STMicroelectronics LM239DT

Overview

LM239DT 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 1.1 mA typical supply current, ±1 mV typical input offset voltage, and input common-mode range extending to ground. It drives TTL, CMOS, and ECL loads and is used in voltage monitoring, window detection, and level-shifting circuits in industrial control systems.

For engineers reviewing the LM239DT datasheet, LM239DT pinout, LM239DT application, or LM239DT equivalent, key selection considerations include its rail-to-rail input capability down to ground, open-collector output stage, low quiescent current across supply voltage, and guaranteed operation over –40 °C to +105 °C industrial temperature range.

Technical Context

The LM239DT integrates four independent comparators with PNP-input differential stages, enabling input voltages down to –0.3 V relative to V_CC– (GND) while maintaining valid logic output states. Its open-collector outputs support wired-AND configurations and interface directly with 5 V TTL or 3.3 V CMOS logic without pull-up resistors beyond system-level requirements.

Each comparator features low input bias current (25 nA typ), low input offset current (±5 nA typ), and differential input voltage range equal to the full supply voltage (±36 V max). The device operates with no phase reversal under common-mode transients and supports fast response times - 1.3 μs typical for 100 mV step with 5 mV overdrive.

Key Specifications

Pinout & Package

LM239DT is housed in a 14-lead SOIC (SO14) plastic micropackage per JEDEC MS-012, with 1.27 mm pitch, 8.75 mm body length, and 4.0 mm body width. Thermal resistance is 105 °C/W (junction-to-ambient, still air).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339DT, LM239DT adds industrial temperature qualification without performance trade-offs; compared with TLV331IPWR, it delivers quad integration and higher drive strength at the cost of higher quiescent current - making it optimal for space-constrained 24 V industrial nodes requiring reliability over ultra-low power.

Availability

LM239DT is available at Aetrix Electronics and suitable for industrial automation, motor control feedback, and power supply monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM239DT 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LM239 series belongs to ST's precision analog comparators product line, engineered specifically for robust, low-cost voltage comparison in harsh industrial environments where ground-referenced sensing and wide supply tolerance are mandatory.

FAQ

Can LM239DT operate from a 3.3 V supply?

Yes - LM239DT functions reliably from +2 V to +36 V single supply. At 3.3 V, input common-mode range is 0 V to 1.8 V, output saturation voltage remains ≤400 mV at 4 mA sink, and supply current drops to ~0.9 mA. Full functionality is preserved, though output logic-high level must be established via external pull-up to 3.3 V.

Does LM239DT require external hysteresis for noise immunity?

Yes - LM239DT has no built-in hysteresis. For noisy input signals (e.g., mechanical switch debouncing or motor back-EMF), positive feedback via resistor from output to non-inverting input is required. Typical values: 1 MΩ from output to +IN and 10 kΩ from +IN to reference yield ~10 mV hysteresis at 5 V supply.

What is the maximum sink current per output of LM239DT?

The absolute maximum sink current is limited by power dissipation and junction temperature. Per datasheet, continuous output sink current is rated at 6 mA minimum (at VO = 1.5 V, Tamb = 25 °C), with short-term peaks up to 20 mA permissible if average power stays within SO14 package limits (500 mW max at 25 °C ambient).

Is LM239DT pin-compatible with LM339DT?

Yes - LM239DT and LM339DT share identical SO14 pinout, electrical characteristics, and functional block diagram. The sole difference is operating temperature range: LM239DT is rated for –40 °C to +105 °C, while LM339DT is rated for 0 °C to +70 °C. No circuit or layout changes are needed for substitution in industrial designs meeting the wider temp spec.