VITESSE VSC7940W, VSC7940RP Datasheet

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

VSC7940

Laser Diode Driver with Automatic Power Control

SONET/SDH 3.125Gb/s

Features Applications

• Power Supply: 5V ±5%

• DC-Coupled to Laser Diode

• Programmable Modulation Current: 5mA to 100mA

• Programmable Bias Current: 1mA to 100mA

• Enable/Disable Control

• Automatic Optical Average Power Control

• Modulation and Bias Current Monitors

• SONET/SDH at 622Mb/s, 1.244Gb/s,

2.488Gb/s, 3.125Gb/s

• Full-Speed Fibre Channel (1.062Gb/s)

General Description

The VSC7940 is a single 5V supply laser diode driver specially designed for SONET/SDH applications up to 3.125Gb/s. External resistors set a wide range of bias and modulation currents for driving the laser. Data and clock inputs accept differential PECL signals. The Automatic Power Control (APC) loop maintains a constant average optical power over temperature and li fetime. The domi nant pole of t he APC loop can be c ontrol led with an external capacitor. Other features include enable/disable control, programmable slow-start circuit to set laser turn-on delay, and failure-monitor output to indicate when the APC loop is unable to maintain the average optical power. The VSC7940 is available in die form or in a 32-pin TQFP package.

Block Diagram

DATA+

DATA-

CLK+ CLK-

ENABLE

DISABLE

SET

CLR

MODSET

MUX

LATCH

BIASMAX

APC

CAPC

APCSET

MODMON

MD FAIL

IOUT+ IOUT-

BIAS

BIASMON

1nF

G52357-0, Rev 3.2 Page 1 05/11/01

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

SONET/SDH 3.125Gb/s

Preliminary Data Sheet

Laser Diode Driver with Automatic Power Control

Electrical Characteristics

Table 1: AC Specifications

AC specifications are guaranteed by design an d characterization. Typical values are for 5V operation.

Symbol Parameter Min Typ Max Units Conditions

PWD Pulse Width Distortion 10 50 ps See Notes 1, 2 CID

NOTES: (1) Measured with 622Mb/s 0-1 pattern , LATCH=high. (2) P WD = (wi der pulse - narrower pulse) / 2).

Input Latch Setup Time 100 ps LATCH=high Input Latch Hold Time 100 ps LATCH=high Enable/Start-up Delay 250 ns Output Rise Time TBD TBD ps 20% to 80% Output Fall Time TBD TBD ps 20% to 80%

Maximum Consecu tive Identical D igits 80 bits

MAX

Jitter Generation 7 20 ps

p-p

Jitter BW=12kHz to 20MHz, 0-1 pattern.

VSC7940

Table 2: DC Specifications

Symbol Parameter Min Typ Max Units Conditions

BIAS

BIAS-OFF

BIAS

MOD

MOD-OFF

Power Supply Voltage 4.75 5.0 5.25 V

Power Supply Current TBD 45 mA

Bias Current Range 1 100 mA Voltage at BIAS pin=(VCC-1.6)

Bias Off Current 100 µA

Bias Current Stability

Bias Current Absolute Accuracy ±15 % Refers to part-to-part variation Monitor Diode Reverse Bias Voltage 1.5 V Monitor Diode Reverse Current Range 18 1000 µA

Monitor Diode Bias Setpoint Stability

Monitor Diode Bias Absolute Accuracy -15 15 % Refers to part-to-part variation Modulation Current Range 5 100 mA

Modulation Off Current 200 µA

Modulation Current Absolute Accuracy ±15 % See Not e 2

-480 -50 480

230 900 APC open loop. I

90 IMD=18µA

ppm/°C

R I

BIAS

ENABLE=low or DISABLE=high

APC open loop. I

IMD=1mA

ENABLE=low or DISABLE=high

MODSET BIASMAX

and I

=7.3kΩ

=4.8kΩ

excluded, VCC=5V

MOD

(1)

BIAS BIAS

(2)

(1)

=100mA =1mA

Page 2 G52357-0, Rev 3.2

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

05/11/01

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

VSC7940

Laser Diode Driver with Automatic Power Control

SONET/SDH 3.125Gb/s

Symbol Parameter Min Typ Max Units Conditions

Modulation Current Stability

BIAS

MOD

NOTES: (1) Both I

BIASMON to I MODMON to I

tion does not change with temperature.

BIAS

and I

-480 -50 480 250 I

Gain 37 I

BIAS

Gain 29 I

MON

will turn off if any of the current set pins are grounded. (2) Assume s l ase r di ode t o monitor diode transfer func-

MOD

ppm/°C

=60mA

MOD

=5mA

MOD BIAS/IBIASMON MOD/IMODMON

Table 3: PECL and TTL/CMOS Input/Output Specifications

Symbol Parameter Min Typ Max Units Conditions

ICM

Differential Input Voltag e 100 1600 mV

1.49

VCC -

1.32

Common-Mode Input Voltage Clock and Data Input Current -1 10 mA

TTL Input High Voltage (ENABLE, LATCH) 2.0 V TTL Input Low Voltage (ENABLE, LATCH) 0.8 V

TTL Output High Voltage (FAIL TTL Output Low Voltage (FAIL

)2.4

) 0.1 0.44 V Sinking 100µA

0.3

VCC V

V PECL-compatible

V Sourcing 50µA

(DATA+)-(DATA-)

p-p

Absolute Maximum Ratings

(1)

Power Supply Voltage (VCC).............................................................................................................-0.5V to +7V

Current into BIAS.....................................................................................................................-20mA to +150mA

Current into OUT+, OUT-...............................................................................................................................TBD

Current into MD.............................................................................................................................-5mA to +5mA

Current into FAIL

Voltage at DATA+, DATA-, CLK+, CLK-, ENABLE, LATCH.........................................-0.5V to (V

Voltage at APCFILT, MODSET, BIASMAX, APCSET, MD, FAIL

Voltage at OUT+, OUT- ..................................................................................................... -0.5V to (V

Voltage at BIAS.................................................................................................................. -0.5V to (V

Continuous Power Dissipation (T

......................................................................................................................... -10mA to 30mA

+ 0.5V)

.............................................-0.5V to +3.0V

+ 1.5V)

+ 0.5V)

= +85°C, TQFP derate 20.8mW/°C above +85°C) .........................1350mW

Operating Junction Temperature Range...................................................................................... -55°C to +150°C

Storage Temperature Range ........................................................................................................ -65°C to +165°C

NOTE: (1) CAUTION: Stresses listed under “Absolute Maximum Ratings” may be applied to devices one at a time without caus-

ing permanent damage. Functionality at or above the values listed is not implied. Exposure to these values for extended periods may affect device reliability.

Recommended Operating Conditions

Positive Voltage Rail (VCC)..............................................................................................................................+5V

Negative Voltage Rail (GND) ............................................................................................................................ 0V

Ambient Temperature Range (T

)..................................................................................................-40°C to +85°C

G52357-0, Rev 3.2 Page 3 05/11/01

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

SONET/SDH 3.125Gb/s Laser Diode Driver with Automatic Power Control

Bare Die Pad Descriptions

Figure 1: Pad Assignments

1773

µm (0.0698")

Pad 10

GND1

Pad 11 LATCH

Pad 12 ENABLE

Pad 13

DISABLE

Pad 14

GND1

Pad 15

BIASMON

Pad 9 VCC1

(Pin 8)

(Pin 9)

(Pin 10)

(Pin 11)

Pad 8

CLK-

Pad 7 CLK+

(Pin 5)

Pad 6 VCC1

Pad 5 GND1

Pad 4 VCC1

Pad 3

DATA-

Pad 2

DATA+

Preliminary Data Sheet

VSC7940

Pad 1

Pad 48

VCC1

GND1

(Pin 1)(Pin 2)(Pin 3)(Pin 4)(Pin 6)(Pin 7)

(Pin 32)

(Pin 31)

(Pin 30)

(Pin 29)

Pad 47

GND2

Pad 46

VCC2

Pad 45

BIASMAX

Pad 44

MODSET

Pad 43

GND2

Pad 42

APCSET

µm

(0.0008")

Pad 16

(Pin 12)

2233

µm

(0.0879")

MODMON

Pad 17

FAIL

Pad 18

GND4

Pad 19

PB_GND

Pad 20

APCFILT

Pad 21

GND4

Pad 22

VCC4

Pad 23

BIAS

(Pin 13)

(Pin 14)

(Pin 15)

(Pin 16)

(Pin 17)

Pad 24

PB_GND1

(Pin 18) (Pin 19) (Pin 20) (Pin 21) (Pin 22) (Pin 23) (Pin 24) Pad 25

VCC4

Pad 26

DB_OUT+

Pad 27

OUT+

VSC7940

Pad 28

OUT-

Die Size: 1773µm x 2233µm (0.0698" x 0.0879") Die Thickness: 625µm (0.0246") Pad Pitch: 115µm (0.0045") Pad to Pad Clearance: 20µm (0.0008") Pad Passivation Opening: 95µm x 95µm (0.0037" x 0.0037")

Pad 29

DB_OUT-

Pad 30

VCC4

Pad 31 GND4

Pad 32 GND3

(Pin 28)

(Pin 27)

(Pin 26)

(Pin 25)

Pad 33

Pad 41

RESERVED

Pad 40

GND2

Pad 39

PB_GND

Pad 38

GND3

Pad 37

PB_GND

Pad 36

CAPC

Pad 35

VCC3

Pad 34

GND3

(0.0030")

µm

Page 4 G52357-0, Rev 3.2

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

05/11/01

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

VSC7940

Table 4: Pad Coordinates

Signal

Name

VCC1 1 (Pin 1) 1211.025 1995.05 VCC4 25 (Pin 18 ) 406.025 80.95 DATA+ 2 (Pin 2) 1096.025 1995.05 DB_OUT+ 26 521.025 80.95 DATA- 3 (Pin 3) 981.025 1995.05 OUT+ 27 (Pin 19) 636.025 80.95 VCC1 4 (Pin 4) 866.025 1995.05 OUT– 28 (Pin 20) 751.025 80.95 GND1 5 751.025 1995.05 DB_OUT– 29 866.025 80.95 VCC1 6 636.025 1995.05 VCC4 30 (Pin 21) 981.025 80.95 CLK+ 7 (Pin 5) 521.025 1995.05 GND4 31 (Pin 22) 1096.025 80.95 CLK- 8 (Pin 6) 406.025 1995.05 GND3 32 (Pin 23) 1211.025 80.95 VCC1 9 (Pin 7) 291.025 1995.05 MD 33 (Pin 24) 1326.025 80.95 GND1 10 80.95 1784.975 GND3 34 1535.05 289.975 LATCH 11 (Pin 8) 80.95 1669.975 VCC3 35 (Pin 25) 1535.05 404.975 ENABLE 12 (Pin 9) 80.95 1554.975 CAPC 36 (Pin 26) 1535.05 519.975 DISABLE 1 3 (Pin 10) 80.95 1439.975 PB_GND 37 1535.05 634.975 GND1 14 80.95 1324.975 GND3 38 (Pin 27) 1535.05 749.975 BIASMON 15 ( Pin 11) 80.95 1209.975 PB_GND 39 1535.05 864.975 MODMON 16 (Pin 12) 8 0.95 109 4.975 GND2 40 1535.05 979.975 FAIL GND4 18 80.95 864.975 APCSET 42 (Pin 29) 1535.05 1209.975 PB_GND 19 80.95 749.975 GND2 43 1535.05 1324.975 APCFILT 20 (Pin 14) 80.95 634.975 MODSET 44 (Pin 30) 1535.05 1439.975 GND4 21 (Pin 15) 80.95 519.975 BIASMAX 45 (Pin 31) 1535.05 1554.975 VCC4 22 (Pin 16) 80.95 404.975 VCC2 46 (Pin 32) 1535.05 1669.975 BIAS 23 (Pin 17) 80.95 289.975 GND2 47 1535.05 1784.975 PB_GND 24 291.025 80.95 GND1 48 1336.025 1995.05

Pad

No.

17 (Pin 13) 80.95 979.975 RESERVED 41 (Pin 28) 1535.05 1094.975

Coordinates (µm)

X Y X Y

Laser Diode Driver with Automatic Power Control

Signal

Name

Pad

SONET/SDH 3.125Gb/s

Coordinates (µm)

No.

G52357-0, Rev 3.2 Page 5 05/11/01

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

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