CS3170 datasheet(7/11 Pages) AMCC

7 / 11 page

S3170 – 2.5 Gbps Transimpedance Amplifier

AMCC Confidential and Proprietary

Revision A – August 12, 2004

Data Sheet

DESIGN PROCEDURES

Determining Capacitor Values

CFILT can be selected using the formula:

Low Frequency -3dB cutoff = 1 / [2

π*400 kΩ*(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 VCC

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.

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