M02139 Datasheet, PDF (15/18 Pages) M/A-COM Technology Solutions, Inc. – 1G/10G Gbps TIA with AGC and Rate Select

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 4-4. 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.
02139-DSH-001-D
Mindspeed Technologies^®
15
Mindspeed Proprietary and Confidential