STMicroelectronics L5958SMTR

Overview

L5958SMTR from STMicroelectronics is a multifunction automotive voltage regulator IC for car radio systems, integrating six linear regulators (8.5 V/200 mA, 5.0 V/300 mA, 3.3 V/250 mA, 1.8 V/350 mA, plus two standby 3.3 V/100 mA and 1.8 V/100 mA outputs) and a 2 A high-side power switch, operating down to 4.5 V battery input with load dump protection up to 28 V.

For engineers reviewing the L5958SMTR datasheet, L5958SMTR pinout, L5958SMTR application, or L5958SMTR equivalent, key selection considerations include dual reset buffers (VDD core and standby), programmable battery warning thresholds (Hold CAN and Hold Audio), ignition comparator, thermal shutdown, and backup capacitor support for persistent 3.3 V/1.8 V supply during sudden battery disconnect.

Technical Context

The L5958SMTR implements a dual-domain regulation architecture: switched regulators (REG1–REG4) powered by VIN2 (4.5–18 V) and permanent regulators (REG5–REG6) powered by VIN1 (9–18 V), each controlled by dedicated enable pins (EN_8P5_5, EN_3P3sw_1P8sw, EN_3P3_1P8). The device uses internal reference voltage (1.2565 V) to set programmable hold thresholds via external resistor dividers on CAN_LOW_IN and AUDIO_LOW_IN.

It features two independent open-drain reset buffers - one monitoring REG5/REG6 (standby outputs) with 3.15 V ±50 mV threshold and 10–100 mV hysteresis, and another monitoring REG3/REG4 (switched outputs) with identical thresholds - plus an ignition buffer with 1.17 V typical falling threshold and 30–100 mV hysteresis, all supporting automotive cold-cranking and battery transient resilience.

Key Specifications

Pinout & Package

Package: Flexiwatt27 (SMD), 27-pin vertical-mount surface-mount package with exposed thermal tab (TAB = Pin 1, connected to GND internally).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multifunction automotive regulator applications.

Compared with NCP380LSN33T2G and TPS65381AQDAGQ1, the L5958SMTR uniquely integrates six LDOs, a 2 A high-side switch, dual reset buffers, and programmable battery warning comparators in a single Flexiwatt27 package-enabling complete car radio power management without supplemental ICs.

Availability

L5958SMTR is available at Aetrix Electronics and suitable for automotive infotainment, telematics control units, and instrument cluster applications requiring stable component supply across extended temperature and harsh electrical environments.

Supply support for L5958SMTR 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 with emphasis on reliability and automotive qualification.

The L5958SMTR belongs to ST's automotive power management IC portfolio, engineered specifically for car radio and infotainment systems requiring integrated voltage regulation, battery monitoring, and fail-safe reset functionality under ISO 16750 conditions.

FAQ

What is the minimum input voltage required for the VIN2-supplied regulators (REG3 and REG4)?

The VIN2 input must be ≥4.5 V for proper operation of REG3 (3.3 V/250 mA) and REG4 (1.8 V/350 mA). Below this, dropout voltage limits prevent regulation: REG3 requires ≥4.05 V (3.3 V + 0.75 V dropout), REG4 requires ≥4.0 V (1.8 V + 2.2 V dropout) at full load. Operation at 4.5 V ensures margin for transients and load steps.

How is the reset delay time set, and what capacitor value achieves a nominal 42 ms delay?

The reset delay is set by capacitor CRES connected to Pin 5 (CRES). Per datasheet Table 5, a 47 nF capacitor yields a typical delay of 42 ms (range 20–70 ms). This capacitor controls the timing of RES signal deassertion after regulator recovery, preventing premature MCU release during voltage recovery.

Can the L5958SMTR's Hold CAN and Hold Audio thresholds be adjusted independently?

Yes - Hold CAN threshold is set by resistor divider on CAN_LOW_IN (Pin 13), Hold Audio threshold by separate divider on AUDIO_LOW_IN (Pin 10). Each uses the internal 1.2565 V reference: V_TH = 1.2565 × (R₁ + R₂) / R₂. Independent adjustment allows tailoring low-voltage warnings for CAN bus stability versus audio subsystem sensitivity.

What thermal derating applies when operating the 2 A power switch continuously at ambient temperatures above 85 °C?

With R_{th j-case} = 1.0 °C/W and T_{j max} = 150 °C, continuous 2 A operation is limited to T_amb ≤ 85 °C when case temperature is maintained near 95 °C. Above 85 °C ambient, derating is required: at 105 °C ambient, maximum sustainable DC current drops to ~1.4 A to keep junction ≤150 °C, assuming 20 °C/W PCB thermal resistance.