THS4552 Datasheet, PDF (48/71 Pages) Texas Instruments – Dual-Channel, Low-Noise, Precision, 150-MHz, Fully Differential Amplifier

THS4552
SBOS831 – DECEMBER 2016
www.ti.com
Figure 86 shows the starting point for a typical band-limited design. At lower frequencies, this example delivers a
gain of 10 V/V with an intentional band limit in the feedback RC at 320 kHz. This single 5-V design targets a
midsupply output common-mode voltage with only a noise reduction capacitor on the V_OCM input control.
High-Gain, Single-Ended
to Differential Output Stage
with Feedback Pole
CF1
250 pF
RF1
2k
THS4552 Wideband,
Fully Differential Amplifier
VS+
VS-
+
5V
0V ⁺
VIN
±
±
RG1
200
VOCM
10 nF
VS+
±
+
FDA
±
+
PD
10
10 nF
SAR ADC
Input
VS- ^VS+
10
RG2
200
RF2
2k
CF2
250 pF
Copyright © 2016, Texas Instruments Incorporated
Figure 86. Single-Ended to Differential Stage with a Feedback Pole
The response shape must be probed at the FDA output pins before the added RC pole to the SAR input.
Running a wideband sweep with the THS4552 TINA-TI™ model using the SBOC475 simulation file shows a
resonance at 50 MHz in Figure 87 resulting from the feedback capacitor.
20
200
Gain (dB)
15
Phase (deg) ¹⁷⁵
10
150
5
125
0
100
-5
75
-10
50
-15
25
-20
0
-25
-25
-30
100k
1M
10M
Frequency (Hz)
100M
-50
D070
Figure 87. Gain and Phase Plot with a Feedback Pole
48
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