STMicroelectronics LDFPUR

Overview

LDFPUR from STMicroelectronics is an adjustable low-dropout linear regulator delivering 1 A output current with 500 mV max dropout at full load, 0.8 V to 12 V output range, and ±1% reference voltage tolerance over temperature. It features logic-controlled enable (EN), open-drain Power Good (PG), and internal thermal/current protection - designed for powering low-voltage microprocessors and memory in space-constrained portable systems.

For engineers reviewing the LDFPUR datasheet, LDFPUR pinout, LDFPUR application, or LDFPUR equivalent, key selection criteria include its 200 µA typical quiescent current at 1 A load, fast dynamic response to load transients, DFN6-3x3 package footprint, and PG threshold set at 92% of V_ADJ with hysteresis.

Technical Context

The LDFPUR implements a high-precision bandgap reference (0.8 V typ.) feeding an error amplifier that controls an N-channel pass transistor. Its adjustable architecture uses external resistor dividers on the ADJ pin to set V_OUT, enabling remote sensing and fine-tuned regulation down to 0.8 V.

It integrates dual-threshold comparators for PG monitoring (rising edge at 0.92×V_ADJ, falling at 0.8×V_ADJ) and a dedicated EN input with defined logic thresholds (0.8 V low, 2 V high). Thermal shutdown activates at 170 °C with 10 °C hysteresis, and short-circuit current is internally limited to 1.5 A.

Key Specifications

Pinout & Package

Supplied in DFN6-3x3 package (3.0 mm × 3.0 mm, 0.9 mm height) with exposed thermal pad connected to GND for enhanced heat dissipation (R_thJC = 10 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and ADM7150ACPZ-3.3-R7, LDFPUR uniquely balances 1 A output, adjustable VOUT, integrated PG/EN, and industrial temperature range in a 3×3 mm DFN - making it optimal for compact, sequenced, and thermally demanding embedded systems.

Availability

LDFPUR is available at Aetrix Electronics and suitable for battery-powered IoT nodes, laptop core voltage rails, and medical patient monitor front-ends requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LDFPUR 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 automotive-grade components.

LDFPUR belongs to ST's LDF family of very low-dropout linear regulators, engineered specifically for high-precision, low-noise, and thermally robust power delivery in portable, industrial, and medical equipment.

FAQ

What is the minimum input voltage required for LDFPUR to regulate 0.8 V output?

The minimum input voltage is 2.6 V per datasheet specification. At V_OUT = 0.8 V, dropout is not characterized below 1.6 V output, so regulation relies on sufficient headroom - typically ≥1.0 V above V_OUT for stability. For reliable 0.8 V operation, VIN ≥ 1.8 V is recommended, though absolute minimum VIN remains 2.6 V per absolute ratings.

Can the PG pin drive a microcontroller GPIO directly?

Yes - the PG pin is an open-drain output rated for 6 mA sink current. A 10–100 kΩ pull-up resistor to a compatible logic voltage (e.g., 3.3 V or 1.8 V) allows direct connection to most MCU GPIOs. The rising/falling thresholds track V_ADJ, so PG assertion remains accurate across the full 0.8–12 V output range.

Is external compensation required for stability with ceramic output capacitors?

No - LDFPUR is internally compensated and stable with standard 2.2 µF X5R/X7R ceramic capacitors (ESR < 10 mΩ). The datasheet specifies allowable ESR vs. C_OUT in Figure 16, confirming stability with typical 0402/0603 MLCCs without added series resistance or external networks.

How does thermal performance differ between DFN6-2x2 and DFN6-3x3 packages?

DFN6-3x3 offers lower thermal resistance: R_thJA = 55 °C/W vs. 65 °C/W for DFN6-2x2, and R_thJC = 10 °C/W vs. 6.5 °C/W. The larger 3x3 variant dissipates heat more effectively under 1 A load, allowing higher ambient temperatures or reduced PCB copper area - critical for sealed industrial enclosures.