 is a graphical illustration of the use of the LUTOFF
register to control the temperature range spanned by the
temperature compensation tables. Note that, if the LUTINDX
becomes greater than 63 or less than zero, the maximum or
minimum table value is used, respectively. The tables do not
“roll over.”
Table 16. Range of Temperature Compensation
Tables vs. LUTOFF
The internal state machine calculates a new table index each
time a new average temperature value becomes available.
This table index is derived from the average temperature
value and LUTOFF. The table index is then converted into a
table address for each of the four look-up tables. These
operations can be expressed as:
LUT(LUTINDX)
+127
0
(a)
63
–128
LUT(t), LUTOFF=0
+127
(b)
–30°C
0
+127°C
(c)
–30°C
LUT(t), LUTOFF=07h
LUT(t), LUTOFF=0Fh
+127
+127
0
+127°C
(d)
–30°C
0
+113°C
–128
–128
+127°C
+98°C
–128
Figure 11. Examples of LUTOFF Operation
M9999-101204
24
October 2004
MIC3000
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Figure 12 llustrates that the table values are used as offsets
to the nominal value of the parameter in question. APCSET
is used as an example, but all four tables function identically.
Note that the shape and magnitude of the compensation
curve do not change as the nominal value changes.
LUT(LUTINDX)
+127
(a)
0
63
LUTOFF = 0Fh
APCSEL = 00h
–128
+127
+127
(b)
–40°C
+127
(c)
0
+34°C
+127°C
+98°C
APCSET0 = 64
–40°C
(d)
0
+34°C
+127°C
+98°C
APCSET0 = 92
–40°C
0
+34°C
+127°C
+98°C
APCSET0 = 128
Figure 12. Temperature Compensation Examples
October 2004
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M9999-101204
MIC3000
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Control and Status I/O
The logic for the transceiver control and status I/O is shown
schematically in Figure 13. Note that the internal drivers on
RXLOS, RATE_SELECT, and TXFAULT are all open-drain.
These signals may be driven either by the internal logic or
external drivers connected to the corresponding MIC3000
pins. In any case, the signal level appearing at the pins of the
MIC3000 will be reported in the control register status bits.
Note that the control bits for TX_DISABLE and RATE_SELECT
and the status bits for TXFAULT and RXLOS do not meet the
timing requirements specified in the SFP MSA or the GBIC
Specification, revision 5.5 (SFF-8053) for the hardware signals. The speed of the serial interface limits the rate at which
these functions can be manipulated and/or reported. The
response time for the control and status bits is given in the
“Electrical Characteristics” section.
Alarms and Warning Flags
There are twenty different conditions that will cause the
MIC3000 to set one of the bits in the WARNx or ALARMx
registers. These conditions are listed in Table 17. The less
critical of these events generate warning flags by setting a bit
in WARN0 or WARN1. The more critical events cause bits to
be set in ALARM0 or ALARM1.
An event occurs when any alarm or warning condition becomes true. Each event causes its corresponding status bit
in ALARM0, ALARM1, WARN0, or WARN1 to be set. This
action cannot be masked by the host. The status bit will
remain set until the host reads that particular status register,
a power on-off cycle occurs, or the host toggles TXDISABLE.
If TXDISABLE is asserted at any time during normal operation, A/D conversions continue. The A/D results for all parameters will continue to be reported. All events will be reported
in the normal way. If they have not already been individually
cleared by read operations, when TXDISABLE is deasserted,
all status registers will be cleared.
Event
Temperature high alarm
Temperature low alarm
Condition
TEMP > TMAX
TEMP < TMIN
MIC3000 Response
Set ALARM0[7]
Set ALARM0[6]
VIN > VMAX
VIN < VMIN
Set ALARM0[5]
Set ALARM0[4]
TX bias high alarm
TX bias low alarm
TX power high alarm
IBIAS > IBMAX
IBIAS < IBMIN
TXOP > TXMAX
Set ALARM0[3]
Set ALARM0[2]
Set ALARM0[1]
TX power low alarm
RX power high alarm
TXOP < TXMIN
RXOP > RXMAX
Set ALARM0[0]
Set ALARM1[7]
RX power low alarm
Temperature high warning
Temperature low warning
RXOP < RXMIN
TEMP > THIGH
TEMP < TLOW
Set ALARM1[6]
Set WARN0[7]
Set WARN0[6]
Voltage high warning
Voltage low warning
VIN > VHIGH
VIN < VLOW
Set WARN0[5]
Set WARN0[4]
TX bias high warning
TX bias low warning
IBIAS > IBHIGH
IBIAS < IBLOW
Set WARN0[3]
Set WARN0[2]
TX power high warning
TX power low warning
RX power high warning
TXOP > TXHIGH
TXOP < TXLOW
RXOP > RXHIGH
Set WARN0[1]
Set WARN0[0]
Set WARN1[7]
RX power low warning
RXOP < RXLOW
Table 17. MIC3000 Events
Set WARN1[6]
Voltage high alarm
Voltage low alarm
M9999-101204
26
October 2004
MIC3000
Micrel
D7 D6 D5 D4 D3 D2 D1 D0
TXDISABLE
LASER_SHUTDOWN
RSIN
RSOUT
TXFAULT
ILD & TX Fault
Comparators
RXLOS
RXLOS Fault
Comparator
Figure 13. Control and Status I/O Logic
System Timing
The timing specifications for MIC3000 control and status
I/O are given in the “Electrical Characteristics” section.
TXDISABLE
tOFF
tON
90% of nominal output
Transmitter Output
10% of nominal output
TXFAULT
Figure 14. Transmitter ON-OFF Timing
tINIT
VDD
tPOR
TXFAULT
TXDISABLE
90% Nominal Output
Transmitter Output
Figure 15. Initialization Timing with TXDISABLE Asserted
October 2004
27
M9999-101204
MIC3000
Micrel
VDD
TXFAULT
TXDISABLE
90% Nominal Output
Transmitter Output
tINIT
Figure 16. Initialization Timing, TXDISABLE Not Asserted
Loss of Signal
tLOSS_OFF
tLOSS_ON
RXLOS
Transmitter Output
Figure 17. Loss-of-Signal (LOS) Timing
Occurance of Fault
tFAULT
TXFAULT
Transmitter Output
10% of Nominal Output
Figure 18. Transmit Fault Timing
M9999-101204
28
October 2004
MIC3000
Micrel
tRESET
TXDISABLE
tINIT
TXFAULT
90% of Nominal Output
Transmitter Output
Figure 19. Successfully Clearing a Fault Condition
Fault Condition
tRESET
TXDISABLE
tINIT
TXFAULT
tFAULT
Transmitter Output
10% of Nominal Output
Figure 20. Unsuccessful Attempt to Clear a Fault
October 2004
29
M9999-101204
MIC3000
Micrel
Actual results will depend upon the operating conditions and
write-cycle endurance of the part in question.
Two registers, POHH and POHl, contain a 15-bit power-on
hour measurement and an error flag, POHFLT. Great care
has been taken to make the MIC3000’s hour meter immune
to data corruption and to insure that valid data is maintained
across power cycles. The hour meter employs multiple data
copies and error correction codes to maintain data validity.
This data is stored in the POHDATA registers. If POHFLT is
set, however, the power-on hour meter data has been corrupted and should be ignored.
It is recommended that a two-byte (or more) sequential read
operation be performed on POHh and POHl to insure coherency between the two registers. These registers are accessible by the OEM using a valid OEM password. The only
operation that should be performed on these registers is to
clear the hour meters initial value, if necessary, at the time of
product shipment. The hour meter result may be cleared by
setting all eight POHDATA bytes to 00h.
Warm Resets
The MIC3000 can be reset to its power-on default state during
operation by setting the reset bit in OEMCFG0. When this bit
is set, TXFAULT and RXLOS will be deasserted, all registers
will be restored to their normal power-on default values, and
any A/D conversion in progress will be halted and the results
discarded. The state of the MIC3000 following this operation
is indistinguishable from a power-on reset.
Power-On Hour Meter
The Power-On Hour meter logs operating hours using an
internal real-time clock and stores the result in NVRAM. The
hour count is incremented at ten-hour intervals in the middle
of each interval. The first increment therefore takes place five
hours after power-on. Time is accumulated whenever the
MIC3000 is powered. The hour meter’s timebase is accurate
to 5% over all MIC3000 operating conditions. The counter is
capable of storing counts of more than thirty years, but is
ultimately limited by the write-cycle endurance of the nonvolatile memory. This implies a range of at least twenty years.
Power-On Hour Result Format
Error flag
High Byte, POHH
Low Byte, POHl
Elapsed Time / 10 Hours, MSB’s
Elapsed Time / 10 Hours, LSB’s
MSB
LSB
Table 18. Power-On Hour Meter Result Format
Test and Calibration Features
Numerous features are included in the MIC3000 to facilitate
development, testing, and diagnostics. These features are
available via registers in the OEM area. As shown in Table19,
these features include:
Function
Description
Control Register(s)
Analog loop-back
Provides analog visibility of op-amp and DAC outputs via the ADC
OEMCFG0
Fault comparator disable control
Disables the fault comparator
OEMCAL0
Fault comparator spin-on-channel mode
Selects a single fault comparator channel
OEMCAL0
Fault comparator output read-back
Allows host to read individual fault comparator outputs
OEMRD
RSOUT, /INT read-back
Allows host to read the state of these pins
OEMRD
Inhibit EEPROM write cycles
Speeds repetitive writes to registers backed up by NVRAM
OEMCAL0
APC calibration mode
Allows direct writes to MODDAC and APCDAC
(temperature compensation not used)
OEMCAL0
Continuity checking
Forcing of RXLOS, TXFAULT, /INT
OEMCAL0
Halt A/D
Stops A/D conversions; ADC in one-shot mode
OEMCAL1
ADC idle flag
Indicates ADC status
OEMCAL1
A/D one-shot mode
Performs a single A/D conversion on the selected input channel
OEMCAL1
A/D spin-on-channel mode
Selects a single input channel
OEMCAL1
Channel selection
Selects ADC or fault comparator channel for spin-on-channel modes
OEMCAL1
LUT index read-back
Permits visibility of the LUT index calculated by the state-machine
LUTINDX
Manufacturer and device ID registers
Facilitates presence detection and version control
MFG_ID, DEV_ID
Table 19. Test and Diagnostic Features
M9999-101204
30
October 2004
MIC3000
Micrel
Page Writes
To increase the speed of multi-byte writes, the MIC3000
allows up to four consecutive bytes (one page) to be written
before the internal write cycle begins. The entire non-volatile
memory array is organized into four-byte pages. Each page
begins on a register address boundary where the last two bits
of the address are 00b. Thus the page is composed of any four
consecutive bytes having the addresses xxxxxx00 b ,
xxxxxx01b, xxxxxx10b, and xxxxxx11b.
The page write sequence begins just like a Write_Byte
operation with the host sending the slave address, R/W bit
low, register address, etc. After the first byte is sent the host
should receive an acknowledge. Up to three more bytes can
be sent in sequence. The MIC3000 will acknowledge each
one and increment its internal address register in anticipation
of the next byte. After the last byte is sent, the host issues a
STOP. The MIC3000’s internal write process then begins. If
more than four bytes are sent, the MIC3000’s internal address counter wraps around to the beginning of the four-byte
page.
To accelerate calibration and testing, NVRAM write cycles
can be disabled completely by setting the WRINH bit in
OEMCAL0. Writes to registers that do not have NVRAM
backup will not incur write-cycle delays when writes are
inhibited. Write operations on registers that exist only in
NVRAM will still incur write cycle delays.
Serial Port Operation
The MIC3000 uses standard Write_Byte, Read_Byte, and
Read_Word operations for communication with its host. It
also supports Page_Write and Sequential_Read transactions. The Write_Byte operation involves sending the device’s
slave address (with the R/W bit low to signal a write operation), followed by the address of the register to be operated
upon and the data byte. The Read_Byte operation is a
composite write and read operation: the host first sends the
device’s slave address followed by the register address, as in
a write operation. A new start bit must then be sent to the
MIC3000, followed by a repeat of the slave address with the
R/W bit (LSB) set to the high (read) state. The data to be read
from the part may then be clocked out. A Read_Word is
similar, but two successive data bytes are clocked out rather
than one. These protocols are shown in Figure 21 to 24.
The MIC3000 will respond to up to four sequential slave
addresses depending upon whether it is in OEM or User
mode. A match between one of the MIC3000’s addresses
and the address specified in the serial bit stream must be
made to initiate communication. The MIC3000 responds to
slave addresses A0h and A2h in User Mode; it also responds
to A4h and A6h in OEM Mode (assuming I2CADR = Axh).
MIC3000 Slave Address
Register Address
Data Byte to MIC3000
DATA S 1 0 1 0 0 0 0 0 A X X X X X X X X A D7 D6 D5 D4 D3 D2 D1 D0 /A P
R/W = WRITE
START
ACKNOWLEDGE
ACKNOWLEDGE
NOT ACKNOWLEDGE
STOP
CLK
Master to slave transfer,
i.e., DATA driven by master.
Slave to master transfer,
i.e., DATA driven by slave.
Figure 21. Write Byte Protocol
MIC3000 Slave Address
Register Address
MIC3000 Slave Address
Data Read From MIC3000
DATA S 1 0 1 0 0 0 0 0 A 0 0 X X X X X X A S 1 0 0 1 X X A0 1 A X X X X X X X X /A P
R/W = WRITE
START
ACKNOWLEDGE
ACKNOWLEDGE
R/W = READ
START
ACKNOWLEDGE
NOT ACKNOWLEDGE
STOP
CLK
Master to slave transfer,
i.e., DATA driven by master.
Slave to master transfer,
i.e., DATA driven by slave.
Figure 22. Read Byte Protocol
MIC3000 Slave Address
DATA S 1 0 1 0 0
START
0
Register Address
0 0 A 0 0 0 0 0 0 X X A S 1 0 1 0 0
R/W = WRITE
ACKNOWLEDGE
ACKNOWLEDGE
High-Order Byte
from MIC3000
MIC3000 Slave Address
0
0 1 A D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 /A P
R/W = READ
START
Low-Order Byte
from MIC3000
ACKNOWLEDGE
ACKNOWLEDGE
NOT ACKNOWLEDGE
STOP
CLK
Master-to-slave tranfer,
i.e., DATA driven by master.
Slave-to-master transfer,
i.e.,DATA driven by slave.
Figure 23. Read_Word Protocol
October 2004
31
M9999-101204
MIC3000
Micrel
MIC3000 Slave Address
1st Data Byte to
MIC3000
Register Address
2nd Data Byte to
MIC3000
DATA S 1 0 1 0 0 0 0 0 A X X X X X X X X A D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 • • •
START
R/W = WRITE
ACKNOWLEDGE
ACKNOWLEDGE
ACKNOWLEDGE
• • •
CLK
4th Data Byte to
MIC3000
3rd Data Byte to
MIC3000
• • • D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 /A P
R/W = READ
ACKNOWLEDGE
NOT ACKNOWLEDGE
STOP
• • •
Master to slave transfer,
i.e., DATA driven by master.
Slave to master transfer,
i.e., DATA driven by slave.
Figure 24. Four-Byte Page_Write Protocol
Acknowledge Polling
The MIC3000’s non-volatile memory cannot be accessed
during the internal write process. To allow for maximum
speed bulk writes, the MIC3000 supports acknowledge polling. The MIC3000 will not acknowledge serial bus transactions while internal writes are in progress. The host may
therefore monitor for the end of the write process by periodically checking for an acknowledgement.
Write Protection and Data Security
OEM Password
A password is required to access the OEM areas of the
MIC3000, specifically the non-volatile memory, look-up tables,
and registers at serial addresses A4h and A6h. A four-byte
field, OEMPWSET, at serial address A6h is used for setting
the OEM password. The OEM password is set by writing
OEMPWSET with the new value. The password comparison
is performed following the write to the MSB of the OEMPW,
address 7Bh at serial address A2h. Therefore, this byte
must be written last! A four-byte burst-write sequence to
address 78h may be used as this will result in the MSB being
written last. The new password will not take effect until after
a power-on reset occurs or a warm reset is performed using
the RST bit in OEMCFG0. This allows the new password to
be verified before it takes effect.
The corresponding four-byte field for password entry, OEMPW,
is located at serial address A2h. This field is therefore always
visible to the host system. OEMPW is compared to the fourbyte OEMPWSET field at serial address A6h. If the two fields
match, access is allowed to the OEM areas of the MIC3000
non-volatile memory at serial addresses A4h and A6h. If
OEMPWSET is all zeroes, no password security will exist.
The value in OEMPW will be ignored. This helps prevent a
deliberately unsecured MIC3000 from being inadvertently
locked. Once a valid password is entered, the MIC3000 OEM
areas will be accessible. The OEM areas may be re-secured
M9999-101204
by writing an incorrect password value at OEMPW, e.g., all
zeroes. In all cases OEMPW must be written LSB first
through MSB last. The OEM areas will be inaccessible
following the final write operation to OEMPW’s LSB. The
OEMPW field is reset to all zeros at power on. Any values
written to these locations will be readable by the host regardless of the locked/unlocked status of the device. If OEMPWSET
is set to zero (00000000h), the MIC3000 will remain unlocked
regardless of the contents of the OEMPW field. This is the
factory default security setting.
NOTE: A valid OEM password allows access to the OEM and
user areas of the chip, i.e., the entire memory map, regardless of any user password that may be in place. Once the
OEM areas are locked, the user password can provide
access and write protection for the user areas.
User Password
A password is required to access the USER areas of the
MIC3000, specifically the non-volatile memory at serial addresses A0h and A2h. A one-byte field, USRPWSET at serial
address A2h is used for setting the USER password.
USRPWSET is compared to the USRPW field at serial
address A2h. If the two fields match, access is allowed to the
USER areas of the MIC3000 non-volatile memory at serial
addresses A0h and A2h.The USER password is set by writing
USRPWSET with the new value. The new password will not
take effect until after a power-on reset occurs or a warm reset
is performed using the RST bit in OEMCFG0. This allows the
new password to be verified before it takes effect.
NOTE: A valid OEM password allows access to the OEM and
user areas of the chip, i.e., the entire memory map, regardless of any user password that may be in place. Once the
OEM areas are locked, the user password can provide
access and write protection for the user areas. If a valid OEM
password is in place, the user password will have no effect.
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Detailed Register Descriptions
Note: Serial bus addresses shown assume that I2CADR = Axh.
Alarm Threshold Registers
Temperature High Alarm Threshold MSB (TMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
00 = 00h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents one degree centigrade. This register is to be used in conjunction with TMAXl to yield a sixteenbit temperature value. The value in this register is uncalibrated. The value in TMAXh is compared against TEMPh.
Alarm bit Ax is set if TEMPh > TMAXh.
Temperature High Alarm Threshold LSB (TMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
01 = 01h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with TMAXh to yield a sixteen-bit temperature value. The value in TMAXh is
compared against TEMPh. Alarm bit Ax is set if TMAXh > TEMPh. Since TEMPl is always zero, it is recommended that
this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by
the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
Temperature Low Alarm Threshold MSB (TMINh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
02 = 02h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents one degree centigrade. This register is to be used in conjunction with TMINl to yield a sixteen-bit
temperature value. The value in TMINh is compared against TEMPh. Alarm bit Ax is set if TEMPh < TMINh.
Temperature Low Alarm Threshold LSB (TMINl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
03 = 03h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with TMINh to yield a sixteen-bit temperature value. The value in TMINh is
compared against TEMPh. Alarm bit Ax is set if TEMPh < TMINh. Since TEMPl is always zero, it is recommended that
this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by
the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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Voltage High Alarm Threshold MSB(VMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
08 = 08h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6mV. This register is to be used in conjunction with VMAXl to yield a sixteen-bit value. The
value in TMINh is compared against VINh. Alarm bit Ax is set if VINh > VMAXh.
Voltage High Alarm Threshold LSB(VMAXl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
09 = 09h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 100µV. This register is to be used in conjunction with VINh to yield a sixteen-bit value. The value
in VMAXh is compared against VINh. Alarm bit Ax is set if VINh > VMAXh. Since VINl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is
not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
Voltage Low Alarm Threshold MSB (VMINh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
10 = 0Ah
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6mV. This register is to be used in conjunction with VMINl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in VMINh is compared against VINh. Alarm bit Ax is set if VINh<VMINh.
Voltage Low Alarm Threshold LSB (VMINl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
11 = 0Bh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 100µV. This register is to be used in conjunction with VINh to yield a sixteen-bit value. The value
in VMINh is compared against VINh. Alarm bit Ax is set if VINh < VMINh. Since VINl is always zero, it is recommended
that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used
by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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Bias Current High Alarm Threshold MSB (IMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
16 = 10h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with IMAXl to yield a sixteen-bit value. The value in this register is
uncalibrated. The value in IMAXh is compared against ILDh. Alarm bit Ax is set if ILDh > IMAXh.
Bias Current High Alarm Threshold LSB (IMAXl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
17 = 11h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 2µA. This register is to be used in conjunction with IMAXh to yield a sixteen-bit value. The value
in this register is uncalibrated. The value in IMAXh is compared against ILDh. Alarm bit Ax is set if ILDh > IMAXh.
Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided
for compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or
warning bits.
Bias Current Low Alarm Threshold MSB (IMINh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
18 = 12h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with IMINl to yield a sixteen-bit value. The value in this register is
uncalibrated. The value in IMINh is compared against ILDh. Alarm bit Ax is set if ILDh < IMINh.
Bias Current Low Alarm Threshold LSB (IMINl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
19 = 13h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 2µA. This register is to be used in conjunction with IMINh to yield a sixteen-bit value. The value
in this register is uncalibrated. The value in IMINh is compared against ILDh. Alarm bit Ax is set if ILDh < IMINh. Since
ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided for
compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or
warning bits.
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TX Optical Power High Alarm MSB (TXMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
24 = 18h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with TXOPl to yield a sixteen-bit value. The
values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXMAXh is compared against TXOPh. Alarm bit Ax is set if TXOPh > TXMAXh.
TX Optical Power High Alarm LSB (TXMAXl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
25 = 19h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with TXMAXh to yield a sixteen-bit value. The
values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXMAXh is compared against TXOPh. Alarm bit Ax is set if TXOPh > TXMAXh. Since TXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
TX Optical Power Low Alarm MSB (TXMINh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
26 = 1Ah
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with TXMINl to yield a sixteen-bit value. The
values in TXMINh:TMINl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXMINh is compared against TXOPh. Alarm bit Ax is set if TXOPh < TXMINh.
TX Optical Power Low Alarm LSB (TXMINl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
27 = 1Bh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with TXMINh to yield a sixteen-bit value. The
values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXMINh is compared against TXOPh. Alarm bit Ax is set if TXOPh < TXMINh. Since TXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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RX Optical Power High Alarm Threshold MSB (RXMAXh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
32 = 20h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with RXMAXl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in RXMAXh is compared against RXOPh. Alarm bit Ax is set if RXOPh
> RXMAXh.
RX Optical Power High Alarm Threshold LSB (RXMAXl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
33 = 21h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with RXMAXh to yield a sixteen-bit value. The
values in RXMAXh:RXMAXl are in an unsigned binary format. The value in this register is uncalibrated. The value in
RXMAXh is compared against RXOPh. Alarm bit Ax is set if RXOPh > RXMAXh. Since RXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
RX Optical Power Low Alarm Threshold MSB (RMINh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
34 = 22h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with RXMINl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in RXMINh is compared against RXOPh. Alarm bit Ax is set if RXOPh <
RXMINh.
RX Optical Power Low Alarm Threshold LSB (RMINl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
35 = 23h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with RXMINh to yield a sixteen-bit value. The
values in RXMINh:RXMINl are in an unsigned binary format. The value in this register is uncalibrated. The value in
RXMINh is compared against RXOPh. Alarm bit Ax is set if RXOPh < RXMINh. Since RXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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Warning Threshold Registers
Temperature High Warning Threshold MSB (THIGHh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
04 = 04h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents one degree centigrade. This register is to be used in conjunction with THIGHl to yield a sixteenbit temperature value. The value in this register is uncalibrated. The value in THIGHh is compared against TEMPh.
Warning bit Wx is set if TEMPh > THIGHh.
Temperature High Warning Threshold LSB (THIGHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
05 = 05h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with THIGHh to yield a sixteen-bit temperature value. The value in this
register is uncalibrated. The value in THIGHh is compared against TEMPh. Warning bit Wx is set if THIGHh > TEMPh.
Since TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is
provided for compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting
alarm or warning bits.
Temperature Low Warning Threshold MSB (TLOWh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
06 = 06h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents one degree centigrade. This register is to be used in conjunction with TLOWl to yield a sixteenbit temperature value. The value in this register is uncalibrated. The value in TLOWh is compared against TEMPh.
Warning bit Wx is set if TEMPh < TLOWh.
Temperature Low Warning Threshold LSB (TLOWl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
07 = 07h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with TLOWh to yield a sixteen-bit temperature value. The value in this register
is uncalibrated. The value in TLOWh is compared against TEMPh. Warning bit Wx is set if TEMPh < TLOWh. Since
TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for
compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or
warning bits.
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Voltage High Warning Threshold MSB (VHIGHh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
12 = 0Ch
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6mV. This register is to be used in conjunction with VHIGHl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in VHIGHh is compared against VINh. Warning bit Wx is set if VINh >
VHIGHh.
Votage High Warning Threshold LSB (VHIGHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
13 = 0Dh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 100µV. This register is to be used in conjunction with VHIGHh to yield a sixteen-bit value. The
value in VHIGHh is compared against VINh. Warning bit Wx is set if VINh > VHIGHh. Since VINl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
Votage Low Warning Threshold MSB (VLOWh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
14 = 0Eh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6mV. This register is to be used in conjunction with VLOWl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in VLOWh is compared against VINh. Warning bit Wx is set if VINh <
VLOWhh.
Voltage Low Warning Threshold LSB (VLOWl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
15 = 0Fh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 100µV. This register is to be used in conjunction with VLOWh to yield a sixteen-bit value. The
value in VLOWh is compared against VINh. Warning bit Wx is set if VINh < VLOWh. Since VINl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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Bias Current High Warning Threshold MSB (IHIGHh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
20= 14h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with IHIGHl to yield a sixteen-bit value. The value in this register is
uncalibrated. The value in IHIGHh is compared against ILDh. Warning bit Wx is set if ILDh > IHIGHh.
Bias Current High Warning Threshold LSB (IHIGHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
21= 15h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 2µA. This register is to be used in conjunction with IHIGHh to yield a sixteen-bit value. The value
in this register is uncalibrated. The value in IHIGHh is compared against ILDh. Warning bit Wx is set if ILDh > IHIGHh.
Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided
for compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or
warning bits.
Bias Current Low Warning Threshold MSB (ILOWh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
22= 16h
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is to be used in conjunction with ILOWl to yield a sixteen-bit value. The value in this register is
uncalibrated. The value in ILOWh is compared against ILDh. Warning bit Wx is set if ILDh < ILOWh.
Bias Current Low Warning Threshold LSB (ILOWl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
23= 17h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 2µA. This register is to be used in conjunction with ILOWh to yield a sixteen-bit value. The value
in this register is uncalibrated. The value in ILOWh is compared against ILDh. Warning bit Wx is set if ILDh < ILOWh.
Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided
for compliance with SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or
warning bits.
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October 2004
MIC3000
Micrel
TX Optical Power High Warning MSB (TXHIGHh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
28= 1Ch
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with TXHIGHl to yield a sixteen-bit value. The
values in TXHIGHh:TXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXHIGHh is compared against TXOPh. Warning bit Wx is set if TXOPh > TXHIGHh.
TX Optical Power High Warning LSB (TXHIGHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
29= 1Dh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with TXHIGHh to yield a sixteen-bit value. The
values in TXHIGHh:TXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXHIGHh is compared against TXOPh. Warning bit Wx is set if TXOPh > TXHIGHh. Since TXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning b.
TX Optical Power Low Warning MSB (TLOWh)
D[7]
read/write
D[6]
D[5]
D[4]
D[3]
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
30 = 1Eh
D[2]
D[1]
D[0]
Each LSB represents 25.6µW. This register is to be used in conjunction with TXLOWl to yield a sixteen-bit value. The
values in TXLOWh:TLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXLOWh is compared against TXOPh. Warning bit Wx is set if TXOPh < TXLOWh.
TX Optical Power Low Warning LSB (TLOWl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
31 = 1Fh
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with TXLOWh to yield a sixteen-bit value. The
values in TXLOWh:TXLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in
TXLOWh is compared against TXOPh. Warning bit Wx is set if TXOPh < TXLOWh. Since TXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
October 2004
41
M9999-101204
MIC3000
Micrel
RX Optical Power High Warning Threshold MSB (RXHIGHh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
36 = 24h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with RXHIGHl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in RXHIGHh is compared against RXOPh. Warning bit Wx is set if
RXOPh > RXHIGHh.
RX Optical Power High Warning Threshold LSB (RXHIGHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
37 = 25h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with RXHIGHh to yield a sixteen-bit value. The
values in RXHIGHh:RXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in
RXHIGHh is compared against RXOPh. Warning bit Wx is set if RXOPh > RXHIGHh. Since RXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
RX Optical Power Low Warning Threshold MSB (RXLOWh)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
38 = 26h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 25.6µW. This register is to be used in conjunction with RXLOWl to yield a sixteen-bit value. The
value in this register is uncalibrated. The value in RXLOWh is compared against RXOPh. Warning bit Wx is set if
RXOPh < RXLOWh.
RX Optical Power Low Warning Threshold LSB (RXLOWl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
39 = 27h
D[2]
read/write
D[1]
read/write
D[0]
read/write
Each LSB represents 0.1µW. This register is to be used in conjunction with RXLOWh to yield a sixteen-bit value. The
values in RXLOWh:RXLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in
RXLOWh is compared against RXOPh. Warning bit Wx is set if RXOPh < RXLOWh. Since RXOPl is always zero, it is
recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
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October 2004
MIC3000
Micrel
Checksum (CHKSUM)
Checksum of bytes 0 - 94 at serial address A2h
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
95 = 5Fh
D[2]
read/write
D[1]
read/write
D[0]
read/write
This register is provided for compliance with SFF-8472. It is implemented as general-purpose non-volatile memory.
Read/write access is possible whenever a valid OEM password has been entered. CHKSUM is read-only in USER
mode.
October 2004
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M9999-101204
MIC3000
Micrel
ADC Result Registers
Temperature Result MSB (TEMPh)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0°C)(1)
Serial Address
A2h = 1010001b
Byte Address
96 = 60h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents one degree centigrade. This register is to be used in conjunction with TEMPl to yield a sixteenbit temperature value. The value in this register is uncalibrated. The host should process the results using the scale
factor and offset provided. See the External Calibration section.
Temperature Result LSB (TEMPl)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0°C)
Serial Address
A2h = 1010001b
Byte Address
97 = 61h
D[2]
read-only
D[1]
read-only
D[0]
read-only
This register is to be used in conjunction with TEMPh to yield a sixteen-bit temperature value. The value in this register
is uncalibrated. The host should process the results using the scale factor and offset provided. See the External
Calibration section. In the MIC3000, this register will always return zero. This register is provided for compliance with
SFF-8472. It is not used by the MIC3000 when doing threshold comparisons and setting alarm or warning bits.
Voltage MSB (VINh)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0V)(2)
Serial Address
A2h = 1010001b
Byte Address
98 = 62h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 25.6mV. This register is to be used in conjunction with VINl to yield a sixteen-bit value. The
values in VINh:VlNl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the scale factor and offset provided. See the External Calibration section.
Voltage LSB (VINl)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0V)
Serial Address
A2h = 1010001b
Byte Address
99 = 63h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 100µV. This register is to be used in conjunction with VINh to yield a sixteen-bit value. The
values in VINh:VINl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3000,
this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the
MIC3000 when doing threshold comparisons and setting alarm or warning bits.
Notes:
1. TEMPh will contain measured temperature data after the completion of one conversion.
2. VINh will contain measured data after one A/D conversion cycle.
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October 2004
MIC3000
Micrel
Laser Diode Bias Current MSB (ILDh)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mA)(3)
Serial Address
A2h = 1010001b
Byte Address
100 = 64h
D[2]
read-only
D[1]
read-only
D[0]
read-only
This register is to be used in conjunction with ILDl to yield a sixteen-bit value. The values in ILDh:ILDl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale
factor and offset provided. See the External Calibration sections.
Laser Diode Bias Current LSB (ILDl)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mA)
Serial Address
A2h = 1010001b
Byte Address
101 = 65h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 2µA. This register is to be used in conjunction with ILDh to yield a sixteen-bit value. The values
in ILDh:ILDl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the
results using the scale factor and offset provided. See the External Calibration section. In the MIC3000, this register
will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3000 when
doing threshold comparisons and setting alarm or warning bits.
Transmitted Optical Power MSB (TXOPh)(4)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mW)(5)
Serial Address
A2h = 1010001b
Byte Address
102 = 66h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 25.6µW. This register is to be used in conjunction with TXOPl to yield a sixteen-bit value. The
values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the scale factor and offset provided. See the External Calibration section.
Transmitted Optical Power LSB (TXOPl)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mW)
Serial Address
A2h = 1010001b
Byte Address
103 = 67h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 0.1µW. This register is to be used in conjunction with TXOPh to yield a sixteen-bit value. The
values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3000,
this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the
MIC3000 when doing threshold comparisons and setting alarm or warning bitsection.
Notes:
3. ILDh will contain measured data after one A/D conversion cycle.
4. The scale factor corresponding to the sense resistor used must be set in the configuration register.
5. TXOPh will contain measured data after one A/D conversion cycle.
October 2004
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M9999-101204
MIC3000
Micrel
Received Optical Power MSB (RXOPh)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mW)(6)
Serial Address
A2h = 1010001b
Byte Address
104 = 68h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 25.6µW. This register is to be used in conjunction with RXOPl to yield a sixteen-bit value. The
values in RXOPh:RXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the scale factor and offset provided. See the External Calibration section.
Received Optical Power LSB (RXOPl)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
Default Value
0000 0000b = 00h (0mW)(6)
Serial Address
A2h = 1010001b
Byte Address
105 = 69h
D[2]
read-only
D[1]
read-only
D[0]
read-only
Each LSB represents 0.1µW. This register is to be used in conjunction with RXOPh to yield a sixteen-bit value. The
values in RXOPh:RXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should
process the results using the coefficients provided. See the External Calibration section. In the MIC3000, this register
will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3000 when
doing threshold comparisons and setting alarm or warning bits.
Control and Status (CNTRL)
D[7]
TXDIS
read only
D[6]
STXDIS
read/write
D[5]
reserved
D[4]
RSEL
read/write
D[3]
SRSEL
read/write
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
110 = 6Eh
Bit(s)
D[2]
XFLT
read only
D[1]
LOS
read only
Function
Operation
Reflects the state of the TXDISABLE pin
1 = disabled, 0 = enabled, read only.
Soft transmit disable
1 = disabled; 0 = enabled.
Reserved
Reserved - always write as zero.
Reflects the state of the RSEL pin
1 = high; 0 = low.
D[0]
POR
read only
D[7]
TXDIS
D[6]
STXDIS
D[5]
D[5]
D[4]
RSEL
D[3]
SRSEL
Soft rate select
1 = high (2Gbps); 0 = low (1Gbps).
D[2]
TXFLT
Reflects the state of the TXFAULT pin
1 = high (fault); 0 = low (no fault).
D[1]
LOS
Loss of signal. Reflects the state of the LOS pin
1 = high (loss of signal); 0 = low (no loss of signal).
D[0]
POR
MIC3000 power-on status
0 = POR complete, analog data ready;
1 = POR in progress.
Notes:
6. RXOPh will contain measured data after one A/D conversion cycle.
M9999-101204
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October 2004
MIC3000
Micrel
Alarm Flags
Alarm Register 0 (ALARM0)
D[7]
A7
read-only
D[6]
A6
read-only
D[5]
A5
read-only
D[4]
A4
read-only
D[3]
A3
read-only
D[2]
A2
read-only
Default Value
0000 0000b = 00h (no events pending)
Serial Address
A2h = 1010001b
Byte Address
112 = 70h
D[1]
A1
read-only
D[0]
A0
read-only
The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending
upon the results.
Bit(s)
Function
Operation
D[7]
A7
High temperature alarm, TEMPh > TMAXh.
1 = condition exists, 0 = normal/OK.
D[6]
A6
Low temperature alarm, TEMPh < TMINh.
1 = condition exists, 0 = normal/OK.
D[5]
A5
High voltage alarm, VINh > VMAXh.
1 = condition exists, 0 = normal/OK.
D[4]
A4
Low voltage alarm, VINh < VMINh.
1 = condition exists, 0 = normal/OK.
D[3]
A3
High laser diode bias alarm, IBIASh > IMAXh.
1 = condition exists, 0 = normal/OK.
D[2]
A2
Low laser diode bias alarm, IBIASh < IMINh.
1 = condition exists, 0 = normal/OK.
D[1]
A1
High transmit optical power alarm,
TXOPh > TXMAXh.
1 = condition exists, 0 = normal/OK.
D[0]
A0
Low transmit optical power alarm,
TXOPh < TXMINh.
1 = condition exists, 0 = normal/OK.
Alarm Register 1 (ALARM1)
D[7]
A15
read-only
D[6]
A14
read-only
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
reserved
reserved
reserved
reserved
reserved
reserved
Default Value
0000 0000b = 00h (no events pending)
Serial Address
A2h = 1010001b
Byte Address
113 = 71h
The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending
on the results.
Bit(s)
Function
Operation
D[7]
A15
High received power (overload) alarm,
RXOPh > RXMAXh.
1 = condition exists, 0 = normal/OK.
D[6]
A14
Low received power (LOS) alarm,
RXOPh < RXMINh.
1 = condition exists, 0 = normal/OK.
Reserved
Reserved - always write as zero.
D[5:0]
October 2004
47
M9999-101204
MIC3000
Micrel
Warning Flags
Warning Register 0 (WARN0)
D[7]
W7
read-only
D[6]
W6
read-only
D[5]
W5
read-only
D[4]
W4
read-only
D[3]
W3
read-only
D[2]
W2
read-only
Default Value
0000 0000b = 00h (no events pending)
Serial Address
A2h = 1010001b
Byte Address
116 = 74h
D[1]
W1
read-only
D[0]
W0
read-only
The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending
upon the results.
Bit(s)
Function
Operation
D[7]
W7
High temperature warning, TEMPh > THIGHh.
1 = condition exists, 0 = normal/OK.
D[6]
W6
Low temperature warning, TEMPh < TLOWh.
1 = condition exists, 0 = normal/OK.
D[5]
W5
High voltage warning, VINh > VHIGHh.
1 = condition exists, 0 = normal/OK.
D[4]
W4
Low voltage warning, VINh < VLOWh.
1 = condition exists, 0 = normal/OK.
D[3]
W3
High laser diode bias warning, IBIASh > IHIGHh.
1 = condition exists, 0 = normal/OK.
D[2]
W2
Low laser diode bias warning, IBIASh < ILOWh.
1 = condition exists, 0 = normal/OK.
D[1]
W1
High transmit optical power warning,
TXOPh > TXHIGHh.
1 = condition exists, 0 = normal/OK.
D[0]
W0
Low transmit optical power warning,
TXOPh < TXLOWh.
1 = condition exists, 0 = normal/OK.
Warning Register 1 (WARN1)
D[7]
W15
read-only
D[6]
W14
read-only
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
read-only
read-only
read-only
read-only
read-only
read-only
Default Value
0000 0000b = 00h (no events pending)
Serial Address
A2h = 1010001b
Byte Address
117 = 75h
The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending
on the results.
Bit(s)
Function
Operation
1 = condition exists, 0 = normal/OK.
D[7]
W15
Received power high warning,
RXOPh > RXHIGHh.
D[6]
W14
Received power low warning, RXOPh < RXMINh. 1 = condition exists, 0 = normal/OK.
D[5:0]
M9999-101204
Reserved
Reserved - always write as zero.
48
October 2004
MIC3000
Micrel
OEM Password Entry (OEMPW)
D[7]
Read/write
D[6]
Read/write
D[5]
Read/write
D[4]
Read/write
D[3]
Read/write
D[2]
Read/write
Default Value
0000 0000b = 00h (reset to zero at power-on)
Serial Address
A2h = 1010001b
Byte Address
120 – 123 =
78h - 7Bh
D[1]
Read/write
D[0]
Read/write
(MSB is 7Bh)
This four-byte field is for entry of the password required to access the OEM area of the MIC3000’s memory and
registers. A valid OEM password will also permit access to the user areas of memory. The byte at address 123 (7Bh) is
the most significant byte. This field is compared to the four-byte OEMPWSET field at serial address A6h, bytes 12 to
15. If the two fields match, access is allowed to the OEM areas of the MIC3000 non-volatile memory at serial addresses A4h and A6h. The OEM password is set by writing the new value into OEMPWSET. The password comparison is performed following the write to the MSB, address 7Bh. This byte must be written last!
A four-byte burst-write sequence to address 78h may be used as this will result in the MSB being written last. The new
password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in
OEMCFG0. This allows the new password to be verified before it takes effect. This field is reset to all zeros at power
on. Any values written to these locations will be readable by the host regardless of the locked/unlocked status of the
device. If OEMPWSET is set to zero (00000000h), the MIC3000 will remain unlocked regardless of the contents of the
OEMPW field. This is the factory default security setting.
BYTE
Weight
3
OEM Password Entry, Most Significant Byte (Address = 7Bh)
2
OEM Password Entry, 2nd Most Significant Byte (Address = 7Ah)
1
OEM Password Entry, 2nd Least Significant Byte (Address = 79h)
0
OEM Password Entry, Least Significant Byte (Address = 78h)
USER Password Setting (USRPWSET)
D[7]
Read/write
D[6]
Read/write
D[5]
Read/write
D[4]
Read/write
D[3]
Read/write
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
250 = FAh
D[2]
Read/write
D[1]
Read/write
D[0]
Read/write
This register is for setting the password required to access the USER area of the MIC3000’s memory and registers.
This field is compared to the USRPW field at serial address A2h, byte 251. If the two fields match, access is allowed to
the USER areas of the MIC3000 non-volatile memory at serial addresses A0h and A2h. If a valid USER password has
not been entered, writes to the serial ID fields, USRCTRL, and the user scratchpad areas of A0h and A2h will not be
allowed, and USRPWSET will be unreadable (returns all zeroes).
A USER password is set by writing the new value into USRPWSET. The new password will not take effect until after a
power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to
be verified before it takes effect. This register is non-volatile and will be maintained through power and reset cycles. A
valid USER or OEM password is required for access to this register. Otherwise, this register will read as 00h. Note: a
valid OEM password overrides the USER password setting. If a valid OEM password is currently in place, the user
password will have no effect.
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USER Password (USRPW)
D[7]
Read/write
D[6]
Read/write
D[5]
Read/write
D[4]
Read/write
D[3]
Read/write
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
251 = FBh
D[2]
Read/write
D[1]
Read/write
D[0]
Read/write
USER passwords are entered in this field. This field is compared to the USRPWSET field at serial address A2h, byte
250. If the two fields match, access is allowed to the USER areas of the MIC3000 non-volatile memory at serial
addresses A0h and A2h. If a valid USER password has not been entered, writes to the serial ID fields and user
scratchpad areas of A0h and A2h will not be allowed and USRPWSET will be unreadable (returns all zeroes).
Power-On Hours MSB (POHh)
D[7]
read-only
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
D[2]
read/write
D[1]
read/write
D[0]
read/write
POH Fault Flag (POHFLT)
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
252 = FCh
The lower seven bits of this register contain the most-significant bits of the 15-bit power-on hours measurement.
POHFLT is an error flag. The value in this register should be combined with the Power-on Hours, Low Byte, POHl, to
yield the complete result. If POHFLT is set, the power-on hour meter data has been corrupted and should be ignored.
It is recommended that a two-byte (or more) sequential read operation be performed on POHh and POHl to insure
coherency between the two registers. This register is non-volatile and will be maintained through power and reset
cycle.
Bit(s)
Function
Operation
D[7]
Power-on hours fault flag
1 = fault; 0 = no fault.
D[6:0]
Power-on hours, high byte
Non-volatile.
Power-On Hours LSB (POHl)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
D[2]
read/write
D[1]
read/write
D[0]
read/write
POH Fault Flag (POHFLT)
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
253 = FDh
This register contains the least-significant eight bits of the 15-bit power-on hours measurement. The value in this
register should be combined with the Power-on Hours, High Byte, POHh, to yield the complete result. If POHFLT is
set, the power-on hour meter data has been corrupted and should be ignored. It is recommended that a two-byte (or
more) sequential read operation be performed on POHh and POHl to insure coherency between the two registers. This
register is non-volatile and will be maintained through power and reset cycles.
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Data Ready Flags (DATARDY)
D[7]
TRDY
read only
D[6]
VRDY
read only
D[5]
IRDY
read only
D[4]
TXRDY
read only
D[3]
RXRDY
read only
Default Value
0000 0000b = 00h
Serial Address
A2h = 1010001b
Byte Address
254 = FEh
D[2]
D[1]
D[0]
reserved
reserved
reserved
When the A/D conversion for a given parameter is completed and the results available to the host, the corresponding
data ready flag will be set. The flag will be cleared when the host reads the corresponding result register.
Bit(s)
Function
Operation
D[7]
TRDY
Temperature data ready flag
0 = old data; 1 = new data ready
D[6]
VRDY
Voltage data ready flag
0 = old data; 1 = new data ready
D[5]
IRDY
Bias current data ready flag
0 = old data; 1 = new data ready
D[4]
TXRDY
Transmit power data ready flag
0 = old data; 1 = new data ready
D[3]
RXRDY
Receive power data ready flag
0 = old data; 1 = new data ready
Reserved
Reserved
D[2:0]
USER Control Register (USRCTL)
D[7]
D[6]
PORM
read/write
reserved
D[5]
PORS
read only
D[4]
IE
read/write
D[3]
APCSEL
read/write
Default Value
0010 0000b = 20h
Serial Address
A2h = 1010001b
Byte Address
255 = FFh
D[2]
D[1]
D[0]
read/write
reserved
reserved
This register provides for control of the nominal APC setpoint and management of interrupts by the end-user.
APCSEL[1:0] select which of the APC setpoint registers, APCSET0, APCSET1, or APCSET2 are used as the nominal
automatic power control setpoint.
IE must be set for any interrupts to occur. If PORM is set, the power-on event will generate an interrupt and warm
resets using RST will not generate a POR interrupt. When a power-on interrupt occurs, assuming PORM=1, PORS will
be set. PORS will be cleared and the interrupt output de-asserted when USRCTL is read by the host. If IE is set while /
INT is asserted, /INT will be de-asserted. The host must still clear the various status flags by reading them. If PORM is
set following the setting of PORS, PORS will remain set, and /INT will not be de-asserted, until USRCTL is read by the
host.
PORM, IE, and APCSEL are non-volatile and will be maintained through power and reset cycles. A valid USER
password is required for access to this register.
Bit
D[7]
Function
Operation
Reserved
Always write as zero; reads undefined.
D[6]
PORM
Power-on interrupt mask
1 = POR interrupts enabled; 0 = disabled; read/write;
non-volatile.
D[5]
PORS
Power-on interrupt flag
1 = POR interrupt occurred; 0 = no POR interrupt;
read-only.
D[4]
IE
Global interrupt enable
1 = enabled; 0 = disabled; read/write; non-volatile.
D[3:2]
APCSEL
Selects APC setpoint register
00 = APCSET0, 01 = APCSET1, 10 = APCSET2;
11 = reserved; read/write; non-volatile.
Reserved
Always write as zero; reads undefined.
D[1:0]
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OEM Configuration Register 0 (OEMCFG0)
D[7]
RST
write only
D[6]
ZONE
read/write
D[5]
DFLT
read only
D[4]
OE
reserved
D[3]
MODREF
reserved
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
00 = 00h
D[2]
VAUX[2]
read/write
D[1]
VAUX[1]
read/write
D[0]
VAUX[0]
read/write
A write to OEMCFG0 will result in any A/D conversion in progress being aborted and the result discarded. The A/D will
begin a new conversion sequence once the write operation is complete. All bits in OEMCFG0 are non-volatile except
DFLT and RST. A valid OEM password is required for access to this register.
Bit(s)
Function
Operation
D[7]
RST
0 = no action; 1 = reset; write-only.
D[6]
ZONE
Selects temperature zone.
0 = internal; 1 = external; non-volatile.
D[5]
DFLT
Diode fault flag.
1 = diode fault; 0 = OK.
D[4]
OE
1 = enabled; 0 = hi-Z; non-volatile.
D[3]
MODREF
Output enable for SHDN, VMOD, and VBIAS.
Selects whether VMOD is referenced to ground
or VDD.
D[2:0]
VAUX[2:0]
Selects the voltage reported in VINh:VINl.
1 = VDD; 0 = GND; non-volatile.
000 = VIN; 001 = VDDA; 010 = VBIAS; 011 = VMOD;
100 = APCDAC; 101 = MODDAC; 110 = FLTDAC;
non-volatile
OEM Configuration Register 1 (OEMCFG1)
D[7]
INV
read/write
D[6]
GAIN
read/write
D[5]
BIASREF
read/write
D[4]
RFB[2]
read/write
D[3]
RFB[1]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
1 = 01h
D[2]
RFB[0]
read/write
D[1]
SRCE
read/write
D[0]
SPOL
read/write
A write to OEMCFG1 will result in any A/D conversion in progress being aborted and the result discarded. The A/D will
begin a new conversion sequence once the write operation is complete. All bits in OEMCFG1 are non-volatile and will
be maintained through power and reset cycles. A valid OEM password is required for access to this register.
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Bit(s)
Function
Operation
D[7]
INV
Inverts the APC op-amp inputs. When set to “0”
0 = emitter follower (no inversion);
the BIAS DAC output is connected to the “+”
1 = common emitter (inverted); read/write;
input and FB is connected to the “–” input of the
non-volatile.
op amp. Set to “0” to use the ADC feedback loop.
D[6]
GAIN
Sets the feedback voltage range by changing the
APCDAC output swing; 0-VREF for optical
feedback, 0-VREF/4 for electrical feedback.
1 = VREF/4 full scale;
0 = VREF full scale; read/write ;non-volatile.
D[5]
BIASREF
Selects whether FB and VMPD are referenced to
ground or VDD and selects feedback resistor
termination voltage (VDDA or GNDA).
1 = VDD; 0 = GND; read/write; non-volatile.
D[4:2]
RFB[2:0]
Selects internal feedback resistance. (Resistors
will be terminated to VDDA or GNDA according
to BIASREF.)
000 = ×;
001 = 800ý,
010 = 1.6ký,
011 = 3.2ký,
100 = 6.4ký,
101 = 12.8ký,
110 = 25.6ký,
111 = 51.2ký;
read/write; non-volatile.
D[1]
SRCE
VBIAS source vs. sink drive.
1 = source (NPN),
0 = sink (PNP); read/write; non-volatile.
D[0]
SPOL
Polarity of shutdown output, SHDN, when active.
1 = high;
0 = low; read/write; non-volatile.
OEM Configuration Register 2 (OEMCFG2)
D[7]
I2CADR[3]
read/write
D[6]
I2CADR[2]
read/write
D[5]
I2CADR[1]
read/write
D[4]
I2CADR[0]
read/write
D[3]
LUTOFF
read/write
D[2]
LUTOFF
read/write
Default Value
1010 xxxxb = xxh (slave address = 1010xxxb)
Serial Address
A6h = 1010011b
Byte Address
2 = 02h
D[1]
LUTOFF
read/write
D[0]
LUTOFF
read/write
CAUTION: Changes to I2CADR take effect immediately! Any accesses following a write to I2CADR must be to the
newly programmed serial bus address. A valid OEM password is required for access to this register. This register is
non-volatile and will be maintained through power and reset cycles.
Bit(s)
Function
Operation
D[7:4]
I2CADR[3:0]
Upper four MSBs of the serial bus slave address;
writes take effect immediately.
Read/write; non-volatile.
D[3:0]
LUTOFF
LUT offset. LUTOFF is added to the result of the
digital temperature sensor to derive the table
index; writes take effect after reset.
Read/write; non-volatile.
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APC Setpoint 0 (APCSET0)
Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 00
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
3 = 03h
D[2]
read/write
D[1]
read/write
D[0]
read/write
When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken
from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded
directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in
the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. A valid OEM
password is required for access to this register. This register is non-volatile and will be maintained through power and
reset cycles.
APC Setpoint 1 (APCSET1)
Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 01
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
4 = 04h
D[2]
read/write
D[1]
read/write
D[0]
read/write
When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken
from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded
directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in
the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. This register
is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to
this register.
APC Setpoint 2 (APCSET2)
Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 10
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
5 = 05h
D[2]
read/write
D[1]
read/write
D[0]
read/write
When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken
from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded
directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in
the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. This register
is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to
this register.
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Modulation DAC Setting (MODSET)
Nominal VMOD setpoint
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
6 = 06h
D[2]
read/write
D[1]
read/write
D[0]
read/write
When A.P.C. is on, the value corresponding to the current temperature is taken from the MODLUT look-up table,
added to MODSET and loaded into the VMOD DAC. This register is non-volatile and will be maintained through power
and reset cycles. A valid OEM password is required for access to this register.
IBIAS Fault Threshold (IBFLT)
Bias current fault threshold
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
7 = 07h
D[2]
read/write
D[1]
read/write
D[0]
read/write
A valid OEM password is required for access to this register. This register is non-volatile and will be maintained
through power and reset cycles. A fault is generated if the bias current is higher than IBFLT value set in this register.
Transmit Power Fault Threshold (TXFLT)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
8 = 08h
D[2]
read/write
D[1]
read/write
D[0]
read/write
A valid OEM password is required for access to this register. This register is non-volatile and will be maintained
through power and reset cycles. A fault is generated if the Transmit power is higher than TXFLT value set in this
register.
Loss-Of-Signal Threshold (LOSFLT)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
9 = 09h
D[2]
read/write
D[1]
read/write
D[0]
read/write
A valid OEM password is required for access to this register. This register is non-volatile and will be maintained
through power and reset cycles. A fault is generated if the received power is lower than LOSFLT value set in this
register.
Bit
D[7:0]
October 2004
Function
Operation
Receive loss-of-signal threshold
Read/write; non-volatile.
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Fault Suppression Timer (FLTTMR)
Fault suppression interval in increments of 0.5ms
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
10 = 0Ah
D[2]
read/write
D[1]
read/write
D[0]
read/write
Saturation faults are suppressed for a time, tFLTTMR, following laser turn-on. This avoids nuisance tripping while the
APC loop starts up. The length of this interval is (FLTTMR∞0.5ms), typical. A value of zero will result in no fault suppression. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles.
Fault Mask (FLTMSK)
D[7]
OEMIM
read/write
D[6]
POHE
read/write
D[5]
D[4]
reserved
reserved
D[3]
SATMSK
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
11 = 0Bh
D[2]
TXMSK
read/write
D[1]
IAMSK
read/write
D[0]
DFMSK
read/write
A valid OEM password is required for access to this register. This register is non-volatile and will be maintained
through power and reset cycles.
Bit
Function
Operation
D[7]
OEMIM
OEM interrupt mask bit
1 = masked; 0 = enabled; Read/write; non-volatile.
D[6]
POHE
OEM Power-on Hour Meter enable bit
1 = enabled; 0 = disabled; Read/write; non-volatile.
D[5:4]
D[5:4]
Reserved
Always write as zero; reads undefined.
D[3]
SATMSK
APC saturation fault mask bit
1 = masked; 0 = enabled; Read/write; non-volatile.
D[2]
TXMSK
High TX optical power fault mask bit
1 = masked; 0 = enabled; Read/write; non-volatile.
D[1]
IAMSK
Bias current high alarm mask bit
1 = masked; 0 = enabled; Read/write; non-volatile.
D[0]
DFMSK
Diode fault mask bit
1 = masked; 0 = enabled; Read/write; non-volatile.
OEM Password Setting (OEMPWSET)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
D[2]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
12 - 15 = 0Fh - 0Fh; 0Ch = MSB
D[1]
read/write
D[0]
read/write
This four-byte field is the password required for access to the OEM area of the MIC3000’s memory and registers. The
byte at address 250 (FAh) is the most significant byte. This field is compared to the four-byte OEMPW field at serial
address A2h, byte 120 to 123. If the two fields match, access is allowed to the OEM areas of the MIC3000 non-volatile
memory at serial addresses A4h and A6h. The OEM password may be set by writing the new value into OEMPWSET.
The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST
bit in OEMCFG0. This allows the new password to be verified before it takes effect. These registers are non-volatile
and will be maintained through power and reset cycles. A valid OEM password is required for access to this register.
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BYTE
Weight
3
OEM Password, Most Significant Byte
2
OEM Password, 2nd Most Significant Byte
1
OEM Password, 2nd Least Significant Byte
0
OEM Password, Least Significant Byte
OEM Calibration 0 (OEMCAL0)
D[7]
D[6]
FLTDIS
read/write
reserved
D[5]
FSPIN
read/write
D[4]
WRINH
read/write
D[3]
APCCAL
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
16 = 10h
D[2]
FRCINT
read/write
D[1]
FRCTXF
read/write
D[0]
FRCLOS
read/write
A valid OEM password is required for access to this register.
Bit
D[7]
Function
Operation
Reserved
Always write as zero; reads undefined.
D[6]
FLTDIS
Fault comparator disable; inhibits output of fault
comparators when set.
0 = faults enabled; 1 = disabled; Read/write.
D[5]
FSPIN
Fault comparator “spin-on-channel” mode select;
do not enable ADC and FC spin-on-channel
modes simultaneously.
0 = normal operation; 1 = spin on channel;
Read/write.
D[4]
WRINH
Inhibit NVRAM write cycles.
0 = normal operation; 1 = inhibit writes; Read/write.
D[3]
APCCAL
Selects APC calibration mode - DACs may be
controlled directly.
0 = normal mode; 1 = calibration mode; Read/write.
D[2]
FRCINT
Forces the assertion of /INT
0 = normal operation; 1 = asserted; Read/write.
D[1]
FRCTXF
Forces the assertion of TXFAULT
0 = normal operation; 1 = asserted; Read/write.
D[0]
FRCLOS
Forces the assertion of RXLOS
0 = normal operation; 1 = asserted; Read/write.
OEM Calibration 1 (OEMCAL1)
D[7]
reserved
D[6]
ADSTP
read/write
D[5]
ADIDL
read/write
D[4]
1SHOT
read/write
D[3]
ADSPIN
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
17 = 11h
D[2]
SPIN[2]
read/write
D[1]
SPIN[1]
read/write
D[0]
SPIN[0]
read/write
A valid OEM password is required for access to this register.
October 2004
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Bit
D[7]
Function
Operation
Reserved
Always write as zero; reads undefined.
D[6]
ADSTP
Stop ADC Halts the analog to digital converter
0 = normal operation; 1 = stopped; Read/write.
D[5]
ADIDL
ADC idle flag
0 = busy; 1 = idle; Read/write.
D[4]
1SHOT
Triggers one-shot A/D conversion cycle
0 = normal operation; 1 = one-shot; Read/write.
D[3]
ADSPIN
Selects ADC spin-on-channel mode; do not
enable ADC and FC spin-on-channel modes
simultaneously
0 = normal operation; 1 = spin-on-channel;
Read/write.
D[2], D[1],
D[0]
SPIN[2:0]
ADC and fault comparator (FC) channel select for ADC: 000 = temperature; 001 = voltage; 010 = VILD;
spin-on-channel mode; do not enable ADC and
011 = VMPD; 100 = VRX; FC: 001 = VILD;
FC spin-on-channel modes simultaneously
001 = VMPD; 010 = VRX; Read/write.
Look-Up Table Index (LUTINDX)
Look-up table index as determined by temperature compensation logic
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
18 = 12h
D[2]
read/write
D[1]
read/write
D[0]
read/write
The look-up table index is derived from the current temperature measurement and LUTOFF as follows:
(µ )⎞
⎛T
INDEX = ⎜ AVG
⎟ + LUTOFF
⎝
2 ⎠
where TAVG(n) is the current average temperature. This register allows the current table
index to be read by the host. The table base address must be added to LUTINDX to form a complete table index in
physical memory. A valid OEM password is required for access to this register. Otherwise, reads are undefined.
BIAS DAC Setting (APCDAC)
Current VBIAS setting
D[7]
read only
D[6]
read only
D[5]
read only
D[4]
read only
D[3]
read only
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
20 = 14h
D[2]
read only
D[1]
read only
D[0]
read only
This register reflects (reads back) the value set in the APC register (APCSET0, APCSET1, or APCSET2 whichever is
selected). A valid OEM password is required for access to this register.
Modulation DAC Setting (MODDAC)
Current VMOD setting
D[7]
read only
D[6]
read only
D[5]
read only
D[4]
read only
D[3]
read only
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
21 = 15h
D[2]
read only
D[1]
read only
D[0]
read only
This register reflects (reads back) the value set in the MODSET register. A valid OEM password is required for access
to this register.
M9999-101204
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October 2004
MIC3000
Micrel
OEM Readback Register (OEMRD)
D[7]
D[6]
D[5]
reserved
reserved
reserved
D[4]
INT
read only
D[3]
APCSAT
read only
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
22 = 16h
D[2]
IBFLT
read only
D[1]
TXFLT
read only
D[0]
RSOUT
read only
This register reflects (reads back) the status of the bits corresponding to the parameters defined below. A valid OEM
password is required for access to this register. Otherwise, reads are undefined and writes are ignored.
Bit
D[7:5]
Function
Operation
Reserved
Always write as zero; reads undefined.
Mirrors state of /INT but active-high; not state of
physical pin!
1 = interrupt; 0 = no interrupt.
D[4]
INT
D[3]
APCSAT
APC saturation fault comparator output state
1 = fault; 0 = normal operation.
D[2]
IBFLT
State of IBIAS over-current fault comparator
output
1 = fault; 0 = normal operation; read-only.
D[1]
TXFLT
State of transmit power fault comparator output
1 = fault; 0 = normal operation; read-only.
D[0]
RSOUT
State of the rate select output pin, RSOUT
1 = high; 0 = low; Read-only.
Power-On Hour Meter Data (POHDATA)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
32-39 = 20h - 27h
D[2]
read/write
D[1]
read/write
D[0]
read/write
These registers are used for backing up the POH result during power cycles. At power-up, the POH meter selects the
larger of the two values as the initial count. Incremental results are stored in alternate register pairs. The power-on
hour meter may be reset or preset by writing to these registers. These registers are non-volatile and will be maintained
through power and reset cycles. A valid OEM password is required for access to these registers.
BYTE
Weight
3
POHA, high-byte
2
POHA, low-byte
1
POHB, high-byte
0
POHB, low-byte
OEM Scratchpad Registers (SCRATCHn)
Default Value
0000 0000b = 00h
Serial Address
A6h = 1010011b
Byte Address
SCRATCH0:
126 = 7Eh
SCRATCH1:
127 = 7Fh
SCRATCH2:
128 = 80h
.......................................
SCRATCH127: 253 = FDh
The scratchpad registers are general-purpose non-volatile memory locations. They can be freely read from and written
to any time the MIC3000 is in OEM mode.
October 2004
59
M9999-101204
MIC3000
Micrel
Manufacturer ID Register (MFG_ID)
Identifies Micrel as the manufacturer of the device. Always returns 2Ah
D[7]
read only
D[6]
read only
D[5]
read only
D[4]
read only
D[3]
read only
D[2]
read only
D[1]
read only
D[0]
read only
0
0
1
0
1
0
1
0
Default Value
0010 1010b = 2Ah
Serial Address
A6h = 1010011b
Byte Address
254 = FEh
The value in this register, in combination with the DEV_ID register, serve to identify the MIC3000 and its revision
number to software. This register is read-only.
Bit(s)
Function
Operation
D[7:0]
Identifies Micrel as the manufacturer of the device.
Always returns 2Ah.
Read only. Always returns Ah
Device ID Register (DEV_ID)
D[7]
read only
D[6]
read only
D[5]
read only
D[4]
read only
D[3]
read only
MIC3000 DEVICE ID
always reads as zero “0” at D [4-7]
D[2]
read only
D[1]
read only
D[0]
read only
DIE REVISION
Default Value
0000 xxxxb = 0xh
Serial Address
A6h = 1010011b
Byte Address
255 = FFh
The value in this register, in combination with the MFG_ID register, serve to identify the MIC3000 and its revision
number to software. This register is read-only.
M9999-101204
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October 2004
MIC3000
Micrel
Applications Information
Controlling Laser Diode Bias
MIC3000
RFB
To ADC
VMPD
FB
VDD
VDDA
RBASE
VBIAS
APCDAC
From laser
driver
Q1
PNP
L1
LDA
IMOD
MDC
CCOMP
VDD
COMP
VILD+
To ADC
LDC/MDC
VILD–
L2
SHDN
Redundant
Switch
(optional)
RSENSE
Figure 25. Example APC Circuit for Common-Cathode TOSA
VDD
RSENSE
MIC3000
Redundant
Switch
(optional)
SHDN
L2
LDC/MDC
VILD–
To ADC
VILD+
VDD
VDDA
APCDAC
RBASE
VBIAS
CCOMP
L1
LDA
Q1
PNP
MDC
IMOD
To laser
driver
COMP
FB
RFB
To ADC
VMPD
Figure 26. Example APC Circuit for Common Anode TOSA
October 2004
61
M9999-101204
MIC3000
Micrel
Choosing CCOMP
The APC loop is compensated by a capacitor, CCOMP,
connected from COMP to either VDDA or GNDA. This
capacitor adjusts the slew rate and bandwidth of the loop as
follows:
SlewRate = dV / dt =
BW =
Application
ISLEW
where:
ISLEW = 64µA,
GM = 125µMho
these relationships are shown graphically in Figure 27 and
Figure 28.
70
SLEW RATE (mV/ s)
60
50
40
30
20
10
1 6 11 16 21 26 31 36 41 46 51
CCOMP (nF)
Figure 27. Slew Rate vs. CCOMP Value
2.50
BANDWIDTH (kHz)
10
SONET (62b/64b encoding), •1Gbps
22
•155Mbps, tON - 1ms
22
•155Mbps
100
While there is no theoretical upper limit on the size of CCOMP,
it is desirable for the loop to be able to track the changes
resulting from periodic temperature compensation. The typical temperature compensation update period is 1.6s. Therefore, a maximum size of 1µF is recommended. If laser turnon time is not a factor, a value between 100nF and 1µF can
be used for virtually any typical application. The tradeoff is
that higher value capacitors have a larger physical size and
cost.
In order to maximize the power supply rejection ratio (PSRR),
CCOMP should be returned to GNDA when the VBIAS output
is sourcing current, e.g., driving an NPN transistor
(SRCE bit = 1). CCOMP should be returned to VDDA when the
VBIAS output is sinking current, e.g., driving a PNP transistor
(SRCE bit =0).
Measuring Laser Bias Current
VILD+ and VILD– form a pair of pseudo-differential A/D
inputs for measuring laser diode bias current via a sense
resistor. The signal applied to these inputs is converted to a
single-ended, ground-referenced signal for input into the
ADC and bias current fault comparator. These inputs have
limited common-mode voltage range. The full-scale differential input range is VREF/4 or about 300mV.
Figure 25 and Figure 26 illustrate the typical implementation
of this function. Note that VILD– is always connected to the
circuit’s reference potential: VDD in the case of a commonanode transmitter optical sub-assembly (TOSA) and GND in
the case of a common-cathode TOSA. Note that the monitor
photodiode current will also flow in the sense resistor. This
will result in a small offset in the measured bias current. The
APC function will hold this term constant, so it can be
corrected for in the external calibration constants. The sensing resistor could also be connected between VDD and the
emitter of Q1 on Figure 25 or between the emitter of Q1 an
GND on Figure 26.
Interfacing To Laser Drivers
In order for the MIC3000 to control the modulation current of
the laser diode, an interface circuit may be required depending on the method used by the driver to set its modulation
current level. Generally, most laser diode driver ICs use one
of three methods:
a) A current, ISET, is sourced into a pin on the driver
IC. The modulation current delivered by the driver
is then some fixed multiple of ISET. The SY88912
is an example of this type of driver. A simple circuit
can be used to create a current source controlled
by the VMOD outputs. The circuit is based on an
external bipolar transistor and a current sensing
resistor.
2πCCOMP
2.00
1.50
1.00
0.50
0
10 20 30 40 50 60 70 80 90 100
CCOMP (nF)
Figure 28. Open Loop Unity-Gain Bandwidth
vs. CCOMP
The loop response should be tailored to the data rate,
encoding format and maximum run-lengths, and required
laser turn-on time. Higher data rates and/or shorter maximum
run lengths and/or faster turn-on times call for smaller capacitors. Lower data rates and/or longer maximum run lengths
and/or slower turn-on times call for larger capacitors. In order
to meet the SFP/GBIC turn-on requirement of 1ms, for
example, do not employ a capacitor larger than 20nF. Low
ESR capacitors such as ceramics will give the best results.
Excessive ESR will reduce the effectiveness of CCOMP. The
capacitor’s voltage rating must exceed VDDA. Some typical
values are shown in Table 20.
M9999-101204
8b/10b encoding, •1Gbps, tON - 1ms
Table 20. Typical Values for CCOMP
CCOMP
GM
0
CCOMP (nF)
62
October 2004
MIC3000
Micrel
b) A current, ISET, is drawn out of a pin on the driver
IC. The modulation current delivered by the driver
is then some fixed multiple of ISET. A simple circuit
can be used to create a current source controlled
by the VMOD outputs. The circuit is based on an
external bipolar transistor and a current sensing
resistor.
c) A voltage, VSET, is applied to a pin on the driver IC.
This voltage may be referenced to GND or VDD.
The MIC3000’s VMOD+ output can supply this
voltage directly. If a voltage swing wider than VREF
is needed, gain can be applied with a pair of
external resistors. The SY88932, SY88982, and
SY89307 are examples of this type of driver.
VDDA
SY88912
CFLTR
100nF
RSET
420
RFLTR
1k
MODDAC
Q1
2N3906
VMOD+
ISET
×23
RSET
IMOD
GND
GNDA
VMOD–
MODREF bit = 1
/EN
SHDN
Optional - see text
Notes:
1. Bypass capacitors not shown for clarity.
Figure 29. Controlling the SY88912
Modulation Current
SY88912 3.3V 3.2Gbps SONET/SDH Laser Driver
The modulation level of the SY88912 driver is controlled by
the current sourced into the RSET pin (Type (a) above). The
circuit shown in Figure 29 allows the MIC3000’s VMOD
outputs to control the SY88912’s modulation current from its
minimum value, 5mA, to its maximum value, 60mA. The
circuit operates as a DAC-controlled current source. The
current source is formed by the VMOD buffer amplifier, external transistor, and current sense resistor. The op-amp acts to
force the voltage drop across RSET to be equal to the DAC
output voltage.
The current, ISET, through RSET is therefore regulated as
ISET = VMOD+/RSET (In this case, the DAC output and
therefore the op-amp output, are referenced to VDDA.) The
SY88912’s current gain, IMOD/ISET, is 23. A modulation
current level of 60mA requires ISET = 60mA/23 = 2.61mA; a
modulation current level of 5mA requires ISET = 5mA/23 =
0.217mA. RFLTR and CFLTR are optional and act to eliminate
any noise that might be present on VDDA or VMOD. The values
shown give a 100µs time constant. Note that the time constant is present whenever the laser is turned on or turned off.
This must be taken into account when designing to system
specifications such as the SFP MSA’s tON and tOFF requirements. The values of RFLTR and/or CFLTR may need to be
adjusted accordingly. The impact of the filter time constant on
the turn off time can be eliminated by using the MIC3000’s
SHDN signal to drive the SY88912’s enable input, /EN.
The use of the SHDN signal is completely optional. The main
benefit to using SHDN, however, is that it shuts down the
driver very quickly and irrespective of the values of RFLTR and
CFLTR. The values of RFLTR and CFLTR can therefore be
increased, enhancing their effect without incurring any turnoff time penalty. Depending on the polarity chosen for SHDN
using the SPOL bit, an inversion may be required between
the MIC3000’s SHDN output and the driver’s /EN input. (The
SHDN output may also be used to drive a redundant safety
switch and the same polarity may not be appropriate for both
functions.)
October 2004
VDD(1)
MIC3000
For the circuit of Figure 29, the modulation current control
range and corresponding DAC values are shown in Table 21
below.
DAC VALUE
ISET
IMOD
0
VDDA – VMOD
0V
0mA
0mA
19
0.091V
0.216mA
4.98mA
127
0.61V
1.45mA
33.4mA
255
1.22V
2.91mA
66.8mA
Table 21. Control Range of SY88912
Modulation Control Circuit
SY88932 3.3V 3.2Gbps SONET/SDH Laser Driver
The modulation level of the SY88932 driver is controlled by
the voltage applied to the VCTRL pin (Type (c) above). The
circuit shown in Figure 30 allows the MIC3000’s VMOD output
to control the SY88932’s modulation current. The circuit
operates as a DAC-controlled voltage source. VCTRL is
simply the DAC output voltage. See section above on SY88912
for RFLTR, CFLTR and SHDN.
VDD(1)
MIC3000
SY88932
VDDA
VCC
IMOD
RFLTR
1k
MODDAC
VMOD+
VCTRL
CFLTR
100nF
GNDA
MODREF bit = 0
GND
VMOD–
SHDN
/EN
Optional - see text
Note:
1. Bypass capacitors not shown for clarity.
Figure 30. Controlling the SY88932
Modulation Current
63
M9999-101204
MIC3000
Micrel
SY89307 5.0V/ 3.3V 2.5Gbps VCSEL Driver
The modulation level of the SY89307 driver is controlled by
the voltage applied to the VCTRL pin (Type (c) above). The
circuit shown in Figure 31 allows the MIC3000’s VMOD output
to control the SY89307’s output swing. VCTRL is simply the
DAC output voltage. The circuit operates as a DAC-controlled voltage source. See section above on SY88912 for
RFLTR, CFLTR.
VDD(1)
MIC3000
MODREF bit = 1
MODDAC
MODREF bit = 1
GNDA
VEE
×23
IMOD
GND
VMOD–
SHDN
VCTRL
ISET
RSET
GNDA
/EN
Optional - see text
Notes:
1. Bypass capacitors not shown for clarity
Figure 32. Controlling the Modulation Current
via a Sink Current
Drivers With Monitor Outputs
Laser diode driver ICs have been introduced with monitor
outputs. These outputs provide ground-referred signals that
mirror critical signals like laser bias current, modulation
current or monitor photodiode current, an analog of transmitted power. Generally, these outputs source a current into an
external resistor to generate a ground referenced voltage.
Using these outputs with the MIC3000 is straightforward
since the MIC3000’s VILD+/– and VMPD inputs are polarity
programmable,
Shutdown Output
The shutdown output, SHDN, can be used in two ways: as an
enable or on/off control for the laser driver IC, and/or to control
a redundant switch in the laser current path. The redundant
switch provides a means for the MIC3000 to shut off the laser
current even if the bias transistor or modulator is damaged or
fails. SHDN is active any time the MIC3000 shuts down the
laser, i.e., if the TXDISABLE function is asserted in hardware
or software, or if the fault detection circuits trigger laser
shutdown. The shutdown output, SHDN, is essentially a logic
output with programmable polarity. The programmable polarity allows SHDN to drive either high-side or low-side switches
or active-high or active-low enable inputs without the need for
external inversion circuits. If an active-low and an active-high
shutdown signal are required, an external inverter will be
necessary. Examples of redundant switch circuits are shown
in Figure 33.
VMOD–
Note:
1. Bypass capacitors not shown for clarity.
Figure 31. Controlling the SY89307
Modulation Current
Laser Drivers Programmed via a Sink Current
The modulation level of some laser diode drivers is controlled
by a current sourced out of the RSET pin (Type (b) above).
The circuit shown in Figure 32 allows the MIC3000’s VMOD
outputs to control the set current, ISET. The circuit operates as
a DAC-controlled current sink. The current sink is formed by
the VMOD buffer amplifier, external transistor, and current
sense resistor. The op-amp acts to force the voltage drop
across RSET to be equal to the DAC output voltage.
The current through R SET is therefore regulated as
IRSET = VMOD+/RSET. ISET is given by the equation:
(8)
where β is the DC gain of Q1
The higher the gain of the transistor, the closer ISET will be to
the current in RSET. RFLTR and CFLTR act to eliminate any
noise that might be present on VDDA or VMOD. The values
shown give a 100µs time constant. See section above on
SY88912 for RFLTR, CFLTR and SHDN.
M9999-101204
RSET
Q1
2N3906
CFLTR
100nF
CFLTR
100nF
VMOD+
⎛ VMOD + ⎞ ⎛ β ⎞
ISET = ⎜
⎟⎜
⎟
⎝ R SET ⎠ ⎝ 1+ β ⎠
VDD
RFLTR
1k
VMOD+
VCC
RFLTR
1k
LD Driver
VDDA
SY89307
VDDA
MODDAC
VDD(1)
MIC3000
64
October 2004
MIC3000
Micrel
High-Side
VDD
RPULLUP
SHDN
RPULLUP
RBASE
Q1
PNP
Q1
P-FET
SHDN
ILD
ILD
Low-Side
ILD
SHDN
Remote Sensing
For remote temperature sensing using the XPN pin, most
small-signal PNP transistors with characteristics similar to
the JEDEC 2N3906 will perform well as thermal diodes. Table
22 lists several examples of such parts that Micrel has tested
for use with the MIC3000. Other transistors equivalent to
these should also work well.
VDD
RBASE
Q1
NPN
ILD
Q1
N-FET
SHDN
RPULLDOWN
RPULLUP
GND
Vendor
Part Number
Package
Fairchild Semiconductor
MMBT3906
SOT-23
On Semiconductor
MMBT3906L
SOT-23
Infineon Technologies
SMBT3906/MMBT3906
SOT-23
Samsung Semiconductor
KST3906-TF
SOT-23
Table 22. Transistors Suitable for
Use as Remote Diodes
GND
Figure 33. Redundant Switch Circuits
Minimizing Errors
Temperature Sensing
The MIC3000 can measure and report its own internal
temperature or the temperature of a remote PN junction or
“thermal diode”. In either case it is important to note that any
board-mounted semiconductor device tends to track the
ground plane temperature around it. The dominant thermal
path to the sensor is often the ground pin. The ground pin
usually connects to the leadframe paddle on which the die is
mounted. Typical semiconductor packages, being non-conductive plastic, insulate the device from the ambient air.
The advantage to using a remote sensor is that the temperature may be sensed at a specific location, such as in the
proximity of the laser diode, or away from any heat sources
where it will more closely track the transceiver’s case temperature. The measured temperature is reported via the
digital diagnostics registers and is used to index the temperature compensation tables. (Note: SFF-8472 does not specify
the meaning of the reported temperature information or the
location from which it is taken. This information is to be
specified in the transceiver vendor’s datasheet.)
Self-Heating
One concern when measuring temperature is to avoid errors
induced by self-heating. Self-heating is caused by power
dissipation within the MIC3000. It is directly proportional to
the internal power dissipation and the junction-to-ambient
thermal resistance, θJA. The dissipation in the MIC3000 must
be calculated and reduced to a temperature offset. The power
dissipation, PDISS, includes the effect of quiescent current
and all currents flowing into or out of any signal pins, especially VBIAS and VMOD. The temperature rise caused by selfheating is given by:
(9)
∆t = PDISS × θ JA
θJA is given in the “Operating Ratings” section above as
43°C/W. The possible contributors to self-heating are listed in
Table 23.
The numbers given in Table 23 suggest that the power
dissipation in a typical application will be no more than a few
tens of milliwatts, leading to self-heating on the order of 1°C.
Description
Magnitude
Notes
Quiescent power
IDD ∞ VDD
Typically VDD = 3.3V, IDD = 2.7mA ∅ 3.3V ∞ 2.7mA = 8.91mW.
SHDN current
IOL ∞ VOL
Negligible if MOSFET is used as shutdown device.
TXFAULT current
IOL ∞ VOL
Worst case is VDD2/RPULLUP; RPULLUP is 4.7ký min. per SFP
MSA ∅ 3.3V2/4.7ký = 2.32mW.
VBIAS current
VBIAS ∞ IVBIAS or (VDD–VBIAS) ∞ IVBIAS
Worst-case is VREF ∞ 10mA = 1.22V ∞ 10mA = 12.3mW.
VMOD current
VMOD ∞ IVMOD or (VDD–VMOD) ∞ IVMOD
Worst-case is VREF ∞ 10mA = 1.22V ∞ 10mA = 12.3mW.
RSOUT current
IOL ∞ VOL
Only for rate-agile applications using RSIN/RSOUT.
DATA current
IOL ∞ VOL ∞ duty_cycle
May be negligible; Depends on bus speed, pullup current,
and bus activity.
RXLOS current
IOL ∞ VOL
Worst case is VDD2/RPULLUP; RPULLUP is 4.7Ký min. per
SFP MSA ∅ 3.3V2/4.7ký = 2.32mW.
Table 23. Contributors to Self-Heating
October 2004
65
M9999-101204
MIC3000
Micrel
In any application, the best and often easiest approach is to
measure performance in the final application environment.
This is especially true when dealing with systems for which
some temperature data may be poorly defined or unobtainable except by empirical means. If desired, the external
calibration constants may be used to correct the temperature
readings.
Series Resistance with External Temperature Sensor
The operation of the MIC3000 depends upon sensing the
VCB-E of a diode-connected PNP transistor (“diode”) at two
different current levels. For remote temperature measurements, this is done using an external diode connected between XPN and ground. Since this technique relies upon
measuring the relatively small voltage difference resulting
from two levels of current through the external diode, any
resistance in series with the external diode will cause an error
in the temperature reading from the MIC3000. A good rule of
thumb is this: for each ohm in series with the external
transistor, there will be a 0.9°C error in the MIC3000’s
temperature measurement. It is not difficult to keep the series
resistance well below an ohm (typically <0.1), so this will
rarely be an issue.
XPN Filter Capacitor Selection
It is desirable to employ a filter capacitor between XPN and
GNDA. The use of this capacitor is especially recommended
in environments with a lot of high frequency noise (such as
digital switching noise), or if long wires are used to connect to
the remote diode. The maximum recommended total capacitance from the XPN pin-to-GND is 2000pF. The recommended typical capacitor is a 1000pF NP0 or C0G ceramic
capacitor with a 10% tolerance. If the remote diode is to be at
a distance of more than 6" to 12" from the MIC3000, using
twisted pair wiring or shielded microphone cable for the
connections to the diode can significantly reduce noise
pickup. If using a long run of shielded cable, remember to
subtract the cable’s conductor-to-shield capacitance from
the 2000pF maximum total capacitance.
XPN Layout Considerations
The following guidelines should be kept in mind when designing and laying out circuits using the MIC3000 and a remote
thermal diode:
1. Place the MIC3000 as close to the remote diode as
possible, while taking care to avoid severe noise
sources such as high speed data busses, and the
like.
2. Since any conductance from the various voltages
on the PC board and the XPN line can induce
errors, it is good practice to guard the remote
diode’s emitter trace with a pair of ground traces.
These ground traces should be returned to the
MIC3000’s own ground pin. They should not be
grounded at any other part of their run. However,
it is highly desirable to use these guard traces to
carry the diode ‘s own ground return back to the
ground pin of the MIC3000, thereby providing a
Kelvin connection for the base of the diode.
M9999-101204
3. When using the MIC3000 to sense the temperature of a processor or other device which has an
integral thermal diode, connect the emitter and
base of the remote sensor to the MIC3000 using
the guard traces and Kelvin return, shown in Figure
34. The collector of the remote diode is typically
inaccessible to the user on these devices.
4. Due to the small currents involved in the measurement of the remote diode’s ∆VBE, it is important to
adequately clean the PC board after soldering to
prevent current leakage. This phenomenon will
most likely show up as an issue in situations where
water-soluble soldering fluxes are used.
5. In general, wider traces for the ground and T1 lines
will help reduce susceptibility to radiated noise
(wider traces are less inductive). Use trace widths
and spacing of 10 mils wherever possible and
provide a ground plane under the MIC3000 and
under the connections from the MIC3000 to the
remote diode. This will help guard against stray
noise pickup.
MIC3000
GNDA
XPN
GUARD/RETURN
REMOTE DIODE (XPN)
GUARD/RETURN
Figure 34. Guard Traces and Kelvin Return
for Remote Thermal Diode
Layout Considerations
Small Form-Factor Pluggable (SFP) Transceivers
The pinout of the MIC3000 digital control and status signals
was optimized for use in small form-factor pluggable (SFP
MSP) optical transceivers. If the MIC3000 is mounted on the
bottom of the PC board with the correct rotation, the control
and status I/O can be routed to the host connector without
changing the order. This is shown in Figure 35 below.
VCCR
1
24 23 22 21 20 19
18
2
3
TOP VIEW
VCCR
17
LOS
16
RATESEL
15
MOD-DEF (0)
5
14
CLOCK
6
13
4
7
8
9 10 11 12
DATA
TXDISABLE
TXFAULT
VCCT
Figure 35. Typical SFP Control and Status I/O
Signal Routing (not to scale)
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October 2004
MIC3000
Micrel
Using The MIC3000 In a 5V System
It is fairly straightforward to use the MIC3000 in a system
powered from a 5V rail. In these systems, the laser diode
driver IC will usually be powered from the 5V rail. A small
linear regulator, such as Micrel’s MIC5213, can be used to
generate a 3.3V power supply rail if one does not otherwise
exist in the system. All of the MIC3000’s digital I/O’s except
for RSOUT are 5V tolerant and may be pulled up to 5.5V
regardless of the MIC3000’s supply voltage. They can be
connected directly to a 5V host. The MIC5213 is ideal, as it is
capable of supplying up to 80mA, is in a tiny SC-70 package,
and is stable with small ceramic output capacitors.
The laser diode driver interface will be unchanged in most
cases. Ground referred voltages and currents can be generated the same way as with 3.3V-powerd drivers. The exception is drivers that are controlled by a voltage referenced to
VDD such as the SY89307. The MIC3000’s VBIAS or VMOD
output will be referenced to its own 3.3V power supply
whereas the driver’s input will be referenced to its 5V power
supply. The solution is a simple level-shifting circuit that
converts the VBIAS/VMOD output into a current and then into
a VDD-referenced voltage.
Power Supplies
The MIC3000 has separate power supply and ground pins for
both the analog and digital supplies. This helps prevent digital
switching noise from corrupting the analog functions. The
individual supply and ground pins are not isolated from one
another inside the IC. Separate analog and digital power and
ground planes are NOT required on the PCB. Having one of
each plane (power and ground) is certainly good practice,
however. If dedicated power and ground layers are not
available, care should be taken to route the digital supply and
return currents back to the supply separate from the analog
supply connections. A schematic of this approach is shown in
Figure 36. Each supply should be bypassed as close to the
IC as possible with 0.01µF capacitor (Low ESR capacitors
such as ceramics are preferred.) as shown. This assumes
that bulk capacitance is already present upstream. If no other
filter capacitance is present nearby, a 1µF filter capacitor
should be added in parallel to the 0.01µF capacitor.
HOST P/S (+)
Power Plane
VDDD
(1)
C1
1.0µF
C2
0.01µF
VDDA
MIC3000
GNDD
(1)
C3
0.01µF
C4
1.0µF
GNDA
Ground Plane
HOST P/S (–)
Figure 36. Power Supply Routing and Bypassing
October 2004
67
M9999-101204
MIC3000
Micrel
Package Information
24-Pin MLF® (ML)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
M9999-101204
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October 2004