Texas Instruments LM139J/SCA

Overview

LM139J/SCA from Texas Instruments is a military-grade quad voltage comparator IC designed for single- or dual-supply operation across 2 V to 36 V (tested to 30 V) or ±1 V to ±18 V (tested to ±15 V), featuring 0.8 mA typical supply current, 2 mV typical input offset voltage, and open-collector outputs compatible with TTL/MOS/CMOS logic-used in power supervision, oscillator circuits, and industrial voltage monitoring systems.

For engineers reviewing the LM139J/SCA datasheet, LM139J/SCA pinout, LM139J/SCA application, or LM139J/SCA equivalent, key selection considerations include its –55°C to +125°C operating range, ±36 V differential input voltage capability, ground-sensing common-mode input range, low 25 nA typical input bias current, and CDIP-14 hermetic ceramic package suitability for high-reliability aerospace and defense designs.

Technical Context

The LM139J/SCA implements four independent comparators with PNP Darlington-pair inputs enabling high gain, fast response, and sub-100 nA input bias current while maintaining rail-to-rail common-mode input capability down to ground. Its open-collector NPN output stage allows wired-AND logic configuration and flexible pull-up voltage translation.

Each comparator operates with input offset voltage ≤5 mV (max), input offset current ≤100 nA (max over temperature), and response time of 1.3 µs (typical at 100-mV overdrive), supporting precise threshold detection in noisy environments without internal hysteresis-requiring external feedback for controlled switching behavior.

Key Specifications

Pinout & Package

LM139J/SCA is supplied in a hermetically sealed 14-pin Ceramic Dual In-line Package (CDIP-J), measuring 21.30 mm × 7.60 mm with 5.08 mm max height, compliant with MIL-STD-1835 GDIP1-T14 and suitable for high-reliability soldering processes including wave and reflow under controlled humidity conditions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM139J/SCA, LM339J sacrifices temperature range and screening rigor for cost efficiency, while LM2901J offers near-identical thermal capability with automotive-aligned qualification-making LM139J/SCA the sole choice for applications demanding MIL-PRF-38535 traceability and full –55°C to +125°C guaranteed operation.

Availability

LM139J/SCA is available at Aetrix Electronics and suitable for aerospace power sequencing, defense subsystem monitoring, and high-reliability industrial control applications requiring stable component supply across extended product lifecycles.

Supply support for LM139J/SCA 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 over 90 years of innovation in precision analog ICs and military-grade components.

The LM139-MIL product line was developed specifically for high-reliability applications in defense, aerospace, and critical infrastructure-emphasizing wide-voltage operation, extreme temperature resilience, and full parameter testing per MIL-PRF-38535 standards.

FAQ

What is the maximum supply voltage rating for LM139J/SCA?

The LM139J/SCA has an absolute maximum supply voltage rating of 36 V for single-supply operation and ±18 V for dual-supply operation. However, production-tested limits are 30 V and ±15 V respectively-designs should not exceed these tested values without derating analysis. The LM139J/SCA maintains functional integrity up to its absolute ratings, but long-term reliability is validated only within the tested envelope.

Does LM139J/SCA include internal hysteresis?

No, the LM139J/SCA does not include internal hysteresis. It is a basic comparator with no built-in positive feedback. Hysteresis must be added externally using resistor feedback from output to the non-inverting input. This design choice provides maximum flexibility for setting custom threshold windows and avoids fixed hysteresis that could compromise precision in applications like peak detection or zero-crossing sensing using LM139J/SCA.

Can LM139J/SCA operate from a single 3.3-V supply?

Yes, LM139J/SCA can operate from a single 3.3-V supply-the minimum recommended single-supply voltage is 2 V. At 3.3 V, it delivers full functionality including ground-sensing inputs and open-collector outputs, though output saturation voltage (VOL) increases slightly versus higher supplies. Designers using LM139J/SCA at 3.3 V should verify VOL remains compatible with downstream logic thresholds under worst-case load conditions.

What is the purpose of the NC pins on LM139J/SCA?

The LM139J/SCA in CDIP-14 package has no NC pins-its 14 pins are fully assigned: four outputs, eight inputs (two per comparator), one VCC, one GND. Confusion may arise from LCCC-20 variants (e.g., LM139FK) which include NC pins. For LM139J/SCA, every pin serves a defined function; unused positions in the package outline do not correspond to physical pins on the LM139J/SCA device.

How does LM139J/SCA differ from standard LM339 in terms of reliability?

The LM139J/SCA differs from LM339 by undergoing full parameter testing per MIL-PRF-38535, including extended temperature screening (–55°C to +125°C), hermetic ceramic packaging, and traceable lot documentation-whereas LM339 is commercial-grade with limited testing and plastic packaging. LM139J/SCA's reliability data supports MTBF >1 million hours in controlled environments, making it suitable for systems where field failure is unacceptable-unlike LM339, which lacks this assurance. LM139J/SCA is the only version qualified for use in flight-critical subsystems.