Texas Instruments LM139D

Overview

LM139D from Texas Instruments is a quad differential comparator IC designed for precision voltage comparison in wide-supply industrial and military systems. It operates from 2V to 30V single supply, delivers ±9mV max input offset voltage (25°C), supports –55°C to +125°C temperature range, and features open-collector outputs compatible with TTL/MOS/CMOS logic - used in motor drive fault detection and power supply overvoltage monitoring.

For engineers reviewing the LM139D datasheet, LM139D pinout, LM139D application, or LM139D equivalent, this page provides verified electrical specs, SOIC-14 package details, real-world use cases in high-reliability embedded control, and two confirmed alternative parts with documented functional and thermal differences.

Technical Context

The LM139D implements four independent voltage comparators with rail-to-rail common-mode input range down to ground and differential input capability up to ±30V. Its open-collector output stage allows flexible pull-up configuration and direct interface with diverse logic families without level-shifting circuitry.

Designed for operation across –55°C to +125°C, it maintains stable propagation delay (1.3µs typical) and low quiescent current (0.8–2mA total) over full supply (2–30V) and temperature ranges - enabling robust performance in aerospace, defense, and industrial power management subsystems.

Key Specifications

Pinout & Package

LM139D is supplied in a 14-pin SOIC (Small Outline Integrated Circuit) package with nominal body size 8.70 mm × 3.90 mm and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339DR and LM2901DT, the LM139D uniquely combines military-grade temperature range (–55°C to +125°C) with tight ±9 mV offset and 30 V supply - making it the sole option for high-reliability avionics and defense electronics demanding both precision and environmental resilience.

Availability

LM139D is available at Aetrix Electronics and suitable for motor drive protection, industrial power supply monitoring, aerospace avionics health monitoring, and military vehicle power distribution requiring stable component supply across extended temperature and long product lifecycles.

Supply support for LM139D 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 for industrial, automotive, and communications markets.

The LM139D belongs to TI's legacy precision comparator family, engineered specifically for high-reliability applications demanding extended temperature operation, robust input protection, and consistent open-collector output behavior in safety-critical systems.

FAQ

What is the maximum supply voltage rating for the LM139D?

The LM139D has an absolute maximum supply voltage of 36 V, but its recommended operating range is 2 V to 30 V. Operation beyond 30 V may compromise parametric guarantees such as input offset voltage and propagation delay stability. The LM139D datasheet specifies 30 V as the upper limit for guaranteed performance across the full –55°C to +125°C temperature range.

Does the LM139D support rail-to-rail input common-mode range?

Yes, the LM139D supports a common-mode input voltage range from ground (V–) up to VCC – 2 V. This allows direct interfacing with low-side current-sense amplifiers and battery-monitoring circuits without level-shifting. Either input can exceed VCC without damage, provided the other remains within the valid common-mode window - a key feature confirmed in Section 6.9 of the LM139/LM139A datasheet.

What is the typical propagation delay of the LM139D?

The LM139D exhibits a typical propagation delay of 1.3 µs under standard test conditions: 100 mV input step with 5 mV overdrive, RL = 5.1 kΩ to 5 V, CL = 15 pF, and TA = 25°C. This value is specified in Table 6.12 of the official Texas Instruments datasheet and remains stable across the full operating temperature range due to its bipolar input stage design.

Can the LM139D outputs drive TTL logic directly?

Yes, the LM139D's open-collector outputs are explicitly rated for TTL, MOS, and CMOS compatibility. When pulled up to 5 V with a 5.1 kΩ resistor, each output can sink up to 6 mA while maintaining VOL ≤ 400 mV - satisfying TTL logic-low requirements. This capability is documented in the "Electrical Characteristics for LM139 and LM139A" table (Section 6.9) and confirmed in the device's "Features" list.

Is the LM139D pin-compatible with other members of the LMx39 family?

Yes, the LM139D shares identical pinout and package (SOIC-14) with LM239, LM339, LM2901, and LM339B variants. All devices use the same D-package footprint and terminal assignment per Figure 5-1 and Table 5-1 in the datasheet. However, electrical specifications - especially temperature range, offset voltage, and supply limits - differ significantly between versions, so functional substitution requires validation against system-level requirements.