OPAX607 datasheet(25/52 Pages) TI

25 / 52 page

9.2.1.2 Detailed Design Procedure

In a difference amplifier circuit, the output voltage is given by:

1 =

(

)

5* 45* + 84'(

(2)

For lowest system noise, small values of RF and RG are preferred. The smallest value of RG is limited by the

input transient voltage (10 V here) seen by the circuit, and is given by:

)

(I=T .) F

F 85

(I=T .)

(3)

Where,

• VIN(maximum) is the maximum input transient voltage seen by the circuit.

• VD is the forward voltage drop of ESD diodes at the amplifier input.

• ID(maximum) is the maximum current rating of the ESD diodes at the amplifier input.

For a difference amplifier gain of 20 V/V, an RF of 12 kΩ and RG of 600 Ω are used. With a clock frequency of 40

MHz and the ADS7056 sampling at 1 MSPS, the available acquisition time for amplifier output settling is 550 ns.

Figure 9-2 shows the simulation results for the circuit in Figure 9-1. The worst-case peak-to-peak input transient

condition is simulated. The output of the OPAx863 device settles to within 0.1% accuracy within 543 ns. If using

a slower clock frequency with the ADC is desired, then the acquisition time reduces with the same sampling rate,

which degrades measurement accuracy. Alternatively, the sampling rate can be reduced to recover the required

acquisition time and 0.1% accuracy.

9.2.1.3 Application Curves

Time (150 ns/div)

-2

-1.5

0.1

-1

0.2

-0.5

0.3

0.4

0.5

0.6

1.5

0.7

0.8

2.5

0.9

3.5

1.1

1.2

D805

VIN x 20

OPAx863 O/P

S/H Voltage

% Error

Figure 9-2. 0.1% Settling Performance

www.ti.com

OPA863, OPA2863, OPA4863

SBOS982J – JUNE 2020 – REVISED JUNE 2023

Submit Document Feedback

Product Folder Links: OPA863 OPA2863 OPA4863

OPAX607 Datasheet(PDF) 25 Page - Texas Instruments

OPAX607 Datasheet(HTML) 25 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Datasheet Download

Link URL