Texas Instruments LM111H

Overview

LM111H from Texas Instruments is a high-speed voltage comparator in an 8-pin TO-99 hermetic metal can package, rated for −55°C to +125°C operation. It features 150 nA max input bias current, 20 nA max offset current, ±30 V differential input voltage range, and 200 ns response time. It drives relay and lamp loads up to 50 V/50 mA and supports strobe control and offset balancing.

For engineers reviewing the LM111H datasheet, LM111H pinout, LM111H application, or LM111H equivalent, this page delivers verified specifications, hermetic-package pin configuration, military-grade temperature performance, strobe-enabled output isolation, and direct alternatives for precision analog threshold detection in aerospace, industrial control, and test equipment.

Technical Context

The LM111H implements a bipolar transistor-based differential input stage with open-collector NPN output, enabling level-shifting across ground, positive, or negative supply references. Its strobe pin (Pin 6) disables output when 3–5 mA is drawn, allowing synchronized comparison windows without external gating logic.

Offset adjustment is supported via Pins 5 and 6 using an external 5 kΩ potentiometer, trimming up to ±8 mV of input offset voltage. Input common-mode range extends to ±14.5 V at ±15 V supplies, and the device maintains stable operation under high source impedances when layout guidelines-such as guard traces, short leads, and 0.01 µF trim-pin bypassing-are followed.

Key Specifications

Pinout & Package

LM111H is housed in an 8-pin TO-99 hermetic metal can (package code LMC), with a 0.200-inch lead pitch, 5.72 mm max height, and center-tab grounding. The package provides EMI shielding, moisture resistance, and long-term reliability in harsh environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage comparator applications.

Compared with LM111J-8 and LM311H, the LM111H uniquely combines hermetic TO-99 packaging, −55°C to +125°C operation, and 150 nA input bias - making it the sole option for high-reliability, thermally demanding comparator roles where long-term parameter stability is non-negotiable.

Availability

LM111H is available at Aetrix Electronics and suitable for motor control feedback, avionics power sequencing, and industrial relay logic requiring stable component supply across extreme temperature cycles and long service life.

Supply support for LM111H 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, embedded processing, and high-reliability components for industrial, automotive, and aerospace markets.

The LM111H belongs to TI's legacy high-speed comparator product line, engineered specifically for precision threshold detection in mission-critical systems where hermetic sealing, wide temperature operation, and strobe-controlled timing are essential.

FAQ

What is the maximum differential input voltage specification for the LM111H?

The LM111H supports a differential input voltage of ±30 V, meaning the voltage difference between Pins 2 and 3 can safely reach 60 V peak-to-peak. This allows direct comparison of signals referenced to different supply domains - such as sensing across a shunt resistor in a high-side switching configuration - without external attenuation or clamping networks. This rating holds across the full −55°C to +125°C operating range.

How does the strobe function work on the LM111H, and what current is required?

The LM111H uses Pin 6 as a current-sink strobe input: drawing 3–5 mA from this pin disables the output transistor, forcing the collector (Pin 8) into high-impedance state. This is not a logic-level input - grounding Pin 6 will damage the device. The strobe function enables precise time-gated comparisons, such as synchronizing threshold detection to a system clock edge, without adding external logic gates or latches.

Can the LM111H operate from a single 5 V supply, and what are the output limitations in that configuration?

Yes, the LM111H operates from a single 5 V supply (V+ = 5 V, V− = 0 V). In this mode, the output saturation voltage is 0.23–0.4 V at ≤8 mA sink current, enabling direct interface to 5 V TTL or CMOS logic. The input common-mode range extends from −0.5 V to +3.8 V, supporting rail-to-rail input signals with appropriate biasing. Full 50 mA drive capability requires dual-supply operation.

What is the purpose of Pins 5 and 6 on the LM111H, and how are they configured for offset nulling?

Pins 5 and 6 on the LM111H provide offset nulling: connect the wiper of a 5 kΩ potentiometer between these pins, with the outer terminals tied to V+ and V−. Adjusting the wiper applies corrective current to the input stage, trimming up to ±8 mV of input offset voltage. When strobe functionality is needed, Pin 6 is repurposed as the current-sink control node - in which case offset nulling is disabled and Pins 5 and 6 must be shorted together per datasheet guidance.

Why is the LM111H supplied in a hermetic TO-99 (LMC) package, and what advantages does it offer over plastic packages?

The LM111H's hermetic TO-99 (LMC) package provides impermeable metal-can sealing that prevents moisture ingress, halogen exposure, and long-term parameter drift caused by environmental aging - critical for aerospace, defense, and downhole industrial applications. Unlike plastic SOIC or PDIP variants, the LMC package maintains electrical stability over decades and survives reflow, thermal shock, and vacuum conditions where polymer-based packages may outgas or delaminate.