VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
SC7937
Features
• Rise Times Typically 100ps
• High Speed Operation
(Up to 2.5Gb/s NRZ Data)
• 3 Volt Output Voltage Compliance
• Single-ended or Differential Input Operation
Single Supply 2.5 Gb/s
Voltage Driver
• Single Power Supply, 5 Volt or 5.2 Volts
• Direct Access to Modulation and Bias FET’s
• On Die Mux for Clocked or Non-clocked
Applications
• On-chip 50 Ohm Input Termination: Clock
and Data
Introduction
The VSC7937 is a single 5V supply, 2.5Gb/s voltage driver with direct access to the output modulation and
bias FET’s. The output stage can drive 60 mA into 50 Ohms with adequate output voltage compliance. Output
bias and modulation currents are set by external components allowing precision monitoring and setting of the
voltage levels.
Applications
• SONET/SDH @ 622Mb/s, 1.244Gb/s, 2.488Gb/s
• Full Speed Fibre Channel (1.062 Gb/s)
VSC7937 Block Diagram
NOUT OUT
I
NOUT
DIN
50
Ω
**
DINTERM*
50
Ω
**
NDIN
D Q
M
U
X
IBIAS1
IMOD
IBIAS2
VIP
CLK
50
Ω
**
CLKTERM*
NCLK
MIB2
SEL
SEL
MIP
MIB1
50
Ω
**
VIB2
VIB1
*Terminated to Off-chip Capacitor
**On Die Components
G52200-0, Rev 2.2
5/22/00
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
Page 1
VITESSE
SEMICONDUCTOR CORPORATION
ingle Supply 2.5 Gb/s
Voltage Driver
Table 1:
.
Signal Pin Reference
Signal
DIN, NDIN
DINTERM
CLK, NCLK
CLKTERM
NOUT
OUT
VSS
GND
VIP
MIP
VIB1, 2
MIB1, 2
DCC
SEL‘
Total Pins
*Applicable to 32 pin TQFP package only
Advance Product Information
VSC7937
Level
DC
DC
Type
In
Ref
In
Ref
Out
Out
Pwr
Pwr
In
In
In
In
In
In
# Pins
2
1
2
1
1
1
Data Termination
Description
Data Input and Data Reference
Clock Input and Clock Reference
Clock Termination
Modulation Current Output (Complementary)
Modulation Current Output (To Laser Cathode)
Negative Voltage Rail
Positive Voltage Rail
Modulation Control Node
Modulation Monitor Node
Bias Control Node
Bias Monitor Node
Duty Cycle Control
Clk/Non-clk Data Select
Pwr
Pwr
DC
DC
DC
DC
DC
DC
2
6/14*
1
1
2
2
1
1
24/32*
Table 2: Mux Select Logic Table
Symbol
VSS
GND
NC
Clocked Data In
Non-clocked Data In
Non-clocked Data In
Rating
Table 3: Absolute Maximum Ratings
Symbol
V
SS
T
j
T
stg
Rating
Negative Power Supply Voltage
Maximum Junction Temperature
Storage Temperature
Limit
V
CC
to -6.0V
-55°C to + 125°C
-65°C to +150°C
Table 4: High Speed Inputs and ECL Outputs
Symbol
V
IN
V
CM
V
OH
V
OL
V
IN
Parameter
Single-ended Input Voltage Swing
Differential Input Common Mode Range
ECL Output High Voltage
ECL Output Low Voltage
On-Chip Terminations
Min
300
-2.3
-1200
Max
1500
-1.3
Units
mVp-p
V
mV
mV
Ohms
Conditions
V
CM
= -2.0V
V
SS
= -5.2V
50 Ohms to -2.0V
50 Ohms to -2.0V
—
—
-1600
65
—
35
Page 2
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
G52200-0, Rev 2.2
5/22/00
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
SC7937
Table 5: Recommended Operating Conditions
Symbol
GND
VSS
VIH
VIL
VIB1
VIB2
VIP
T
C
Single Supply 2.5 Gb/s
Voltage Driver
Parameter
Positive Voltage Rail
Negative Voltage Rail
HIGH Level Input Voltage
LOW Level Input Voltage
BIAS Control Voltages
Modulation Control Voltage
Operational Case Temperature
Min
-5.5
-1.0
—
VSS
VSS
-40
Typ
0
-5.2
-0.9
-1.7
Max
-4.75
-0.8
-1.6
VSS +1.8
VSS +1.4
85*
Units
V
V
V
V
V
V
°C
Conditions
VREF = -1.3V
VREF = -1.3V
V
SS
= -5.2
I
MOD
= 60mA
I
BIAS
= 30mA
Note: *Lower limit of specification is ambient temperature and upper limit is case temperature
Table 6: Power Dissipation
Symbol
I
VSS
Pd
Parameter
Power Supply Current (VSS)
Total Power Dissipation
Min
—
—
Typ
—
-
—
Max
120
700
Units
mA
mW
Conditions
V
SS
= -5.5, I
MOD
= I
BIAS
= 0 mA,
MK/NMK open circuit
V
SS
= -5.5, I
MOD
= I
BIAS
= 0 mA,
Rload = 25 Ohms to GND, MK/NMK
terminated 50Ω to -2V
Table 7: Electrical Specifications
(Vss = -5.2V, RL = 50
Ω
at I
OUT
Pin)
Symbol
I
NOUT
Parameter
Maximum Peak Current
Min
60
Typ
—
Max
—
Units
mA
Conditions
VIP = VSS + 1.4V
VIB1 = -5.2V
VIB2 = -5.2V
DIN = “Lo”
VIP = -4.1V
VIB1 = -5.2V
VIB2 = -5.2V
DIN = “Hi”
VIB1, 2 = VSS + 1.8V
VIP = -5.2V
20% to 80%
20% to 80%
VIP = -4.1V
VIB1 = -5.2V
VIB2 = -5.2V
DIN = “Lo”
I
NOUT
I
BIAS1,
I
BIAS2
t
r
t
f
V
OUT
Maximum Peak Current
—
—
4
mA
Maximum Bias Current
Rise Time
Fall Time
Output Voltage
30
—
—
—
—
—
—
—
—
100
100
-3.0
mA
ps
ps
V
G52200-0, Rev 2.2
5/22/00
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
Page 3
VITESSE
SEMICONDUCTOR CORPORATION
ingle Supply 2.5 Gb/s
Voltage Driver
Advance Product Information
VSC7937
Parameter
Min
20
—
Table 7: Electrical Specifications
(Vss = -5.2V, RL = 50
Ω
at I
OUT
Pin)
Symbol
t
SU
t
H
Typ
50
50
Max
—
90
Units
ps
ps
Conditions
—
—
Set-up Time - Data to CLK
Hold Time
Note: 100mA when RL = 30 Ohm at (N) OUT pin
Table 8: Package Thermal Specifications
Symbol
θ
JCC
θ
JCP
Parameter
Thermal Resistance from Junction to Case
Thermal Resistance from Junction to Case
Min
—
—
Typ
25
15
Max
—
—
Units
°C/W
°C/W
Conditions
Ceramic Package
Plastic Package
Figure 1: On-chip Data and Clock Input Configuration
GND
DIN
(CLK)
DINTERM
(CLKTERM)
NDIN
(NCLK)
GND
DATA BUFFER
(CLOCK BUFFER)
X
*
50
*
*
4.0K
6.4K
X
*
50
X
*On-chip
Components
VSS
VSS
Page 4
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
G52200-0, Rev 2.2
5/22/00
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
SC7937
Figure 2: Single Ended Operation
Single Supply 2.5 Gb/s
Voltage Driver
7937
DATA
SOURCE
0.1µf
GND
0.1µf
DIN
DINTERM
NDIN
0.1µf
0.1µf
GND
CLOCK
SOURCE
0.1µf
GND
CLK
CLKTERM
NCLK
0.1µf
GND
Figure 3: Single Ended AC Coupled
GND
0.1µf
SOURCE
DINTERM
(CLKTERM)
DIN
(CLK)
X
50
4.0K
-2.0V
50
6.4K
X
X
0.1µf
GND
NDIN
(NCLK)
0.1µf
VSS
GND
G52200-0, Rev 2.2
5/22/00
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
Page 5
