Texas Instruments INA105KPG4

Overview

INA105KPG4 from Texas Instruments is a precision unity-gain differential amplifier IC designed for high-accuracy signal conditioning in measurement systems. It delivers 72dB minimum CMRR, 0.025% maximum gain error, and 1MHz bandwidth, with input common-mode range extending beyond ±15V rails. It is used in battery cell formation equipment to reject noise while amplifying small differential voltage signals across series-connected cells.

For engineers reviewing the INA105KPG4 datasheet, INA105KPG4 pinout, INA105KPG4 application, or INA105KPG4 equivalent, key selection criteria include guaranteed CMRR over temperature, laser-trimmed resistor matching for stable gain, rail-to-rail common-mode input capability, and compatibility with ±5V to ±18V dual supplies in industrial sensor interfaces.

Technical Context

The INA105KPG4 integrates a precision bipolar op amp with four on-chip 25kΩ laser-trimmed metal-film resistors, enabling accurate unity-gain difference amplification without external precision resistors. Its internal resistor network provides matched TCR for stable CMRR and gain drift across –40°C to +85°C.

It operates in a single functional mode with fixed G = 1 configuration, where differential input (pins 2/3), reference (pin 1), sense (pin 5), and output (pin 6) terminals define its signal path. Input common-mode voltage range reaches ±20V at ±15V supply, enabled by internal resistor division before the op amp inputs.

Key Specifications

Pinout & Package

INA105KPG4 is supplied in an 8-pin plastic DIP (PDIP) package measuring 9.81 mm × 9.43 mm, with through-hole mounting and industry-standard lead spacing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision differential amplifier applications.

Compared with INA105KP and INA105U, the INA105KPG4 offers identical precision performance in a through-hole PDIP package optimized for lab validation and repair-friendly designs, while INA105U provides footprint reduction and thermal advantages in volume SMT manufacturing.

Availability

INA105KPG4 is available at Aetrix Electronics and suitable for battery test systems, industrial data loggers, servo feedback circuits, and process level transmitters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for INA105KPG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal chain solutions.

The INA105 belongs to TI's precision differential amplifier product line, engineered specifically for high-accuracy measurement systems where laser-trimmed resistor matching and rail-overlapping input range are essential for industrial and test equipment reliability.

FAQ

What is the maximum common-mode input voltage for INA105KPG4 at ±15V supply?

The INA105KPG4 supports a common-mode input voltage range of ±20V when operated with ±15V supplies. This rail-overlapping capability allows direct connection to high-voltage differential sources-such as battery strings or industrial transducers-without external attenuation. The internal 25kΩ resistor network divides the input prior to the op amp, protecting inputs while preserving CMRR. Exceeding ±25V risks damage, per absolute maximum ratings.

Does INA105KPG4 require external precision resistors to achieve specified CMRR?

No, the INA105KPG4 does not require external precision resistors. It integrates four laser-trimmed 25kΩ metal-film resistors on-die, matched for ratio and temperature coefficient (TCR). This monolithic network guarantees ≥72dB CMRR and ≤0.025% gain error without discrete resistor selection or trimming-reducing design complexity, board area, and long-term drift in field-deployed instrumentation.

Can INA105KPG4 operate from a single supply?

Yes, the INA105KPG4 can operate from a single supply between 10V and 36V, as specified in Recommended Operating Conditions. However, its input common-mode and output swing ranges are optimized for dual-supply use (±5V to ±18V). In single-supply mode, the Ref pin (Pin 1) must be biased to mid-supply to center the output, and input signals must remain within the device's specified V_CM limits relative to ground and V_CC.

What is the purpose of the Sense pin (Pin 5) on INA105KPG4?

The Sense pin (Pin 5) connects via an internal 25kΩ trimmed resistor to the op amp's inverting input. While unused in basic unity-gain difference mode, it enables alternate configurations such as precision inverting amplifiers (G = –1), summing amplifiers, or buffered voltage references. Its presence expands circuit flexibility without adding external components-leveraging the same matched resistor network that ensures accuracy in the primary differential mode.

How does the NC pin (Pin 8) affect PCB layout for INA105KPG4?

Pin 8 (NC) on the INA105KPG4 has no internal connection and must remain electrically floating-never tied to supply, ground, or signal traces. In PCB layout, it may be left unconnected or optionally grounded for mechanical stability, but grounding introduces no functional benefit and risks parasitic coupling if routed near sensitive analog paths. Maintain clearance from high-impedance nodes and avoid routing signal traces beneath this pad to prevent unintended capacitive coupling.