STMicroelectronics ST715C33R

Overview

ST715C33R from STMicroelectronics is a fixed-output 3.3 V, high-input-voltage (2.5–24 V), ultra-low-quiescent-current (3.75–5.5 µA) LDO linear regulator delivering up to 85 mA output current with 500 mV typical dropout at full load. It features internal current limiting, thermal protection, and stability with ceramic output capacitors as low as 0.47 µF. It is deployed in battery-powered portable electronics requiring long runtime and wide input voltage tolerance.

For engineers reviewing the ST715C33R datasheet, ST715C33R pinout, ST715C33R application, or ST715C33R equivalent, key selection criteria include dropout voltage at 85 mA, quiescent current across temperature and input voltage, output accuracy over load/line/temperature, compatibility with low-ESR ceramic capacitors, and package thermal resistance for power dissipation management.

Technical Context

The ST715C33R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling low dropout and high PSRR (38 dB @ 1 kHz, 57 dB @ 100 kHz). Its feedback loop is internally compensated for stability with 0.47–10 µF ceramic output capacitors without external components.

Protection circuitry includes foldback current limiting (120 mA short-circuit current) and thermal shutdown activated above 125 °C junction temperature. The device operates across –40 °C to +125 °C ambient, with guaranteed performance over full industrial temperature range and input voltage swing from 4.3 V to 24 V.

Key Specifications

Pinout & Package

ST715C33R is available in SOT23-5L, SOT323-5L, and DFN8 (3×3 mm) packages. Pin functions are identical across variants; only mechanical dimensions and thermal resistance differ. SOT23-5L offers R_thJA = 195 °C/W; DFN8 provides 52 °C/W for higher power handling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B332MR-G and ADM7172ACPZ-3.3-R7, ST715C33R uniquely balances ultra-low I_Q, 24 V input tolerance, and industrial temperature operation - making it optimal for long-life, wide-input, battery-constrained systems where 85 mA suffices.

Availability

ST715C33R is available at Aetrix Electronics and suitable for wearable health monitors, smart meter sensor nodes, industrial handheld scanners, and automotive cabin camera modules requiring stable component supply across extended temperature and input voltage ranges.

Supply support for ST715C33R 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The ST715 product line targets ultra-low-power, high-input-voltage LDO regulation in space-constrained, battery-sensitive applications - emphasizing quiescent current optimization, wide VIN capability, and robustness across harsh environmental conditions.

FAQ

What is the maximum allowable input voltage for ST715C33R?

The absolute maximum DC input voltage is 26 V, but the recommended operating range is 2.5 V to 24 V. Operation above 24 V risks exceeding safe power dissipation limits, especially in SOT23-5L and SOT323-5L packages due to their higher thermal resistance (195 °C/W and 245 °C/W respectively). For sustained 24 V input, DFN8 (52 °C/W) is strongly preferred.

Can ST715C33R be used with a 0.47 µF ceramic output capacitor?

Yes - the ST715C33R is explicitly characterized and guaranteed stable with ceramic output capacitors from 0.47 µF to 10 µF, including X5R and X7R dielectrics. No series resistor or additional compensation is required. This eliminates ESR dependency and simplifies layout versus traditional LDOs requiring ≥2.2 µF tantalum capacitors.

Does ST715C33R have an enable pin?

No - ST715C33R does not include an enable (EN) or shutdown control pin. It operates continuously when input voltage is applied within specification. For applications requiring on/off control, an external MOSFET switch on the IN rail or selection of the adjustable ST715xxR variant with FB pin control is necessary.

How does thermal performance differ between SOT23-5L and DFN8 packages?

DFN8 (3×3 mm) has R_thJA = 52 °C/W versus 195 °C/W for SOT23-5L - a 3.8× improvement. At 85 mA and 24 V input, power dissipation is (24 − 3.3) × 0.085 ≈ 1.76 W; DFN8 limits junction rise to ~92 °C above ambient, while SOT23-5L would exceed 125 °C junction limit even at 25 °C ambient. DFN8 is mandatory for high-VIN/high-I_OUT operation.