STMicroelectronics ST715M33R

Overview

ST715M33R from STMicroelectronics is a fixed-output 3.3 V, 85 mA low-dropout linear regulator designed for high-input-voltage battery-powered systems. It operates from 2.5 V to 24 V input, delivers 500 mV typical dropout at full load, draws only 3.75–5.5 µA quiescent current, and is stable with 0.47–10 µF ceramic output capacitors - enabling long-life operation in portable medical sensors and industrial IoT edge nodes.

For engineers reviewing the ST715M33R datasheet, ST715M33R pinout, ST715M33R application, or ST715M33R equivalent, key selection criteria include ultra-low IQ for standby power budgeting, wide VIN range for unregulated battery inputs, ±5% output accuracy over -40 °C to 125 °C, thermal shutdown and short-circuit protection, and compatibility with compact SOT23-5L packaging.

Technical Context

The ST715M33R integrates a bandgap reference, bias generator, current-limit circuitry, and thermal protection in a monolithic LDO architecture. Its feedback loop is internally configured for fixed 3.3 V output, eliminating external resistor networks and reducing layout sensitivity.

It employs a PMOS pass transistor enabling low dropout and near-zero reverse current during shutdown. The device achieves 38 dB PSRR at 1 kHz and 57 dB at 100 kHz while maintaining stability with minimal 0.47 µF ceramic output capacitance across its full operating temperature range.

Key Specifications

Pinout & Package

ST715M33R is packaged in SOT23-5L - a 5-pin, surface-mount plastic package measuring 2.95 mm × 1.60 mm × 1.45 mm with 0.95 mm lead pitch. The exposed pad is not electrically connected and may be left floating or tied to GND for improved thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6206P332MR and NCP1117ST33T3G, ST715M33R uniquely balances ultra-low IQ, 24 V input tolerance, and 85 mA output - making it optimal for space-constrained, long-life battery systems where both wide VIN and microamp-level standby matter.

Availability

ST715M33R is available at Aetrix Electronics and suitable for portable medical sensors, industrial wireless transmitters, smart home hubs, and automotive body control modules requiring stable component supply across extended product lifecycles.

Supply support for ST715M33R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The ST715 series was developed specifically for ultra-low-power, high-input-voltage LDO applications in battery-operated and harsh-environment electronics - emphasizing longevity, thermal resilience, and ceramic-capacitor simplicity.

FAQ

Is ST715M33R pin-compatible with other ST715 variants?

Yes - all ST715 fixed-output versions (e.g., ST715M25R, ST715M33R, ST715C50R) share identical SOT23-5L pinout and electrical behavior except for nominal output voltage. No layout change is needed when swapping between 2.5 V, 3.3 V, or 5.0 V variants.

Can ST715M33R be used with aluminum polymer capacitors?

Yes - while optimized for ceramic capacitors (0.47–10 µF), ST715M33R remains stable with aluminum polymer types meeting ESR < 100 mΩ and capacitance ≥1 µF. However, ceramic offers superior lifetime, temperature stability, and size efficiency.

Does ST715M33R include an enable pin?

No - ST715M33R has no enable (EN) or shutdown control pin. It operates continuously when input voltage exceeds ~2.5 V. For controlled on/off sequencing, an external MOSFET switch on the IN rail is required.

What is the maximum power dissipation for ST715M33R in SOT23-5L at 85°C ambient?

Using RthJA = 195 °C/W and TJMAX = 125 °C, maximum allowable PD is (125 − 85)/195 ≈ 205 mW. At 3.3 V output and 85 mA load, power dissipation is (VIN − 3.3) × 0.085 - so VIN must stay ≤ 5.7 V to remain within thermal limits at 85°C ambient.