STMicroelectronics ST715CR

Overview

ST715CR from STMicroelectronics is a high-input-voltage, ultra-low-quiescent-current LDO linear regulator with fixed 5.0 V output, rated for 85 mA continuous current, 2.5–24 V input range, 500 mV typical dropout at full load, and –40 °C to 125 °C operating temperature. It delivers stable regulation in battery-powered portable electronics using ceramic output capacitors as low as 0.47 µF.

For engineers reviewing the ST715CR datasheet, ST715CR pinout, ST715CR application, or ST715CR equivalent, key selection criteria include its 3.8 µA quiescent current at full load, compatibility with small-footprint SOT323-5L packaging, thermal protection, internal current limiting, and suitability for low-power industrial and handheld systems requiring wide VIN tolerance and minimal standby power loss.

Technical Context

The ST715CR implements a bandgap-referenced error amplifier with internal bias generator, short-circuit current limiting, and thermal shutdown circuitry. Its feedback loop is optimized for stability with ceramic capacitors from 0.47 µF to 10 µF, eliminating need for ESR-tuned tantalum or aluminum electrolytics.

As a fixed-output variant, it omits the FB pin functionality present in adjustable versions-pin 1 on SOT323-5L is not connected-and relies on trimmed internal resistor network to set VOUT = 5.0 V with ±5% total accuracy across temperature and load. Dropout behavior remains defined by V_IN – V_OUT ≥ 500 mV (typ.) at I_OUT = 85 mA.

Key Specifications

Pinout & Package

ST715CR is packaged in SOT323-5L - a 1.8 mm × 2.1 mm, 5-pin surface-mount package with exposed pad for thermal enhancement. Pin 1 is NC (not internally connected); pins 2 (GND), 4 (IN), and 5 (OUT) form the functional core; pin 3 is NC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B502MR-G and AP7361-C5-33, ST715CR uniquely balances wide 2.5–24 V input, ultra-low 3.8 µA IQ, and 85 mA output in a thermally robust SOT323-5L package - making it the only option among the three qualified for both automotive battery and long-life portable applications.

Availability

ST715CR is available at Aetrix Electronics and suitable for portable medical sensors, industrial remote I/O modules, smart home motion detectors, and automotive cabin sensors requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for ST715CR 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 quiescent current optimization, ceramic capacitor compatibility, and extended temperature qualification.

FAQ

What is the minimum input voltage required for ST715CR to regulate 5.0 V output?

The ST715CR requires VIN ≥ VOUT + VDROP to maintain regulation. With typical dropout of 500 mV at 85 mA, minimum functional input is 5.5 V. At lighter loads, dropout decreases - e.g., 200 mV at 10 mA - allowing regulation down to 5.2 V. Absolute minimum VIN per datasheet is 2.5 V, but regulation is not guaranteed below 5.2–5.5 V depending on load and temperature.

Can ST715CR be used with a 0.22 µF ceramic output capacitor?

No. The datasheet specifies a minimum output capacitance of 0.47 µF for stability across all operating conditions. Using 0.22 µF risks oscillation, poor transient response, and potential thermal runaway under load steps. ST confirms stability only with ≥0.47 µF X7R or C0G MLCCs rated for ≥6.3 V DC.

Does ST715CR include an enable (EN) pin?

No. ST715CR has no enable functionality. It operates continuously when VIN is within specification. For applications requiring controlled startup or shutdown, an external MOSFET switch on the IN rail or a version with EN (e.g., ST715xx with "E" suffix) must be selected - the CR variant is always-on by design.

How does thermal performance differ between SOT323-5L and DFN8 packages for ST715CR?

SOT323-5L has R_thJA = 245 °C/W, limiting max continuous power dissipation to ~0.45 W at 25 °C ambient. DFN8 (3×3 mm) achieves R_thJA = 52 °C/W - over 4× better - enabling ~2 W dissipation with proper PCB copper area. For 24 V → 5 V conversion at 85 mA (1.615 W dissipation), DFN8 is mandatory; SOT323-5L would exceed 125 °C junction temperature.