Texas Instruments INA188ID

Overview

INA188ID from Texas Instruments is a precision zero-drift instrumentation amplifier optimized for high-voltage, low-error sensor signal conditioning. It delivers 55 μV max input offset voltage, 0.2 μV/°C max drift, 104 dB min CMRR at G ≥10, rail-to-rail output swing within 250 mV of rails, and operates from ±2 V to ±18 V dual supply - used in ECG amplifiers, bridge-based weigh scales, and thermocouple interfaces.

For engineers reviewing the INA188ID datasheet, INA188ID pinout, INA188ID application, or INA188ID equivalent, this page provides verified specifications, SOIC-8 package layout, RFI-filtered input architecture, gain-setting resistor interface (G = 1 + 50 kΩ/RG), and validated alternatives for medical, industrial, and portable instrumentation designs.

Technical Context

The INA188ID implements a three-op-amp topology with laser-trimmed 25-kΩ internal feedback resistors and integrated RFI filtering on both inputs. Its auto-zeroing core enables near-zero drift and <0.25 μVPP 0.1–10 Hz noise, while the REF pin supports level-shifting in single-supply configurations.

It achieves >104 dB CMRR at G ≥10 by rejecting common-mode signals across –40°C to +125°C, and maintains stable gain accuracy (±0.007% at G=1) without requiring matched external resistors - unlike discrete op-amp INAs.

Key Specifications

Pinout & Package

INA188ID is housed in an SOIC-8 (D) package measuring 4.90 mm × 3.91 mm with standard 1.27-mm pitch. The exposed thermal pad on the underside is not electrically connected and may be left floating or grounded per layout requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8421ARMZ and INA128UA, the INA188ID uniquely combines zero-drift stability, integrated RFI filtering, and laser-trimmed gain accuracy - making it optimal for battery-powered medical devices and high-reliability industrial transmitters where long-term calibration stability is mandatory.

Availability

INA188ID is available at Aetrix Electronics and suitable for ECG amplifiers, bridge-based weigh scales, thermocouple interfaces, RTD sensor amplifiers, and portable instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for INA188ID 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 delivering analog and embedded processing solutions, with decades of expertise in precision signal chain components.

The INA188ID belongs to TI's precision instrumentation amplifier product line, engineered specifically for high-accuracy, low-drift sensor signal conditioning in medical, test equipment, and industrial measurement systems.

FAQ

What is the maximum gain achievable with INA188ID?

The INA188ID supports gains from 1 to 1000 using a single external resistor RG per the equation G = 1 + 50 kΩ/RG. At G = 1000, RG = 50 Ω (1% tolerance recommended). Bandwidth reduces to 1.5 kHz at this gain, and output swing remains rail-to-rail with 250-mV headroom into 10-kΩ loads. The INA188ID does not support gains beyond 1000 per datasheet specifications.

Does INA188ID require external resistors for gain setting at G = 1?

No, the INA188ID does not require external resistors at G = 1. Pins 1 and 8 (RG) are left unconnected (NC) per TI's datasheet Table 1. Internally, the device routes the signal path directly through the zero-drift amplifier stages without engaging the gain-setting network - enabling minimal component count and highest accuracy (±0.007% gain error) in unity-gain configurations.

Can INA188ID operate from a single 3.3-V supply?

No, the INA188ID requires a minimum total supply voltage of 4 V - meaning it cannot operate from a single 3.3-V rail. It supports single supplies from 4 V to 36 V, so a 5-V or higher supply is required. For 3.3-V systems, consider TI's INA333 or ADI's AD8237, which are specified down to 2.7-V operation.

How does the REF pin function in INA188ID?

The REF pin on the INA188ID sets the output DC bias level. When driven by a low-impedance source (e.g., resistor divider from V+), it offsets the output voltage by that reference voltage - essential for single-supply operation where the output must be centered above ground. The REF input impedance is 40 kΩ, and its voltage range spans from V– to V+, allowing flexible level-shifting without external op-amps.

Is INA188ID pin-compatible with other TI instrumentation amplifiers like INA128 or INA118?

No, the INA188ID is not pin-compatible with INA128 or INA118. It uses an SOIC-8 pinout with RG on pins 1/8, VIN– on pin 2, VIN+ on pin 3, V– on pin 4, REF on pin 5, VOUT on pin 6, and V+ on pin 7 - whereas INA128 uses pin 1 for REF and pin 8 for V+, and INA118 has different gain-setting and supply pin assignments. PCB layout must be redesigned for INA188ID replacement.