STMicroelectronics L6374FP

Overview

L6374FP from STMicroelectronics is a quad-channel industrial line driver IC designed for 24 VDC digital output modules in PLCs and motor controllers. It features four independent push-pull outputs (100 mA per channel), 10.8–35 V operating range, 300 kHz max switching speed, integrated overcurrent/overtemperature/undervoltage protection, and open-drain diagnostic output - enabling robust IEC 61131-compliant control signal distribution.

For engineers reviewing the L6374FP datasheet, L6374FP pinout, L6374FP application, or L6374FP equivalent, this device serves as a fault-protected, high-noise-immunity digital output driver with programmable current-limit delay, analog input comparators (−7 V to +35 V), and thermal shutdown recovery hysteresis - critical for industrial automation BOM validation and reliability-critical output stage design.

Technical Context

The L6374FP implements four independent high-side and low-side MOSFET output stages with dead-time control (~200 ns) to prevent cross-conduction. Each channel uses internal comparators with 200 mV hysteresis and a shared REF pin (1.25 V bandgap or externally biased) for noise-immune analog input sensing across −7 V to +35 V.

Diagnostic logic aggregates overcurrent (per-output 200 mA limit), undervoltage (10.8 V threshold with 450 mV hysteresis), and overtemperature (170 °C trip with 20 °C hysteresis) events onto a single open-drain Diag pin. A programmable external capacitor on C3 sets current-limit diagnostic delay (≈10 pF/μs).

Key Specifications

Pinout & Package

Package: SO-20 (Small Outline, 20-pin, 0.050" pitch), RoHS-compliant ECOPACK® with thermal pad-compatible footprint (R_thJA1 = 65 °C/W with PCB heatsink).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel industrial line driver applications.

Compared with TBD72004FNG and VNQ7E050AJTR, the L6374FP uniquely combines push-pull output architecture, wide-range analog input comparators, and hardware-diagnostic aggregation - making it optimal for high-noise, high-reliability 24 V I/O modules where deterministic fault response and minimal external components are essential.

Availability

L6374FP is available at Aetrix Electronics and suitable for programmable logic controllers, high-density digital output modules, and motor controllers requiring stable component supply, long-term industrial lifecycle support, and traceable sourcing.

Supply support for L6374FP 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 specializing in automotive, industrial, and power management solutions, with strong focus on functional safety and industrial-grade reliability.

The L6374FP belongs to ST's industrial line driver product line, engineered specifically for IEC 61131-compliant 24 VDC control systems - emphasizing fault resilience, noise immunity, and seamless integration into modular PLC and motion control architectures.

FAQ

What is the purpose of the REF pin (Pin 11) on the L6374FP?

The REF pin provides a shared reference voltage for all four input comparators. When left floating, it defaults to an internal 1.25 V bandgap reference; when externally biased (0–5 V), it sets custom input thresholds. ST recommends connecting a ≥10 nF capacitor to ground for noise filtering - especially critical when driving capacitive loads or operating as a line receiver with negative input voltages.

How does the L6374FP handle inductive load switching and kickback?

The L6374FP does not integrate flyback diodes; instead, it relies on external clamping (e.g., TVS or diode networks) at the output. Its output voltage clamp to Vs and ground limits transient excursions, while the 200 ns dead-time prevents shoot-through during transitions. For inductive loads, ST advises placing clamping components close to the output pins and verifying waveform integrity using the recommended test configurations in DS0188 Figure 10.

Can the L6374FP be used with supply voltages below 10.8 V?

No - operation below 10.8 V triggers undervoltage protection (UV), forcing all outputs into high-impedance state. The UV circuit has a 450 mV hysteresis (V_sh = 10.8 V, lower threshold ≈10.35 V), preventing oscillation near the trip point. Sustained operation requires stable Vs ≥10.8 V; brief transients up to 50 V (t_W ≤10 ms) are tolerated per absolute maximum ratings.

What thermal considerations apply when using the L6374FP in high-power-density layouts?

With R_thJA1 = 65 °C/W (PCB heatsink) and R_thJP = 17 °C/W (junction-to-pad), thermal performance depends heavily on copper area under pins 5,6,15,16. ST specifies a minimum 35 mm² dissipating surface on the bottom side of the PCB. Without such heatsinking (R_thJA2 = 80 °C/W), junction temperature can exceed 125 °C at full 100 mA per channel - triggering overtemperature shutdown. Thermal simulation and IR imaging are recommended for >200 mW total dissipation.