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Texas Instruments INA128PA — Analog & Data Acquisition

INA128PA Instrumentation Amplifier, 4V/µs Slew Rate, 8-DIP

MPNINA128PA
Active

Texas Instruments INA128PA precision instrumentation amplifier, single channel, 4V/µs slew rate, 1.3 MHz bandwidth, 25 µV input offset, 2 nA input bias, 4.5 V to 36 V supply, -40°C to 85°C, 8-DIP through-hole package.

$10.7700Ref. price · indicative, final on quote
Texas Instruments INA128PA datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

INA128PA specifications
ParameterValue
MountingThrough Hole
Amplifier typeInstrumentation
Voltage - input offset25 µV
Voltage - supply span4.5 V
Current - supply700µA
Current - input bias2 nA
Current - output (Channel)15 mA
Operating temperature-40°C~85°C
-3db bandwidth1.3 MHz
PackageTube
Slew rate4V/µs
Case8-DIP (0.300\", 7.62mm)
Number of circuits1

Product details

Precision instrumentation amplifier for bridge and medical front-ends

A single 4.5 V to 36 V supply span covers both single-supply 5 V systems and split-supply ±15 V industrial rails.

Slew rate and bandwidth — what they mean for signal fidelity

The 4V/µs slew rate and 1.3 MHz -3 dB bandwidth are not headline numbers for a fast op-amp, but they are more than adequate for the sub-100 kHz signals that instrumentation amplifiers typically handle. The slew rate ensures the output can track a 10 V peak-to-peak step at roughly 60 kHz without slewing into distortion — well above the bandwidth of most bridge and biopotential signals. The 700 µA supply current per channel keeps the self-heating low in the DIP package, which matters when the input offset drift over temperature is a concern.

The 8-DIP (0.300", 7.62 mm) package with through-hole mounting is socket-friendly for prototyping and remains preferred in some medical and industrial designs where field replacement without rework is a requirement.

Frequently asked questions

What is the gain of INA128PA?

The INA128PA is a classic three-op-amp instrumentation amplifier whose gain is set by a single external resistor. The datasheet provides the standard gain equation: G = 1 + (50 kΩ / R_G). With no external resistor the gain is 1; with R_G = 50 Ω the gain reaches 1000.

Can INA128PA be used for ECG applications?

Yes. The 25 µV input offset, 2 nA bias current, and high common-mode rejection make the INA128PA a common choice for ECG front-end stages. The 1.3 MHz bandwidth is well above the ECG signal band (0.05–150 Hz), and the 4V/µs slew rate preserves the QRS complex shape without distortion.

What is the closest pin-compatible alternative to INA128PA in this component family?

Within the same TI family, the INA129PA is a pin-compatible variant with a slightly different gain equation (G = 1 + (49.4 kΩ / R_G)) and similar precision specs. The INA128PA uses the 50 kΩ internal resistor network; the INA129PA uses 49.4 kΩ. For most applications the gain difference is negligible, but the resistor value matters if you are matching a specific gain-set resistor from an existing BOM.