STMicroelectronics LD39080PT-R

Overview

LD39080PT-R from STMicroelectronics is an ultra-low-dropout BiCMOS linear voltage regulator delivering 0.8 A output current with 150 mV typical dropout at full load, ±1.5% output voltage tolerance at 25 °C, and adjustable output from 1.22 V to 5.0 V. It operates from 2.5 V to 6 V input, features logic-controlled shutdown, thermal/current protection, and stable operation with ceramic capacitors - used as post-regulator for switching supplies and core power for low-voltage microprocessors.

For engineers reviewing the LD39080PT-R datasheet, LD39080PT-R pinout, LD39080PT-R application, or LD39080PT-R equivalent, key selection criteria include dropout performance at 0.8 A, quiescent current in on/off modes (1 mA / 1 µA), ADJ-pin-based output programming, PPAK thermal resistance (R_thJC = 8 °C/W), and stability with ≥2.2 µF ceramic output capacitance.

Technical Context

The LD39080PT-R implements a BiCMOS-based error amplifier and pass transistor architecture enabling ultra-low quiescent current independent of load, fast transient response to load steps, and high PSRR (65 dB @ 120 Hz). Its ADJ pin connects to an internal 1.22 V reference, allowing external resistor-divider programming of output voltage.

Thermal shutdown activates at 170 °C with 10 °C hysteresis; current limiting engages at ~1.6 A short-circuit condition. The inhibit input (VINH) requires explicit logic-level control (≥2 V for ON, ≤0.3 V for OFF) with no internal pull-up/down - floating operation is prohibited per design specification.

Key Specifications

Pinout & Package

LD39080PT-R is housed in a thermally enhanced PPAK-5 (5-lead Power Package) with exposed thermal pad, offering R_thJC = 8 °C/W for efficient heat transfer to PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G and BD3572FP-E2, LD39080PT-R uniquely combines 0.8 A current, 150 mV dropout, ±1.5% accuracy, and 1 µA shutdown in a thermally optimized PPAK package - making it optimal for high-efficiency, wide-temperature, adjustable-rail applications where precision and thermal resilience are critical.

Availability

LD39080PT-R is available at Aetrix Electronics and suitable for microprocessor power supply, DSP power rail, and automotive body control module applications requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.

Supply support for LD39080PT-R 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 LD39080 belongs to ST's high-performance linear regulator product line, engineered specifically for low-noise, low-dropout power delivery in space- and thermal-constrained embedded systems requiring precise voltage regulation across extended temperature ranges.

FAQ

What is the minimum output capacitance required for stability?

The LD39080PT-R requires a minimum 2.2 µF ceramic output capacitor with ESR within the stable region defined in Figures 15–16 of the datasheet. Using capacitors outside this ESR range may cause oscillation or poor transient response, especially at temperature extremes or high load currents.

Can the inhibit pin (VINH) be left unconnected?

No - the VINH pin has no internal pull-up or pull-down and must never be left floating. To enable continuous operation, tie VINH directly to VI. To disable, drive VINH ≤0.3 V with a low-impedance source; floating VINH risks unpredictable output behavior and violates absolute maximum ratings.

Is the LD39080PT-R qualified for automotive applications?

While not explicitly AEC-Q100 certified in its standard grade, the LD39080PT-R operates across -40 °C to +125 °C junction temperature, includes thermal shutdown and current limiting, and is widely deployed in automotive body control modules. For formal qualification, consult ST's automotive-grade variants (e.g., LD39080PU33R) or request PPAP documentation.

How does the ADJ pin set output voltage?

The ADJ pin connects to an internal 1.22 V reference. Output voltage is set by VO = 1.22 V × (1 + R1/R2), where R2 connects between ADJ and GND, and R1 connects between VO and ADJ. Resistor values must ensure ADJ pin current remains negligible (<100 nA) - typical R2 = 4.7 kΩ yields practical R1 values for common output voltages.