–5 V

V

(V–)

Optional

(2)

C1

100 nF

R1

(1)

100 Ω

R2

50 kΩ

C2

100 nF

V

(V+)

5 V

SD1

BAS40

V

0 to 4.096 V

I

ADS8326

16-Bit

250kSPS

C3

(1)

1 nF

C4

100 nF

5 V

REF IN

–I x

N

+I x

N

REF3240

4.096V

5 V

OPA320-Q1

½

OPA2320-Q1

R3

25 kΩ

R2

25 kΩ

R

(G)

R1

100 kΩ

R4

100 kΩ

R

(L)

10 kΩ

V

O

50 kΩ

G = 5 +

200 kΩ

R

(G)

5 V

5 V

REF1004-2.5

4

8

(2.5 V)

5 V

½

OPA2320-Q1

20

OPA320-Q1, OPA2320-Q1

SLOS884B – SEPTEMBER 2014 – REVISED DECEMBER 2018

www.ti.com

Product Folder Links: OPA320-Q1 OPA2320-Q1

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Copyright © 2014–2018, Texas Instruments Incorporated

8.2.3 Driving ADCs

The OPAx320-Q1 series op amps are an excellent choice for driving sampling analog-to-digital converters

(ADCs) with sampling speeds up to 1 MSPS. The zero-crossover distortion input stage topology allows the

OPAx320-Q1 to drive ADCs without degradation of differential linearity and THD.

The OPAx320-Q1 can be used to buffer the ADC switched input capacitance and resulting charge injection while

providing signal gain. Figure 42 shows the OPAx320-Q1 configured to drive the ADS8326.

Figure 41. Two Op-Amp Instrumentation Amplifier With Improved High-Frequency Common-Mode

Rejection

(1) Suggested value; may require adjustment based on specific application.

(2) Single-supply applications lose a small number of ADC codes near ground as a result of op amp output swing limitation. If a negative

power supply is available, this simple circuit creates a –0.3-V supply to allow output swing to true ground potential.

Figure 42. Driving the ADS8326