OPA4197IPWR datasheet(30/56 Pages) TI2

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NŸ

10 µF

RISO

37.4

VREF

2.5 V

RFx

NŸ

39 nF

V+

OPA197

VOUT

VCC

OPA197, OPA2197, OPA4197

SBOS737C – JANUARY 2016 – REVISED MARCH 2018

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8.2.3 Precision Reference Buffer

The OPAx197 features high output current drive capability and low input offset voltage, making the device an

excellent reference buffer to provide an accurate buffered output with ample drive current for transients. For the

10-µF ceramic capacitor shown in Figure 56, RISO, a 37.4-Ω isolation resistor, provides separation of two

feedback paths for optimal stability. Feedback path number one is through RF and is directly at the output, VOUT.

Feedback path number two is through RFx and CF and is connected at the output of the op amp. The optimized

stability components shown for the 10-µF load give a closed-loop signal bandwidth at VOUT of 4 kHz, while still

providing a loop gain phase margin of 89°. Any other load capacitances require recalculation of the stability

components: RF, RFx, CF, and RISO.

Figure 56. Precision Reference Buffer

9 Power Supply Recommendations

The OPAx197 is specified for operation from 4.5 V to 36 V (±2.25 V to ±18 V); many specifications apply from

–40°C to +125°C. Parameters that can exhibit significant variance with regard to operating voltage or

temperature are presented in the Typical Characteristics.

CAUTION

Supply voltages larger than 40 V can permanently damage the device; see the

Absolute Maximum Ratings.

Place 0.1-µF bypass capacitors close to the power-supply pins to reduce errors coupling in from noisy or high-

impedance power supplies. For more detailed information on bypass capacitor placement, refer to the Layout

section.

OPA4197IPWR Datasheet(PDF) 30 Page - Texas Instruments