SE1050W SIGE [SiGe Semiconductor, Inc.], SE1050W Datasheet - Page 3

• Manufacturer Part Number: SE1050W
• Manufacturer: SIGE [SiGe Semiconductor, Inc.]

Functional Description
Amplifier Front-End
The transimpedance front-end amplifies the current
from a PIN photodetector, anode connected to pad
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).
The input pad TZ_IN is biased at nominally 1.29 V
above ground, allowing the photodetector to have a
wide reverse-bias by connecting the cathode to VCC.
This enables single rail operation and normally
ensures that the PIN operates in its c onstant, low-
capacitance region.
The output stage has its own supply connection
VCC2 (+5 V) to maintain integrity of the high-speed
signal path. The output stage shares the GND (0 V)
connection with the remainder of the circuitry, which
has a separate supply connection VCC1 (+5 V).
Output Driver Stage
The output driver acts as a buffer stage, capable of
swinging up to 1.1 V pk-pk differential into a 100
load.
System Block Diagram
45-DST-01 § Rev 1.5 § May 24/02
Data
Ck In
Data
Clock
CDR &
Demux
Mux
2
SE1250
LOS
Amplifier
SE1150/51/52
Post
LightCharger
Driver
Laser
2
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
OUTN. For single-ended operation, the ACGND pad
is required to be wire bonded to an external capacitor
to
circumstances, OUTP operates as a single-ended
50
level gives a positive-going output signal on the
OUTP pin.
Power Supply Rejection
An on-chip power supply rejection circuit is used to
achieve both single-ended and differential rejection
from the +5 V VCC rail. This rejection ensures that
performance is not degraded by noise on the power
supply. The circuit achieves a power supply rejection
on the outputs of 38 dB for single-ended and 24 dB
for differential operation, up to 100 kHz. The use of
external decoupling will help to remove any unwanted
signals at higher frequencies.
Amplifier
ground
™
output. In both cases, increasing optical input
SE1050W
TZ
Receiver Module
10 Gb/s Transimpedance Amplifier
(recommend
output, on the pins OUTP and
PIN
1 nF).
SE1050W
Under
3 of 11
Final
these