Texas Instruments UC37132N

Overview

UC37132N from Texas Instruments is a smart high-side/low-side power switch IC designed for industrial load control, featuring 300mA continuous output current, 8V–65V operating voltage range, programmable input comparator hysteresis (1%–30%), overload/short-circuit protection, and integrated 6V/8mA regulated reference. It drives resistive or inductive loads in automotive lighting, PLC I/O modules, and industrial solenoid control.

For engineers reviewing the UC37132N datasheet, UC37132N pinout, UC37132N application, or UC37132N equivalent, key selection considerations include its dual-configuration capability (high-side or low-side), CDEL-programmable turn-on delay and VCC interruption recovery, internal 72V zener clamp for inductive kickback suppression, and discrete current-sense pin architecture (CSH/CSL) enabling precise overcurrent threshold setting.

Technical Context

The UC37132N integrates a bandgap-based 6V reference (±200ppm/°C drift), a high-gain input comparator with user-programmable hysteresis via HYST pin, and fault logic that gates the output driver based on CDEL capacitor timing. Its composite PNP/NPN output stage delivers low saturation voltage (<1.4V at –55°C) while supporting both high-side (HS pin as emitter-connected output) and low-side (LS pin as collector-connected output) topologies.

Fault response is governed by a single CDEL capacitor: it sets both VCC interruption ignore time (t_D(OFF) ≈ 500µs typical) and overcurrent recovery time (t_R(OFF) ≈ 10ms), with automatic low-duty-cycle pulsing (~0.7%) during persistent overload. Current limiting is implemented via external sense resistors-R_CSH to VCC for high-side (ITH-H = 250–400mA), R_CSL to GND for low-side (ITH-L = 250–400mA)-with fixed 300mV short-circuit threshold.

Key Specifications

Pinout & Package

UC37132N is supplied in a 14-pin plastic DIP (Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin 1 is located at the left end of the top row when viewed from the top with notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar smart power switch applications.

Compared with UC37132N, UC37132D offers superior manufacturability and environmental compliance but requires layout changes, while UC27132D extends thermal capability without altering board design-making it the drop-in replacement for temperature-critical retrofits.

Availability

UC37132N is available at Aetrix Electronics and suitable for industrial automation, factory control systems, and automotive aftermarket electronics requiring stable component supply and long-term obsolescence management.

Supply support for UC37132N 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of heritage in industrial and automotive power ICs.

The UC3713x family was developed specifically for ruggedized industrial load switching, emphasizing fault resilience, wide supply range, and configurability across high-side/low-side topologies-targeting PLCs, motor controls, and distributed I/O systems.

FAQ

What is the maximum continuous output current rating for the UC37132N?

The UC37132N supports 300mA continuous output current under specified thermal conditions (T_J ≤ 150°C). This rating applies to both high-side and low-side configurations and assumes proper PCB copper pour and ambient temperature ≤ 70°C. Peak current capability reaches 700mA for short durations, but sustained operation above 300mA requires thermal derating per the device's SOA curves. The UC37132N datasheet specifies saturation voltage <1.4V at –55°C, confirming robust conduction performance across its full temperature range.

Can the UC37132N be used in high-side and low-side configurations interchangeably?

Yes-the UC37132N is explicitly designed for dual-configuration operation. In high-side mode, the HS pin drives the load toward GND and CSH is connected to VCC; in low-side mode, the LS pin drives the load toward VCC and CSL is connected to GND. Critical interconnections (e.g., tying HS to CSL in low-side mode) are defined in the UC37132N application diagrams. This flexibility eliminates the need to stock separate high-side and low-side switches, reducing inventory complexity for multi-topology designs.

How does the CDEL capacitor affect both VCC interruption recovery and overcurrent protection timing in the UC37132N?

The CDEL capacitor on the UC37132N serves a dual function: its discharge time (from 5.8V to 1.0V at ~94µA) determines the maximum VCC interruption duration before output re-enable delay, while its recharge time (from 1.0V to 4.9V at ~4µA) sets the overcurrent recovery interval. For example, a 10nF CDEL yields ~478µs VCC interruption tolerance and ~10ms overcurrent recovery. This unified timing mechanism simplifies design validation and ensures consistent fault response behavior across both power-supply and load-fault events in the UC37132N.

What is the purpose of the HYST pin on the UC37132N, and how is it configured?

The HYST pin on the UC37132N allows programmable input comparator hysteresis from 1% to 30% of the 3V threshold voltage-unique to the UC37132 variant (UC37131/33 fix hysteresis at 30%). It is configured by connecting a resistor between HYST and GND; the value follows R_HYST = (3000 + 3330 × %Hysteresis) Ω. For instance, a 10kΩ resistor yields ~10% hysteresis (300mV), enhancing noise immunity on long or unterminated control lines. This feature is absent on UC37131/33, making HYST a key differentiator for the UC37132N in electrically noisy environments.

Does the UC37132N require external flyback diodes when switching inductive loads?

No-the UC37132N integrates internal 72V zener clamps between HS and LS pins, enabling safe energy dissipation during inductive load turn-off without external components. In high-side operation, the clamp limits HS-to-LS voltage to 72V; in low-side operation, it limits LS-to-GND swing to +72V. This eliminates board space and cost for discrete flyback diodes while maintaining reliable operation with solenoids, relays, and DC motors. The UC37132N's clamp is rated for 250–400mA peak currents, matching its output capability.