STMicroelectronics ST732M36R

Overview

ST732M36R from STMicroelectronics is a 300 mA, fixed 3.6 V output low-dropout (LDO) voltage regulator in SOT23-5L package, designed for post-regulation and battery-powered systems requiring ultra-low quiescent current (5 µA typ.), ±2% output accuracy, and operation across -40 °C to +125 °C. It delivers stable regulation from 2.5 V to 28 V input with dropout as low as 200 mV at 100 mA.

For engineers reviewing the ST732M36R datasheet, ST732M36R pinout, ST732M36R application, or ST732M36R equivalent, this LDO is selected for permanent-battery-connected devices like smoke detectors and electronic meters where standby power budget, thermal robustness, and low-ESR capacitor compatibility (≥0.47 µF) are critical design constraints.

Technical Context

The ST732M36R implements a bandgap-referenced error amplifier with internal bias generator and thermal feedback loop, enabling precise 3.6 V regulation across wide input voltage (2.5–28 V) and load (0–300 mA) ranges. Its SOA-based current limit dynamically scales with (VIN−VOUT) to constrain power dissipation under overload.

Protection circuitry includes thermal shutdown at 160 °C (20 °C hysteresis), short-circuit current limiting (450 mA typical), and ESD resilience (±2 kV HBM). Stability is guaranteed with ceramic output capacitors ≥0.47 µF and ESR between 5–500 mΩ-no external compensation required.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount, 1.45 mm height, 2.95 mm × 1.60 mm footprint, with exposed pad not electrically connected. Designed for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with XC6219B362MR-G and AP7361-C36W5-7, the ST732M36R uniquely balances 28 V input capability, 5 µA IQ, and fully characterized thermal hysteresis - making it optimal for battery-backed industrial sensors where both voltage headroom and longevity are non-negotiable.

Availability

ST732M36R is available at Aetrix Electronics and suitable for electronic meters, smoke detectors/alarm systems, and portable instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance across automotive and industrial temperature grades.

Supply support for ST732M36R 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 power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

The ST732 series belongs to ST's high-reliability LDO portfolio targeting ultra-low-power, wide-input-voltage applications such as utility meters and safety-critical battery systems - emphasizing longevity, thermal resilience, and minimal external component count.

FAQ

What is the minimum output capacitance required for ST732M36R stability?

The ST732M36R requires a minimum 0.47 µF ceramic output capacitor with ESR between 5 mΩ and 500 mΩ for guaranteed loop stability across temperature and load. X5R or X7R dielectrics are recommended; capacitance must remain within specification over the full -40 °C to +125 °C range.

Can ST732M36R operate with an input voltage below 2.5 V?

No - the absolute minimum input voltage is 2.5 V per datasheet Section 4 (Table 2). Operation below this threshold risks functional failure or undefined regulation. At 2.5 V input, the device can sustain 3.6 V output only if load current is zero; any load requires VIN > VOUT + dropout (≥3.8 V for 100 mA).

How does the current limit behave under varying input-output differential?

The ST732M36R implements a voltage-dependent current limit: short-circuit current decreases as (VIN − VOUT) increases to cap power dissipation. At VIN = 2.5 V and VOUT = 0 V, short-circuit current is ~450 mA; at VIN = 28 V, it drops to ~100 mA - preventing thermal runaway during sustained overload.

Is the NC pin (Pin 4 or 5) usable as a thermal pad or for PCB grounding?

No - Pins 4 and 5 are Not Connected (NC), with no internal bond wire or silicon connection. They must remain unconnected on the PCB. Using them as thermal pads or ground paths violates the SOT23-5L mechanical specification and may cause solder joint reliability issues or electrical interference.