VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC7969
3.125Gb/s Integrated Transimpedance
and Limiting Amplifier with Signal Detect
G52355-0, Rev 2.0
Page 1
02/09/01
VITESSE
SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Features
Applications
General Description
The VSC7969 is a 3.125Gb/s transimpedance amplifier IC with a built-in limiting amplifier, a signal detect
feature and a photocurrent monitor. The VSC7969 does not require any external electrical components in the
construction of a high performance optical receiver such as for SONET/SDH applications. The analog output is
a differential signal with a minimum amplitude of 200mVp-p (single-ended). The VSC7969 operates with a sin-
gle power supply with a maximum power dissipation of 300mW. A PIN photodiode or APD can be connected
and separately biased to provide optimal performance.
The VSC7969 provides filtered bias for MSM and PIN photodetectors; applications using an APD photode-
tector must supply bias separately. The VSC7969 also provides a photocurrent monitor whose output is linearly
proportional to the input photocurrent.
The VSC7969 can operate from a single +3.3V supply or a +5V or -5.2V supply. The VSC7969 is offered
in die form and in a 16-pin plastic thin-shrink small outline package (TSSOP-16). A fully tested TO-46 outline
packaged receiver with a photodetector is also available.
Block Diagram
Integrated TIA and Limiting Amplifier
Low Power Consumption for SFF Applications
TO Package-Compatible Layout
On-Chip Signal Detect
On-Chip Linear Photocurrent Monitor
Single 3.3V Supply
5V Supply Operation via Wirebond Option
Compatible with PIN or Avalanche Detectors
Packages: 16-Pin TSSOP, TO-46, Bare Die
50
Regulator
VSC7969
+3.3V
0.1F
VOUTP
VCCD
Outputs need to
be AC-coupled
Dual power supply pins are
provided for +5V or +3.3V
operation. Only one power
supply pin should be connected.
VCCS
VOUTN
SD_OUT
SD_ADJ
IMON
0.1F
+3.3V
+5V
50
Signal
Detect
Monitor
Filter
In
GND
2.488Gb/s, 3.125Gb/s SONET OC-48/
SDH STM-16
2.125Gb/s Fibre Channel
2.5Gb/s or 3.125Gb/s Ethernet Applications with
8B/10B Overhead
SFF Transceivers
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC7969
3.125Gb/s Integrated Transimpedance
and Limiting Amplifier with Signal Detect
Page 2
G52355-0, Rev 2.0
02/09/01
VITESSE
SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Electrical Characteristics
Table 1: AC Specifications
Symbol
Parameter
Min
Typ
Max
Units
Conditions
I
PH
Input Photocurrent Swing
2.2
mA
Peak-to-peak AC current
amplitude
I
PHS-AVG
Average Photocurrent Sensitivity
4
A
-23dBm average optical power
with a detector responsitivity of
0.8A/W.
I
PHS-PEAK
Peak Input Photocurrent Sensitivity
8
A
-23dBm average optical power
with a detector responsitivity of
0.8A/W.
V
OUT-SE
Single-Ended Output Voltage
Amplitude
200
250
300
mV
Single-ended peak-to-peak
measurement, I
IN
>20A.
V
OUT-DIFF
Differential Output Voltage Amplitude
400
500
600
mV
Differential peak-to-peak
measurement, I
IN
>20A.
t
R
, t
F
Rise and Fall Time
60
100
ps
At 2.2mAp-p input photocurrent
swing. 20% to 80%.
Z
T
(1)
Transimpedance Gain
20k
27k
40k
Differential measurement
Z
T
(1)
Ripple in Passband Transimpedance
1
dB
Modulation frequency between F
L
and BW
BW
Upper -3dB Bandwidth
2.2
2.5
3.0
GHz
Referenced to 10MHz,
CPD = 0.6pF
F
L
Lower -3dB Cutoff Frequency
100
kHz
Referenced to 10MHz, CPD =
0.6pF with no external
components
Z
O
Output Impedance
50
Single-ended
PSRR
Power Supply Rejection Ratio
TBD
I
NOISE
Input-Referred rms Noise Current
500
nA
30kHz to 2.5GHz
C
PD
Photodetector Capacitance
0.4
0.6
0.8
pF
Bias voltage on detector at 2.0V
SD
H
Signal Detect Hysterisis
1
2
4
dB
Electrical measurement on SD pin
SD
A-OPEN
Signal Detect Assertion Level
3
5
9
A
Average photocurrent with SD
open.
SD
D-OPEN
Signal Detect Deasseration Level
1.0
2.2
3.0
A
Average photocurrent with SD
open.
SD
A-SHORT
Signal Detect Asseration Level
6
10
18
A
Average photocurrent with SD
shorted to ground.
SD
D-SHORT
Signal Detect Deasseration Level
2.0
4.4
6.0
A
Average photocurrent with SD
shorted to ground.
SD
HIGH
Signal Detect HIGH Logic Level
V
CCS
- 0.3
V
SD
LOW
Signal Detect LOW Logic Level
0.5
0.8
V
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC7969
3.125Gb/s Integrated Transimpedance
and Limiting Amplifier with Signal Detect
G52355-0, Rev 2.0
Page 3
02/09/01
VITESSE
SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com
Internet: www.vitesse.com
NOTES: (1) The transimpedance gain is defined as Z
T
= (
V
OUT
- DIFF
)/
I
PH
. (2) Using 1111100000 pattern at 2.5Gb/s to measure the
standard deviation of the edge of the pattern, multiply the standard deviation by 14 to achieve the total random jitter. (3) +K28.5
- K28.5 (00111110101100000101).
Table 2: DC Specifications
Absolute Maximum Ratings
(1)
(at T
A
= +25
C, unless otherwise specified)
Power Supply Voltage (V
CCS
)......................................................................................................................... 3.6V
Power Supply Voltage (V
CCD
) ........................................................................................................................ 5.5V
Junction Temperature Range ........................................................................................................ -40C to +125C
Storage Temperature Range ......................................................................................................... -40C to +125C
Relative Ambient Humidity ................................................................................................................. 85%/+85C
NOTE: (1) CAUTION: Stresses listed under "Absolute Maximum Ratings" may be applied to devices one at a time without caus-
ing permanent damage. Functionality at or above the values listed is not implied. Exposure to these values for extended
periods may affect device reliability.
Recommended Operating Conditions
Positive Voltage Supply (V
CCS
) ...................................................................................................................... 3.3V
Positive Voltage Supply (V
CCD
)...................................................................................................................... 5.0V
Negative Voltage Rail (GND) ............................................................................................................................ 0V
Ambient Temperature Range (T
A
)
(1)
.............................................................................................. -40C to +85C
MON
Slope of Linear Analog Photocurrent
Monitor vs Input Optical Power
0.8
A/W
0
to 2k
to V
CC
with a detector
responsitivity of 0.8A/W
DC
Duty Cycle
-5
+5
%
IMON
RANGE
Photocurrent Monitor Linearity Range
5
200
A
IMON
OFFSET
Photocurrent Monitor Offset
0
10
A
R
J
Random Jitter
(2)
TBD
ps
Peak-to-peak
D
J
Deterministic Jitter
(3)
TBD
ps
Peak-to-peak
Symbol
Parameter
Min
Typ
Max
Units
Conditions
GND
Negative Supply Rail
0
V
V
CCS
Positive Supply Rail for 3.3V Operation
3.0
3.3
3.6
V
V
CCD
Positive Supply Rail for 5V Operation
4.5
5.0
5.5
V
ICC
Power Supply Current
65
75
mA
3.3V
V
OUT-CM
Common-Mode Voltage on Output Pins
V
CCS
-
125mV
Applicable to VOUTP and
VOUTN pins at 50
load.
V
ANODE
Internal DC Bias Voltage on Detector
Anode Contact
0.8
0.9
1.0
V
V
CATHODE
Interal DC Bias Voltage on Detector
Cathode Contact
V
CCS
-
0.15V
V
CCS
V
V
CAT-EXT
External DC Bias Voltage Permissable
on Detector Cathode Contact
3.3
10
V
V
APD
External DC Bias Voltage for Use with
Avalanche Photodetector
60
V
Symbol
Parameter
Min
Typ
Max
Units
Conditions
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC7969
3.125Gb/s Integrated Transimpedance
and Limiting Amplifier with Signal Detect
Page 4
G52355-0, Rev 2.0
02/09/01
VITESSE
SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Bare Die Descriptions
Figure 1: Pad Assignments
VSC7969
Die Size: 1143m x 1453m (45.0mil x 57.2mil)
Die Thickness: 279
m (11.0mil)
Pad Size:
100m x 100m (3.9mil x 3.9mil)
Pad Passivation Opening:
86m x 86m (3.4mil x 3.4mil)
Scribe Size: 143m (5.6mil)
Pad 7
SD_OUT
Pad 8
GND
Pad 9
VOUTN
Pad 10
GND
Pad 11
VOUTP
Pad 12
GND
Pad 13
IMON
Pad 14
VOUTP
Pad 15
GND
Pad 16
CSDN
Pad 17
CSDP
1143m
(45.0mil)
1467m (57.2mil)
143m
(5.6mil)
Pad 18
GND
Pad 19
GND
Pad 5
SD_ADJ
Pad 4
SD_TP
Pad 3
GND
Pad 2
BG_VREF
Pad 1
GND
Pad 6
VOUTN
Pad 25
VCCS
Pad 24
GND
Pad 23
IN
Pad 22
FILTER
Pad 21
GND
Pad 20
GND
Pad 26
VCCD
VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC7969
3.125Gb/s Integrated Transimpedance
and Limiting Amplifier with Signal Detect
G52355-0, Rev 2.0
Page 5
02/09/01
VITESSE
SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Table 3: Pad Coordinates
Signal
Name
Pad
Number
Coordinates (m)
Description
X
Y
GND
1
130
250
Negative power supply rail (typically 0V)
BG_VREF
2
130
375
Band Gap voltage reference 1.24V for testpoint, no connect
GND
3
130
500
Negative power supply rail (typically 0V)
SD_TP
4
130
625
Signal Detect test point, DO NOT CONNECT.
SD_ADJ
5
130
750
Signal Detect threshold adjustment (see Application amd Usage
section)
VOUTN
6
137
875
Complementary logic output (logic LOW when photocurrent is
HIGH)
SD_OUT
7
280
875
Signal detect output (logic HIGH when photocurrent exceeds
SD
A
)
GND
8
405
875
Negative power supply rail (typically 0V)
VOUTN
9
530
875
Complementary logic output (logic LOW when photocurrent is
HIGH)
GND
10
655
875
Negative power supply rail (typically 0V)
VOUTP
11
780
875
Positive logic output (logic HIGH when photocurrent is HIGH)
GND
12
905
875
Negative power supply rail (typically 0V)
IMON
13
1030
875
Photocurrent Monitor
VOUTP
14
1173
875
Positive logic output (logic HIGH when photocurrent is HIGH)
GMD
15
1180
750
Negative power supply rail (typically 0V)
CSDN
16
1180
625
Test point for Signal Detect capacitor. DO NOT CONNECT.
CSDP
17
1180
500
Test point for Signal Detect capacitor. DO NOT CONNECT.
GND
18
1180
375
Negative power supply rail (typically 0V)
GND
19
1180
250
Negative power supply rail (typically 0V)
GND
20
1030
125
Negative power supply rail (typically 0V)
GND
21
905
125
Negative power supply rail (typically 0V)
FILTER
22
780
125
Photodetector cathode connection (filtered V
CC
)
IN
23
530
125
Photodetector anode connection
GND
24
405
125
Negative power supply rail (typically 0V)
VCCS
25
280
125
Positive power supply rail for 3.3V operation
VCCD
26
137
125
Positive power supply rail for 5V operation
PDF 
ZIP