10 Power Supply Recommendations

The minimum power supply voltage for INA12x is ±2.25 V and the maximum power supply voltage is ±18 V.

This minimum and maximum range covers a wide range of power supplies; but for optimum performance, ±15

V is recommended. Add a bypass capacitor at the input to compensate for the layout and power supply source

impedance.

10.1 Low-Voltage Operation

The INA12x operate on power supplies as low as ±2.25 V. Performance remains excellent with power supplies

ranging from ±2.25 V to ±18 V. Most parameters vary only slightly throughout this supply voltage range; see

Section 7.6.

Operation at very-low supply voltages requires careful attention to make sure that the input voltages remain

within the linear range. Voltage swing requirements of internal nodes limit the input common-mode range with

low power-supply voltage. Figure 7-6 shows the range of linear operation for ±15-V, ±5-V, and ±2.5-V supplies.

11 Layout

11.1 Layout Guidelines

Place the power-supply bypass capacitor as close as possible to the supply and ground pins. The recommended

value of this bypass capacitor is 0.1 μF to 1 μF. If necessary, add more decoupling capacitance to compensate

for noisy or high-impedance power supplies. These decoupling capacitors must be placed between the power

supply and INA12x devices.

The gain resistor must be placed close to pin 1 and pin 8. This placement limits the layout loop and minimizes

any noise coupling into the devices.

11.2 Layout Example

Bypass

Capacitor

Bypass

Capacitor

Gain Resistor

R

6

V

IH–

V +

IH

V–

R

6

V+

V

O

REF

–

+

V+

V

OUT

GND

V

IN

V

IN

GND

V–

Figure 11-1. Recommended Layout

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INA128, INA129

SBOS051F – OCTOBER 1995 – REVISED MAY 2022

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