Texas Instruments THS4601EVM, User Manual, Page: 20 / 26

T-Network Gain Stages
3-8
Figure 3-8. Transimpedance Gains
65
70
75
80
85
90
10 k 100 k 1 M 10 M 100 M
Frequency - Hz
T
ransimpedance Gain - dB
10 k
Ω
TRANSIMPEDANCE BANDWIDTH
FOR VARIOUS SOURCE CAPACITANCES
C
S
= 18 pF, C
F
= 2.2 pF
C
S
= 47 pF,
C
F
= 3.3 pF
C
S
= 100 pF,
C
F
= 3.9 pF
C
S
= 220 pF,
C
F
= 5.6 pF
60
65
70
75
80
85
90
95
100
105
10 k 100 k 1 M 10 M
C
S
= 18 pF,
C
F
= 0.6 pF
C
S
= 47 pF,
C
F
= 0.6 pF
C
S
= 100 pF,
C
F
= 1.5 pF
C
S
= 220 pF,
C
F
= 1.8 pF
Frequency - Hz
T
ransimpedance Gain - dB
100 k
Ω
TRANSIMPEDANCE BANDWIDTH
FOR VARIOUS SOURCE CAPACITANCES
90
95
100
105
110
115
120
125
130
10 k 100 k 1 M 10 M
C
S
= 18 pF, C
F
= 0
C
S
= 47 pF,
C
F
= 0
C
S
= 100 pF,
C
F
= 0
C
S
= 220 pF,
C
F
= 0.4 pF
Frequency - Hz
T
ransimpedance Gain - dB
1 M
Ω
TRANSIMPEDANCE BANDWIDTH
FOR VARIOUS SOURCE CAPACITANCES
3.4 T-Network Gain Stages
To get higher transimpedance gains a T-Network is sometimes used. The
components in the feedback path of the op amp that are shown in Figure 3-9
can be used to create either a purely resistive T-Network covered in this
section, or a transimpedance network which is covered in the next section.