SE1030W
LightCharger
™
2.5 Gb/s Transimpedance Amplifier
Final
Applications
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SONET/SDH-based transmission systems, test
equipment and modules
OC-48 fibre optic modules and line termination
ATM optical receivers
Gigabit Ethernet
Fibre Channel
Product Description
SiGe Semiconductor offers a portfolio of optical
networking ICs for use in high-performance optical
transmitter and receiver functions, from 155 Mb/s up
to 12.5 Gb/s.
SiGe Semiconductor’s SE1030W is a fully integrated,
silicon bipolar transimpedance amplifier; providing
wideband, low noise preamplification of signal current
from a photodetector. It features differential outputs,
and incorporates an automatic gain control
mechanism to increase dynamic range, allowing input
signals up to 2.6 mA peak. A decoupling capacitor on
the supply is the only external circuitry required. A
system block diagram is shown after the functional
description, on page 3.
Noise performance is optimized for 2.5 Gb/s
operation, with a calculated rms noise based
-10
sensitivity of –26 dBm for 10 bit error rate, achieved
using a detector with 0.5 pF capacitance and a
responsivity of 0.9 A/W, with an infinite extinction ratio
source.
Features
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Single +3.3 V power supply
Input noise current = 360 nA rms when used with
a 0.5 pF detector
Transimpedance gain = 2.3 kΩ into a 50
Ω
load
(differential)
On-chip automatic gain control gives input
current overload of 2.6 mA pk and max output
voltage swing of 300 mV pk-pk
Differential 50
Ω
outputs
Bandwidth (-3 dB) = 2.4 GHz
Wide data rate range = 50 Mb/s to 2.5 Gb/s
Constant photodiode reverse bias voltage = 1.5 V
(anode to input, cathode to VCC)
Minimal external components, supply decoupling
only
Operating junction temperature range = -40°C to
+125°C
Equivalent to Nortel Networks AB89-A2A
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Ordering Information
Type
SE1030W
Package
Bare Die
Remark
Shipped in
Waffle Pack
Functional Block Diagram
SE1030
TzAmp
2.5 Gb/s
Automatic Gain Control
Integrator
VCC or +ve supply
Rectifier
Input
Current
TZ_IN
Rf
Tz Amp
Output
Driver
50
Ω
50
Ω
OUTP
OUTN
Bandgap
Reference
43-DST-01
§
Rev 1.5
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May 24/02
1 of 9
SE1030W
LightCharger
™
2.5 Gb/s Transimpedance Amplifier
Final
Bondpad Diagram
VCC
1
11
VCC
DNC
2
Top
View
10
TZ_IN
3
9
OUTN
OUTP
4
5
6
7
8
VEE2
VEE1
VEE1
VEE1
VCC
Bondpad Description
Pad No.
1
2
3
4
5
6
7
8
9
10
11
Name
VCC
DNC
TZ_IN
VEE2
VEE1
VEE1
VEE1
VCC
OUTN
OUTP
VCC
Description
Positive supply (+3.3 V), pads 1, 8 & 11 are connected on chip. Only one pad needs
to be bonded.
Do not connect.
Input pad (connect to photodetector anode).
Negative supply (0V) – Note this is separate ground for the input stage, which is AC
coupled on chip. There is no DC current through this pad.
Negative supply (0V), pads 5, 6 & 7 are connected on chip. Only one pad needs to be
bonded.
Negative supply (0V), pads 5, 6 & 7 are connected on chip. Only one pad needs to be
bonded.
Negative supply (0V), pads 5, 6 & 7 are connected on chip. Only one pad needs to be
bonded.
Positive supply (+3.3 V), pads 1, 8 & 11 are connected on chip. Only one pad needs
to be bonded.
Negative differential voltage output.
Positive differential voltage output.
Positive supply (+3.3 V), pads 1, 8 & 11 are connected on chip. Only one pad needs
to be bonded.
43-DST-01
§
Rev 1.5
§
May 24/02
2 of 9
SE1030W
LightCharger
™
2.5 Gb/s Transimpedance Amplifier
Final
Functional Description
Amplifier Front-End
The transimpedance front-end amplifies an input
current from a photodetector, at pin TZ_IN, to produce
a differential output voltage with the feedback resistor
Rf determining the level of amplification (see the
functional block diagram on page 1). An automatic
gain control loop varies this resistor, to ensure that
the output from the front-end does not saturate the
output driver stage that follows. This gain control
allows input signals of up to 2.6 mA peak.
The input pin TZ_IN is biased at 1.5 V below the
supply voltage VCC, allowing a photodetector to have
a constant reverse bias by connecting the cathode to
3.3 V. This enables full single rail operation.
The front-end stage has its own supply ground
connection (VEE2) to achieve optimum noise
performance and maintain integrity of the high-speed
signal path. The front-end shares the VCC (+3.3 V)
connection with the remainder of the circuitry, which has
a separate ground (VEE1).
Output driver stage
The output driver acts as a buffer stage, capable of
swinging up to 300 mVpk-pk differential into a 100
Ω
load. The small output swings allow ease of use with
low voltage post amplifiers (e.g. 3.3 V parts).
Increasing optical input level gives a positive-going
output signal on the OUTP pin.
Automatic Gain Control (AGC)
The AGC circuit monitors the voltages from the output
driver and compares them to an internal reference
level produced via the on-chip bandgap reference
circuit. When this level is exceeded, the gain of the
front-end is reduced by controlling the feedback
resistor Rf.
A long time-constant integrator is used within the
control loop of the AGC with a typical low frequency
cut-off of 5 kHz.
System Block Diagram
Receiver Module
AGC
Amplifier
Clock
Clock & Data
Recovery
Data
LOS
2
SE1230
2
2.5 GHz
2
SE1030W
TZ
Amplifier
PIN
2.5 Gb/s
2
43-DST-01
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Rev 1.5
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May 24/02
3 of 9
SE1030W
LightCharger
™
2.5 Gb/s Transimpedance Amplifier
Final
Absolute Maximum Ratings
These are stress ratings only. Exposure to stresses beyond these maximum ratings may cause permanent damage
to, or affect the reliability of the device. Avoid operating the device outside the recommended operating conditions
defined below.
Symbol
VCC
V
IO
I
IO
I
IO
V
ESD
V
ESD
Tstg
Supply Voltage
Voltage at any input or output
Current sourced into any input or output except
TZ_IN
Current sourced into pin TZ_IN
Electrostatic Discharge (100 pF, 1.5 kΩ) except
TZ_IN
Electrostatic Discharge (100 pF, 1.5 kΩ) pin
TZ_IN
Storage Temperature
Parameter
Min
–0.7
–0.5
–20
–5
–2
–0.25
–65
Max
6.0
VCC+0.5
20
5
2
0.25
150
Unit
V
V
mA
mA
kV
kV
°C
Recommended Operating Conditions
Symbol
VCC
Tj
Supply Voltage
Operating Junction Temperature
Parameter
Min
3.1
–40
Typ
3.3
Max
3.5
125
Unit
V
°C
DC Electrical Characteristics
Symbol
ICC max
ICC zero
lagc
Vin
Vout
Rout
Parameter
Supply Current (max input current)
Supply Current (zero input current)
AGC Threshold
Input Bias Voltage
Output Bias Voltage
Output Resistance
35
42
VCC–
1.57
VCC–
1.52
VCC–
0.30
50
65
VCC–
1.47
Min
Typ
66
52
Max
101
85
Unit
mA
mA
µA
pk-pk
V
V
Ω
43-DST-01
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Rev 1.5
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May 24/02
4 of 9
SE1030W
LightCharger
™
2.5 Gb/s Transimpedance Amplifier
Final
AC Electrical Characteristics
Symbol
BW (3dB)
Tz
Dri
Voutmax
Flf
l
OL
Pol
Nrms
Parameter
Small Signal Bandwidth at –3dB point
Differential Transimpedance (50
Ω
on each output,
f = 100 MHz)
Input Data Rate
Maximum Differential Output Voltage
Low Frequency Cut-off
Input Current before overload (2.5 Gb/s NRZ data)
Optical Overload
Input Noise Current (in 2 GHz)
2600
+1.6
360
500
5
Min
1.8
1.6
50
Typ
2.4
2.3
3.1
2500
300
Max
Unit
GHz
kΩ
Mb/s
mV pk-pk
kHz
µA
pk-pk
dBm
nA rms
DC and AC electrical characteristics are specified under the following conditions:
Supply Voltage (VCC).........................................3.1 V to 3.5 V
Junction Temperature (Tj)..................................–40°C to 125°C
Load Resistor (R
L
)...............................................50
Ω
AC coupled via 220 nF, for each output
Photodetector Capacitance (Cd).......................0.5 pF
Input bond wire inductance................................1 nH
Photodetector responsivity.................................0.9 A/W
Transimpedance (Tz) measured with 4
µA
mean photocurrent
43-DST-01
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Rev 1.5
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May 24/02
5 of 9
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