Analog Devices Inc. LT1168CS8#PBF

Overview

LT1168CS8#PBF from Analog Devices (acquired Linear Technology) is a micropower, laser-trimmed precision instrumentation amplifier requiring only one external resistor to set gains from 1 to 10,000. It delivers 10nV/√Hz input voltage noise at 1kHz, 40µV max input offset voltage, and 90dB CMRR at G=1 while consuming only 530µA max supply current across ±2.3V to ±18V supplies - enabling high-accuracy bridge sensing in battery-powered medical and industrial instrumentation.

For engineers reviewing the LT1168CS8#PBF datasheet, LT1168CS8#PBF pinout, LT1168CS8#PBF application, or LT1168CS8#PBF equivalent, this page provides verified pin functions, gain-error vs. temperature behavior, ESD robustness (13kV HBM), load-driven nonlinearity specs (2kΩ min), and validated alternatives for strain gauge and thermocouple signal conditioning where low drift (0.3µV/°C) and wide common-mode range are critical.

Technical Context

The LT1168CS8#PBF implements a three-op-amp topology with laser-trimmed 24.7kΩ internal resistors (R1/R2) and superbeta NPN input transistors (Q1/Q2), enabling precise gain setting via single external RG and achieving <20ppm gain nonlinearity at G=10 with 2kΩ load. Its transconductance-scaling architecture maintains bandwidth stability across gain settings - 400kHz at G=1, 1kHz at G=1000 - without proportional roll-off.

Input bias current (250pA max) is achieved through superbeta processing, and ESD protection (13kV HBM) is integrated on both inputs. The REF pin establishes output reference level, and series resistance >6Ω degrades CMRR to 80dB - confirming strict layout requirements for high-precision applications.

Key Specifications

Pinout & Package

LT1168CS8#PBF is housed in an 8-lead plastic SOIC (S8) package with standard JEDEC MS-012AC dimensions (4.9mm × 3.9mm × 1.75mm, 1.27mm pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1168CS8#PBF, AD8421ARMZ trades micropower operation for speed and noise performance, while INA128UA offers mechanical compatibility at the expense of precision and drift - making LT1168CS8#PBF the optimal balance for portable, high-accuracy sensor interfaces.

Availability

LT1168CS8#PBF is available at Aetrix Electronics and suitable for medical instrumentation, industrial bridge sensing, and battery-powered data loggers requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LT1168CS8#PBF 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

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LT1168CS8#PBF belongs to ADI's precision instrumentation amplifier product line, engineered specifically for low-power, high-accuracy sensor signal conditioning in resource-constrained and thermally variable environments.

FAQ

What is the maximum gain error specification for LT1168CS8#PBF at G=10?

The LT1168CS8#PBF has a maximum gain error of 0.4% at G=10, measured under standard conditions (TA = 25°C, VS = ±15V). This specification holds across the full operating temperature range (–40°C to +85°C) for the 'C' grade variant, and is enabled by laser trimming of internal 24.7kΩ resistors - ensuring consistent performance without external calibration.

Can LT1168CS8#PBF operate from a single 5V supply?

Yes, LT1168CS8#PBF supports single-supply operation from +5V (with ground as –VS), but the input common-mode range is restricted to –VS + 1.9V to +VS – 1.4V (i.e., 1.9V to 3.6V for 5V supply). To maintain accuracy, the REF pin must be biased above ground (e.g., 2.5V), and one input should remain ≥2.5V - as demonstrated in the barometer application circuit in the datasheet.

What is the minimum load resistance supported by LT1168CS8#PBF while maintaining 20ppm gain nonlinearity?

The LT1168CS8#PBF guarantees ≤20ppm gain nonlinearity at G=10 with a 2kΩ load resistor, as explicitly specified in the Electrical Characteristics table. This is a key differentiator versus prior monolithic instrumentation amplifiers, which typically degrade beyond 10kΩ loads - enabling direct driving of low-impedance ADC inputs or active filters without buffer stages.

How does LT1168CS8#PBF achieve 13kV HBM ESD protection without external components?

The LT1168CS8#PBF integrates on-chip ESD protection diodes on both input pins (+IN and –IN), rated to 13kV per Human Body Model (HBM). This is verified per JEDEC JESD22-A114 and eliminates the need for discrete TVS devices in handheld or field-deployed equipment - confirmed by passing IEC 1000-4-2 Level 4 (±15kV contact discharge) when used with two external 5kΩ resistors.

Is LT1168CS8#PBF pin-compatible with AD620 or INA118?

Yes, LT1168CS8#PBF is explicitly described in its datasheet as a "pin-for-pin improved second source" for AD620 and INA118, sharing identical 8-pin SOIC (S8) and PDIP footprints. However, it improves upon both with lower supply current (530µA vs. 1.3mA), better CMRR (90dB vs. 80dB at G=1), and enhanced ESD rating (13kV vs. 2kV HBM), enabling drop-in upgrades in existing designs.