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2.5Gbps Fiber-Optics LD/VCSEL Driver
CS6724
BLOCK DIAGRAM
GENERAL DESCRIPTION
Century Semiconductor Inc.
FEATURES
APPLICATIONS
USA:
4020 Moorpark Avenue Suite 115
San Jose, CA, 95117
Tel: 408-243-8388 Fax: 408-243-3188
Sales@century-semi.com
Sales@century-semi.com.tw
www.century-semi.com
Rev.0.0 July 2001
page 1 of 6
Century Semiconductor, Inc.
Taiwan:
No. 2, Industry East Rd. 3rd,
Science-Based Industrial Park, Hsin-Chu, Taiwan
Tel: 886-3-5784866 Fax: 886-3-5784349
The CS6724 is a high speed laser driver IC with
automatic power control (APC) for application up to
2.5Gbps. The IC accepts differential PECL data and
clock input (if the latch pin is enabled) for better jitter
performance and TTL enable pin for bias and
modulation currents control. The APC circuit is used
to keep stable average optical power against the
changes in operating temperature. In addition, the
modulation current is temperature compensated in
order to have constant extinction ratio of laser diode.
The bias and modulating currents of the CS6724
can be set separately via two external resistors, and
monitors of these two output currents are also
provided. Moreover, APC-failure detector, and a
slow-start circuit are provided to prevent laser diode
damage.
Programmable modulation current up to 60mA
Programmable bias current up to 100mA
Maximum 2V laser diode forward voltage
Differential PECL input
Automatic power control with failure detector
Rise/Fall time < 140ps
Operation temperature range: -40C ~ +85C
Temperature compensated modulation current
Single 3.3V power supply
32-pin TQFP package
Fiber channel optical transmission system
SDH/SONET optical transmission system
Gigabit Ethernet optical transmission system
TEMPERATURE
DIN
CLK
ENABLE
L
ATCH
OUTPUT
DRIVER
APC
MODN
MODP
PIN
PCB
FAIL
RMOD
I
BIAS
50
I
MOD
40
BIASMON
MODMON
COMPENSATION SET
BIAS
GENERATOR
CONTROL
D
Q
START
MODCM
RPIN
RDCB
ROFS
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