M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
Applications
Features
•
•
•
•
• High speed operation; suitable for SFP/SFF applications from
155Mbps to 2.0 Gbps. Typical rise/fall times < 110 ps.
• Supports Common Anode VCSEL, Common Cathode VCSEL, or FP
LASER. May be used with or without a monitor photodiode.
• Programmable temperature compensation. Modulation output and
bias output can be controlled using a few discrete resistors.
• Supports DDMI (SFF-8472) diagnostics.
• DC or AC coupled modulation drive.
• Peaking circuit to optimize VCSEL response.
• Low overshoot allows high extinction ratio with low jitter.
• Supports E-PON burst mode with no extra components
• Automatic Laser Power Control, with “Slow-Start”.
• 3.3V or 5V operation
EPON FTTH modules
Gigabit Ethernet modules
1G/2G Fibre Channel modules
Digital Video
The M02094 is a highly integrated, programmable VCSEL driver intended for SFP/SFF modules to 2.0 Gbps. Using
differential PECL data inputs, the M02094 supplies the bias and modulation current required to drive a VCSEL or
edge-emitting laser. The modulation output can be AC or DC-coupled to a FP laser diode or AC coupled to a common anode or common cathode VCSEL.
Peaking adjustment is available to improve VCSEL fall time.
EPON burst mode operation is supported with no extra components.
Integrated safety circuitry detects faults and provides latched bias and modulation current shutdown.
Internal
3.3V reg.
PEAKAD J
GND
C C3
V
VC C
Functional Block Diagram
SV
Internal Power Bus
CC
and
IBOUT_CC
OUT-
DIN +
Input
Buffer
D IN-
Output
Buffer
Laser
Driver
OUT+
GND0
VCC3 -1.3V
IB OUT_CA
and
SGND
IPIN
APC
CCSEL
C
DISDLY
TxPwr MON
BIASMON
SET
APC
SET
Automatic Power Control
(laser bias current)
MOD MON
MOD
TCSLOPE
Modulation
Control
VCC3SEL
FAIL
DIS
RESET
Safety
Circuitry with
Latched Fault
TX
Disable
1
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
Ordering Information
Part Number
Package
Operating Temperature
M02094-12 *
QFN24
M02094-EVM
Combination Electrical and Optical Evaluation board
* The letter “G” designator after the part number indicates that the device is RoHS-compliant.
Revision History
Revision
Level
Date
Description
V5
Release
May 2015
Updated logos and page layout. No content changes.
F (V4)
Release
July 2008
-12 part.
E (V3)
Release
February 2006
D (V2)
Release
September 2005
C (V1)
Release
March 2005
Released. New datasheet format. Changes to Absolute Maximum Ratings, Operating Temperature, AC and
DC specifications. New section on video operation.
B
Preliminary
March 2004
Preliminary release.
A
Advance
October 2003
Custom part.
Corrected error in Pin 6 description in Table 2-1.
Advance.
2
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
24
VCC
CCSEL
CAPC
VCC3
PEAKADJ
MODSET
Pin Configuration
TCSLOPE
Typical Electrical Eye Diagram, Common Anode Mode
Rev V5
19
1
18
SVCC/
IBOUTCC
OUT-
DIN+
OUT+
DIN\
VCC3SEL
GND0
GND, connect to
PCB ground
IBOUTCA/
SGND
DIS
6
13
IPIN
APCSET
TXPWRMON
BIASMON
12
MODMON
7
DISDLY
FAIL
RESET
Typical Electrical Eye Diagram,
Common Cathode Mode with Peaking
4 X 4 mm
3
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
1.0 Product Specification
1.1
Absolute Maximum Ratings
These are the absolute maximum ratings at or beyond which the IC can be expected to fail or be damaged. Reliable operation at these extremes for any length of time is not implied.
Table 1-1.
Absolute Maximum Ratings
Symbol
Parameter
Rating
Units
VCC
Power supply voltage
-0.4 to +6.0
V
VCC3
3.3V power supply voltage
-0.4 to +4.0
V
TSTG
Storage temperature
-65 to +150
°C
IBIASOUTCA (MAX)
Maximum bias output current for common anode laser
75
mA
IBIASOUTCC (MAX)
Maximum bias output current for common cathode laser
30
mA
IMODCA (MAX)
Maximum modulation current for common anode laser
70
mA
IMODCC (MAX)
Maximum modulation current for common cathode laser
30
mA
DIN+/-
Data inputs
-0.4 to VCC3 + 0.4
V
DIS
Disable input
-0.4 to VCC + 0.4
V
BIASMON, MODMON
Bias and modulation output current mirror compliance
voltage
-0.4 to VCC3 + 0.4
V
IPIN
Photodiode anode voltage
-0.4 to VCC3 + 0.4
V
IPIN
Sink or Source Current
2.0
mA
FAIL
Status flag
-0.4 to VCC + 0.4
V
APCSET, MODSET
Set inputs
-0.4 to VCC3 + 0.4
V
TCSLOPE
Temperature compensation slope
-0.4 to VCC3 + 0.4
V
OUT+, OUT-
Output
-0.4 to VCC3 + 0.4
V
4
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
1.2
Rev V5
Recommended Operating Conditions
Table 1-2.
Recommended Operating Conditions
Parameter
Power supply (VCC-GND)
Rating
Units
3.3 ± 7.5%
or 5.0 + 10%,-5%
V
-40 to + 95
°C
Operating ambient
1.3
DC Characteristics
(VCC = +3.05V to +3.55V or 4.75V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted.
Table 1-3.
Symbol
ICC
DC Characteristics
Parameter
Conditions
Supply current excluding IMOD PEAKADJ high (no peaking adjust)
and IBIAS
Min.
Typ.
Max.
Units
–
mA
Common anode operation(1)
–
28
48
Common cathode operation(1)
-
35
55
Additional current when PEAKADJ is used.
-
2
15
Additional current when operating from a 5V
supply(2)
IBOUTCA
Bias current adjust range, V(IBIASOUT) > 0.7V
common anode mode
1
50
mA
IBOUTCC
Bias current adjust range, V(IBIASOUT) < 2.5V
common cathode mode
0.5
15
mA
IBOFF
Bias current with optical output DIS = high
disabled
V(IBOUTCA) = VCC3 for common anode
operation.
–
–
150
µA
–
45.7
–
A/A
V(IBOUTCC) = 0V for common cathode
operation.
Ratio of IBIAS current to CCSEL low, common anode mode
BIASMON current
CCSEL high, common cathode mode
13.5
5
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 1-3.
DC Characteristics
Symbol
Parameter
VMD
IMD
Conditions
Min.
Typ.
Max.
Units
Monitor diode reverse bias
voltage
1.5
–
–
V
Monitor
diode
adjustment range
10
–
1500
µA
current Adjusted with RAPCSET
Ratio of TxPwrMON current to
monitor photodiode current
CMD_MAX
Rev V5
1
Maximum monitor photodiode
capacitance for APC loop
stability. Includes all associated
parasitic capacitances.
A/A
100
pF
TTL/CMOS input high voltage
(DIS)
2.0
–
5.5
V
TTL/CMOS input low voltage
(DIS)
–
–
0.8
V
CMOS input
(VCC3SEL)
high
voltage
2.4
V
CMOS input
(VCC3SEL)
low
voltage
1.2
V
Logic output high voltage (FAIL) With external 10kΩ pull-up to VCC.
Logic output low voltage (FAIL) For 6.8k to 10k ohm resistor when pulled up to
5V
VCC - 0.6
–
–
V
–
–
0.4
V
--
6800
–
Ω
--
VCC3 - 1.3
--
V
VCC3-1.45
–
VCC3-[VIN(Diff)]/4
V
200
–
2400
mVpp
For 4.7k to 10k ohm resistor when pulled up to
3.3V
RIN
Differential input impedance
VSELF
Self-biased
input voltage
VINCM
Common-mode
compliance voltage
VIN(DIFF)
Data inputs
common-mode
input Data inputs
Differential input voltage
= 2 x (DIN+HIGH - DIN+LOW)
(3)
3.3V supply detection, lower
threshold
2.5
2.8
2.95
V
VCC3THH(3)
3.3V supply detection, upper
threshold
3.65
3.8
4.1
V
VCC5THL
5V supply detection, lower
threshold
3.9
4.25
4.65
V
VCC5THH
5V supply detection, upper
threshold
5.45
5.8
6.2
V
VREF1
Reference voltage for MODSET
1.18
1.3
1.4
V
VAPCSET
Reference voltage for APCSET
VCC3THL
1.35
6
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V
M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 1-3.
Rev V5
DC Characteristics
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
VBL
Bias_OK
threshold
lower
voltage
0.88
1.0
1.05
V
VBH
Bias_OK
threshold
upper
voltage
1.45
1.6
1.7
V
300
400
mV
VFAULTL(4)
Lower voltage threshold for FAIL asserts if any of these signals fall below this
fault inputs IBOUTCA, OUT+, value.
CAPC, and MODSET
VFAULTH(5)
Upper voltage threshold for FAIL asserts if any of these signals fall above this
fault inputs IBOUTCC
value.
2.6
2.9
VCC3 - 0.2
V
VSELFL
Self bias voltage for IBOUTCA During disable state
and OUT+
0.5
1.65
2.0
V
VSELFH
Self bias voltage for IBOUTCC
0
1.25
V
During disable state
Notes:
1. Excludes bias and modulation currents.
2. Bias and modulation currents add directly to power supply current in 5V applications. The additional supply current noted excludes these currents.
3. VCC3 “supply OK” circuitry monitors the internally regulated 3.3V supply when VCC = 5V (VCC3SEL =low). When VCC = 3.3V, VCC3 “supply OK” circuitry
monitors VCC (VCC3SEL =high).
4. A low level at IBOUTCA does not trigger a fault condition during common cathode operation.
5. A low level at IBOUTCC does not trigger a fault condition during common anode operation.
7
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
1.4
Rev V5
AC Characteristics
(VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted.
Table 1-4.
AC Characteristics
Symbol
IMOD
Parameter
Modulation current adjust range
Conditions
Common Cathode Mode
Min.
Typ.
Max.
Units.
1
–
15
mA
OUT+ and OUT- AC coupled into 50Ω load.
3
Common Anode Mode
45
OUT+ and OUT- DC coupled into 25Ω load.(1)
IMOD(OFF)(2)
Modulation current with output disabled
DIS = high
Ratio of modulation current to MODMON CCSEL = high, RLOAD = 50Ω
current
–
–
150
µA
–
30
–
A/A
104
ppm/°C
CCSEL = low
IMOD-TC
TTCSTART
Programmable range for modulation Adjustable using TCSLOPE
current temperature coefficient
20
20% to 80% into 25 Ω(3). For IMOD from 3 mA to 30
mA. Measured using 11110000 pattern at 2.5 Gbps
°C
110
140
ps
Modulation output fall time
–
110
140
ps
Overshoot of modulation output current in into 25 Ω load
the “off” direction
--
1
2
%
–
1.2
–
psrms
20
45
20
45
tf
DJ
–
–
Modulation output rise time
RJ
0
Temperature at which modulation current
TC compensation enables
tr
OSOFF
65
Random jitter
Deterministic jitter
Measured into 25Ω load, 2
Gbps
31
- 1 PRBS at 2.0
K28.5 pattern at 2.0 Gbps
pspp
(includes pulse width distortion)
Notes:
1. Minimum voltage at OUT+ > 0.7V.
2. The current through the laser in this state can be made negligible by adding a 1kΩ or less resistor in parallel with the laser.
3. The M02094 is designed to drive 25Ω loads. External resistance should be added in series or parallel to the Laser to create this load impedance. In common
cathode mode, 50Ω resistors internal to the M02094 are in parallel with the laser.
8
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
1.5
Rev V5
Safety Logic Timing
(VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted.
Table 1-5.
Safety Logic Timing
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units.
t_off
DIS assert time
Rising edge of DIS to fall of output signal below
10% of nominal(1)
10
μs
t_on
DIS negate time
Falling edge of DIS to rise of output signal above
90% of nominal(1)
1
ms
t_init
Time to initialize(2)
Includes reset of FAIL; from power on after
Supply_OK or from negation of DIS during reset of
FAIL condition
5
ms
t_fault
Laser fault time - from fault condition to From occurrence of fault condition or when
assertion of FAIL
Supply_OK is beyond specified range
100
μs
t_reset
DIS time to start reset
10(3)
μs
t_onBM
DIS negate (turn-on) time during burst- Using integrated switch at SVCC (3.3V operation)
(4)
mode operation
300
500
ns
t_offBM
DIS assert (turn-off) time during burst- Using integrated
mode operation
operation)(4)
200
500
ns
2
3
DIS or ENA pulse width required to initialize safety
circuitry or reset a latched fault
switch
at
SVCC
(3.3V
Notes:
1. With CAPC = 2.2nF
2. User-adjustable. Specifications reflect timing with no external RESET capacitor.
3. With < 1nF capacitor from RESET pin to ground.
4. Imod > 12mA
9
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Figure 1-1.
Rev V5
Safety Logic Timing Characteristics
Slow Rise on Vcc=3.3V at Power-up (DIS Low)
Hot Plug (DIS Low)
3.3V
VCC3
and
VCC5
status
V CC3 and VCC5
“OK”
VCC
3.3V
VCC3
(low)
FAIL
FAIL state at power-up will
depend on pull-up voltage
FAIL
(low)
DIS
(low)
(low)
DIS
t_on < 1ms,
(300 us typ.)
LASER
OUTPUT
t_on < 1ms,
(300 us typ.)
LASER
OUTPUT
10
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Slow Rise on Vcc=5V at Power-up (DIS Low)
5V
V CC
3.3V
Rev V5
Transmitter Enable (DIS transition Low)
VCC3
and
VCC5
status
(high)
FAIL
(low)
DIS
(low)
VCC3 and VCC5
“OK”
VCC3
FAIL
DIS
(low)
t_on < 1ms,
(300 us typ.)
LASER
OUTPUT
t_on < 1ms,
(300 us typ.)
(low)
LASER
OUTPUT
11
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Transmitter Disable (DIS transition high)
(high)
VCC3
and
VCC5
status
VCC3 and VCC5
“OK”
Fault Recovery Behaviour
Fault
recovery at:
MODSET.
C APC, OUT+,
IBOUT CA or
IBOUT CC
(low)
FAIL
DIS
LASER
OUTPUT
Response to Fault
FAIL remains high
until reset by DIS
going high
t_reset,
10 us,
min.
t_on < 1ms
LASER
OUTPUT
Unsuccessful Fault Reset Attempt
Fault at:
MODSET.
CAPC, OUTP,
IBOUT CC or
IBOUT CA
FAIL
Fault
Removed
FAIL
DIS
t_off < 10 us,
(1 us typ.)
Rev V5
Fault Occurs
Fault Remains
Fault at:
APC SET
t_fault < 100 us,
(4 us typ.)
DIS
LASER
OUTPUT
t_init < 5ms,
(3 ms typ.)
FAIL
DIS
t_reset,
10 us,
min.
LASER
OUTPUT
12
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Figure 1-2.
Rev V5
Relationship Between Data Inputs and Modulation Outputs
DIN+
100 mV 1200 mV
DIN-
200 mV 2400 mV
VIN(DIFF)
VOUT-
VOUT+
> 0.7V
GND
13
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
2.0 Pin Description
2.1
Pin Definitions
Table 2-1.
Pin Definitions
Pin Number
Pin Name
1
VCC
Pin equivalent load
Function
Power supply, 5V or 3.3V.
VCC
VCC3
Positive data input. Self biased. Compatible with AC coupled PECL, AC coupled CML,
and DC-coupled PECL (when VCC = 3.3V).
When DIN+ is high, OUT+ will sink current.
VCC3-1.3V
D +, D IN
2
DIN+
3
DIN-
4 kΩ
IN
See DIN+ drawing
Negative data input. Self biased Compatible with AC coupled PECL, AC coupled CML,
and DC-coupled PECL (when VCC = 3.3V).
14
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
VCC
VCC3
Function
3.3V VCC Select.
Connect to VCC for VCC = 3.3V operation.
Connect to GND for VCC = 5V operation.
4
VCC3SEL
VCC3 SEL
190 Ω
72 kΩ
Bias and modulation output disable (TTL/CMOS).
VCC
VCC3
When high or left floating, the bias and modulation outputs are disabled. Set low for
normal operation.
7 kΩ
5
DIS
DIS
80 k Ω
15
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
Function
Safety circuit fault output (TTL/CMOS). Goes high when a safety logic fault is detected.
This output will be low when DIS is high.
VCC
Requires an external pull-up.
FAIL
6
FAIL
VCC3
V
CC
Safety circuit reset. Leave open for normal operation or add a capacitor to ground to
extend the reset time.
Connect to GND to disable window comparators at APCSET
7
RESET
RESET
190 Ω
16
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
Function
Disable delay control. Connect to ground for normal operation.
VCC
8
DISDLY
In burst mode operation add a capacitor from this pin to ground to set the maximum
disable time. Disable times greater than this maximum will engage the “slow-start”
circuitry.
DISDLY
190 Ω
V CC
Modulation Current Monitor. Connect to a resistor to GND.
VCC3
The current through this pin is typically 1/50th of the MODULATION current to the laser
when CCSEL is low or 1/25th the MODULATION current when CCSEL is high.
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by 0.5mA typically.
MOD MON
9
MODMON
190 Ω
Bias Current Monitor. Connect to a resistor to GND.
The current through this pin is typically:
10
BIASMON
See MODMON drawing
1/45.7th of the BIAS current to the laser when CCSEL is low
1/13.5th of the BIAS current to the laser when CCSEL is high
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by 0.5mA typically.
17
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
VCC
Function
Transmit Power Monitor. Connect to a resistor to GND.
VCC3
The current through this pin is approximately the same as the photodiode current into
IPIN. The current out of this pin is low pass filtered (no external filtering required).
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by the IPIN current.
TxPwr MON
11
TxPwrMON
33 Ω
V CC
VCC3
Average Power Control, laser bias current adjustment. Connect to a resistor between
this pin and ground to set the bias current to the laser.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V. The current sourced from this pin is approximately the same as the
current into IPIN.
12
APCSET
APCSET
V
CC
VCC3
For CCSEL low - Current input from monitor photodiode anode.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V and at this pin of approximately one VGS.
For CCSEL high - Current source for monitor photodiode cathode.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V and at this pin of approximately one VGS below VCC3.
IPIN
13
IPIN
33 Ω
18
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
V CC
Function
Laser bias current output for common anode lasers (CCSEL must be low).
Connect directly to laser cathode or at higher bit rates through a ferrite or a resistor to
isolate the capacitance of this pin from the modulation drive, (~ 6pF).
Maintain a voltage at least 0.7V above GND at this pin
IBOUTCA
(CCSEL = low)
IBOUTCA
14
VCC
SGND (CCSEL
= high)
GNDO
Provides redundant shutdown during a disable or fault condition. This switch is disabled
during common anode operation.
SGND
V
15
Switched ground connection for common cathode lasers (CCSEL must be high).
CC
Ground for output stage. May be connected directly to circuit board ground. At high bit
rates (>2Gb/s) an optional inductor or ferrite may be added to reduce switching
transients.
GND0
19
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
Function
Positive modulation current output (AC or DC coupled to cathode of laser in common
anode designs). Sinks current when DIN+ is HIGH.
V
CC
Maintain a voltage > 0.7V at this pin.
16
OUT+
OUT+
GND 0
17
OUT-
See OUT+ drawing
Negative modulation current output (AC coupled to anode of laser in common cathode
designs). Sinks current when DIN- is HIGH
Maintain a voltage > 0.7V at this pin.
VCC
VCC3
Switched VCC. Supplies laser current for common anode designs. (CCSEL must be
LOW).
Provides redundant shutdown during a disable or fault condition. This switch is disabled
during common cathode operation.
SVCC (CCSEL =
low)
SV CC
18
VCC
Laser bias current output for common cathode laser designs (CCSEL must be high).
V
Connect directly to laser anode or at higher bit rates through a ferrite or a resistor to
isolate the capacitance of this pin from the modulation drive.
CC3
Maintain a voltage of < 2.5V at this pin.
IBOUTCC
(CCSEL = high)
IBOUT
CC
12 kΩ
20
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
Function
Laser select input.
V
V CC3
CC
When high, common cathode operation is selected; IBOUTCC and SGND are functional
and internal 50Ω output terminations are switched in at the modulation outputs OUT+
and OUT-.
When low or floating, common anode operation is selected; IBOUTCA and SVCC are
functional and the 50Ω internal termination resistors at OUT+ and OUT- are
disconnected.
19
CCSEL
CC SEL
24 kΩ
48 kΩ
Automatic power control loop dominant pole capacitor. (Connect a capacitor between
this pin and VCC3.)
VCC
A nominal capacitance of 2.2nF will give a bias current enable time of less than 1 ms.
20
CAPC
C APC
100 Ω
3.3V applications - Power supply input. Connect to VCC.
VCC
21
VCC3
VCC
5V applications - Do not connect to 5V. Internally generated 3.3V power supply output.
Do not attach to non-M02094 circuitry.
VCC3
21
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 2-1.
Pin Number
Rev V5
Pin Definitions
Pin Name
Pin equivalent load
V
CC
Function
Peaking adjustment input. A resistor (2kΩ to 20kΩ) between this pin and ground sets
the amount of peaking current on OUT- to improve the fall time of the laser output. The
peaking current is approximately (4 * (1.3V / resistance to ground)).
VCC3
Connect to VCC3 to disable peaking control.
22
PEAKADJ
+
-
PEAKADJ
1.28V
1.8 kΩ
Modulation current control. Connect a resistor to ground to set the modulation current.
V
CC
23
MODSET
24
TCSLOPE
CENTER
PAD
GND
VCC3
+
-
MODSET
1.28V
190 Ω
See MODSET drawing
Modulation current temperature compensation slope adjustment. Connect a resistor to
ground to set the temperature coefficient. Leave open to minimize the temperature
compensation coefficient.
Ground. Must be connected to ground for proper operation. This is the only package
ground connection.
22
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
24
VCC
CCSEL
CAPC
VCC3
PEAKADJ
MODSET
Pin Assignments for M02094 Device
TCSLOPE
Figure 2-1.
Rev V5
19
1
18
SVCC/
IBOUTCC
DIN+
OUT-
DIN-
OUT+
\
VCC3SEL
GND0
GND, connect to
PCB ground
IBOUTCA/
SGND
DIS
6
13
IPIN
TXPWRMON
BIASMON
MODMON
12
DISDLY
RESET
7
APCSET
FAIL
4 X 4 mm
23
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
3.0 Functional Description
3.1
Overview
The M02094 is a highly integrated laser driver intended for applications to 2.0 Gbps.
Many features are user-adjustable, including common anode or common cathode laser mode, the APC (automatic
power control) loop bias control (via a monitor photodiode), modulation current, temperature compensation control
of modulation current, and peaking adjustment. The part may be operated from a 3.3V or 5V supply.
For E-PON and other burst-mode applications, the part supports fast and accurate turn-on and turn-off of the laser
bias and modulation currents.
Safety circuitry is also included to provide a latched shut-down of laser bias and modulation current if a fault condition occurs. An internal VCC switch provides redundant shutdown when operating the device in common anode
configuration. An internal ground switch provides redundant shutdown when operating the device in common cathode configuration.
Modulation, bias, and transmit power monitor current mirrors are provided for DDMI applications and allow monitoring without disturbing the analog signal path.
24
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Internal
3.3V reg.
PEAKAD J
V
GND
C C3
M02094 Block Diagram Example
VC C
Figure 3-1.
Rev V5
SVCC and
Internal Power Bus
IBO UT_CC
OUT-
DIN +
Input
Buffer
D IN -
Output
Buffer
Laser
Driver
OUT+
GND0
VCC3 -1.3V
IB O UT_CA
and
SGND
IPIN
APC
CCSEL
C
DISDLY
TxPwr MON
BIASMON
APC
SET
Automatic Power Control
(laser bias current)
MOD MON
SET
MOD
TCSLOPE
Modulation
Control
VCC3SEL
FAIL
DIS
RESET
Safety
Circuitry with
Latched Fault
TX
Disable
25
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.2
•
•
•
•
•
•
•
•
•
•
Rev V5
Features
High speed operation; suitable for SFP/SFF applications from 155Mbps to 2.0 Gbps. Typical rise/fall times <
110 ps.
Supports Common Anode VCSEL, Common Cathode VCSEL, or FP LASER. May be used with or without a
monitor photodiode.
Programmable temperature compensation. Modulation output and bias output can be controlled using a few
discrete resistors.
Supports DDMI (SFF-8472) diagnostics.
DC or AC coupled modulation drive.
Peaking circuit to optimize VCSEL response.
Low overshoot allows high extinction ratio with low jitter.
Supports E-PON burst mode with no extra components
Automatic Laser Power Control, with “Slow-Start”.
3.3V or 5V operation
3.3
General Description
3.3.1
Detailed Description
The M02094 laser driver consists of the following circuitry: an internal regulator, common anode/common cathode
configuration control, bias current generator and automatic power control, data inputs, peaking adjust, modulation
current control, modulator output, laser fail indication, disable control, and monitor outputs for the bias current,
modulation current, and transmitted power.
3.3.2
Internal Regulator
The M02094 contains an internal 3.3V regulator so high bit rate performance can be achieved with 5V or 3.3V
power supply.
When operating from a 5V supply (VCC is connected to +5V), an internal regulator provides a voltage of approximately 3.3V to the majority of the on-chip circuitry. The on-chip regulator is internally compensated, requiring no
external components. When a 3.3V supply is used (VCC and VCC3 connected to 3.3V) the regulator is switched off
and the internal circuitry is powered directly through the VCC3 supply pin. The decision as to whether or not the
internal regulator is required is made via the VCC3SEL pin, which also determines whether the safety circuitry
needs to monitor for proper +5V supply voltage.
SVCC is sourced from VCC3 through a switch for common anode applications (this pin becomes IBOUT_CC in common cathode applications). When a fault condition is present, FAIL will assert and the switch sourcing SVCC will
open so no current can pass through the laser. SVCC does not need any external capacitance, if capacitance to
ground is added at SVCC it should be less than or equal to 100 pF.
VCC and VCC3 status are internally monitored by the M02094 during power-up and normal operation. During
power-up the “slow-start” circuitry requires that VCC and VCC3 each reach an acceptable level before enabling bias
or modulation current.
26
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 3-1.
Rev V5
Pin Connection for 3.3V and 5V VCC
Pin Connection For:
Pins Dependent on VCC Voltage
VCC = 3.3V
3.3.3
VCC = 5V
VCC3
(pin 21)
Connect to VCC
Reference for CAPC and PEAKADJ
CAPC
(pin 20)
Capacitor between CAPC and VCC3 or VCC
Capacitor between CAPC and VCC3 (not VCC)
PEAKADJ
(pin 22)
Connect to VCC3 or VCC to disable
Connect to VCC3 to disable (not VCC)
VCC3SEL
(pin 4)
Connect to VCC3 or VCC
Connect to GND
Common Cathode/Common Anode Configuration Control
When CCSEL is programmed high, the M02094 is configured for common cathode lasers. When CCSEL is low, the
M02094 is configured for common anode lasers.
The state of the CCSEL pin determines:
1.
2.
3.
4.
whether bias current is sourced or sunk
whether monitor photodiode current is sunk or sourced
whether internal termination resistors at OUT+ and OUT- are active
whether the redundant safety switch disconnects VCC or GND from the output circuitry.
The affected pins are OUT+, OUT-, SVCC/IBOUTCC, and SGND/IBOUTCA. The Table 3-2 below shows the configuration of each pin for the 2 states of CCSEL.
27
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 3-2.
Rev V5
Pin Connection for Common Anode and Common Cathode Laser Modes
Pin Connection When:
CCSEL = High
SVCC
Pins Dependent on CCSEL Setting
Pin 18
IBOUTCC
SGND
Pin 14
IBOUTCA
Pin 13
IPIN
Pin 22
PEAKADJ
Inactive
Supply for laser and all output load components.
Laser bias source current.
Inactive
Ground for laser and all output load components
Inactive
Inactive
Laser bias sink current.
Monitor photodiode source current
Monitor photodiode sink current
Controls Negative going edge of OUT-
Controls Negative going edge of OUT-, (do not
use)
Internal 50Ω pull-up resistors on OUT+ Active
and OUTRatio of Bias current to BIASMON
current
Ratio of Modulation current to
MODMON current
3.3.4
CCSEL = Low
Inactive
13.5:1
45.7:1
30:1
65:1
Bias Current Generator and Automatic Power Control
The M02094 can either source or sink bias current for the laser diode depending on whether it is in common anode
or common cathode mode. In common cathode mode (CCSEL high) IBOUTCC will source current. In common anode
mode (CCSEL low) IBOUTCA will sink current.
Regardless of whether the M02094 is configured for common anode or common cathode mode, the following information applies.
To maintain constant average optical power, the M02094 incorporates a control loop to compensate for the
changes in laser threshold current over temperature and lifetime. The bias current will be determined by the value
of the external resistor RAPCSET and the transfer efficiency between the laser and monitor photodiode.
The photo current from the monitor photodiode mounted in the laser package is sunk or sourced at IPIN. This photo
current is mirrored and an equivalent current is sourced from pins TxPwrMON and APCSET. The APC loop adjusts
the laser bias current (hence the monitor diode photo current) to maintain a voltage of 1.3V at APCSET.
RAPCSET * IPIN = 1.3 V
The APC loop has a time constant determined by CAPC, RAPCSET and the transfer efficiency between the laser and
monitor photodiode. The larger the CAPC capacitor the lower the bandwidth of the loop and the larger the RAPCSET
resistor the lower the bandwidth of the loop.
28
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
In general, it is recommended that at least 2.2 nF of external capacitance be added externally between CAPC and
VCC3 to assure loop stability. With use of a 2.2 nF capacitor, the bias current can reach 90% of its final value within
1 millisecond.
In Common Anode mode with a 2.2nF CAPC capacitor the APC loop bandwidth is less than 30 kHz for almost all
combinations of RAPCSET and transfer efficiency., which should be adequate for bit rates of 155Mbps. (and all
higher bit rates).
In Common Cathode mode with a 2.2nF CAPC capacitor the APC loop bandwidth will be slightly higher, but should
be less than 40 kHz for almost all combinations of RAPCSET and transfer efficiency. Contact the factory with your
specific values of CAPC, RAPCSET, and transfer efficiency to determine the maximum APC loop bandwidth in your
application.
The bias generator also includes a bias current monitor mirror (BIASMON), whose output current is typically 1/
45.7th of the bias current in common anode mode (CCSEL = low) or 1/13.5th of the bias current in common cathode mode (CCSEL = high). This pin can be connected through a resistor to ground. If this function is not needed
this pin can be left open.
The M02094 can be used without a monitor photodiode by connecting BIASMON to APCSET (see Figure 3-7 and
Figure 4-3). In this case the M02094 will increase the bias current (hence the BIASMON current) to the laser until
the voltage at APCSET is approximately 1.3V.
3.3.5
Data Inputs
The inputs to the data buffers are self-biased through 4 kΩ resistors to an internal voltage VTT which is approximately VCC3 - 1.3V. Both CML and PECL inputs signals can be AC coupled to the M02094, or in 3.3V applications
PECL inputs can be DC coupled to the data inputs. In most applications the data inputs are AC coupled with controlled impedance pcb traces which will need to be terminated externally with a 100Ω or 150Ω resistor between the
+ and - inputs.
3.3.6
Peak Adjust
Some VCSELs do not turn off quickly without peaking the negative going edge.
In common cathode applications, peaking on this edge can be added with a resistor connected between the PEAKADJ input and GND. The amount of peaking is approximately
Peaking current = 4 * (1.3V / resistance to ground).
The resistance to ground should be between 2kΩ and 20kΩ. (Which will result in a peaking currents from 2.6mA to
260μA.)
Peaking control can be disabled by connecting PEAKADJ to VCC3, resulting in no peaking current and reducing supply current by approximately 2mA.
In common anode configuration the PEAKADJ pin should be connected to VCC3.
Note: Unlike the rest of the signal currents in the M02094, the output Peak Adjust current is unbalanced (singlesided drive). The designer should be aware that the use of peaking may result in unwanted EMI emissions. If EMI
problems are traced to the use of peaking, high frequency decoupling (10pF capacitor or smaller) may be needed
on the VCC line.
29
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.3.7
Rev V5
Modulation Control
There are two programmable control lines for controlling the modulation current and its temperature compensation.
These inputs can be programmed simply with a resistor to ground .
The modulation current amplitude is controlled by the MODSET input pin. The modulation current is temperature
compensated by the TCSLOPE input.
If the temperature compensation at TCSLOPE is disabled, the modulation output current is simply:
IOUT = 42 x (1.3V / RMODSET) when CCSEL is low
and
IOUT = 22 x (1.3V / RMODSET) when CCSEL is high and a 50Ω VCSEL is used.
Where RMODSET is the resistance from pin MODSET to ground.
To temperature compensate the modulation current, choose RTCSLOPE to meet the following relationship:
RTCSLOPE = 19.5*(TC)-1.5, where TC is the desired slope of the modulation current from 25°C to 85°C in%/°C and
RTCSLOPE is in kΩ. If no temperature compensation is desired, leave RTCSLOPE open.
In any case, RTCSLOPE will have negligible effect at M02094 case temperatures below 10°C.
For example:
Given a common cathode VCSEL with a desired modulation current at low temperatures of 10mA and a temperature coefficient of -0.5%/°C at high temperatures (which will require a laser driver temperature coefficient of
+0.5%).
Choose RMODSET = 22 x (1.3V / 10mA) = 2.8kΩ.
Choose RTCSLOPE =19.5*(0.5)-1.5 kΩ = 55kΩ.
30
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Figure 3-2.
Rev V5
Selecting TCSLOPE Resistance in Common Anode Configuration
RTCslope:
60.00
22k
27k
50.00
33k
39k
40.00
47k
% change in modulation current
51k
30.00
62k
75k
82k
20.00
100k
120k
150k
10.00
220k
390k
0.00
750k
-40
-20
0
20
40
60
80
open
100
-10.00
-20.00
-30.00
Ambient Temperature in degrees C
31
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Figure 3-3.
Rev V5
Selecting TCSLOPE Resistance in Common Cathode Configuration
RTCslope:
70.0
27k
60.0
33k
39k
50.0
47k
51k
62k
% change in modulation current
40.0
75k
82k
100k
30.0
120k
150k
180k
20.0
220k
10.0
390k
510k
0.0
open
-40
-20
0
20
40
60
80
100
-10.0
-20.0
-30.0
Ambient Temperature in degrees C
3.3.8
Modulator (Figure 3-4)
The output stages OUT+ and OUT- are designed to drive 25Ω output loads over a wide range of currents and circuit architectures. The VCSEL may be a common anode or common cathode device. The output can be AC, DC, or
Differentially coupled depending on the supply voltage and laser configuration.
In a common anode configuration with a VCSEL (Figure 4-1), OUT+ should be connected through a capacitor to
the VCSEL. A pull-up resistor should be added in parallel to the VCSEL from SVCC to the OUT+ output. The
dynamic impedance of the parallel combination of the VCSEL and pull-up resistor should be roughly 25 ohms. A 24
ohm pull-up resistor should also be added from SVCC to OUT- so the currents and voltage swings in the two outputs are balanced.
In a common anode configuration with a Fabry-Perot laser (Figure 4-4), OUT+ may be AC, DC, or Differentially
coupled to the laser cathode. A resistor should be added in series with the laser such that the dynamic impedance
of the series combination of the laser and resistor should be roughly 25 ohms. A 24 ohm pull-up resistor to SVCC is
needed on the OUT- output.
For common cathode operation with a VCSEL (Figure 4-3), internal 50 ohm terminations are switched in between
the OUT+ and OUT- outputs and VCC3. VCSELs with impedances from 25-75Ω can be simply AC coupled to the
OUT- output with no additional load matching resistors. In this case OUT+ should be AC coupled to ground through
50Ω.
32
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
The VCSEL driver output stage is separately grounded from the rest of the circuitry (through GND0). At higher data
rates (above 2Gb/s) GND0 may be connected to ground through a minimum of 2 nH of inductance to improve the
transient response. A ferrite can also provide the extra isolation (Murata BLM18HG471SN1 or equivalent recommended).
Figure 3-4.
Modulator Output
0.4pF
0.75 nH
*
0.75 nH
*
OUT-
OUT+
OUT+ and OUT- should not be
driven below 0.7V
GND0
(optional
external
inductance)
3.3.9
* Denotes bond
wire internal to
MLF package
Fail Output
The M02094 has a FAIL alarm output which is compatible with the TX_FAULT signalling requirements of common
pluggable module standards.
The ESD protection on this pin provides a true open collector output that can withstand significant variation in VCC
when signalling between circuit boards. Also, if the M02094 loses power the FAIL output will continue to pull up and
signal a fail condition. In a simple static protection scheme used by other ICs the protection diodes would clamp the
FAIL signal to ground when the chip loses power.
3.3.10
TX Disable and Disable Delay Control
The DIS pin is used to disable the transmit signal. When the transmit is disabled both the bias and modulation currents are off.
The DIS input is compatible with TTL levels regardless of whether VCC = 5V or VCC = 3.3V. In most module applications a pull-up resistor to VCC between 4.7 kΩ and 10 kΩ is required. Because this pin has an internal 7 kΩ
resistor to VCC, no external pull-up resistor is required.
The DISDLY pin is used in conjunction with the DIS pin to control bias current enable time. (The modulation current
enable time is always less than 600 ns). Unless the DISDLY pin is programmed for burst mode, the APC loop
enable time will be slow (less than 1 ms with a CAPC = 2.2 nF).
When a capacitor C is added to the DISDLY pin, the slow-start circuitry is disabled for typically
33
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
T = 3 * 106 (sec/F)* C (F)
following the DIS high transition. If DIS transitions low during this time, the bias current will quickly return to within
90% of its final value (within less than 500 ns). If DIS transitions low after this time the slow-start circuitry will
engage and the bias current will not return to its final value for approximately 1ms (depending on the CAPC capacitor).
3.3.11
Burst Mode Operation (Figure 3-5)
The M02094 will meet the timing requirements of EPON with the addition of a capacitor at DISDLY (see paragraph
above and Figure 3-5).
As shown in Figure 4-4, the laser should be DC coupled to OUT+. VCC may be 3.3V or 5V.
34
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Figure 3-5.
Rev V5
DIS and DISLY Timing
EPO N Burst M ode O peration
D IS
D ISD LY
IBIAS O U T
O U T+
t_off BM < 500ns
t_on BM < 500ns for I M O D > 10m A
Norm al O peration, (slow-start whenever part enabled)
D IS
D ISD LY
t_on < 1m s, depending on C APC
IBIAS O U T
O U T+
t_off < 10μs
35
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.3.12
Rev V5
Video Operation
The M02094 can be used to transmit video optical data even in the presence of the pathological pattern. This is
done by fully DC coupling the signal from the input to the laser output.
In most data communications applications, AC coupling occurs at three points in a laser driver schematic: the data
inputs, the APC control, and coupling the modulation current to the laser. In the M02069, DC coupling can be used
at all three of these points. With DC coupling the laser output will not be a function of the data input one/zero density.
The data inputs can be DC coupled using PECL or CML levels.
The APC of the bias current is controlled by feedback from the monitor photodiode in the laser package in most
communications applications. In video applications this monitor photodiode should not be used if the pathological
pattern may occur. Instead, the APC should be controlled in an "open loop" configuration. (Open loop simply
means a monitor photodiode is not used). In the open loop configuration the APC is controlled by a resistor or a
thermistor network or a look-up table and DAC. This removes AC time constants from the bias current. In
Figure 3-6 the BIASmon pin is connected to the APCset pin. In this case the bias current is:
IBIAS = 45.7 x (1.35V / RAPCSET)
The modulation current output OUT+ can be DC coupled to the laser as shown in Figure 3-6. There are no AC
time constants in the modulation current amplitude in this configuration.
Video Application Block Diagram
VC C
DIN +
V CC3
V CC3
VCC3
V CC
PEAKAD J
Figure 3-6.
Internal Power
Bus
Internal
3.3V reg.
SV
CC
OUTInput
Buffer
Output
Buffer
Laser
Driver
OUT+
GND0
DIN V CC3 -1.3V
IB OUT_CA
IPIN
CC SEL
CAPC
DISDLY
APCSET
MODMON
Automatic Power Control
(laser bias current)
TxPwr MON
Connect to V CC
when V CC = 3.3V
MODSET
TCSLOPE
Modulation
Control
VCC3SEL
RESET
FAIL
DIS
TX
Disable
BIASMON
Safety
Circuitry with
Latched Fault
For V CC=3.3V, tie VCC3 to V CC.
V CC3
Connect to GND
when V CC = 5V
36
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.3.13
Rev V5
Current Monitors
To facilitate complying with laser safety and DDMI1 requirements, output monitors are provided for transmit power
(TxPwrMON), bias (BIASMON), and modulation current (MODMON).
These outputs will source current proportional to the emitted optical power (TxPwrMON) the bias current (BIASMON)
and modulation current (MODMON).
To use these pins they should be terminated with a resistor to ground that sets the desired full-scale voltage (not to
exceed 2.5V).
If the outputs of these monitors are not needed, TxPwrMON, BIASMON, and MODMON can all be left floating and the
chip current consumption will be reduced by the value of the monitor currents.
3.4
Laser Eye Safety
Using this laser driver in the manner described herein does not ensure that the resulting laser transmitter complies
with established standards such as IEC 825. Users must take the necessary precautions to ensure that eye safety
and other applicable standards are met. Note that determining and implementing the level of fault tolerance
required by the applications that this part is going into is the responsibility of the transmitter designer and manufacturer since the application of this device cannot be controlled by MACOM.
1
Digital Diagnostic Monitoring Interface for Optical Tranceivers, defined in SFF-8472.
37
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.4.1
Rev V5
Safety Circuitry
Safety Circuitry in the M02094 will disable the modulation and bias current and assert the FAIL output immediately
upon detecting a fault condition. In addition, the supply voltage that sources or sinks the laser current (SVCC or
SGND) will immediately go open circuit and prevent any current from passing through the laser.
Fault conditions checked by the M02094 include shorts to ground or VCC of all pins which can increase the laser
modulation or bias current.
For an initialization or power-up sequence to be successful, all the fault detection monitors must signal that the chip
is “healthy”.
When DIS goes low, pins are checked for shorts to ground or VCC and a FAIL condition is latched if there is a fault.
If the state of the pins is OK, a one-shot at the reset pin begins a countdown which will latch a FAIL condition if the
bias current has not stabilized to an acceptable level during the one-shot time. The one-shot can be extended with
an external capacitor connected from the RESET pin to ground.
The one-shot1 width is approximately
TONE-SHOT = 3 ms + (0.3 ms/pF)x(external capacitance).
Figure 3-7.
Safety Circuit Block Diagram
DIS
If chip is ‘healthy’, then Enable
the outputs and Start 3msec
Reset Pulse(one-shot)
AND
AND
OUTPUT_ENABLE
AND
Latch for
CrudeFaults
VccOK Detection:
SRlatch:
AND
5v Mode:
Reset
Q
Vcc Pin
Set
5v Hi/Lo Limits
FAILout
(open-collector)
AND
Vcc3 Pin
Latch for
Bias_OK
Delay
3.3v Hi/Lo Limits
3.3v Mode:
VCC_OK
ON E-SHOT:
t=0
Vcc Pin
RESET
5v Hi/Lo Limits
Start
3ms + Tcap
SRlatch:
Reset
PULSE
NOTE: Pulse stays high
if Reset pin is GNDed.
Set
‘1’
AND
OR
Q
optional cap for longer T_init
Vcc3 Pin
3.3v Hi/Lo Limits
CrudeFaults Detection:
BiasOK Detection:
OutP
Cmpc
MODset
> 300mV
> 300mV
> 300mV
HI Limit
IbiasOut
> 300mV
IboutCA
> 300mV
(2061)
Window Compare:
CrudeFaults_OK
(2069 – Common Anode)
IboutCC
< (Vcc3 – 300mV)
MPCset
OR
BIAS_OK
LOW Limit
(2069 – Common Cathode)
38
1.The one-shot is actually comprised of an oscillator and 10-bit counter.
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
3.5
Rev V5
Fault Conditions
This section describes the M02094 operating modes during fault conditions. Over voltage, under voltage, pins
shorted to VCC and pins shorted to ground are included in the fault Table 3-3.
Table 3-3.
Pin Name
Circuit Response to Single-Point Fault Conditions
Circuit Response to Over-voltage Condition or Short to
VCC
Circuit Response to Under-Voltage Condition or Short to
Ground
VCC
Bias and modulation outputs are disabled once VCC rises above the Bias and modulation outputs are disabled once VCC drops below the
supply detection (high voltage) threshold (see Table 1-3)
supply detection (low voltage) threshold
DIN+, DIN-
The APC loop will attempt to compensate for the change in output The APC loop will attempt to compensate for the change in output
power. If the APC loop can not maintain the set average power, a power. If the APC loop can not maintain the set average power, a fault
state occurs.(1,2,3)
fault state occurs.(1,2,3)
VCC3SEL
Does not affect laser power.
Does not affect laser power.
DIS
Bias and modulation outputs are disabled.
Does not affect laser power (normal condition for circuit operation).
SVCC is opened when CCSEL is low or floating (or SGND is opened
when CCSEL is high)
FAIL
Does not affect laser power.
Does not affect laser power.
RESET
Does not affect laser power.
Does not affect laser power.
MODMON
Does not affect laser power.
Does not affect laser power.
BIASMON
Does not affect laser power.
Does not affect laser power.
TxPWRMON
Does not affect laser power.
Does not affect laser power.
APCSET
A fault state occurs.
(1)
A fault state occurs.(1)
IPIN
A fault state occurs.(1)
A fault state occurs.(1)
IBOUTCA(3)
The laser will be turned off, then a fault state occurs.(1)
A fault state occurs.(1)
IBOUTCC(4)
A fault state occurs.(1)
The laser will be turned off, then a fault state occurs.(1)
OUT+(3)
Laser modulation is prevented; the APC loop will increase the bias A fault state occurs.(1)
current to compensate for the drop in laser power if it is DC
coupled. If the set output power can not be obtained, a fault state
occurs.(1,2)
OUT-(4)
Does not affect laser power during common cathode operation Does not affect laser power during common cathode operation
because output is AC coupled.
because output is AC coupled.
SVCC(3)
Does not affect laser power.
Laser bias current will be shut off and a fault state occurs.(1)
CAPC
Laser bias current will be shut off, then a fault state occurs.(1)
A fault state occurs.(1)
VCC3
Bias and modulation outputs are disabled once VCC3 rises above Bias and modulation outputs are disabled once VCC3 drops below the
the supply detection (high voltage) threshold
supply detection (low voltage) threshold
PEAKADJ
Does not affect laser power.
CCSEL
Normal operation for common cathode configuration. If the M02094 Normal operation for common anode configuration. If the M02094 is
is configured for common anode drive, a fault state will occur.(1)
configured for common cathode drive, a fault state will occur.(1)
Does not affect laser power
39
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Table 3-3.
Pin Name
Rev V5
Circuit Response to Single-Point Fault Conditions
Circuit Response to Over-voltage Condition or Short to
VCC
Circuit Response to Under-Voltage Condition or Short to
Ground
MODSET
When the laser is DC coupled in common anode configuration, the A fault state occurs.(1)
APC loop will attempt to compensate for the drop in output power. If
the APC loop can not maintain the set average power, a fault state
occurs.(1,2)
TCSLOPE
Does not affect laser power.
When the laser is DC coupled in common anode configuration, the
APC loop will attempt to compensate for any change in output power.
If the APC loop can not maintain the set average power, a fault state
occurs.(1,2)
DISDLY
Does not affect laser power.
Does not affect laser power.
Notes:
1. A fault state will assert the FAIL output, disable bias and modulation outputs and will either open the switch at SVCC (CCSEL=high) or SGND (CCSEL=low).
2. Does not affect laser power when the output is AC coupled to the laser.
3. Does not affect laser power during common cathode operation.
4. Does not affect laser power during common anode operation.
40
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
4.0 Applications
4.1
EPON FTTH modules
Gigabit Ethernet modules
1G/2G Fibre Channel modules
Digital Video
Figure 4-1.
Application Diagram, Common Anode VCSEL (may be DC coupled, but extra bias current will
be required for the pull-up resistor on OUT+)
VCC
DIN +
V CC3
V CC3
VCC3
V CC
V CC3
PEAKA D J
•
•
•
•
Applications
Internal Power
Bus
Internal
3.3V reg.
SV C C
OUT-
Input
Buffer
Output
Buffer
Laser
Driver
OUT+
GND0
DIN V CC3 -1.3V
IB OUT_CA
IPIN
CC SEL
CA P C
DISDLY
APCSET
MODMON
Automatic Power Control
(laser bias current)
TxPwr MON
Connect to V CC
when V CC = 3.3V
MODSET
TCSLOPE
VCC3S E L
RESET
FAIL
DIS
Modulation
Control
BIASMON
Safety
Circuitry with
Latched Fault
TX
Disable
For VCC=3.3V, tie V CC3 to VCC.
V CC3
Connect to GND
when V CC = 5V
41
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Application Diagram, Common Cathode VCSEL
PEAKAD J
V CC3
V CC
V CC
V CC3
Figure 4-2.
Rev V5
Internal Power Bus
Internal
3.3V reg.
OUT+
Input
Buffer
DIN+
Output
Buffer
Laser
Driver
OUTGND0
DINV CC3 -1.3V
IB OUT_CC
SGND
IPIN
Connect to V CC
when V CC = 3.3V
CCSEL
CAPC
DISDLY
TxPwr MON
BIASMON
APCSET
Automatic Power Control
(laser bias current)
MODMON
MODSET
TCSLOPE
Modulation
Control
VCC3 SEL
FAIL
DIS
RESET
Safety
Circuitry with
Latched Fault
TX
Disable
V CC
For VCC=3.3V, tie VCC3 to VCC.
V CC3
Connect to GND
when V CC = 5V
42
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Application Diagram, Common Cathode VCSEL w/o Monitor Diode
PEAKADJ
V CC3
V CC
V CC
V CC3
Figure 4-3.
Rev V5
Internal Power
Bus
Internal
3.3V reg.
OUT+
Output
Buf f er
Input
Buf f er
DIN+
Laser
Driv er
OUTGND0
DINV CC3 -1.3V
IBOUT_CC
SGND
IPIN
Connect to V CC
when V CC =3.3V
CCSEL
CAPC
DISDLY
TxPwrMON
BIASMON
APCSET
Automatic Power Control
(laser bias current)
MODMON
TCSLOPE
MODSET
Modulation
Control
VCC3SEL
FAIL
DIS
RESET
Saf ety
Circuitry with
LatchedFault
TX
Disable
V CC3
For V CC=3.3V, tie V CC3 to V CC.
V CC3
Connect toGND
when V CC = 5V
43
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Application Diagram, Common Anode FP Laser, DC Coupling
VC C
DIN +
V CC3
V CC3
VCC3
V CC
PEAKAD J
Figure 4-4.
Rev V5
Internal Power
Bus
Internal
3.3V reg.
SV C C
OUT-
Input
Buffer
Output
Buffer
Laser
Driver
OUT+
GND0
DIN V CC3 -1.3V
IB OUT_CA
IPIN
CAPC
DISDLY
TxPwr MON
SET
Automatic Power Control
(laser bias current)
APC
MODMON
SLOPE
TC
Connect to V CC
when V CC = 3.3V
MODSET
Modulation
Control
VCC3SEL
RESET
FAIL
DIS
TX
Disable
BIASMON
Safety
Circuitry with
Latched Fault
CC SEL
For V CC=3.3V, tie VCC3 to V CC.
For EPON operation, add a
capacitor to GND at DISDLY.
V CC3
Connect to GND
when V CC = 5V
44
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
5.0 Packaging Specification
5.1
Package Specification
Figure 5-1.
QFN24 Package Information
Note: View is for a 20 pin package. All dimensions in the
tables apply for the 24 pin package
45
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M02094-12
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Rev V5
M/A-COM Technology Solutions Inc. All rights reserved.
Information in this document is provided in connection with M/A-COM Technology Solutions Inc ("MACOM")
products. These materials are provided by MACOM as a service to its customers and may be used for
informational purposes only. Except as provided in MACOM's Terms and Conditions of Sale for such products or
in any separate agreement related to this document, MACOM assumes no liability whatsoever. MACOM assumes
no responsibility for errors or omissions in these materials. MACOM may make changes to specifications and
product descriptions at any time, without notice. MACOM makes no commitment to update the information and
shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to its
specifications and product descriptions. No license, express or implied, by estoppel or otherwise, to any
intellectual property rights is granted by this document.
THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR
IMPLIED, RELATING TO SALE AND/OR USE OF MACOM PRODUCTS INCLUDING LIABILITY OR
WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, CONSEQUENTIAL OR INCIDENTAL
DAMAGES, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER
INTELLECTUAL PROPERTY RIGHT. MACOM FURTHER DOES NOT WARRANT THE ACCURACY OR
COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE
MATERIALS. MACOM SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS,
WHICH MAY RESULT FROM THE USE OF THESE MATERIALS.
MACOM products are not intended for use in medical, lifesaving or life sustaining applications. MACOM customers
using or selling MACOM products for use in such applications do so at their own risk and agree to fully indemnify
MACOM for any damages resulting from such improper use or sale.
46
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