STMicroelectronics ST5R50MTR

Overview

ST5R50MTR from STMicroelectronics is a micropower VFM step-up DC/DC converter optimized for battery-powered systems requiring ultra-low quiescent current (18 µA), regulated 5.0 V ±5% output, and operation down to 0.6 V hold-on input voltage. It delivers up to 100 mA output current with 87% typical efficiency at 50 mA, uses only three external components (inductor, Schottky diode, capacitor), and targets space-constrained portable electronics.

For engineers reviewing the ST5R50MTR datasheet, ST5R50MTR pinout, ST5R50MTR application, or ST5R50MTR equivalent, key selection criteria include start-up voltage (≤1.2 V), internal 700 mΩ switch RDSON, fixed 5 µs TON time, VFM control architecture for light-load efficiency, and SOT23-5L package compatibility with high-density PCB layouts.

Technical Context

The ST5R50MTR employs a Voltage-Frequency Modulation (VFM) control architecture where TON is fixed at ~5 µs and TOFF varies dynamically based on output load and error amplifier feedback-enabling ultra-low 18 µA no-load supply current and maintaining >82% efficiency even at 1 mA. Its internal power switch features 700 mΩ RDSON (at ILX = 150 mA), enabling higher efficiency than lower-output variants in the ST5Rxx series due to elevated internal supply voltage from the 5.0 V output rail.

Operation supports bootstrapped start-up: once running, input voltage may sag to 0.6 V while sustaining 1 mA output; however, VIN must not exceed VOUT (5.0 V) or absolute maximum 5.5 V. The LX pin drives an external inductor/diode network, and the VOUT pin serves dual roles-as regulated output and internal IC supply-eliminating need for separate bias rails.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount, 1.45 mm height, 3.0 mm × 1.75 mm footprint, exposed pad not present, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up DC/DC converter applications.

Compared with TPS610995DRVR and MAX17222ELT+T, the ST5R50MTR uniquely balances ultra-low 18 µA IQ, 100 mA capability, and VFM noise suppression in a proven SOT23-5L footprint-making it optimal for cost-sensitive, noise-aware, medium-current portable systems.

Availability

ST5R50MTR is available at Aetrix Electronics and suitable for wireless remote controls, digital cameras, pager receivers, and medical sensor nodes requiring stable component supply across long-lifecycle consumer and industrial programs.

Supply support for ST5R50MTR 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 automotive, industrial, and consumer markets.

The ST5Rxx series was developed specifically for ultra-low-power, single-cell battery applications demanding high conversion efficiency at microampere quiescent currents and minimal external component count.

FAQ

What is the minimum input voltage required for ST5R50MTR to start switching?

The ST5R50MTR starts switching when VIN minus the forward voltage (VF) of the external Schottky diode reaches ≥0.8 V (typical 1.2 V max). With a diode VF of 0.3 V (e.g., STPS1L30A), start-up occurs at ~1.1 V input. This value is independent of load and confirmed per Table 8 test conditions at IOUT = 1 mA with rising VIN.

Can ST5R50MTR operate with input voltage higher than its 5.0 V output?

Yes-when VIN exceeds VOUT, the output follows VIN minus diode VF, but neither VIN nor VOUT may exceed the absolute maximum rating of 5.5 V. Exceeding this risks permanent damage. The device does not regulate in this mode; it functions as a pass-through with diode drop, and internal circuitry remains powered via VOUT.

Why does ST5R50MTR have a No-Connect (NC) pin, and how should it be handled on PCB?

Pin 5 is a non-functional NC terminal resulting from die pad layout in the SOT23-5L mold; it has no internal connection. STMicroelectronics recommends leaving it unconnected or tying it to GND for mechanical stability-no electrical impact. Do not route signals or apply voltage to this pin.

How does the internal RDSON of 700 mΩ affect thermal performance at 100 mA output?

At 100 mA output, conduction loss is ~7 mW (I²×R = 0.1² × 0.7), contributing <1°C junction rise in SOT23-5L per Figure 2 thermal data (Rθj-case = 63°C/W). Combined with switching losses, total dissipation remains <25 mW at full load-well within the 170 mW absolute maximum at 25°C ambient.