OPA340 datasheet(14/46 Pages) TI2

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ADS7816

12-Bit A/D

DCLOCK

OUT

OPA340

+5V

V+

+In

-In

REF

GND

Serial

Interface

0.1 F

NOTE: A/D Input = 0 to V

REF

= 0V to 5V for

0V to 5V output.

RC network filters high-frequency noise.

500W

3300pF

CS/SHDN

20W

OPAx340

V+

OUT

OPA340, OPA2340, OPA4340

SBOS073C – SEPTEMBER 1997 – REVISED AUGUST 2016

www.ti.com

Product Folder Links: OPA340 OPA2340 OPA4340

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Feature Description (continued)

One method of improving capacitive load drive in the unity-gain configuration is to insert a 10-

Ω to 20-Ω resistor

in series with the output, as shown in Figure 25. This resistor significantly reduces ringing with large capacitive

loads. However, if there is a resistive load in parallel with the capacitive load, it creates a voltage divider

introducing a DC error at the output and slightly reduces output swing. This error can be insignificant. For

instance, with RL = 10 kΩ and RS = 20 Ω, there is only an approximate 0.2% error at the output.

When used with the miniature package options of the OPA340 series, the combination is ideal for space-limited

and low-power applications. For further information, consult the ADS7816 data sheet, 12-Bit High Speed Micro

Power Sampling Analog-To-Digital Converter (SBAS061). With the OPA340 in a noninverting configuration, an

RC network at the output of the amplifier can be used to filter high-frequency noise in the signal (see Figure 26).

In the inverting configuration, filtering may be accomplished with a capacitor across the feedback resistor (see

Figure 27).

Figure 25. Series Resistor in Unity-Gain Configuration Improves Capacitive Load Drive

7.3.5 Driving A/D Converters

The OPA340 series operational amplifiers are optimized for driving medium-speed (up to 100 kHz) sampling A/D

converters. However, they also offer excellent performance for higher speed converters. The OPA340 series

provides an effective means of buffering the converter input capacitance and resulting charge injection while

providing signal gain. Figure 26 and Figure 27 show the OPA340 driving an ADS7816. The ADS7816 is a 12-bit,

micro-power sampling converter in the tiny 8-pin VSSOP package.

Figure 26. OPA340 in Noninverting Configuration Driving ADS7816

OPA340 Datasheet(PDF) 14 Page - Texas Instruments

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