IEEE Circuits and Systems Magazine - Q1 2020 - 26

input noise of Inv-TIA and CS-TIA. This is achieved because of the relatively high open loop again and high
effective transconductance of the core amplifier. Therefore, RIC-TIA and InvCas-TIA achieves the highest FoM 1
among the four topologies. The claim that higher open
loop gain topologies obtain higher performance is also
observed in this case as in the previous case; the InvTIA shows superiority over the CS-TIA.
However, since the aim of this simulation case is to
minimize the power consumption, the DR, in general, is
decreased compared to the previous case. Regarding
the CR-TIA and the CR-RGC-TIA, both achieve the highest GBW of all studied topologies as in case 1. Also, the
CR-RGC-TIA can achieve higher GBW at the expense of
the input referred noise current and power consumption overhead compared to the CR-TIA.

C. Case 3: CPD = 2 pF, 100 MHz BW, Minimum Noise
The frequency response and the input referred noise
current spectral density of the reviewed TIAs are
shown in Figs. 16 and 17 respectively. Also, a summary of the obtained simulation results for this case is
listed in table XI.
A general rule of thumb regarding the four first topologies listed in the comparison table is that the
higher the open loop gain the better the performance;
similar to what is obtained in the 5 KHz BW results. The
RIC-TIA and the InvCas-TIA exhibit the highest transimpedance gain and the highest FoM 1 as well among
all of the eight topologies. This is achieved due to their
large open loop gain and high effective transconductance of the core amplifiers' transistors. However, the
RIC-TIA slightly outperforms the InvCas-TIA in term of

Table X.
A comparison between the reviewed TIA topologies at CPD = 10 pF and 5 KHz BW while targeting minimum power.
BW
(kHz)

Total Integrated
Input Noise pA rms

Power
μW

I Ovl
p -p
nAp-p

DR
(dB)

FoM1

FoM2

CS-TIA

138.1

5

13.6

85.2

80

75.4

346.7

27738.4

Inv-TIA

142.3

5

13.6

28.25

67

73.9

1695.9

113628.5

InvCas-TIA

144.3

5

13.6

14.9

42

69.8

4048

170017.7

RIC-TIA

145.1

5

13.6

19.8

41

69.6

3340

136946

CR-TIA

153

5

23.2

25

2.5

40.6

3850.7

9626.8

CR-RGC-TIA

155.8

5

23.2

68.7

1.3

35

1934.3

2514.6

CG-TIA

141.5

5

10.56

0.044

0.67

36

1279 x 103

857 x 103

RGC-TIA

144

5

14.3

6.8

0.53

31.4

8149.4

4319.2

Transimpedance Gain (dBΩ)

100
95
90
85
80
75
70
65
60
100

1K

10 K 100 K 1 M 10 M 100 M 1,000 M
Frequency (Hz)
CS-TIA
Inv-TIA
InvCas-TIA
RIC-TIA

CG-TIA
CR-TIA
CR-RGC-TIA
RGC-TIA

Figure 16. Frequency response of the reviewed TIAs while
targeting min noise and 100 MHz BW.
26

IEEE CIRCUITS AND SYSTEMS MAGAZINE

Input Noise Spectral Density (pA /√Hz)

Topology

Gain
(dBΩ)

10
9
8
7
6
5
4
3
2
1
0
100

1K

10 K 100 K 1 M 10 M 100 M 1,000 M
Frequency (Hz)
CS-TIA
Inv-TIA
InvCas-TIA
RIC-TIA

CG-TIA
CR-TIA
CR-RGC-TIA
RGC-TIA

Figure 17. Input noise current spectral density of the reviewed TIAs while targeting min noise and 100 MHz BW.

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IEEE Circuits and Systems Magazine - Q1 2020

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