Infineon FOA2322A 3.2 gbi t /s laser driver ic for telecom and datacom application Datasheet

P r e li m i na r y D a t a S h ee t , M ay 20 0 1
F O A 23 2 2A
3 . 2 G b it / s L a s e r D r i v e r I C f o r
T el ec o m a n d D a t a c o m
Ap pl ic a t io ns
IC s f or C om m u n i c a ti o n s
N e v e r
s t o p
t h i n k i n g .
Edition 2001-05
Published by Infineon Technologies AG,
St.-Martin-Strasse 53,
D-81541 München, Germany
© Infineon Technologies AG 2001.
All Rights Reserved.
Attention please!
The information herein is given to describe certain components and shall not be considered as warranted
characteristics.
Terms of delivery and rights to technical change reserved.
We hereby disclaim any and all warranties, including but not limited to warranties of non-infringement, regarding
circuits, descriptions and charts stated herein.
Infineon Technologies is an approved CECC manufacturer.
Information
For further information on technology, delivery terms and conditions and prices please contact your nearest
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be endangered.
P r e li m i na r y D a t a S h ee t , M ay 20 0 1
F O A 23 2 2A
3 . 2 G b it / s L a s e r D r i v e r I C f o r
T el ec o m a n d D a t a c o m
Ap pl ic a t io ns
IC s f or C om m u n i c a ti o n s
N e v e r
s t o p
t h i n k i n g .
FOA2322A
Revision History:
2001-05
Previous Version:
Page
Subjects (major changes since last revision)
For questions on technology, delivery and prices please contact the Infineon
Technologies Offices in Germany or the Infineon Technologies Companies and
Representatives worldwide: see our webpage at http://www.infineon.com
FOA2322A
Table of Contents
Page
1
1.1
1.2
1.3
1.4
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2.1
2.2
2.3
2.4
2.4.1
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
General Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Characteristics and Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Characteristics of Temperature Compensation (Mode 1) . . . . . . . 14
Modulation Current Swing versus RMOD, RTC,
Junction Temperature and Supply Voltage / High Current Drive . . . . . . 14
Modulation Current Swing versus RMOD, RTC,
Junction Temperature and Supply Voltage / Low Current Drive . . . . . . 16
Principle of Modulation Current Control by Using a Pilot Signal (Mode 2) 18
Data / Clock Input Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Timing of Clock and Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Laser and VCC Supervising Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Input Signal Monitoring and Hardware Alarm
(Consideration in absence of Laser Fault) . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4.2
2.5
2.6
2.7
2.8
2.9
2
2
2
2
2
3
3.1
Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Pad Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4
Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Preliminary Data Sheet
1
2001-05
3.2 Gbit/s Laser Driver IC for Telecom and Datacom
Applications
FOA2322A
FOA2322A
1
Overview
1.1
Features
•
•
•
•
•
Data rate up to 3.2 Gbit/s
Supply range from +3.0 V to +5.5 V
Modulation current adjustable up to 75 mA
Bias current adjustable up to 80 mA
Choice between temperature compensation and integrated Two-Loop-Control of bias
and modulation current
• Integrated laser supervisor
• Monitor output for optical output power
1.2
Applications
• Fiber optics telecom and data communication systems
• SDH / SONET, Fiber Channel, Gigabit Ethernet
1.3
Technology
• Bicmos B6HFC
1.4
General
This document defines the ratings and characteristics of a laser driver circuit dedicated
for applications within telecom and datacom modules with respect to various
transmission standards and laser safety requirements. A block diagram of this circuit is
shown in Figure 1.
Modulation Control / Modulator / Input Stage
The modulator is capable of driving modulation currents up to 75 mA. There are two
modes for adjusting the modulation current:
Mode 1: The modulation current is adjusted by an external resistor (RMOD). The IC has
an internal temperature compensation circuit for compensating the temperature
characteristic of laser diode slope efficiency. With the external resistor (RTC) the
modulation current temperature coefficient is adjustable. The temperature input itself is
derived from chip junction temperature.
Preliminary Data Sheet
2
2001-05
FOA2322A
Overview
Mode 2: The modulation current is controlled by using a low frequency pilot signal. The
controller cutoff frequency is adjustable by external capacitor (CMOD). Mode 2 is suitable
for data rates 1.25 Gbit/s (depending on laser diode).
There is an option for using data input latch.
Input Signal Monitor
An input signal monitor circuit delivers a logic signal HWA and an internal signal which
is used for laser disabling if data input is constantly high or low.
Bias Control / Bias Generator
The bias controller controls the LD optical output power by adjusting the bias current.
The controller cutoff frequency is adjustable by external capacitor (CBIAS). A min. cutoff
frequency is integrated. The laser bias current will start at < 500 µA after laser enable.
Laser Supervisor / VCC Supervisor
The laser supervisor circuit monitors the laser output power by the means of monitor
diode feedback. The voltage generated by monitor diode circuit is compared to a
reference. If the input voltage deviates more than ±2 dB (optical power ±1 dB) from this
reference the laser diode is switched off and a fault indication is generated. The VCC
supervisor monitors the circuit power supply and switches off the laser if the VCC level is
below the reset threshold. It is keeping the laser output down for the adjusted delay time
(power on delay) after VCC has risen above the VCC reset threshold.
Preliminary Data Sheet
3
2001-05
FOA2322A
Overview
CFDEL
CISM
CILM
VCCD2
VCCD VCCA
LDOFF
LF
LEN
RST
RSTN
Laser Supervisor
VCC
Supervisor
HWA
Bias
Enable
VMOD
Modulation
Enable
D
DN
Input Stage
CLK
CLKN
Modulator
VEE2
Latch
VEE2
RBRIP
RMRIP
CMOD
MX
COSC
CSELN
Modul. Control
Incl. Oscillator
Mode
Start
Temperature
Compensation
RTC
RMOD
IBIAS
MD
Bias
Generator
Bias Control
VEE VEE CBIAS
Figure 1
O
O
ON
ON
RPOUT MPOUT
VEE1
VBIAS
ITB11326
General Circuit Block Diagram
– Number of pins: 42
– IC available as die
Preliminary Data Sheet
4
2001-05
FOA2322A
Electrical Characteristics
2
Electrical Characteristics
2.1
Absolute Maximum Ratings
Absolute Maximum Ratings which may not be exceeded to the device without causing
permanent damage or degradation. Exposure to these values for extended periods may
effect device reliability. If the device is operated beyond the range of Operating
Conditions and Characteristics functionality is not guaranteed. All voltages given within
this data sheet are referred to VEE if not otherwise mentioned.
Table 1
Absolute Maximum Ratings
Parameter
SymLimit Values
bol
min.
max.
Supply Voltage
-0.3
Output Voltage at O, ON
V
–
VCC - 2.6 VCC + 0.3
-0.3
VCC + 0.3
-0.3
VCC + 0.3
-0.3
VCC + 0.3
-0.3
VCC + 0.3
V
1)
V
1)2)
V
1)
V
1)2)
V
1)
Differential Data Input Voltage
|VD - VDN|
–
2.5
V
–
Differential Data Input Voltage
|VCLK - VCLKN|
–
2.5
V
–
Sink Current at Logic Output LF, HWA
–
5
mA
–
Source Current at LDOFF
-4
–
mA
–
Source Current at RPOUT
-2
–
mA
–
Modulation Current at O, ON
(both Outputs)
–
80
mA
–
Bias Current at IBIAS
–
95
mA
–
Modulation Control Sink Current at VMOD
(Input Current for Current Mirror 1:10)
–
9.6
mA
–
Bias Control Sink Current at VBIAS
(Input Current for Current Mirror 1:25)
–
4.8
mA
–
Modulation Current Adjust Resistor RMOD
800
–
Ω
–
Output Voltage at MPOUT
Output Voltage at Logic Output LF, HWA
Output Voltage at IBIAS
Input Voltage at Logic Inputs LEN, RST,
RSTN, CSELN
Preliminary Data Sheet
5
6
Unit Conditions
2001-05
FOA2322A
Electrical Characteristics
Table 1
Absolute Maximum Ratings (cont’d)
Parameter
SymLimit Values
bol
min.
max.
Unit Conditions
Modulation Temperature Coefficient
Resistor RTC
50
–
Ω
–
Junction Temperature
-40
125
°C
–
Storage Temperature
-55
150
°C
–
Relative Humidity (non-condensing)
–
95
%
–
Electrostatic Discharge Voltage Capability
–
1
kV
–
1)
Maximum voltage is 6 V.
2)
For applications with VCC + 5 V (please refer to Figure 13).
Note: Stresses above the ones listed here may cause permanent damage to the
device. Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.
2.2
General Operating Conditions
Under the below defined operating conditions all specified characteristics will be met
unless otherwise noted.
Table 2
General Operating Conditions
Parameter
SymLimit Values
bol
min.
max.
Unit Conditions
Environmental
Junction Temperature
Relative Humidity (non-condensing)
°C
1)
-40
125
-40
110
–
95
%
–
3
5.5
V
3)
2)
Supply Voltage
VCC Range
1)
For modulation current IOH ≤ 50 mA
2)
For modulation current 50 mA < IOH ≤ 75 mA
3)
Valid for VCCA and VCCD; VCCA ≥ VCCD
Preliminary Data Sheet
6
2001-05
FOA2322A
Electrical Characteristics
2.3
Characteristics and Operating Conditions
Table 3
Characteristics and Operating Conditions
SP Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Condition
Modulator / Modulation Control
1
Data Transmission Rate
DR
0
–
2.5
Gbit/s 1)
2
Supply Current
ICC
–
30
63
mA
2)3)
3
Modulation Current High
at O/ON
for VCC = 3.3 V
for VCC = 5 V
IOH IOL
mA
4)5)
Modulation Current Low
at O/ON
IOL
mA
6)
5
Modulation Current at
Laser Shut Down
IOSD
6
O, ON Output Voltage
Range
for VCC = 3.3 V
V O,
VON
4
5
5
–
–
65
75
0
–
2
Offset
0
–
200
µA
7)
V
8)
VCC -
–
VCC
1.65 V
VCC 2.0 V
–
VCC
800
–
Open Input Ω
9)10)
RTC
50
–
Open Input Ω
9)11)
Data Input Voltage High
VIHD
–
–
VCCD
V
–
10 Data Input Voltage Low
for VCCD = 3.3 V
for VCCD = 5 V
VILD
V
–
1.0
2.2
–
–
–
–
11 Data Input Voltage Swing |VD VDN|
250
–
1600
mV
–
12 Clock Input Voltage High VIHCLK
–
–
VCCD - 0.65 V
for VCC = 5 V
7
Modulation Current Adjust RMOD
Resistor Range
(MOD-Resistor)
8
Modulation Temperature
Coefficient Resistor
Range
Serial Data/Clock Input
9
Preliminary Data Sheet
7
–
2001-05
FOA2322A
Electrical Characteristics
Table 3
Characteristics and Operating Conditions (cont’d)
SP Parameter
Symbol
Limit Values
min.
typ.
max.
1.0
2
–
–
–
–
1100
13 Clock Input Voltage Low
for VCCD = 3.3 V
for VCCD = 5 V
VILCLK
14 Clock Input Voltage
Swing
|VCLK VCLKN|
250
–
15 Bias Voltage at D/DN
VBBD
–
16 Bias Voltage at
CLK/CLKN
VBBC
17 Differential Data/Clock
Input Termination
Unit Condition
V
–
mV
–
VCCD - 1.0 –
V
12)
–
VCCD - 1.3 –
V
12)
RIN
80
100
120
Ω
12)13)
19 Input Capacitance
D/DN/CLK/CLKN
CIN
–
–
0.6
pF
–
20 Setup Time (Data/Clock)
tSETUP
–
20
–
ps
–
21 Hold Time (Data/Clock)
tHOLD
–
20
–
ps
–
22 Eye Opening at
2.5 Gbit/s (w. Latch)
tEO
–
360
–
ps
–
23 Internal ISM cutoff
frequency
fISM
165
238
372
kHz
14)
24 Cutoff frequency of ISM
with external CISM
fISM
(6.1 µs
+ 84 kΩ
× CISM)-1
(4.2 µs
+ 70 kΩ
× CISM)-1
(2.7 µs
+ 56 kΩ
× CISM)-1
25 Internal ILM cutoff
frequency
fILM
–
160
–
kHz
14)
26 Cutoff frequency of ILM
with external CILM = 1nF
fILM
–
73
–
kHz
14)15)
27 Duty Cycle for laser
enable
25
–
75
%
–
28 Duty Cycle for laser
disable
0
–
5
%
Input
low
29 Duty Cycle for laser
disable
95
–
100
%
Input
high
Input Signal Monitor (ISM)
Preliminary Data Sheet
8
14)15)
2001-05
FOA2322A
Electrical Characteristics
Table 3
Characteristics and Operating Conditions (cont’d)
SP Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Condition
30 Bias Current
IIBIASmax
0
–
80
mA
–
31 Start Bias Current
IIBIASmin
–
–
500
µA
–
32 Bias Current at Laser
Shut Down
IIBIASSD
–
–
500
µA
–
33 Output Voltage Range
IBIAS
VIBIAS
0.5
–
VCC
V
–
34 Power Monitor Current
IMPOUT
0
VMD
RPOUT
1
mA
16)
35 Output Voltage Range
MPOUT
VMPOUT
VRPOUT +
–
VCC
V
–
36 Resistor Range RPOUT
RPOUT
2.4
–
Open Input kΩ
–
37 Output Voltage Range
RPOUT
VRPOUT
0
VMD
VCC - 1.2
V
–
38 Internal cutoff frequency
of bias controller
fBIAS
23
37
62
kHz
17)
39 Cutoff frequency of bias
controller with external
fBIAS
(44 µs +
306 kΩ ×
CBIAS)-1
(27 µs +
204 kΩ ×
CBIAS)-1
(16 µs +
131 kΩ ×
CBIAS)-1
GBIAS
–
100
–
–
VMDnom +
VMDnom +
1.5 dB
2 dB
VMDnom -
VMDnom -
–
2 dB
1.55 dB
VMDnom -
–
Laser Power Control
0.5
CBIAS
40 Conversion gain of bias
generator
15)17)
mA/V –
Laser Supervising Circuit
41 MD Failure Voltage High
42 MD Failure Voltage Low
43 MD Range without Failure
Recognition
1.2 dB
VMDnom +
tFDEL
38
60
86
45 Additional Failure
Recognition Time by
external CFDEL
tFDEL
CFDEL ×
CFDEL ×
CFDEL ×
Preliminary Data Sheet
9
18)
V
19)
µs
17)20)
1.2 dB
44 Internal Failure
Recognition Time
0.7 µs/pF
18)
1.0 µs/pF
15)17)20)
1.3 µs/pF
2001-05
FOA2322A
Electrical Characteristics
Table 3
Characteristics and Operating Conditions (cont’d)
SP Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Condition
46 Shut Off Time after LF
tLDdis
transition or Laser Disable
0
–
3
µs
21)
47 VCC Reset Threshold for
Laser Enable/Disable
2.5
2.75
2.99
V
22)
333
480
µs
23)
48 Internal Power On Delay
tPDEL
213
49 Additional Power On
Delay by external COSC
tPDEL
64 × COSC 64 × COSC 64 × COSC
× 138 kΩ
× 173 kΩ
× 208 kΩ
15)23)
50 LDOFF low Output
Current
1.5
–
4
mA
sink
current
51 LDOFF high Output
Current
–
–
2
µA
sink
current
52 LDOFF high Output
Voltage
VCC - 0.1
–
–
V
–
53 LDOFF low Output
Voltage
VCC - 2.0
–
VCC - 1.2
V
without
external
load
Reference Voltage
54 MD Reference Value
VMDR
1.12
–
1.32
V
24)
55 VMDR Drift over
Temperature Range
|∆VMDR/
VMDR|
–
–
5
%
–
56 VMDR Drift over Supply
Voltage Range
3 V … 5.5 V
|∆VMDR/
VMDR|
–
–
10
%
–
57 VMDR Drift over
Temperature Range at
Supply Voltage Range
3 V … 3.6 V
|∆VMDR/
VMDR|
–
–
5
%
–
58 VMDR Drift over
Temperature Range at
Supply Voltage Range
4.7 V … 5.3 V
|∆VMDR/
VMDR|
–
–
5
%
–
Preliminary Data Sheet
10
2001-05
FOA2322A
Electrical Characteristics
Table 3
Characteristics and Operating Conditions (cont’d)
SP Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Condition
Logic Inputs RSTN, RST, LEN
59 Input Voltage High
VIHLOGIC 2.0
–
VCC
V
25)
60 Input Voltage Low
VILLOGIC
0
–
0.8
V
25)
61 Input Current High
IIHLOGIC
–
–
5
µA
–
62 Input Current Low
IILLOGIC
-5
–
–
µA
–
2.2
–
VCC
V
–
Logic Inputs CSELN
63 Input Voltage High for
VIHLOGIC
disabling data input latch
(nonclocked mode) or let
CSELN open
64 Input Voltage Low for
enabling data input latch
(clocked mode)
VILLOGIC
0
–
0.8
V
–
65 Internal Pull-Up-Resistor
RCSELN
8
10
12
kΩ
–
Logic Outputs LF, HWA
66 Output Voltage Low
VOLLOGIC –
–
0.4
V
–
67 Output Current High
(Leakage Current)
IOHLOGIC –
–
100
µA
open
collector
68 Output Current Low
IOLLOGIC 2
–
–
mA
sink
current
69 Mode 1 select
VMODE
VCC - 0.8
–
VCC
V
–
70 Mode 2 select
VMODE
0
–
0.8
V
–
71 Internal pilot frequency
fPILOT
7.7
12
17.3
kHz
–
72 Pilot frequency with
external COSC
fPILOT
(130 µs + (83 µs +
(58 µs +
16 × COSC 16 × COSC 16 × COSC
× 208 kΩ)-1 × 173 kΩ)-1 × 138 kΩ)-1
Modulation Control (Mode 2)
73 Effective pilot current
amPILOT
amplitude on modulation
current high level (default)
Preliminary Data Sheet
–
3.5
11
–
15)
%
26)
2001-05
FOA2322A
Electrical Characteristics
Table 3
Characteristics and Operating Conditions (cont’d)
SP Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Condition
74 Pilot current amplitude on abPILOT
bias current (default)
–
5.05
–
%
75 Cutoff frequency of
fMOD
modulation controller with
external CMOD
(306 kΩ ×
CMOD)-1
(204 kΩ ×
CMOD)-1
(131 kΩ ×
CMOD)-1
26)
15)17)
1)
Measured into 25 Ω .
2)
The bias-, modulation-, the LF-, HWA- and MPOUT- output currents are not included.
3)
The typical supply current is defined for driving a laser with about 20 mA bias current and about 20 mA
modulation current and a IC junction temperature of about 50 °C and a VCC of 5 V. The maximum supply
current is defined for driving the upper limits of bias current and modulation current with worst case junction
temperature and with a VCC of 5.5 V (VCC = VCCA = VCCD).
4)
This describes the AC modulation current (the DC component is the overall offset current). AC modulation
current is drawn by O at VD > VDN, it is drawn by ON at VD < VDN. IOH refers to drawn modulation current
(AC + DC). IOL refers to an inactive current output (DC current only).
5)
See Table 2 for operating conditions junction temperature.
6)
Inactive current output (see also 4)).
7)
Modulation current when the laser diode is disabled.
8)
Valid for VCC = VCCA = VCCD = 5 V. It is possible to increase the output voltage range for the VCC range of
5 V ± 0.5 V of about 0.85 V by using the Pad VCCD2 instead of VCCD (see Figure 14). The specified limits for
data and clock inputs are valid for VCCD.
9)
Adjustment of programmable parameter by resistor value within this range (see Chapter 2.4).
10)
Adjusting the modulation current by RMOD notice that the decreasing of RMOD will increase the modulation
current. RMOD in combination with RTC has to be adjusted that the modulation current is smaller than 50 mA
or 75 mA respectively over specified temperature range. If RMOD-Pad is not connected (open input) there will
be no modulation current at the output O/ON.
11)
Modulation current adaptation within junction temperature range. Low junction temperature represents a low
additional modulation current. High junction temperature represents a high additional modulation current. If
RTC-Pad is not connected there will be no noteworthy modulation current adaptation.
12)
Data/clock inputs are internally connected to VBBD/VBBC by resistor R1/R2 with a differential termination by RIN.
See data input stage description (see Figure 9).
13)
The resistance is guaranteed for junction temperature 25 °C.
Preliminary Data Sheet
12
2001-05
FOA2322A
Electrical Characteristics
14)
If data input duty cycle falls below lower limit or exceeds upper limit the laser will be disabled by ISM circuit.
On the other hand, the laser will be enabled whenever the data input duty cycle goes back to the allowed range.
Data input duty cycle refers to the quotient given by number of ones divided by number of zeros within serial
data stream. The ISM-circuit evaluates the mean value of the duty cycle (integrator). The cutoff frequency of
ISM fISM is defined for data pattern 1010 …. In case of data frequency is to small the ISM circuit will disable
the laser because of long High- or Low-series. The ISM-circuit can be deactivated by a 25 kΩ resistor from
CISM to VEE. The ILM-circuit additionally is used for ac-coupled data inputs. It works as a peak detector. The
laser will be disabled if data are set to a static state. The cutoff frequency of ILM fILM is defined for data pattern
1010 …. (Specified value is for data input voltage swing of 400 mV).The ILM-circuit is direct AC-coupled to the
data input. So the cutoff frequency depends on data input swing. The ILM-circuit can be deactivated by a short
from CILM to VCC.
15)
A capacitor within this range programs the time (or frequency).
16)
Open collector output for pulling up a resistor to monitor the current.
17)
Difference and temperature drift of passive IC component parameters match to passive IC component
parameters in other circuit parts.
18)
The supervisor circuit will detect a failure condition if MD voltage exceeds VMDnom ± 2 dB range. VMDnom is
given by nominal voltage level at MD which is set by VMDR. The deviation is calculated with 20lg(VMD/VMDnom).
The deviation of optical power is calculated with 10lg(VMD/VMDnom).
19)
The supervisor circuit will detect no failure condition if MD input voltage ranges from VMDnom - 1.2 dB to
VMDnom + 1.2 dB. VMDnom is given by nominal voltage level at MD which is set by VMDR. The deviation is
calculated with 20lg(VMD/VMDnom). The deviation of optical power is calculated with 10lg(VMD/VMDnom).
20)
A failure condition will be reported by LF = H if this condition lasts for tFDEL. Minimal capacitor on CFDEL has
to be chosen that the failure recognition time is longer than the setting time of the bias controller.
21)
Time between LF high (or LEN high) and LDOFF high.
22)
At supply voltages below VCC threshold the laser diode bias and modulation current will be held disabled and
LDOFF will be held high. Above the laser diode will be enabled after the Power On Delay.
23)
The Power On Delay is the Reset time after VCC voltage has risen above the VCC reset threshold. During the
Power On Delay the Laser diode bias and modulation current will be held disabled and LDOFF will be held
high.
24)
Temperature and voltage drift are included.
25)
The minimal enable pulse width time for RST = L or RSTN = H or LEN = L has to be longer then tFDEL .
26)
Out of amPILOT and abPILOT a factor K = abPILOT/amPILOT can be defined, which is an important factor for the
pilot control (for definition of amPILOT and abPILOT see Figure 8). For most laser diodes the optimum value of
K is 1.44 (default value). If K is set close to factor 2 the modulation current and jitter may increase. If K is set
close to factor 1 the modulation current may decrease. In both cases a malfunction of laser control is possible.
A resistor between VCC and RMRIP can be used for decreasing amPILOT. Further a resistor between VCC and
RBRIP can be used for decreasing abPILOT. So the factor K can be adjusted. For default factor K let RBRIP
and RMRIP connected to VCC (= VCCA).
Preliminary Data Sheet
13
2001-05
FOA2322A
Electrical Characteristics
2.4
Typical Characteristics of Temperature Compensation (Mode 1)
2.4.1
Modulation Current Swing versus RMOD, RTC,
Junction Temperature and Supply Voltage / High Current Drive
ITD11327
2.8
F
2.6
2.4
2 k Ω/5 V
4 k Ω/5 V
4 k Ω/3.3 V
2 k Ω/3.3 V
2.2
2.0
1.8
1.6
1.4
1.2
0
500
1000
kΩ
1500
2000
RTC
Figure 2
F = I100 °C/I0 °C versus RTC, Parameter RMOD, VCC
ITD11328
80
mA
IO 70
60
2 kΩ/200 Ω
2 kΩ/700 Ω
2 kΩ/2 kΩ
4 kΩ/200 Ω
4 kΩ/700 Ω
4 kΩ/2 kΩ
50
40
30
20
10
-50
-30
-10
10
30
50
70
90
110 ˚C 130
t
Figure 3
I0 versus Tj, Parameter RMOD, RTC (VCC = 3.3 V)
Preliminary Data Sheet
14
2001-05
FOA2322A
Electrical Characteristics
ITD11329
100
mA
IO
80
2 kΩ/200 Ω
2 kΩ/700 Ω
2 kΩ/2 kΩ
4 kΩ/200 Ω
4 kΩ/700 Ω
4 kΩ/2 kΩ
70
60
50
40
30
20
10
0
-50
-30
-10
10
30
50
70
90
110 ˚C 130
t
Figure 4
I0 versus Tj, Parameter RMOD, RTC (VCC = 5.0 V)
Preliminary Data Sheet
15
2001-05
FOA2322A
Electrical Characteristics
2.4.2
Modulation Current Swing versus RMOD, RTC,
Junction Temperature and Supply Voltage / Low Current Drive
ITD11330
1.40
F
10 kΩ/3.3 V
10 kΩ/5 V
5 kΩ/5 V
5 kΩ/3.3 V
1.30
1.25
1.20
1.15
1.10
1.05
1.00
1800
2800
3800
4800
5800
6800
kΩ
7800
9800
RTC
Figure 5
F = I100 °C/I0 °C versus RTC, Parameter RMOD, VCC
ITD11331
18
mA
5 kΩ/2 kΩ
5 kΩ/5 kΩ
5 kΩ/9.5 kΩ
IO 16
15
14
13
12
11
10
10 kΩ/2 kΩ
10 kΩ/5 kΩ
10 kΩ/9.5 kΩ
9
8
7
6
5
-50
-30
-10
10
30
50
70
90
110 ˚C 130
t
Figure 6
I0 versus Tj, Parameter RMOD, RTC (VCC = 3.3 V)
Preliminary Data Sheet
16
2001-05
FOA2322A
Electrical Characteristics
ITD11332
18
mA
5 kΩ/2 kΩ
5 kΩ/5 kΩ
5 kΩ/9.5 kΩ
IO 16
15
14
13
12
11
10
10 kΩ/2 kΩ
10 kΩ/5 kΩ
10 kΩ/9.5 kΩ
9
8
7
6
5
-50
-30
-10
10
30
50
70
90
110 ˚C 130
Tj
Figure 7
I0 versus Tj, Parameter RMOD, RTC (VCC = 5.0 V)
Preliminary Data Sheet
17
2001-05
FOA2322A
Electrical Characteristics
2.5
Principle of Modulation Current Control by Using a Pilot Signal
(Mode 2)
The DC-part of the monitor current controls the bias current. The difference of the optical
low frequency AC-part ∆Ppp is used for the modulation current control. ∆Ppp is
measured over the monitor current. The aim of the control is to settle ∆Ppp to Zero. (That
means a part of the pilot current amplitude on bias current is modulated below laser
current threshold. Therefore please take into account the laser characteristics, e.g.
switch-on delay, for higher data rates.) Mode 2 can only be used for DC-coupled laser
diodes.
POpt
∆P1
P1
P
∆Ppp
P0
∆P0
abPILOT
amPILOT
∆Ppp = ∆P0 - ∆P1
Figure 8
ILaser
ITD11333
Modulation Current Control by Using a Pilot Signal
Preliminary Data Sheet
18
2001-05
FOA2322A
Electrical Characteristics
2.6
Data / Clock Input Stage
Data and clock inputs are terminated with 100 Ω and are connected to a VBB reference
by resistors R1/R2. (VBB for Clock input is VBBC, VBB for Data input is VBBD.) This easily
provides the input reference voltage at AC coupling. A schematic of the input stage is
shown below:
P
RIN
N
R1
R2
Reference
Generator
VBB
R1, R2 = 5 kΩ
RIN = 100 Ω ±20%
Figure 9
2.7
ITS11334
Data/Clock Input Stage
Timing of Clock and Data
Daten D/DN
50%
tSETUP
Clock CLK
tHOLD
50%
ITT11335
Figure 10
Timing of Clock and Data
Preliminary Data Sheet
19
2001-05
FOA2322A
Electrical Characteristics
2.8
Laser and VCC Supervising Circuit
If there is a laser fault (optical power deviates ±1 dB) this signal is stored and indicated
by LF (logic high). The fault indication (LF) can be reset with low level at RSTN or with
high level at RST or with power down (VCC < VCC Reset Threshold) only. After power up,
LF will always be cleared. Disabling the laser by LEN does not influence a previous fault
indication by LF. The laser fault generation can be switched off by connecting CFDEL to
VCC. During RSTN is logic low or RST is logic high the circuit is in Reset state.
In case of changing RST = H or RSTN = L after laser fault recognition LF = H (after
tFDEL) there is an additional delay time implemented which has the same value as the
Power On Delay.
If the supply voltage is lower than the VCC reset threshold the indicator Hardware Alarm
(HWA) is still at the low level and the circuit is in Reset state.
During Power On Delay the circuit is in Reset state too. The Power On Delay is defined
as the delay after VCC voltage has risen above the VCC reset threshold. This time can be
adjusted by an external capacitor at COSC (Mode 1). The Reset N-Output of the
MAX 809S Power Supervisor IC can be connected to RSTN to use the reset function of
the MAX 809S.
The laser control by RST and RSTN is fully redundant. This means only an AND
combination of RST = 0 / RSTN = 1 can switch the laser on. The OR combination of
RST = 1 / RSTN = 0 switches the laser off (see Table 4 for clarification).
Table 4
Laser Diode Currents Enable / Disable Signals
RST
LEN
RSTN
In Case of VCC < Reset
LDOFF Modulation Bias
LF (high
Laser Fault Threshold VCC
Enable1)
Enable1) active)
X
1
X
0
X
1
0
0
0
1
X
X
X
X
1
0
0
0
X
X
0
X
X
1
0
0
0
X
X
X
X
yes
1
0
0
0
0
0
1
1
no2)
13)
0
0
13)
0
0
1
0
no2)
04)
1
1
0
1)
Internal signal
2)
After Power On Delay
3)
After tFDEL
4)
Sink current enabled = Low
Table 4 shows the static states of these signals. Dynamic changes or delays due to
external delay capacitors are not shown.
Preliminary Data Sheet
20
2001-05
FOA2322A
Electrical Characteristics
Bias current is disabled by setting Bias Enable low, modulation current is disabled by
setting Modulation Enable low.
LEN do not effect LF. This means LF can not be reset by LEN.
2.9
Input Signal Monitoring and Hardware Alarm
(Consideration in absence of Laser Fault)
Table 5
Function of ISM Circuit and Hardware Alarm Indicator (HWA)
Data Level
(after delay
of ISM)
VCC < Reset
Constant High
ISM Laser LDOFF HWA (low
Enable1)
active)
Modulation Bias
Enable1)
Enable1)
No
0
1
0
0
0
Constant Low
No
0
1
0
0
0
Constant High
Yes
0
1
0
0
0
Constant Low
Yes
0
1
0
0
0
Duty Cycle ok
Yes
1
1
0
0
0
Duty Cycle ok
No
1
02)
1
1
1
Threshold of VCC
/Circuit in Reset
state
1)
Internal signal
2)
Sink current enabled = Low
Preliminary Data Sheet
21
2001-05
FOA2322A
Pin Description
3
Table 6
Pin Description
Pin Definitions and Functions
Signal Name Function
Explanation
D / DN
Differential Input
Differential data input. D corresponds to O and DN
to ON current output. With a high level at D and a
low level at DN modulation current is drawn by O
and ON is inactive. With a low level at D and a high
level at DN modulation current is drawn by ON and
O is inactive. Both inputs are prebiased to internal
VBBD. The input termination is 100 Ω.
CLK / CLKN
Differential Input
Differential clock input for input data latch. The
input termination is 100 Ω.
CSELN
Logic Input
A low level at CSELN enables the data input latch
(clocked mode), a high level or an open input
disables the data input latch (nonclocked mode). It
has an internal pull-up-resistor of about 10 kΩ.
O / ON
Differential Current These output signals drive the modulation current
Output
switched by D / DN data inputs.
CMOD
Control
The modulation controller characteristic can be set
to an i-controller with an external capacitor at
CMOD to VEE and the time constants are
adjustable in mode 2. Let open if mode 1 is used.
VMOD
Output
Base of the output current mirror 1:10. For normal
application it can be leave open if not used.
CISM
Control
With an external capacitor at CISM to VCC the
delay time for detection of a bad duty cycle data
input situation can be increased. If the input signal
monitor is not used CISM has to be pulled down by
25 kΩ resistor to VEE.
CILM
Control
With an external capacitor at CILM to VCC the
delay time for detection of static data input situation
can be increased. If the peak detector is not used
CILM has to short to VCC.
HWA
Logic Output
HWA is an open collector output (indicator output).
A low level is generated whenever a bad duty cycle
data input situation is detected by the input signal
monitor circuit or if the supply voltage is lower than
the VCC reset. Let open if not used.
Preliminary Data Sheet
22
2001-05
FOA2322A
Pin Description
Table 6
Pin Definitions and Functions (cont’d)
Signal Name Function
Explanation
IBIAS
Bias Output
A sink current drawn by IBIAS determines the laser
diode bias current.
CBIAS
Control
The bias controller characteristic is set to an
i-controller. The cutoff frequency can be decreased
by an external capacitor at CBIAS to VEE.
MPOUT
Monitor Output
MPOUT is an open collector output for pulling up a
resistor to monitor the deviation of the optical
power over the monitor diode current. Let open if
not used.
RPOUT
Control
A resistor between RPOUT and VEE can adjust the
relation of optical power measured over the
monitor diode current to output current at MPOUT.
Let open if the monitoring of the optical power is not
used.
VBIAS
Bias Output
This output can be connected to the base of an
external bias current NPN transistor. It can be
leave open if not used. It is dedicated for
applications which can not use the internal bias
transistor. Base of the output current mirror 1:25.
MD
Monitor Diode
Input
This is the controller feedback input. The voltage at
this input represents the monitor diode current and
by this the laser output power. The bias current will
be controlled to an equal level of VMD and VMDR.
LDOFF
Laser Shut Down
Output
Whenever the laser diode is disabled LDOFF will
deliver a high voltage level closed to VCC. If the
laser diode is enabled there is a sink current to
drive the base of an external pnp transistor to
support a laser diode supply shut down. If not used
this output can be leave open without Laser Driver
performance restrictions. There is an internal pull
up resistor between LDOFF and VCCA of 10k.
RSTN
Logic Input
Low active reset input. This input resets the LF
indication if present. Further the laser diode is held
within shut down mode if this signal is at low level.
For constant laser diode enable this signal can be
tied to VCC.
Preliminary Data Sheet
23
2001-05
FOA2322A
Pin Description
Table 6
Pin Definitions and Functions (cont’d)
Signal Name Function
Explanation
RST
Logic Input
High active reset input. This input resets the LF
indication if present. Further the laser diode is held
within shut down mode if this signal is at low level.
For constant laser diode enable this signal can be
tied to VEE.
LEN
Logic Input
A low level at LEN enables the laser diode, a high
level disables the laser diode. For constant enable
this input can be tied to VEE.
LF
Logic Output
Fault Indicator. A high level is generated whenever
a fault situation is detected by the supervisor
circuit. Fault situations are laser power failures
indicated by MD input voltage deviation from
VMDnom. Let open if not used.
CFDEL
Control
With an external capacitor at CFDEL to VEE the
laser fault detection delay time can be increased.
This means if a constant fault condition is present
a laser fault indication will be generated and the
laser will be shut down after this delay time. The
laser safety circuit can be switched off if CFDEL is
connected to VCC.
COSC
Control
With an external capacitor at COSC to VEE the
piloton frequency can be decreased (mode 2).
COSC determines the power on delay.
MODE
Logic Input
A high level at MODE sets the modulation control
circuit to mode 1 (using temperature compensation
circuit). A low level at MODE sets the modulation
control circuit to mode 2 (using modulation control
by pilot signal).
RMOD
Control
An external resistor at RMOD to VEE sets the
modulation current level (in mode 1). Let open if
mode 2 is used.
RTC
Control
An external resistor at RTC to VEE sets the
modulation current temperature coefficient. The
temperature information is derived from chip
junction temperature (in mode 1). Let open if
mode 2 is used.
Preliminary Data Sheet
24
2001-05
FOA2322A
Pin Description
Table 6
Pin Definitions and Functions (cont’d)
Signal Name Function
Explanation
RBRIP
Control
The pilot current amplitude on bias current
(mode 2) can be decreased by connecting a
resistor between RBRIP and VCC. For default
values do connect to VCC. It has no influence if
using mode 1. Let open if mode 1 is used.
RMRIP
Control
The pilot current amplitude on modulation current
high level (mode 2) can be decreased by
connecting a resistor between RMRIP and VCC.
For default values do connect to VCC. It has no
influence if using mode 1. Let open if mode 1 is
used.
START
–
Do not connect.
MX
–
Do not connect.
VCCA
VCCD
VCCD2
Power Supply
Positive power supply for analog circuit part.
Power Supply
Positive power supply for digital circuit part.
Power Supply
Positive power supply for digital circuit part with an
additional serial diode to increase the modulation
output voltage range of about 0.85 V for VCC range
of 5 V ± 0.5 V. Let open if it is not used.
VEE1
Power Supply
Negative power supply, only connected to the
output current mirror stage of bias generator,
normally GND.
VEE2
Power Supply
Negative power supply, only connected to the
output stage, normally GND.
VEE
Power Supply
Negative power supply of the rest of circuit,
normally GND.
Preliminary Data Sheet
25
2001-05
FOA2322A
Pin Description
VEE2
O
O
ON
ON
VEE2
IBIAS
VBIAS
VEE1
32
VCCD2
33
VMOD
Pad Layout
VCCD
3.1
31
30
29
28
27
26
25
24
23
22
LDOFF
34
21
VEE
HWA
35
20
MX
LF
36
19
MODE
RBRIP
37
18
COSC
START
38
17
VEE
RMRIP
39
16
MD
CMOD
40
15
CBIAS
RMOD
41
14
MPOUT
VCCA
42
13
RPOUT
2
3
4
5
6
7
8
9
10
11
12
x
CSELN
CLKN
CLK
LEN
DN
D
RST
CILM
RSTN
CFDEL
RTC
S1048 1
CISM
y
ITP11336
Figure 11
The pad center x/y positions are given in Table 7 (related to the chip origin 0/0 excl. Seal
ring):
Preliminary Data Sheet
26
2001-05
FOA2322A
Pin Description
Table 7
Pad Positions
Bottom:
1-12
Right:
13-21
Top:
33-22
Left:
42-34
x / µm
y / µm
x / µm
y / µm
x / µm
y / µm
x / µm
y / µm
271
137
1777
267
271
1498
141
267
396
137
1777
391
396
1498
141
391
521
137
1777
516
521
1498
141
516
646
137
1777
693
646
1498
141
693
771
137
1777
818
771
1498
141
818
896
137
1777
943
896
1498
141
943
1021
137
1777
1119
1021
1498
141
1119
1146
137
1777
1244
1146
1498
141
1244
1271
137
1777
1369
1271
1498
141
1369
1396
137
–
–
1396
1498
–
–
1521
137
–
–
1521
1498
–
–
1646
137
–
–
1646
1498
–
–
–
–
–
–
–
–
Die size: 1.92 mm × 1.64 mm (excl. seal ring)
Chip thickness: 300 µm
Frame grid: 2.024 mm × 1.75 mm
Bondpad window: 80 µm × 80 µm
Bondpad material: Aluminium
Substrate: VEE
Preliminary Data Sheet
27
2001-05
FOA2322A
Application Examples
4
Application Examples
VCC
CFDEL CISM
CILM
VCCD2
VCC
VCCD VCCA
LDOFF
LF
LEN
RST
RSTN
Laser Supervisor
VCC
Supervisor
Bias
Enable
HWA
VMOD
Modulation
Enable
D
DN
Input Stage
Modulator
O
O
ON
ON
VEE2
CLK
CLKN
Latch
VEE2
RBRIP
RMRIP
CMOD
MX
COSC
CSELN
VCC
VCC
Mode
Start
Modul. Control
Incl. Oscillator
Optional
RTC
Temperature
Compensation
RMOD
IBIAS
MD
Bias
Generator
Bias Control
VEE VEE
CBIAS
RPOUT
MPOUT
VBIAS
VEE1
Optional
Optional
ITS11337
Figure 12
Application Example A:
Using Mode 1
Preliminary Data Sheet
28
2001-05
FOA2322A
Application Examples
-5 V
CFDEL CISM
CILM
VCCD2
VCCD VCCA
LDOFF
LF
LEN
RST
RSTN
Laser Supervisor
VCC
Supervisor
Bias
Enable
X2
VMOD
Modulation
Enable
D
DN
Input Stage
CLK
CLKN
HWA
Modulator
Latch
CSELN
-5 V Mode
Start
Modul. Control
Incl. Oscillator
O
O
ON
ON
VEE2
-5 V
VEE2
-5 V
RBRIP
RMRIP
CMOD
MX
COSC
-5 V
-5 V
Optional
RTC
Temperature
Compensation
RMOD
IBIAS
Bias
Generator
Bias Control
VEE VEE
CBIAS
RPOUT
MPOUT
VEE1
Optional
X1
-5 V -5 V
-5 V
-5 V
VBIAS
-5 V
Current outputs pulled up to
+5 V (e.g. 2 × BCX68)
X1
Figure 13
X2
ITS11338
Application Example B: Power Supply with +5 V … 0 V (GND) … -5 V
Using Mode 2
Preliminary Data Sheet
29
2001-05
FOA2322A
Application Examples
VCC
CFDEL CISM
CILM
VCC
VCCD2
VCCD VCCA
LDOFF
LF
LEN
RST
RSTN
Laser Supervisor
VCC
Supervisor
Bias
Enable
HWA
VMOD
Modulation
Enable
D
DN
Input Stage
Modulator
O
O
ON
ON
VEE2
CLK
CLKN
Latch
VEE2
RBRIP
RMRIP
CMOD
MX
COSC
CSELN
VCC
VCC
Mode
Start
Modul. Control
Incl. Oscillator
Optional
RTC
Temperature
Compensation
RMOD
IBIAS
MD
Bias
Generator
Bias Control
VEE VEE
CBIAS
RPOUT
MPOUT
VBIAS
VEE1
Optional
Optional
ITS11344
Figure 14
Application Example C: Using VCCD2 for increasing the Modulation
Output Voltage Range for the VCC Range of 5 V ± 0.5 V (here mode 1)
Preliminary Data Sheet
30
2001-05
FOA2322A
Application Examples
VCC
VCC
50 Ω
50 Ω
100 nF 20 Ω
50 Ω
220 nH
ON
16.7 Ω
ON
CComp [x pF]
CComp [x pF]
RComp [xx Ω]
RComp [xx Ω]
20 Ω
20 Ω
O
O
100 nF
100 nF
220 nH
IBIAS
220 nH
IBIAS
ITS11339
VCC
ITS11340
VCC
15 Ω
220 nH
10 Ω
ON
ON
CComp [x pF]
CComp [x pF]
RComp [xx Ω]
RComp [xx Ω]
10 Ω
10 Ω
O
O
220 nH
IBIAS
Figure 15
220 nH
IBIAS
ITS11341
ITS11342
Application Example D: Several Kinds for Connecting Laser Diode
(1300 nm-FP-laser, 5 Ω);
Resistor values are proposed values. They depend on used laser diodes, currents and
mechanical and PCB design.
Preliminary Data Sheet
31
2001-05
FOA2322A
Application Examples
VCC
LLarge
100 Ω LLarge
100 Ω
L = 5.6 nH
L = 5.6 nH
ON
CComp [x pF]
RComp [xx Ω]
20 Ω
O
100 nF
220 nH
IBIAS
Figure 16
ITS11343
Application Example D: Several Kinds for Connecting Laser Diode
(1300 nm-FP-laser, 5 Ω) (cont’d);
Preliminary Data Sheet
32
2001-05
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idleness and wastefulness for all of us, more professional
success, more accurate information, a better overview and,
thereby, less frustration and more satisfaction.”
Dr. Ulrich Schumacher
http://www.infineon.com
Published by Infineon Technologies AG
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