STMicroelectronics ST1L08SPUR

Overview

ST1L08SPUR from STMicroelectronics is an adjustable ultra-low-dropout linear regulator (LDO) delivering up to 800 mA output current with a maximum dropout voltage of 90 mV at full load, ±2.0% output voltage accuracy at 25 °C, and high PSRR (80 dB @ 100 Hz). It features logic-controlled shutdown, Power Good indication, bias-input architecture for low-V_IN operation, and operates across –40 °C to 125 °C in DFN8 2×3 mm package - deployed in SSD power rails and battery-powered point-of-load systems.

For engineers reviewing the ST1L08SPUR datasheet, ST1L08SPUR pinout, ST1L08SPUR application, or ST1L08SPUR equivalent, key selection criteria include its dual-rail bias input (V_Bias ≥ V_OUT + 1.5 V), ADJ-pin-based output setting (0.5–4.0 V), thermal/short-circuit protection, and PG open-drain functionality - all critical for low-noise, high-stability embedded power domains.

Technical Context

The ST1L08SPUR uses an N-channel pass transistor driven by a separate bias rail (V_Bias), enabling stable regulation even when input voltage approaches the output level - unlike standard PMOS LDOs. Its internal reference is trimmed to 0.500 V at the ADJ pin, supporting precise external resistor-divider programming of V_OUT.

It integrates independent protection circuits: thermal shutdown triggers at 165 °C (20 °C hysteresis), current limit clamps at ~1.8 A, and Power Good asserts when V_OUT reaches 92% of target and de-asserts at 80%. The PG pin is open-drain, requiring external pull-up.

Key Specifications

Pinout & Package

ST1L08SPUR is housed in a thermally enhanced DFN8 2×3 mm package with exposed pad (EXP) for PCB thermal relief. Pin 1 is marked by a dot; EXP must be soldered to a GND copper pour for optimal thermal performance (R_thJC = 12 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and ADM7172ACPZ-R7, ST1L08SPUR uniquely combines ADJ-based voltage flexibility, ultra-low dropout (<90 mV), integrated PG, and dual-rail biasing - making it the only choice for compact, multi-rail, low-headroom industrial and storage applications demanding both precision and protection.

Availability

ST1L08SPUR is available at Aetrix Electronics and suitable for solid-state drive power rails, low-voltage FPGA core supplies, and battery-powered medical sensor nodes requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ST1L08SPUR 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 ST1L08SPUR belongs to ST's high-performance LDO portfolio targeting ultra-low-dropout, high-PSRR point-of-load regulation in space-constrained, thermally demanding applications - especially where bias-rail independence and Power Good sequencing are mandatory.

FAQ

What is the minimum required V_Bias voltage for ST1L08SPUR?

V_Bias must be ≥ V_OUT + 1.5 V and ≥ 2.7 V per datasheet Section 6.3. For example, when configuring V_OUT = 1.2 V, V_Bias must be ≥ 2.7 V; for V_OUT = 3.3 V, V_Bias must be ≥ 4.8 V. This ensures proper gate drive for the N-channel pass transistor and stable regulation under full load.

Can ST1L08SPUR be used without connecting the PG pin?

Yes - the PG pin is optional and may be left floating or tied to V_Bias via a pull-up resistor only if power-good monitoring is needed. The device operates normally without PG connection; however, system-level power sequencing and fault detection will lack this status signal.

What is the recommended output capacitor value and type?

A minimum 4.7 μF X5R/X7R ceramic capacitor with ESR ≤ 10 mΩ is required at V_OUT. ST's Figure 21 confirms stability across C_OUT = 1–22 μF and ESR = 0.01–25 Ω. Place the capacitor within 3 mm of V_OUT and GND pins, and connect the GND terminal directly to the EXP pad.

How does thermal shutdown behave during sustained overload?

At junction temperature ≥165 °C (typ.), the output shuts off; it automatically resumes regulation once T_J falls below 145 °C (165 °C – 20 °C hysteresis). During cycling, average output current is limited by thermal resistance (R_thJA = 55 °C/W) and ambient conditions - e.g., at 60 °C ambient, max continuous power dissipation is ~1.18 W.