INA125PA - 10V Reference Bridge Amplifier | Texas Instruments
MPN: INA125PA ✓ ActiveINA125PA Overview
An instrumentation amplifier is a specialized amplifier IC that converts a low-level differential signal into a single-ended or differential output. Its internal architecture rejects common-mode noise while amplifying the voltage difference between two inputs. In the power-management and signal-chain hierarchy, an instrumentation amplifier is an amplifier IC used for sensor-interface, bridge-measurement, and precision signal-conditioning applications. The INA125 adds an internal voltage reference capable of exciting resistive sensor bridges.
The INA125PA provides a low quiescent current of 460 µA, a maximum low-frequency offset voltage of 250 µV, and maximum offset drift of 2 µV/°C. Its precision voltage reference is fixed at 10 V. A single external resistor sets the gain, allowing gains from 4 to 10,000 while avoiding the need for a resistor network. Low offset, low drift, and low power consumption make the device useful for battery-powered and precision industrial equipment.
Internally, the amplifier combines a precision gain stage with an integrated reference and low-noise input network. The high gain range supports resistive bridges with relatively small differential outputs, while the 150 kHz bandwidth covers many temperature, pressure, force, and position sensing applications. Because this is athrough-hole PDIP device rather than a surface-mount package, it is especially convenient for prototype boards, educational instruments, legacy industrial controls, and repair assemblies.
Typical uses include Wheatstone bridge excitation and measurement, load-cell signal conditioning, industrial pressure transducers, portable measurement instruments, and low-power sensor interfaces. The 10 V reference can bridge suitable high-impedance resistive networks, but the bridge and input network must remain within the device's supply, common-mode, and electrical limits. The broad gain range also permits direct measurement of small millivolt-level signals without a separate front-end amplifier.
Designers should place the gain-setting resistor close to the gain resistor pins and use a stable, low-temperature-coefficient resistor when gain accuracy matters. Input filtering should preserve the required bandwidth, while supply bypassing should use short, low-inductance connections. Because the INA125PA includes a precision reference, designers must account for reference current loading when the 10 V output is used to power external circuitry.
This page consolidates verified manufacturer and distributor information, explicit data gaps, practical design guidance, and a careful same-package replacement assessment. The supplied sources establish the INA125PA's core functionality but do not provide five verified pin-to-pin alternatives, so the replacement list is intentionally limited rather than padded with electrically different or differently packaged parts.
Drop-in alternatives for INA125PA — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with INA125PA (same form factor and footprint) — differing in Package, Product Type, Quiescent Current.
INA125P
✅ Drop-InContact for price
View Datasheet →INA125PA Maximum Ratings & Electrical Characteristics
| Product Type | Single-channel instrumentation amplifier with precision voltage reference |
| Amplifier Count | 1 circuit |
| Gain Range | 4 to 10,000 |
| Gain Configuration | Single external resistor |
| Internal Reference Voltage | 10 V |
| Supply Voltage Range | 1.35 V to 18 V |
| Quiescent Current | 460 µA |
| Offset Voltage | 250 µV maximum |
| Offset Voltage Drift | 2 µV/°C maximum |
| Bandwidth | 150 kHz |
| Gain Error | 0.02% |
| Package | 16-pin PDIP |
| Mounting Type | Through-hole |
INA125PA 16-pin pdip Pin Configuration Guide
Pin configuration for INA125PA (16-pin pdip package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for INA125PA.
Refer to the datasheet for full pin configuration.
Typical Applications
INA125PA is suitable for 6 applications: Wheatstone Bridge Sensor Conditioning, Load Cell Signal Amplification, Industrial Pressure Transducer Interface, Battery-Powered Measurement Instruments, Temperature and Strain Measurement, Educational and Prototype Instrumentation.
Wheatstone Bridge Sensor Conditioning
The INA125PA fits Wheatstone bridge conditioning because it combines differential input amplification with a 10 V precision reference in one 16-pin PDIP device. The reference can establish the bridge excitation voltage, while the amplifier rejects common-mode voltage and boosts the small differential output generated by resistance changes. Gains from 4 to 10,000 provide useful flexibility for pressure, position, and force transducers. The design should verify that bridge excitation current, input common-mode voltage, and output swing remain within the manufacturer limits, especially when the 10 V reference also powers external circuitry.
Recommended
Load Cell Signal Amplification
The INA125PA is appropriate for load-cell interfaces that require a stable excitation reference and high differential gain. Its 10 V internal reference provides a defined bridge supply, while the adjustable gain from 4 to 10,000 can accommodate typical millivolt-level bridge imbalance. Low offset voltage of 250 µV maximum and low offset drift of 2 µV/°C maximum are important when force readings must remain repeatable. The gain resistor should use low tolerance and low thermal coefficient, and the bridge must remain within the input common-mode and supply constraints.
Recommended
Industrial Pressure Transducer Interface
The INA125PA can condition the differential output of a resistive industrial pressure bridge while supplying a 10 V excitation reference. Its low quiescent current of 460 µA reduces the burden in distributed or portable measurement equipment, and the broad 4-to-10,000 gain range supports multiple bridge sensitivities. Designers should use a stable gain resistor, protect inputs from industrial transients, and place filtering close to the amplifier. The selected bridge must also maintain a common-mode voltage compatible with the INA125PA supply and input limits.
Recommended
Battery-Powered Measurement Instruments
The INA125PA suits portable measurement instruments because its 460 µA quiescent current complements a supply range beginning at 1.35 V. Sleep mode can further reduce consumption when measurements are taken intermittently, while the integrated 10 V reference supports bridge excitation without an additional reference IC. The circuit still requires efficient regulation, careful reference loading analysis, and a low-leakage gain network. For instruments powered from batteries, total supply current should include reference output loading and any external filtering or protection components.
Recommended
Temperature and Strain Measurement
The INA125PA is suitable for temperature, strain, and displacement bridges where a small differential output must be amplified accurately. The 250 µV maximum low-frequency offset and 2 µV/°C maximum drift help minimize measurement error as environmental temperature changes, while the 10 V reference provides a repeatable excitation basis. The 150 kHz bandwidth supports relatively slow sensor systems but may not suit high-frequency dynamic measurements. Resistor self-heating and reference loading should be included in the error budget for precision strain-gauge installations.
Recommended
Educational and Prototype Instrumentation
The 16-pin PDIP package makes the INA125PA convenient for educational benches, prototype boards, and repair-oriented instrumentation. Through-hole construction is easy to solder and inspect, while the integrated reference and single-resistor gain setting reduce assembly complexity. A gain of 4 to 10,000 allows the same device to demonstrate bridge conditioning at several sensitivities. The prototype should still include supply bypassing and input protection, and the designer should consult the manufacturer pinout before assigning signals because individual pin names were not included in the supplied search results.
Recommended
Recommended Products Summary
Engineering reference data for INA125PA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA125P |
|---|---|---|
| Brand | Texas Instruments | Texas Instruments |
| Package | PDIP-16 | PDIP-16 |
| Product Type | Instrumentation amplifier with precision voltage reference | Instrumentation amplifier with precision voltage reference |
| Amplifier Count | 1 circuit | 1 circuit |
Key Differentiators
- Integrated precision excitation source (vs INA125P)
- Low-power precision operation (vs INA125P)
- Single-resistor gain programming (vs INA125P)
Design Notes
Connect the gain-setting resistor directly between the INA125PA gain pins with a short, compact route and a low-ESR ground return. Parasitic resistance at the gain pins can create an error proportional to the programmed gain, particularly near the upper limit of 10,000. For high-gain measurements, use a precision resistor with low temperature coefficient, avoid test-point leakage paths, and keep the gain network away from high-impedance input routing.
Decouple the supply close to the INA125PA with low-ESR ceramic capacitance and provide a short return path to the device ground. The verified operating range is 1.35 V to 18 V, but output swing and input common-mode limits can restrict usable signal range at lower supplies. If the internal 10 V reference supplies external circuitry, include its load current when checking the reference budget, regulator headroom, thermal condition, and start-up behavior.
Treat the differential inputs as a matched, high-impedance network. Route them away from switching nodes and relay contacts, use symmetrical input filtering where practical, and terminate unused or multiplexed inputs according to the manufacturer's guidance. The 150 kHz bandwidth can amplify high-frequency noise when a large gain is selected, so add filtering only after confirming that its added phase and settling behavior are acceptable for the required measurement bandwidth.
Do not assume that a related part number is a drop-in replacement without checking every package pin and function. In particular, INA125P, INA125PAG4, INA125UA, and INA2126P appear in comparison material, but the supplied data does not establish that all share the same PDIP-16 pinout, reference behavior, gain implementation, and electrical limits. Verify the official ordering table and datasheet before substituting any candidate into production equipment.
Compliance Information
The supplied verified search results do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. No compliance claim was inferred from the manufacturer association or distributor listings.
