VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7925
Features
• Rise Times Less Than 100ps
• High Speed Operation (Up to 2.5Gb/s NRZ Data)
• Single-ended Inputs
• Single Supply
• Direct Access to Modulation and Bias FET’s
• Data Density Monitors
• On-Chip Reclocking Register
• 24-Pin Ceramic Package
SONET/SDH 2.5Gb/s Laser Diode Driver
Applications
• SONET/SDH at 622Mb/s, 1.244Gb/s, and
2.488Gb/s
• Full-Speed Fibre Channel (1.062Gb/s)
General Description
The VSC7925 is a single 5V supply, 2.5Gb/s laser diode driver with direct access to the laser modulation
and bias FETs. Laser bias and modulation currents are set by external components allowing precision monitor-
ing and setting of the current levels. Data density outputs are provided to allow the user to adjust the laser bias
in unbalanced data applications. Clock and data inputs have nominal 50
Ω
termination resistors and high fre-
quency decoupling capacitors.P
VSC7925 Block Diagram
MK
NMK
NIOUT
DIN
50Ω
NDIN*
10pF
**
DCC
CLK
50Ω
NCLK*
10pF
**
**
VIB
MIP
* Terminated to off-chip capacitor
** On-die components
MIB
VIP
I
MOD
I
BIAS
**
D
Q
DCC
IBIAS
IOUT
G52157-0, Rev 3.2
05/01/01
©
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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