VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7939
Symbol
Parameter
Modulation Current Absolute Accuracy
Modulation Current Stability
A
BIAS
A
MOD
BIASMON to I
BIAS
Gain
MODMON to I
MON
Gain
SONET/SDH 3.125Gb/s
Laser Diode Driver with Automatic Power Control
Min
-480
Typ
±15
-50
250
37
29
Max
480
Units
%
ppm/°C
A/A
A/A
Conditions
See Note 2
I
MOD
=60mA
I
MOD
=5mA
I
BIAS
/I
BIASMON
I
MOD
/I
MODMON
NOTES: (1) Both I
BIAS
and I
MOD
will turn off if any of the current set pins are grounded. (2)
Assumes laser diode to monitor diode transfer func-
tion does not change with temperature.
Table 3: PECL and TTL/CMOS Inputs and Outputs Specifications
Symbol
V
ID
V
ICM
I
IN
V
IH
V
IL
Parameter
Differential Input Voltage
Common-Mode Input Voltage
Clock and Data Input Current
TTL Input High Voltage
(ENABLE, LATCH)
TTL Input Low Voltage
(ENABLE, LATCH)
TTL Output High Voltage (FAIL)
TTL Output Low Voltage (FAIL)
Min
100
V
CC
-
1.49
-1
2.0
Typ
V
CC
-
1.32
Max
1600
V
CC
-
V
ID
/4
10
Units
mV
p-p
V
µA
V
Conditions
(DATA+)-(DATA-)
PECL-compatible
0.8
2.4
0.1
V
CC
-
0.3
V
CC
0.44
V
V
V
Sourcing 50µA
Sinking 100µA
G52350-0, Rev 3.2
02/26/01
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
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