Analog Devices Inc. LT1008IN8#PBF

Overview

LT1008IN8#PBF from Analog Devices (acquired Linear Technology) is a precision operational amplifier designed for ultra-low-input-bias-current, microvolt-offset, low-noise analog signal conditioning in high-accuracy instrumentation. It delivers 120μV max input offset voltage, 600pA max input bias current over –40°C to 85°C, 0.5μV_P-P 0.1Hz–10Hz noise, 114dB min CMRR/PSRR, and ±13V output swing into 10kΩ - enabling use in standard cell buffers, thermocouple amplifiers, and charge integrators.

For engineers reviewing the LT1008IN8#PBF datasheet, LT1008IN8#PBF pinout, LT1008IN8#PBF application, or LT1008IN8#PBF equivalent, key selection considerations include guaranteed picoampere bias current across temperature, microvolt-level offset stability, external frequency compensation flexibility, low 1/f noise corner, and compatibility with LM108A/LM308A sockets in precision DC-critical circuits.

Technical Context

The LT1008IN8#PBF employs a proprietary JFET-input stage with back-to-back protection diodes and dual external compensation terminals (COMP1, COMP2), enabling user-defined bandwidth/slew rate trade-offs via single capacitor selection (e.g., CF = 3pF → 5MHz GBW; CF = 30pF → 60° phase margin). Its architecture maintains sub-100pA bias current at 125°C while achieving <1.5μV/°C offset drift and >200 V/mV large-signal gain with 5mA load.

It operates from ±2V to ±20V supplies, supports rail-to-rail input common-mode range (±13.5V), and features guard-ring-compatible pinout (Pin 4 = V– case connection) for leakage-sensitive applications like photodiode transimpedance stages and Kelvin-Varley divider buffering where nanoamp-level board leakage must be suppressed.

Key Specifications

Pinout & Package

N8 package: 8-lead narrow-body plastic DIP (0.300" width), through-hole mount, RoHS-compliant lead finish (#PBF).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision op amp applications.

Compared with LT1012CN8#PBF and OPA2189IDR, the LT1008IN8#PBF uniquely balances picoampere bias stability across temperature, external compensation control, and ultra-low 1/f noise - making it irreplaceable in metrology-grade standard cell buffers and charge-integration systems where long-term drift and flicker noise dominate error budgets.

Availability

LT1008IN8#PBF is available at Aetrix Electronics and suitable for precision instrumentation, thermocouple signal conditioning, and charge-integration applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LT1008IN8#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 semiconductors, formed through the acquisition of Linear Technology in 2017.

The LT1008IN8#PBF belongs to Linear Technology's legacy precision op amp family, engineered specifically for metrology, scientific instrumentation, and calibration equipment demanding picoampere input bias, microvolt offset, and sub-μV/°C drift performance.

FAQ

What is the maximum operating temperature range for the LT1008IN8#PBF?

The LT1008IN8#PBF is rated for operation from –40°C to +85°C. This industrial temperature grade is confirmed in the Electrical Characteristics table under "LT1008I" ordering option, with all key parameters (bias current, offset voltage, CMRR) guaranteed across this full range. The device's 600pA max input bias current and 120μV max offset voltage apply specifically within this interval, distinguishing it from the commercial (0°C to 70°C) and military (–55°C to 125°C) variants.

Does the LT1008IN8#PBF require external frequency compensation capacitors?

Yes, the LT1008IN8#PBF requires external frequency compensation via its dedicated COMP1 and COMP2 pins. Unlike internally compensated op amps, it uses a single capacitor (e.g., 30pF on COMP1) to set dominant-pole response. This design allows users to optimize bandwidth, slew rate, and phase margin for specific closed-loop gains - such as achieving 5MHz GBW at AV = 10 or enhancing capacitive load drive with overcompensation.

Can the LT1008IN8#PBF replace LM108A or LM308A op amps in existing designs?

Yes, the LT1008IN8#PBF is socket-compatible with LM108A and LM308A devices in N8 (PDIP) packages and shares identical pinout and standard compensation topology. It upgrades DC performance - delivering lower offset (120μV vs. 500μV), lower bias current (600pA vs. 30nA), and higher PSRR (114dB vs. 90dB) - while maintaining AC behavior compatible with existing feedback networks.

What is the purpose of Pin 4 (V–) on the LT1008IN8#PBF, and how should it be connected?

Pin 4 on the LT1008IN8#PBF is the negative supply terminal and also serves as the case connection in metal-can variants. In the N8 PDIP package, it remains an electrical node tied to V–. For optimal leakage suppression in high-impedance applications, it must be connected directly to the system ground plane and used as the guard ring reference - especially critical in photodiode or standard cell buffer circuits where board surface leakage would otherwise dominate input error.

How does the LT1008IN8#PBF achieve low 0.1Hz–10Hz noise performance?

The LT1008IN8#PBF achieves 0.5μV_P-P 0.1Hz–10Hz noise through a combination of JFET input stage optimization and proprietary die layout that minimizes 1/f noise sources. Its 2.5Hz 1/f corner frequency - verified in Figure 10 of the datasheet - ensures flicker noise contributes minimally below 10Hz, making it suitable for DC-coupled applications like precision weigh scales and electrochemical sensors where low-frequency noise directly impacts measurement resolution.