Revision A – August 12, 2004
S3170 – 2.5 Gbps Transimpedance Amplifier
Data Sheet
DESIGN PROCEDURES
Determining Capacitor Values
C
can be selected using the formula:
FILT
Low Frequency -3dB cutoff = 1 / [2π*400 k
Ω
*(10pF + C
)]
FILT
APPLICATION INFORMATION
Filtering Through RBYPASS
To reduce the effect of supply voltage noise at the cathode of the photodiode, the cathode connection to V
CC
should be made through the RBYPASS resistor. The RBYPASS resistor and an external capacitor to ground at the
cathode of the photodiode will act as a filter to reduce this noise and dampen any resonance at the cathode of the
photodiode.
Wire Bonding and Layout information
For best performance all GND pads should be connected and the bond wire inductance between the photodiode
and the IIN pin should be kept to below 1.5 nH – 2 nH. The back of the die is not metallized and should be con-
nected to ground or left electrically unconnected.
The outputs OUTP and OUTN should be terminated equally to prevent instabilities. Figures 4 and 5 show differen-
tial and single-ended termination.
AMCC Confidential and Proprietary
7
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
