STMicroelectronics L4925

Overview

L4925 from STMicroelectronics is a monolithic 5 V low-dropout linear voltage regulator with integrated power-on reset and programmable reset delay, designed for microcomputer-controlled automotive systems. It operates from 6–28 V DC input, delivers up to 500 mA output current, maintains dropout voltage below 0.6 V at full load, and includes thermal shutdown, short-circuit protection, and transient tolerance up to 40 V for ≤1 s.

For engineers reviewing the L4925 datasheet, L4925 pinout, L4925 application, or L4925 equivalent, key selection considerations include its 4.9–5.1 V output precision over load/temperature, reset threshold of 4.2–4.8 V, programmable delay via external capacitor (e.g., 60–140 ms with 100 nF), and PowerSO-20 package thermal performance (R_th(j-c) = 3.5 °C/W).

Technical Context

The L4925 integrates a PNP-based pass transistor enabling sub-0.6 V dropout at 500 mA while sustaining regulation down to 3 V input. Its internal 1.23 V reference and resistor divider set a precise 5 V output with ±2% tolerance across –40 to 125 °C junction temperature.

The dedicated reset circuit monitors V_OUT against a 4.5 V nominal threshold (±0.3 V) and generates an open-drain reset signal with user-defined delay (t_RD = CT × 2 V / 2 µA); reaction time is 5–30 µs, enhancing noise immunity during supply transients.

Key Specifications

Pinout & Package

Package: PowerSO-20 (JEDEC MO-166), surface-mount, thermally enhanced with exposed die pad (pin 1–10–11–20 connected to GND). R_th(j-c) = 3.5 °C/W supports high-power dissipation in compact automotive layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5 V automotive LDO regulator applications.

Compared with TLV73350PDBVR and MAX6495ATT+T, the L4925 uniquely combines 500 mA capability, programmable reset delay, 40 V transient tolerance, and PowerSO-20 thermal performance - making it optimal for ECU and BCM designs requiring integrated supervision and ruggedness.

Availability

L4925 is available at Aetrix Electronics and suitable for engine control units, body control modules, and instrument clusters requiring stable component supply under automotive temperature and transient conditions.

Supply support for L4925 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and qualification capabilities.

The L4925 belongs to ST's automotive-grade linear regulator product line, engineered specifically to meet stringent AEC-Q100 requirements and support microcontroller power domains in harsh-temperature, high-transient automotive subsystems.

FAQ

What is the minimum input voltage required for regulation at 500 mA output?

The L4925 maintains regulation down to 3 V input supply voltage in dropout mode, but functional regulation at full 500 mA requires V_IN ≥ V_OUT + V_DP = 5.0 V + 0.6 V = 5.6 V. Below this, output voltage drops linearly with input; datasheet Figure 4 confirms stable 5 V output starting at ~5.8 V input under 500 mA load.

How does the reset output behave during input undervoltage conditions?

The RES pin asserts low when V_OUT falls below 4.2–4.8 V, independent of V_IN. During undervoltage, the regulator enters dropout but continues supplying current until V_IN drops near 3 V; RES remains asserted as long as V_OUT stays below threshold, providing accurate brownout detection even during slow battery discharge.

Can the L4925 be used without the external CT capacitor?

Yes - omitting CT disables programmable delay; the reset output responds immediately to V_OUT crossing the threshold (5–30 µs reaction time). However, absence of CT removes noise immunity enhancement and may cause false resets during brief transients; ST recommends CT ≥ 10 nF for robust operation per Application Note AN2872.

Is the PowerSO-20 package RoHS-compliant and lead-free?

Yes - the L4925 PowerSO-20 package (order codes L4925PD and L4925PD013TR) is RoHS-compliant and lead-free per STMicroelectronics' standard manufacturing process, with matte tin (Sn) termination and halogen-free molding compound, fully compliant with EU Directive 2011/65/EU and JEDEC J-STD-020.