STMicroelectronics L5963D-EHX

Overview

L5963D-EHX from STMicroelectronics is an AEC-Q100 qualified automotive dual monolithic switching regulator IC integrating two synchronous step-down DC/DC converters (3.5–26 V input, 3.0 A each), one programmable LDO (250 mA, standby I_Q = 25 μA), and one protected high-side driver (0.5 V drop @ 0.5 A). It supports 180° phase-shifted PWM, external synchronization (250 kHz–2 MHz), and independent power-good outputs for use in body control modules and ADAS domain controllers.

For engineers reviewing the L5963D-EHX datasheet, L5963D-EHX pinout, L5963D-EHX application, or L5963D-EHX equivalent, key selection considerations include its dual-DC/DC + LDO + HSD integration, load dump protection, programmable under-voltage detection via VDIN, and PowerSSO-36 (exposed pad) thermal performance in automotive under-hood environments.

Technical Context

The L5963D-EHX implements voltage-mode control with feed-forward compensation across both DC/DC regulators, enabling stable operation across wide input (3.5–26 V) and output (≥1 V) ranges while supporting 250 kHz free-run or externally synchronized switching up to 2 MHz. Each regulator features independent enable (ENSW1/ENSW2), soft-start, and dedicated power-good (SW1OK/SW2OK) with configurable delay via external capacitors on SW1OKDLY/SW2OKDLY pins.

The integrated LDO operates in either standby mode (I_Q = 25 μA, ENLDO tied to VINLDO) or normal mode (higher current, higher I_Q), with LDOOK open-drain reset output and adjustable delay via LDOOKDLY. The high-side driver includes short-to-battery, short-to-ground, loss-of-ground, and unsupplied-short protection, enabled via ENHSD with 1.8/3.3 V logic compatibility.

Key Specifications

Pinout & Package

Package: PowerSSO-36 (exposed pad), thermally enhanced slug-down configuration requiring PCB ground plane connection for heatsinking. Pin count: 36. Exposed thermal pad (Pin 1, TAB) must be soldered to GND for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-rail automotive power management applications.

Compared with MPQ4332-AEC1, L5963D-EHX reduces component count by integrating LDO and HSD; versus TPS65381A-Q1, it offers smaller PowerSSO-36 footprint and programmable VDIN for adaptive battery monitoring, at the cost of one fewer DC/DC channel.

Availability

L5963D-EHX is available at Aetrix Electronics and suitable for automotive body control modules, ADAS domain controllers, infotainment head units, and electric power steering ECUs requiring stable component supply across extended temperature and qualification lifecycles.

Supply support for L5963D-EHX 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 specializing in automotive, industrial, and power management solutions, with broad AEC-Q100 product portfolio and manufacturing certified to IATF 16949.

The L5963 belongs to ST's automotive power system-on-chip (SoC) family, designed specifically for centralized power architectures in modern vehicles where integration, thermal efficiency, and functional safety compliance are critical.

FAQ

What is the maximum allowable input voltage during load dump conditions?

The L5963D-EHX incorporates built-in load dump protection rated to withstand ISO 7637-2 Pulse 5a (clamped to ≤40 V) without external TVS diodes. Its absolute maximum input rating is 45 V, and internal clamp circuitry activates above 28 V to protect internal regulators and drivers, ensuring reliable operation in harsh automotive environments.

How is the 180° phase shift between PWM1 and PWM2 implemented and what benefit does it provide?

The 180° phase shift is hardwired in the internal oscillator logic and cannot be disabled. It reduces input capacitor RMS current by distributing charge/discharge cycles across complementary intervals, lowering peak input ripple by ~40% and permitting smaller, lower-ESR bulk capacitors - critical for space-constrained automotive modules.

Can the LDO operate independently while both DC/DC converters are disabled?

Yes. The LDO (enabled via ENLDO) functions fully independently: it can remain active in standby mode (I_Q = 25 μA) while ENSW1 and ENSW2 are low, supplying always-on rails such as real-time clocks or CAN wake-up receivers. Its output voltage is set by external resistor divider on FBLDO, and LDOOK provides reset signaling.

What thermal derating applies when using the PowerSSO-36 (exposed pad) package without a heatsink?

With 4-layer PCB (2 oz Cu, 10 cm² exposed pad connected to internal ground planes), the PowerSSO-36 achieves θ_JA ≈ 35 °C/W. At T_A = 85 °C, maximum continuous power per DC/DC is ~2.8 W (≈1.2 A @ 12 V input → 3.3 V output). Full 3.0 A operation requires ambient ≤70 °C or supplemental airflow/heatsink attachment to the exposed pad.