STMicroelectronics ST730M50R

Overview

ST730M50R from STMicroelectronics is a 5.0 V fixed-output, 300 mA low-dropout (LDO) linear regulator in SOT23-5L package, featuring ultra-low 5 μA quiescent current at no-load, ±0.5% output voltage accuracy at 25 °C, and stable operation from 2.5 V to 28 V input. It integrates thermal shutdown, current limit, and SOA protection, and is designed for battery-backed or permanently powered systems such as electronic meters and smoke detectors.

For engineers reviewing the ST730M50R datasheet, ST730M50R pinout, ST730M50R application, or ST730M50R equivalent, key selection criteria include dropout voltage at 300 mA (max 1.2 V), enable logic thresholds (V_IL ≤ 0.35 V, V_IH ≥ 1.2 V), stability with 0.47 µF ceramic output capacitors, and guaranteed operation across –40 °C to +125 °C.

Technical Context

The ST730M50R employs a bandgap-referenced op-amp control loop with internal bias generator and thermal feedback. Its adjustable version uses an ADJ pin with 1.20 V reference (±2% over temperature), while the fixed 5.0 V variant routes internal feedback directly-eliminating external resistors and reducing component count.

Protection circuitry includes voltage-dependent current limiting (clamping short-circuit current to ~450 mA at low dropout, decreasing as (V_IN–V_OUT) increases), thermal shutdown at 160 °C with 20 °C hysteresis, and EN pin logic-controlled shutdown with sub-1 µA standby current.

Key Specifications

Pinout & Package

SOT23-5L package: 2.95 mm × 1.60 mm × 1.45 mm body height, thermally enhanced leadframe with exposed pad (not electrically connected), JEDEC-compliant footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B502MR-G and AP2202K-5.0TRG1, the ST730M50R uniquely balances ultra-low quiescent current (5 µA), 28 V input tolerance, integrated enable, and full industrial temperature support - making it the sole option for battery-backed 24 V field instruments requiring decade-long operation and robust fault handling.

Availability

ST730M50R is available at Aetrix Electronics and suitable for electronic meters, smoke detectors, and industrial sensor nodes requiring stable component supply, long-lifecycle assurance, and guaranteed parametric performance across –40 °C to +125 °C.

Supply support for ST730M50R 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The ST730 series belongs to ST's precision low-quiescent-current LDO portfolio, engineered specifically for energy-constrained, always-on applications where battery longevity, wide input flexibility, and robust protection are non-negotiable design requirements.

FAQ

What is the minimum output capacitor required for stable operation of ST730M50R?

The ST730M50R requires a minimum 0.47 µF ceramic capacitor (X5R or X7R dielectric) on the VOUT pin for guaranteed stability. The capacitor must maintain its rated capacitance and ESR (5–500 mΩ) across –40 °C to +125 °C and full load range. Larger values improve transient response but are not required.

Can ST730M50R be used with a 12 V automotive battery input?

Yes - the ST730M50R supports input voltages up to 28 V DC, making it suitable for 12 V automotive systems including cold-crank (down to ~6 V) and load-dump (up to 28 V) conditions. External TVS or overvoltage clamping is recommended for sustained >28 V transients per ISO 7637-2.

Does ST730M50R require an input capacitor, and what value is recommended?

Yes - a minimum 0.1 µF ceramic capacitor must be placed between VIN and GND, located within 2 mm of the pins. This reduces high-frequency noise, improves ripple rejection, and stabilizes the control loop. Higher values (e.g., 1–10 µF) are recommended for fast load transients or high-ESR source impedances.

How does the current limit behave under short-circuit conditions?

The ST730M50R implements voltage-dependent current limiting: short-circuit current starts at ~450 mA when (V_IN–V_OUT) is low, then decreases as the dropout increases - inherently limiting power dissipation. If sustained, thermal shutdown activates at 160 °C and recovers automatically at 140 °C.