Texas Instruments INA117BM

Overview

INA117BM from Texas Instruments is a precision unity-gain difference amplifier optimized for high common-mode voltage measurement in industrial power systems. It delivers ±200V common-mode input range (at ±15V supply), 0.05% max gain error, 0.001% max nonlinearity, and 70dB min DC CMRR - enabling accurate differential sensing across motor drives, semiconductor test fixtures, and ultrasound front-ends.

For engineers reviewing the INA117BM datasheet, INA117BM pinout, INA117BM application, or INA117BM equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation insights, and two confirmed alternative parts with documented functional trade-offs.

Technical Context

The INA117BM integrates a precision op amp with a laser-trimmed thin-film resistor network to achieve stable unity-gain transfer (V_OUT = V_+IN – V_–IN + 20×V_REFA – 19×V_REFB). Its input stage withstands ±500V transient common-mode and differential overloads, eliminating need for external protection in many high-voltage monitoring roles.

Bandwidth is fabrication-dependent: CSO:SHE variant delivers 200kHz (–3dB), while CSO:TID achieves 500kHz; both support full-power bandwidth up to 32kHz at 2V_PP. Input impedance is 400kΩ (CSO:SHE) or 200kΩ (CSO:TID) common-mode, with 800kΩ differential impedance - critical for minimizing loading error in current-sense resistor interfaces.

Key Specifications

Pinout & Package

The INA117BM is supplied in an 8-pin SOIC (D) package measuring 3.91mm × 4.9mm, rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high common-mode voltage difference amplifier applications.

Compared with INA117BM, INA149BDWTR trades bandwidth for superior DC CMRR and extended common-mode range, while AMC1301DWVR adds isolation at the cost of analog interface simplicity and added system-level processing.

Availability

INA117BM is available at Aetrix Electronics and suitable for motor drive current monitoring, semiconductor ATE shunt sensing, ultrasound transducer bias monitoring, and industrial machine tool power rail diagnostics requiring stable component supply across automotive-grade temperature ranges.

Supply support for INA117BM 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, embedded processing, and connectivity solutions with emphasis on reliability and industrial-grade performance.

The INA117 product line targets high-voltage industrial measurement where galvanic isolation is unnecessary - designed specifically to replace costly isolated amplifiers in servo drives, test equipment, and medical imaging systems.

FAQ

What is the maximum common-mode voltage the INA117BM can handle continuously?

The INA117BM supports continuous common-mode input voltages up to ±200V when operated with ±15V supplies. This rating is explicitly specified in Section 5.5 of the datasheet under "Common-mode voltage" with test condition VS = ±15V. Exceeding ±200V requires verification against absolute maximum ratings (±500V peak for 0.1s), but sustained operation above ±200V risks violating recommended operating conditions and may degrade CMRR or cause long-term reliability issues. The INA117BM's design centers on stable ±200V continuous operation.

Does the INA117BM require external trimming for offset or CMRR calibration?

No, the INA117BM does not require external trimming for offset or CMRR calibration under standard conditions. Its laser-trimmed thin-film resistor network achieves ≥70dB CMRR and ≤0.05% gain error without user adjustment. Trim circuits shown in the datasheet (Figures 7-2 and 7-3) are optional and only needed if application-specific tolerances exceed the device's inherent specifications - for example, when >86dB CMRR is required or when source impedances unbalance the inputs. The INA117BM's factory-trimmed architecture eliminates routine calibration in production.

How does the CSO designation affect the INA117BM's electrical performance?

The INA117BM is manufactured exclusively using the CSO:SHE fabrication flow, as confirmed in Table 8-1 of the datasheet. This means its guaranteed specifications align with the SHE column in Section 5.5: 200kHz bandwidth (–3dB), 400kΩ common-mode input impedance, 8.5µV/°C offset drift, and 200kHz full-power bandwidth. Unlike generic INA117KU parts, the INA117BM's performance is fixed to SHE characteristics - no TID-related variants apply. Designers can rely on these SHE values without cross-flow validation.

Can the INA117BM operate from a single supply, and what is the minimum voltage?

Yes, the INA117BM supports single-supply operation with a minimum total supply voltage of 10V (e.g., V+ = 10V, V– = 0V), as stated in Section 5.3 "Recommended Operating Conditions". At 10V single supply, the common-mode input range shrinks proportionally but remains functional for mid-rail referenced signals. Output swing is specified down to 0V (rail-to-rail output not supported), with typical VO = 10V min at IO = 20mA. For full ±200V common-mode capability, dual ±15V supplies are required - the INA117BM's single-supply mode trades common-mode range for simplified power architecture.

What is the purpose of the REFA and REFB pins on the INA117BM?

The REFA (Pin 5) and REFB (Pin 1) pins enable extended transfer function operation beyond basic unity-gain differencing. While V_OUT = V_+IN – V_–IN in standard use, applying voltages to REFA and REFB yields V_OUT = V_+IN – V_–IN + 20×V_REFA – 19×V_REFB. This allows precise output offset control, common-mode voltage boosting (e.g., shifting a ±200V signal into a 0–5V ADC range), or rejection of unwanted common-mode components. The INA117BM's internal resistor ratios fix the 20× and –19× gains - no external components needed.