M02014 Datasheet, PDF (16/19 Pages) M/A-COM Technology Solutions, Inc. – CMOS Transimpedance Amplifier with AGC for Fiber Optic Networks up to 2.5 Gbps

Applications Information
4.5
TIA Use with Externally Biased Detectors
In some applications, Mindspeed TIAs are used with detectors biased at a voltage greater than available from TIA
PIN cathode supply. This works well if some basic cautions are observed. When turned off, the input to the TIA
exhibits the following I/V characteristic:
Figure 4-5. TIA Use with Externally Biased Detectors, Powered Off
PINA Unbiased
100
50
-800
-600
-400
-200
0
0
-50
200
400
600
800
1000
1200
-100
-150
-200
-250
-300
mV
In the positive direction the impedance of the input is relatively high.
02014-DSH-001-D
Mindspeed Technologies^®
14
Mindspeed Proprietary and Confidential