STMicroelectronics LM139ADT

Overview

LM139ADT from STMicroelectronics is a low-power quad voltage comparator in SO14 package, designed for single-supply operation from +2 V to +36 V (or ±1 V to ±18 V dual supply), with ±1 mV typical input offset voltage, 25 nA typical input bias current, and 250 mV typical output saturation voltage at 4 mA sink current. It enables precision threshold detection in industrial control, power supply monitoring, and sensor interface circuits where ground-referenced inputs and rail-to-rail common-mode range are required.

For engineers reviewing the LM139ADT datasheet, LM139ADT pinout, LM139ADT application, or LM139ADT equivalent, key selection criteria include input offset voltage stability over temperature, output sink capability into TTL/CMOS loads, common-mode range including ground on single supply, and thermal resistance (105 °C/W junction-to-ambient) for SO14 packaging in constrained PCB layouts.

Technical Context

The LM139ADT integrates four independent comparators with PNP differential input stages, enabling input common-mode voltage down to ground even under single-supply operation. Its open-collector outputs support wired-OR logic and level translation across logic families (TTL, DTL, ECL, MOS, CMOS).

It operates across –55 °C to +125 °C, with supply current of 1.1 mA (typ) independent of supply voltage, and large-signal voltage gain of 50–200 V/mV. Input offset voltage is specified at ±2 mV maximum (LM139A grade), and differential input voltage range equals full supply voltage (±36 V).

Key Specifications

Pinout & Package

LM139ADT is supplied in SO14 (Small Outline, 14-pin) plastic micropackage per ECOPACK® standards, with 1.27 mm pitch, body size 8.75 × 4.0 mm, and thermal resistance θ_JA = 105 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339DT, LM139ADT provides wider temperature range and tighter offset for mission-critical monitoring; versus TLV339IPWR, it offers higher supply flexibility and legacy-compatible open-collector outputs at the cost of higher quiescent current.

Availability

LM139ADT is available at Aetrix Electronics and suitable for industrial power monitoring, sensor interface design, and automotive subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM139ADT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, sensing, and control solutions for industrial, automotive, and consumer markets.

The LM139 series belongs to ST's precision analog comparator product line, engineered for reliability in harsh environments - specifically targeting applications demanding ground-sensing capability, wide supply range, and guaranteed performance from –55 °C to +125 °C.

FAQ

Can LM139ADT operate from a single 3.3 V supply?

Yes - LM139ADT functions down to +2 V single supply. At 3.3 V, its input common-mode range extends from 0 V to 1.8 V, and output saturation voltage remains ≤400 mV at 4 mA sink. However, output high-level voltage is undefined (open-collector), so an external pull-up to 3.3 V is required for logic-level compatibility.

Does LM139ADT require external hysteresis for noise immunity?

Yes - LM139ADT has no internal hysteresis. For noisy input signals (e.g., motor current sensing), positive feedback via resistor from output to non-inverting input adds 10–50 mV of hysteresis. The datasheet Figure 15 shows a verified implementation using 100 kΩ and 1 MΩ resistors for ~20 mV hysteresis at 5 V supply.

What is the maximum sink current per output under continuous operation?

The absolute maximum sink current is not specified as a continuous rating, but electrical characteristics guarantee ≥6 mA at VO = 1.5 V. Thermal limits govern sustained operation: with θ_JA = 105 °C/W and max T_J = +150 °C, continuous power dissipation must stay below ~120 mW - limiting practical sink current to ~8 mA at 15 V V_CC, assuming ambient ≤+50 °C.

Is LM139ADT pin-compatible with LM239ADT or LM339ADT?

Yes - all three share identical SO14 pinout and electrical behavior, differing only in temperature grade (LM139ADT: –55 °C to +125 °C; LM239ADT: –40 °C to +105 °C; LM339ADT: 0 °C to +70 °C) and input offset voltage specification (±2 mV max for A-grade variants). Substitution is electrically valid if temperature and precision requirements align.