STMicroelectronics L6370D

Overview

L6370D from STMicroelectronics is a 2.5 A high-side intelligent power switch in PowerSO-20 package, designed for industrial load control with integrated non-dissipative short-circuit protection, open-load detection, and dual diagnostic outputs. It operates from 9.5 V to 35 V, features internal negative voltage clamping to VS − 50 V for fast inductive demagnetization, and supports robust operation in automation systems driving solenoids, relays, and valves.

For engineers reviewing the L6370D datasheet, L6370D pinout, L6370D application, or L6370D equivalent, key selection criteria include its programmable ON-delay short-circuit response (1.28 μs/pF), differential input with ±7 V common-mode range and 400 mV hysteresis, thermal shutdown at 135 °C, and IEC 61000-4-4/5 transient immunity - all critical for reliable PLC output stage design.

Technical Context

The L6370D integrates a high-voltage DMOS output stage with internal current limiting set via external RSC resistor (15/RSC kΩ typical), enabling precise short-circuit current control between 2.6 A and 4 A. Its differential input section includes built-in +1.4 V offset and hysteresis to reject noise in electrically harsh industrial environments.

Diagnostic logic continuously monitors output status, supply voltage, junction temperature, and load condition, reporting faults via two open-drain outputs (DIAG1/DIAG2) using a deterministic truth table. The non-dissipative short-circuit protection uses a programmable ON-DELAY capacitor to limit linear-mode conduction time, avoiding thermal shutdown during capacitive or cold-filament inrush.

Key Specifications

Pinout & Package

Package: PowerSO-20 - thermally enhanced surface-mount package with exposed die pad for efficient heat dissipation in high-power industrial applications. Pin 1–3, 8–9, 10–11, and 20 are GND; pins 8 and 9 are paralleled for high-current output path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side intelligent power switch applications.

Compared with VND5E025AKTR-E and TPS27081A, the L6370D uniquely combines differential analog inputs, programmable short-circuit timing, and integrated clamp diode - making it optimal for legacy 24 V DC industrial systems requiring analog compatibility and minimal BOM count.

Availability

L6370D is available at Aetrix Electronics and suitable for PLC digital output modules, industrial valve controllers, motor starter auxiliaries, and factory automation I/O terminals requiring stable component supply across extended product lifecycles.

Supply support for L6370D 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 microcontrollers, power ICs, sensors, and automotive-grade components since 1987.

The L6370D belongs to ST's Intelligent Power Switch (IPS) product line, engineered specifically for industrial automation applications demanding high reliability, integrated protection, and diagnostic feedback in harsh electromagnetic environments.

FAQ

What is the purpose of the ON-DELAY pin on the L6370D?

The ON-DELAY pin connects to an external capacitor that sets the duration of the non-dissipative short-circuit conduction window (t_ON = 1.28 μs per pF). This allows the device to sustain inrush currents from capacitive or cold-filament loads without triggering thermal shutdown, while still detecting persistent faults after the programmed interval.

How does the L6370D detect open-load conditions?

The L6370D detects open-load conditions by monitoring output current; if it falls below 1–6 mA (typical 3 mA) while the output is commanded ON, the diagnostic logic asserts a specific pattern on DIAG1/DIAG2. This occurs independently of supply voltage and temperature, enabling real-time wire-break detection in safety-critical I/O systems.

Can the L6370D drive inductive loads without external components?

Yes - the L6370D includes an internal zener clamp limiting VS−VO to 48–58 V, enabling safe demagnetization of inductive loads up to 1 J energy (at Tj = 85 °C). No external flyback diode or TVS is required, reducing BOM count and PCB area in relay and solenoid driver designs.

What is the function of the OUTSTATUS pin?

The OUTSTATUS pin is a 2–4 mA current-source output that actively drives an LED when the OUTPUT pin is high. It provides visual status indication without requiring external driver transistors or current-limiting resistors, simplifying front-panel indicator design in industrial control hardware.