SE1010W
LightCharger
TM
622 Mb/s Transimpedance Amplifier
Final
Applications
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SONET/SDH-based transmission systems, test
equipment and modules
OC-12 fibre optic modules and line termination
ATM optical receivers
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 SE1010W is a fully integrated,
silicon bipolar transimpedance amplifier; providing
wideband, low noise preamplification of signal current
from a photodetector. It features single-ended or
differential outputs, selectable by wire bond options,
and incorporates an automatic gain control
mechanism to increase dynamic range, allowing input
signals up to 2.6 mA peak. For differential outputs, a
decoupling capacitor on the supply is the only
external circuitry required.
Noise performance is optimized for 622 Mb/s
operation, with a calculated rms noise based
-10
sensitivity of –35 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 +5 V power supply
Input noise current = 45 nA rms when used with a
0.5 pF detector
Transimpedance gain = 5.6 kΩ into a 50
Ω
load
(single-ended)
On-chip automatic gain control gives input
current overload of 2.6 mA pk and max output
voltage swing of 300 mV pk-pk
50
Ω
single-ended or 100
Ω
differential wire bond
selectable outputs
Bandwidth (-3 dB) = 400 MHz (min)
Wide data rate range = 10 Mb/s to 622 Mb/s
High input bias level = 2 V
Minimal external components, supply decoupling
only
Operating junction temperature range = -40°C to
+95°C
Equivalent to Nortel Networks AB53
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Ordering Information
Type
SE1010W
Package
Bare Die
Remark
Shipped in
Waffle Pack
Functional Block Diagram
SE1010
TzAmp
622 Mb/s
Automatic Gain Control
Integrator
Rectifier
Rf
TZ_IN
Input
Current
Tz Amp
Output
Driver
50
Ω
50
Ω
50
Ω
OUTP
OUTN
Bandgap
Reference
Power
Supply
Rejection
GND or –ve supply
ACGND
Wire bond option for single-ended operation
41-DST-01
§
Rev 1.5
§
May 24/02
1 of 9
SE1010W
LightCharger
TM
622 Mb/s Transimpedance Amplifier
Final
Bondpad Diagram
VCC2
1
10
VCC1
VCC1
2
Top
View
9
TZ_IN
3
8
OUTN
OUTP
4
VEE2
5
ACGND
6
VEE1
7
VEE1
Bondpad Description
Pad No.
1
2
3
4
5
6
7
8
9
10
Name
VCC2
VCC1
TZ_IN
VEE2
ACGND
VEE1
VEE1
OUTN
OUTP
VCC1
Description
Positive supply (+5.0 V), front end circuitry only.
Positive supply (+5.0 V), pads 2 & 10 are connected on chip. Only one pad needs to
be bonded.
Input pad (connect to photodetector cathode).
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.
Bond option: Connected to external capacitor to ground for single-ended operation
(recommended 1 nF); unconnected for differential operation.
Negative supply (0V), pads 6 & 7 are connected on chip. Only one pad needs to be
bonded.
Negative supply (0V), pads 6 & 7are connected on chip. Only one pad needs to be
bonded.
Negative differential voltage output; leave unconnected for single-ended operation.
Positive differential or single-ended voltage output.
Positive supply (+5.0 V), pads 2 & 10 are connected on chip. Only one pad needs to
be bonded.
41-DST-01
§
Rev 1.5
§
May 24/02
2 of 9
SE1010W
LightCharger
TM
622 Mb/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
an 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 3 V below the supply
voltage VCC, allowing a photodetector to easily be
reverse biased by connecting the anode to ground,
and hence enabling single rail operation.
The front-end stage has its own supply pins, VCC2
(+5 V) and VEE2 (0 V), to achieve optimum noise
performance and maintain integrity of the high-speed
signal path. The remainder of the circuitry uses the
supply pins VCC1 (+5 V) and VEE1 (0 V).
to ground (recommend 1 nF).
Under these
circumstances, OUTP operates as a single-ended
50
Ω
output. In both cases, 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 8 kHz.
Power Supply Rejection
An on-chip power supply rejection circuit is used t
o
achieve both single-ended and differential rejection
from the +5 V VCC rail.
This stable DC reference minimizes the variation in
the noise and bandwidth performance of the circuit
due to power supply variation of +4.7 V to +5.3 V.
The AC rejection ensures that performance is not
degraded by noise on the power supply. The circuit
achieves a power supply rejection on the outputs of
40 dB for both single-ended and differential operation,
up to 100 kHz. The use of external decoupling will
help to remove any unwanted signals at higher
frequencies.
Output driver stage
The output driver acts as a buffer stage, capable of
swinging up to 150 mVpk-pk into a 50
Ω
load (or
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).
The output can be configured in a differential or
single-ended mode. For differential operation, the pad
ACGND is not wire bonded and the circuit provides a
fully balanced 100
Ω
output, on the pins OUTP and
OUTN. For single-ended operation, the ACGND pad
is required to be wire bonded to an external capacitor
41-DST-01
§
Rev 1.5
§
May 24/02
3 of 9
SE1010W
LightCharger
TM
622 Mb/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
4.7
–40
Typ
5.0
Max
5.3
95
Unit
V
°C
DC Electrical Characteristics
Symbol
ICC
lagc
Vin
Vout
Rout
Supply Current
AGC Threshold
Input Bias Voltage
Output Bias Voltage
Output Resistance
10
VCC–3.2
2.9
35
50
VCC–3.0
VCC–2.7
3.5
65
Parameter
Min
Typ
39
Max
61
Unit
mA
µA
pk-pk
V
V
Ω
41-DST-01
§
Rev 1.5
§
May 24/02
4 of 9
SE1010W
LightCharger
TM
622 Mb/s Transimpedance Amplifier
Final
AC Electrical Characteristics
Symbol
BW (3dB)
Tz
Dri
Voutmax
Flf
PSRR
l
OL
Pol
Nrms
Parameter
Small Signal Bandwidth at –3dB point
Single-ended Transimpedance (50
Ω
on output,
f = 50 MHz)
Input Data Rate
Maximum Differential Output Voltage
Low Frequency Cut-off
Power Supply Rejection Ratio (single-ended or
differential) up to 100 kHz
Input Current before overload (622 Mb/s NRZ
data)
Optical Overload
Input Noise Current (in 400 MHz)
2600
+1.6
45
61
8
40
Min
400
4
10
5.6
7.6
622
300
Typ
Max
Unit
MHz
kΩ
Mb/s
mV pk-pk
kHz
dB
µA
pk-pk
dBm
nA rms
DC and AC electrical characteristics are specified under the following conditions:
Supply Voltage (VCC).........................................4.7 V to 5.3 V
Junction Temperature (Tj)..................................–40°C to 95°C
Load Resistor (R
L
)...............................................50
Ω
AC coupled via 220 nF (single-ended)
Photodetector Capacitance (Cd).......................0.5 pF
Input bond wire inductance................................1 nH
Photodetector responsivity.................................0.9 A/W
Transimpedance (Tz) measured with 1
µA
mean photocurrent
41-DST-01
§
Rev 1.5
§
May 24/02
5 of 9
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