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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
Never
stop
thinking.
Edition 2001-05 Published by Infineon Technologies AG, St.-Martin-Strasse 53, D-81541 Munchen, Germany
(c) 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 Infineon Technologies Office in Germany or our Infineon Technologies Representatives worldwide. Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may 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
Never
stop
thinking.
FOA2322A Revision History: Previous Version: Page Subjects (major changes since last revision) 2001-05
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 1 1.1 1.2 1.3 1.4 2 2.1 2.2 2.3 2.4 2.4.1 2.4.2 2.5 2.6 2.7 2.8 2.9 3 3.1 4
Page 2 2 2 2 2
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Pad Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Preliminary Data Sheet
1
2001-05
3.2 Gbit/s Laser Driver IC for Telecom and Datacom Applications FOA2322A
FOA2322A
1
1.1
* * * * *
Overview
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 A 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
LEN RST RSTN
LDOFF LF Laser Supervisor Supervisor HWA Bias Enable Modulation Enable
VCC
VMOD
O O ON ON
D DN Input Stage CLK CLKN CSELN Mode Start Modul. Control Incl. Oscillator Latch Modulator
VEE2 VEE2
RBRIP RMRIP CMOD MX COSC
Temperature Compensation
RTC RMOD
MD Bias Control
IBIAS
Bias Generator
VBIAS
VEE VEE CBIAS
RPOUT MPOUT
VEE1
ITB11326
Figure 1
General Circuit Block Diagram
- Number of pins: 42 - IC available as die
Preliminary Data Sheet
4
2001-05
FOA2322A
Electrical Characteristics
2
2.1
Electrical Characteristics
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 Parameter Supply Voltage Output Voltage at O, ON Output Voltage at MPOUT Output Voltage at Logic Output LF, HWA Output Voltage at IBIAS Input Voltage at Logic Inputs LEN, RST, RSTN, CSELN Differential Data Input Voltage |VD - VDN| Differential Data Input Voltage |VCLK - VCLKN| Sink Current at Logic Output LF, HWA Source Current at LDOFF Source Current at RPOUT Modulation Current at O, ON (both Outputs) Bias Current at IBIAS Modulation Control Sink Current at VMOD (Input Current for Current Mirror 1:10) Bias Control Sink Current at VBIAS (Input Current for Current Mirror 1:25) Modulation Current Adjust Resistor RMOD Absolute Maximum Ratings SymLimit Values bol min. max. -0.3 6 Unit Conditions V V V V V V V V mA mA mA mA mA mA mA -
1) 1)2) 1) 1)2) 1)
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
- - - -4 -2 - - - - 800 2.5 2.5 5 - - 80 95 9.6 4.8 -
- - - - - - - - - -
Preliminary Data Sheet
5
2001-05
FOA2322A
Electrical Characteristics Table 1 Parameter Modulation Temperature Coefficient Resistor RTC Junction Temperature Storage Temperature Relative Humidity (non-condensing) Electrostatic Discharge Voltage Capability
1) 2)
Absolute Maximum Ratings (cont'd) SymLimit Values bol min. max. 50 -40 -55 - - - 125 150 95 1 Unit Conditions C C % kV - - - - -
Maximum voltage is 6 V. 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 Parameter General Operating Conditions SymLimit Values bol min. max. Unit Conditions
Environmental Junction Temperature Relative Humidity (non-condensing) Supply Voltage -40 -40 - 125 110 95 % C
1) 2)
-
VCC Range
1) 2) 3)
3
5.5
V
3)
For modulation current IOH 50 mA For modulation current 50 mA < IOH 75 mA Valid for VCCA and VCCD; VCCA VCCD
Preliminary Data Sheet
6
2001-05
FOA2322A
Electrical Characteristics
2.3
Table 3
Characteristics and Operating Conditions
Characteristics and Operating Conditions Symbol Limit Values min. typ. max. Unit Condition
SP Parameter
Modulator / Modulation Control 1 2 3 Data Transmission Rate Supply Current Modulation Current High at O/ON for VCC = 3.3 V for VCC = 5 V Modulation Current Low at O/ON Modulation Current at Laser Shut Down O, ON Output Voltage Range for VCC = 3.3 V for VCC = 5 V 7 Modulation Current Adjust RMOD Resistor Range (MOD-Resistor) Modulation Temperature Coefficient Resistor Range DR 0 - - 30 2.5 63 Gbit/s 1) mA mA 5 5 - - - - 65 75 2 200 mA A V
6) 2)3) 4)5)
ICC IOH IOL
4 5 6
IOL IOSD V O, VON
0 0
Offset
7)
8)
VCC 1.65 V VCC 2.0 V 800
- - -
VCC VCC
Open Input
9)10)
8
RTC
50
-
Open Input
9)11)
Serial Data/Clock Input 9 Data Input Voltage High
VIHD VILD
- 1.0 2.2 250 -
- - - - -
VCCD
- - 1600
V V
- -
10 Data Input Voltage Low for VCCD = 3.3 V for VCCD = 5 V
11 Data Input Voltage Swing |VD VDN| 12 Clock Input Voltage High VIHCLK
mV
- -
VCCD - 0.65 V
Preliminary Data Sheet
7
2001-05
FOA2322A
Electrical Characteristics Table 3 Characteristics and Operating Conditions (cont'd) Symbol
VILCLK
1.0 2 |VCLK VCLKN| 250 - - 80 - - - - - - - - - 1100 mV V V pF ps ps ps -
12) 12)
SP Parameter
13 Clock Input Voltage Low for VCCD = 3.3 V for VCCD = 5 V 14 Clock Input Voltage Swing 15 Bias Voltage at D/DN 16 Bias Voltage at CLK/CLKN 17 Differential Data/Clock Input Termination 19 Input Capacitance D/DN/CLK/CLKN 20 Setup Time (Data/Clock) 21 Hold Time (Data/Clock) 22 Eye Opening at 2.5 Gbit/s (w. Latch) Input Signal Monitor (ISM) 23 Internal ISM cutoff frequency 24 Cutoff frequency of ISM with external CISM 25 Internal ILM cutoff frequency 26 Cutoff frequency of ILM with external CILM = 1nF 27 Duty Cycle for laser enable 28 Duty Cycle for laser disable 29 Duty Cycle for laser disable
Limit Values min. typ. max.
Unit Condition
V -
VBBD VBBC RIN CIN tSETUP tHOLD tEO
VCCD - 1.0 - VCCD - 1.3 -
100 - 20 20 360 120 0.6 - - -
12)13)
- - - -
fISM
fISM
165 (6.1 s + 84 k x CISM)-1 - - 25 0 95
238 (4.2 s + 70 k x CISM)-1 160 73 - - -
372 (2.7 s + 56 k x CISM)-1 - - 75 5 100
kHz
14)
14)15)
fILM fILM
kHz kHz % % %
14)
14)15)
- Input low Input high
Preliminary Data Sheet
8
2001-05
FOA2322A
Electrical Characteristics Table 3 Characteristics and Operating Conditions (cont'd) Symbol Limit Values min. typ. max. Unit Condition
SP Parameter
Laser Power Control 30 Bias Current 31 Start Bias Current 32 Bias Current at Laser Shut Down 33 Output Voltage Range IBIAS 34 Power Monitor Current 35 Output Voltage Range MPOUT 36 Resistor Range RPOUT 37 Output Voltage Range RPOUT 38 Internal cutoff frequency of bias controller 39 Cutoff frequency of bias controller with external IIBIASmax IIBIASmin IIBIASSD 0 - - 0.5 0 - - - - 80 500 500 mA A A V mA V - - - -
16)
VIBIAS IMPOUT VMPOUT RPOUT VRPOUT fBIAS fBIAS
VCC
1
VMD RPOUT
- -
VRPOUT +
0.5 2.4 0 23 (44 s + 306 k x CBIAS)-1 -
VCC
- - -
17)
Open Input k
VMD
37 (27 s + 204 k x CBIAS)-1 100
VCC - 1.2
62 (16 s + 131 k x CBIAS)-1 -
V kHz
15)17)
CBIAS
40 Conversion gain of bias generator Laser Supervising Circuit 41 MD Failure Voltage High 42 MD Failure Voltage Low 43 MD Range without Failure Recognition 44 Internal Failure Recognition Time 45 Additional Failure Recognition Time by external CFDEL
GBIAS
mA/V -
-
VMDnom +
1.5 dB
VMDnom +
2 dB -
18)
VMDnom 2 dB
VMDnom 1.55 dB - 60
18)
VMDnom 1.2 dB
VMDnom +
1.2 dB 86
V s
19)
tFDEL tFDEL
38
17)20)
0.7 s/pF
CFDEL x
1.0 s/pF
CFDEL x
1.3 s/pF
CFDEL x
15)17)20)
Preliminary Data Sheet
9
2001-05
FOA2322A
Electrical Characteristics Table 3 Characteristics and Operating Conditions (cont'd) Symbol Limit Values min.
0 2.5
SP Parameter
typ.
- 2.75 333
max.
3 2.99 480
Unit Condition
s V s
21)
46 Shut Off Time after LF tLDdis transition or Laser Disable 47 VCC Reset Threshold for Laser Enable/Disable 48 Internal Power On Delay 49 Additional Power On Delay by external COSC 50 LDOFF low Output Current 51 LDOFF high Output Current 52 LDOFF high Output Voltage 53 LDOFF low Output Voltage
22)
tPDEL tPDEL
213
23) 15)23)
64 x COSC 64 x COSC 64 x COSC x 138 k x 173 k x 208 k 1.5 - - - - - 4 2 - mA A V V
sink current sink current - without external load
VCC - 0.1 VCC - 2.0
VCC - 1.2
Reference Voltage 54 MD Reference Value 55 VMDR Drift over Temperature Range 56 VMDR Drift over Supply Voltage Range 3 V ... 5.5 V 57 VMDR Drift over Temperature Range at Supply Voltage Range 3 V ... 3.6 V 58 VMDR Drift over Temperature Range at Supply Voltage Range 4.7 V ... 5.3 V
VMDR
1.12 - -
- - -
1.32 5 10
V % %
24)
|VMDR/ VMDR| |VMDR/ VMDR| |VMDR/ VMDR| |VMDR/ VMDR|
- -
-
-
5
%
-
-
-
5
%
-
Preliminary Data Sheet
10
2001-05
FOA2322A
Electrical Characteristics Table 3 Characteristics and Operating Conditions (cont'd) Symbol Limit Values min. typ. max. Unit Condition
SP Parameter
Logic Inputs RSTN, RST, LEN 59 Input Voltage High 60 Input Voltage Low 61 Input Current High 62 Input Current Low 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) 65 Internal Pull-Up-Resistor Logic Outputs LF, HWA 66 Output Voltage Low 67 Output Current High (Leakage Current) 68 Output Current Low 2.2 -
VIHLOGIC 2.0 VILLOGIC IIHLOGIC IILLOGIC
0 - -5
- - - -
VCC
0.8 5 -
V V A A
25) 25)
- -
VCC
V
-
VILLOGIC
0
-
0.8
V
-
RCSELN
8
10
12
k
-
VOLLOGIC - IOHLOGIC - IOLLOGIC 2
- - -
0.4 100 -
V A mA
- open collector sink current
Modulation Control (Mode 2) 69 Mode 1 select 70 Mode 2 select 71 Internal pilot frequency 72 Pilot frequency with external COSC
VMODE VMODE fPILOT fPILOT
VCC - 0.8
0 7.7
- - 12
VCC
0.8 17.3
V V kHz
- - -
15)
(130 s + (83 s + (58 s + 16 x COSC 16 x COSC 16 x COSC x 208 k)-1 x 173 k)-1 x 138 k)-1 - 3.5 - %
73 Effective pilot current amPILOT amplitude on modulation current high level (default) Preliminary Data Sheet
26)
11
2001-05
FOA2322A
Electrical Characteristics Table 3 Characteristics and Operating Conditions (cont'd) Symbol Limit Values min.
- (306 k x CMOD)-1
SP Parameter
typ.
5.05 (204 k x CMOD)-1
max.
- (131 k x CMOD)-1
Unit Condition
%
26)
74 Pilot current amplitude on abPILOT bias current (default) 75 Cutoff frequency of fMOD modulation controller with external CMOD
1) 2) 3)
15)17)
Measured into 25 . The bias-, modulation-, the LF-, HWA- and MPOUT- output currents are not included. 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). 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). See Table 2 for operating conditions junction temperature. Inactive current output (see also 4)). Modulation current when the laser diode is disabled. 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. Adjustment of programmable parameter by resistor value within this range (see Chapter 2.4). 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. 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. 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). The resistance is guaranteed for junction temperature 25 C.
4)
5) 6) 7) 8)
9) 10)
11)
12)
13)
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 k 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. A capacitor within this range programs the time (or frequency). Open collector output for pulling up a resistor to monitor the current. Difference and temperature drift of passive IC component parameters match to passive IC component parameters in other circuit parts. 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). 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). 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. Time between LF high (or LEN high) and LDOFF high. 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. 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. Temperature and voltage drift are included. The minimal enable pulse width time for RST = L or RSTN = H or LEN = L has to be longer then tFDEL . 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).
15) 16) 17)
18)
19)
20)
21) 22)
23)
24) 25) 26)
Preliminary Data Sheet
13
2001-05
FOA2322A
Electrical Characteristics
2.4 2.4.1
Typical Characteristics of Temperature Compensation (Mode 1) Modulation Current Swing versus RMOD, RTC, Junction Temperature and Supply Voltage / High Current Drive
2.8
ITD11327
F
2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 2 k/5 V 4 k/5 V 4 k/3.3 V 2 k/3.3 V
0
500
1000
1500
k
2000
RTC
Figure 2
F = I100 C/I0 C versus RTC, Parameter RMOD, VCC
80 mA
ITD11328
IO 70
60 50 40 30 20 10 -50 2 k/200 2 k/700 2 k/2 k 4 k/200 4 k/700 4 k/2 k
-30
-10
10
30
50
70
90
110 C 130
t
Figure 3
I0 versus Tj, Parameter RMOD, RTC (VCC = 3.3 V)
14 2001-05
Preliminary Data Sheet
FOA2322A
Electrical Characteristics
100 mA
ITD11329
IO
80 70 60 50 40 30 20 10 0 -50 -30 -10 10 30 50 70 90 110 C 130 2 k/200 2 k/700 2 k/2 k 4 k/200 4 k/700 4 k/2 k
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
1.40
ITD11330
F
1.30 1.25 1.20 1.15 1.10 1.05 1.00 1800 2800 3800 4800 5800 6800 7800 k 9800 10 k/3.3 V 10 k/5 V 5 k/5 V 5 k/3.3 V
RTC
Figure 5
F = I100 C/I0 C versus RTC, Parameter RMOD, VCC
18 mA
ITD11331
IO 16
15 14 13 12 11 10 9 8 7 6 5 -50 -30 -10 10
5 k/2 k 5 k/5 k 5 k/9.5 k
10 k/2 k 10 k/5 k 10 k/9.5 k
30
50
70
90
110 C 130
t
Figure 6
I0 versus Tj, Parameter RMOD, RTC (VCC = 3.3 V)
16 2001-05
Preliminary Data Sheet
FOA2322A
Electrical Characteristics
18 mA
ITD11332
IO 16
15 14 13 12 11 10 9 8 7 6 5 -50 -30 -10 10
5 k/2 k 5 k/5 k 5 k/9.5 k
10 k/2 k 10 k/5 k 10 k/9.5 k
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 Ppp = P0 - P1
amPILOT
ILaser
ITD11333
Figure 8
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 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 k RIN = 100 20%
ITS11334
Figure 9
Data/Clock Input Stage
2.7
Timing of Clock and Data
Daten D/DN
50%
tSETUP
tHOLD
Clock CLK
50%
ITT11335
Figure 10
Timing of Clock and Data
19 2001-05
Preliminary Data Sheet
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
RST X 1 X X 0 0
1) 2) 3) 4)
Laser Diode Currents Enable / Disable Signals
RSTN X X 0 X 1 1 In Case of VCC < Reset LDOFF Modulation Bias LF (high Laser Fault Threshold VCC Enable1) Enable1) active) 0 X X X 1 0 X X X yes no2) no2) 1 1 1 1 13) 04) 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 13) 0
LEN 1 X X X 0 0
Internal signal After Power On Delay After tFDEL 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)
Function of ISM Circuit and Hardware Alarm Indicator (HWA)
VCC < Reset
Threshold of VCC /Circuit in Reset state No No Yes Yes Yes No ISM Laser LDOFF HWA (low Enable1) active) Modulation Bias Enable1) Enable1)
Table 5
Data Level (after delay of ISM) Constant High Constant Low Constant High Constant Low Duty Cycle ok Duty Cycle ok
1) 2)
0 0 0 0 1 1
1 1 1 1 1 02)
0 0 0 0 0 1
0 0 0 0 0 1
0 0 0 0 0 1
Internal signal Sink current enabled = Low
Preliminary Data Sheet
21
2001-05
FOA2322A
Pin Description
3
Table 6 D / DN
Pin Description
Pin Definitions and Functions Explanation 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 . Differential clock input for input data latch. The input termination is 100 . 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 k. Differential Input
Signal Name Function
CLK / CLKN
Differential Input Logic Input
CSELN
O / ON CMOD
Differential Current These output signals drive the modulation current Output switched by D / DN data inputs. 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. Base of the output current mirror 1:10. For normal application it can be leave open if not used. 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 k resistor to VEE. 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 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.
22 2001-05
VMOD CISM
Output Control
CILM
Control
HWA
Logic Output
Preliminary Data Sheet
FOA2322A
Pin Description Table 6 IBIAS CBIAS Pin Definitions and Functions (cont'd) Explanation A sink current drawn by IBIAS determines the laser diode bias current. 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 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. 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. 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. 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. 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. 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. Bias Output Control
Signal Name Function
MPOUT
Monitor Output
RPOUT
Control
VBIAS
Bias Output
MD
Monitor Diode Input
LDOFF
Laser Shut Down Output
RSTN
Logic Input
Preliminary Data Sheet
23
2001-05
FOA2322A
Pin Description Table 6 RST Pin Definitions and Functions (cont'd) Explanation 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. 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. 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. 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. With an external capacitor at COSC to VEE the piloton frequency can be decreased (mode 2). COSC determines the power on delay. 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). An external resistor at RMOD to VEE sets the modulation current level (in mode 1). Let open if mode 2 is used. 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. Logic Input
Signal Name Function
LEN
Logic Input
LF
Logic Output
CFDEL
Control
COSC
Control
MODE
Logic Input
RMOD
Control
RTC
Control
Preliminary Data Sheet
24
2001-05
FOA2322A
Pin Description Table 6 RBRIP Pin Definitions and Functions (cont'd) Explanation 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. 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. Do not connect. Do not connect. Positive power supply for analog circuit part. Positive power supply for digital circuit part. 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. Negative power supply, only connected to the output current mirror stage of bias generator, normally GND. Negative power supply, only connected to the output stage, normally GND. Negative power supply of the rest of circuit, normally GND. Control
Signal Name Function
RMRIP
Control
START MX
- - Power Supply Power Supply Power Supply
VCCA VCCD VCCD2
VEE1
Power Supply
VEE2 VEE
Power Supply Power Supply
Preliminary Data Sheet
25
2001-05
FOA2322A
Pin Description
3.1
Pad Layout
VCCD2
VMOD
VBIAS
23
VCCD
VEE2
VEE2
33 LDOFF HWA LF RBRIP START RMRIP CMOD RMOD 34 35 36 37 38 39 40 41 42
S1048 1
32
31
30
29
28
27
26
25
24
22 21 20 19 18 17 16 15 14 13
VEE1
IBIAS
ON
ON
O
O
VEE
MX MODE COSC
VEE
MD CBIAS MPOUT RPOUT
VCCA
y
2
CISM
3
CSELN
4
CLKN
5
CLK
6
LEN
7
DN
8
D
9
RST
10
CILM
11
RSTN
12
CFDEL
RTC
x
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 Bottom: x / m 271 396 521 646 771 896 1021 1146 1271 1396 1521 1646 - - - - - - Pad Positions 1-12 y / m 137 137 137 137 137 137 137 137 137 137 137 137 Right: x / m 1777 1777 1777 1777 1777 1777 1777 1777 1777 - - - 13-21 y / m 267 391 516 693 818 943 1119 1244 1369 - - - Top: x / m 271 396 521 646 771 896 1021 1146 1271 1396 1521 1646 33-22 y / m 1498 1498 1498 1498 1498 1498 1498 1498 1498 1498 1498 1498 Left: x / m 141 141 141 141 141 141 141 141 141 - - - 42-34 y / m 267 391 516 693 818 943 1119 1244 1369 - - -
Die size: 1.92 mm x 1.64 mm (excl. seal ring) Chip thickness: 300 m Frame grid: 2.024 mm x 1.75 mm Bondpad window: 80 m x 80 m Bondpad material: Aluminium Substrate: VEE
Preliminary Data Sheet
27
2001-05
FOA2322A
Application Examples
4
Application Examples
VCC VCC VCC
CFDEL CISM LEN RST RSTN
CILM
VCCD2
VCCD VCCA
LDOFF LF
Laser Supervisor
Supervisor Bias Enable D DN Input Stage CLK CLKN CSELN Latch Modulator
VCC
HWA
VMOD
Modulation Enable O O ON ON
VEE2 VEE2
RBRIP RMRIP CMOD MX COSC
VCC
Mode Start
Modul. Control Incl. Oscillator
Optional
RTC Temperature Compensation RMOD
IBIAS
MD Bias Control Bias Generator RPOUT MPOUT
VBIAS
VEE VEE
CBIAS Optional
VEE1
Optional
ITS11337
Figure 12
Application Example A: Using Mode 1
28 2001-05
Preliminary Data Sheet
FOA2322A
Application Examples
-5 V CFDEL CISM LEN RST RSTN CILM
VCCD2
VCCD VCCA
LDOFF LF
Laser Supervisor
Supervisor Bias Enable D DN Input Stage CLK CLKN CSELN -5 V Mode Start Modul. Control Incl. Oscillator Latch Modulator
VCC
HWA
X2
VMOD
Modulation Enable O O ON ON
VEE2 VEE2
RBRIP RMRIP CMOD MX COSC
-5 V -5 V
-5 V -5 V Optional
RTC Temperature Compensation RMOD
IBIAS
Bias Generator RPOUT MPOUT X1 -5 V -5 V -5 V -5 V -5 V
VBIAS
Bias Control
VEE VEE
CBIAS
VEE1
Optional
Current outputs pulled up to +5 V (e.g. 2 x BCX68) X1 X2
ITS11338
Figure 13
Application Example B: Power Supply with +5 V ... 0 V (GND) ... -5 V Using Mode 2
29 2001-05
Preliminary Data Sheet
FOA2322A
Application Examples
VCC
VCC
VCC
CFDEL CISM LEN RST RSTN
CILM
VCCD2
VCCD VCCA
LDOFF LF
Laser Supervisor
Supervisor Bias Enable D DN Input Stage CLK CLKN CSELN Latch Modulator
VCC
HWA
VMOD
Modulation Enable O O ON ON
VEE2 VEE2
RBRIP RMRIP CMOD MX COSC
VCC
Mode Start
Modul. Control Incl. Oscillator
Optional
RTC Temperature Compensation RMOD
IBIAS
MD Bias Control Bias Generator RPOUT MPOUT
VBIAS
VEE VEE
CBIAS Optional
VEE1
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)
30 2001-05
Preliminary Data Sheet
FOA2322A
Application Examples
VCC
50 ON 50 100 nF 20 220 nH
VCC
50 ON 16.7
CComp [x pF] RComp [xx ]
20 O 100 nF 220 nH O
CComp [x pF] RComp [xx ]
20 100 nF 220 nH
IBIAS
ITS11339
IBIAS
ITS11340
VCC
220 nH 10 ON
VCC
15 ON
CComp [x pF] RComp [xx ]
10 O 220 nH O
CComp [x pF] RComp [xx ]
10
220 nH
IBIAS
ITS11341
IBIAS
ITS11342
Figure 15
Application Example D: Several Kinds for Connecting Laser Diode (1300 nm-FP-laser, 5 );
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 LLarge 100
L = 5.6 nH
ON
L = 5.6 nH
CComp [x pF] RComp [xx ]
20 O 100 nF 220 nH
IBIAS
ITS11343
Figure 16
Application Example D: Several Kinds for Connecting Laser Diode (1300 nm-FP-laser, 5 ) (cont'd);
Preliminary Data Sheet
32
2001-05
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