STMicroelectronics L6370Q

Overview

L6370Q from STMicroelectronics is a 2.5 A single high-side smart power switch in VFQFPN48 (7 × 7 mm) package, designed for industrial load switching with integrated current limiting, thermal shutdown, open-load detection, and dual diagnostic outputs. It operates from 9.5 V to 35 V supply, delivers up to 2.5 A continuous output current, features R_DS(on) = 0.1 Ω, and supports fast demagnetization of inductive loads via internal clamping (V_cl ≈ 53 V).

For engineers reviewing the L6370Q datasheet, L6370Q pinout, L6370Q application, or L6370Q equivalent, this device is selected for rugged industrial I/O modules requiring non-dissipative short-circuit protection, differential input noise immunity, and LED-driven output status feedback - especially where programmable on-delay timing and dual open-drain diagnostics are critical.

Technical Context

The L6370Q integrates a high-voltage DMOS output stage with BCDmultipower technology, enabling direct drive of resistive, capacitive, and inductive loads without external flyback components. Its differential input stage provides ±7 V common-mode range and 1.4 V internal offset with 400 mV hysteresis, ensuring robust operation in noisy industrial environments.

Short-circuit protection uses a non-dissipative linear-mode current-limiting scheme with externally programmable t_ON (via ON-DELAY pin capacitor), delivering 3.2 A typical short-circuit current for up to 2.56 ms before fault latching. Diagnostic logic maps six distinct fault conditions-including open load (<3 mA), overtemperature (135 °C trip), and undervoltage (<8.5 V)-to two open-drain outputs (DIAG1/DIAG2) per a defined truth table.

Key Specifications

Pinout & Package

VFQFPN48 (7 × 7 × 1.0 mm) package with exposed thermal pad; RoHS-compliant ECOPACK® grade, suitable for automated SMT assembly and high-power density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VNS3NV04PTR-E and TPS27082LDR, the L6370Q uniquely combines differential input noise immunity, dual diagnostic state encoding, programmable short-circuit timing, and integrated inductive clamp - making it optimal for industrial automation where reliability under EMI and precise fault classification are mandatory.

Availability

L6370Q is available at Aetrix Electronics and suitable for programmable logic controllers, industrial PC peripheral I/O, and numerical control machines requiring stable component supply across extended temperature ranges (−40 °C to +105 °C) and long product lifecycles.

Supply support for L6370Q 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, specializing in intelligent power, microcontrollers, sensors, and automotive ICs.

The L6370Q belongs to ST's Intelligent Power Switch (IPS) family, engineered specifically for industrial automation systems demanding high reliability, comprehensive diagnostics, and robust transient immunity in harsh electromagnetic environments.

FAQ

What is the maximum inductive energy the L6370Q can safely absorb during demagnetization?

The L6370Q absorbs up to 6.0 J of single-pulse avalanche energy at T_amb = 125 °C, V_CC = 24 V, and I_load = 2.0 A, as specified in its absolute maximum ratings table. This value corresponds to the internal Zener clamp's capability to dissipate stored inductor energy without damage, eliminating need for external snubbers in typical 24 V solenoid or brake applications.

How does the ON-DELAY pin affect short-circuit response timing?

Connecting a capacitor (50 pF to 2 nF) between ON-DELAY and GND sets t_ON = 1.28 × C_ON (μs), defining the duration the output remains active during a ground fault before latching off. For example, a 1 nF capacitor yields t_ON ≈ 1.28 μs, allowing brief inrush currents from cold filaments or capacitors without triggering diagnostics - unlike fixed-timing alternatives.

Can the L6370Q drive loads beyond its 2.5 A rating under pulsed conditions?

No - the 2.5 A rating is the maximum continuous output current at T_j = 125 °C. While short-circuit current is 3.2 A (typ.), this is strictly limited by internal current sensing and only sustainable for t_ON durations (up to 2.56 ms). Exceeding 2.5 A continuously violates thermal limits and risks permanent damage, even with heatsinking.

What diagnostic conditions cause both DIAG1 and DIAG2 to go low simultaneously?

Both DIAG1 and DIAG2 go low only during supply undervoltage (V_S < 8.5 V typ.) or overtemperature (T_j > 135 °C), as defined in Table 7 of the datasheet. This dual-low state unambiguously distinguishes these critical system-level faults from load-specific issues like open load or short-to-ground, enabling prioritized firmware response.