VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7928
Features
• Rise Times Less Than 100ps
• High Speed Operation
(Up to 3.2Gb/s NRZ Data)
• Differential or Single-Ended Inputs
• Single Supply
• ECL Compatible Clock and Data Inputs
• Direct Access to Modulation and Bias FETs
• Data Density Monitors
• On-chip Reclocking Register
• On-chip Mux for Clocked or Non-clocked Appli-
cations
• On-chip 50
Ω
Input Termination: Clock and Data
• Enhanced Pinout
SONET/SDH 3.2Gb/s Laser Diode Driver
Applications
• SONET/SDH @ 622Mb/s, 1.244Gb/s,
2.488Gb/s, and 3.125Gb/s
• Full Speed Fibre Channel (1.062Gb/s)
General Description
The VSC7928 is a single 5V supply, 3.2Gb/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 high unbalanced data applications. Clock and data inputs are differentially terminated to 50
Ω
.
VSC7928 Block Diagram
MK
NMK
NIOUT
DIN
50
Ω
**
DINTERM*
50
Ω
**
NDIN
DCC
CLK
50
Ω
**
CLKTERM*
50
Ω
**
NCLK
SEL
MIP
*Terminated to Off-chip Capacitor
**On Die Components
MIB
VIB
VIP
I
MOD
I
BIAS
M
U
X
IOUT
D Q
IBIAS
G52246-0, Rev 3.0
04/05/01
©
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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