STMicroelectronics VN920-B5

Overview

VN920-B5 from STMicroelectronics is a single-channel high-side solid-state relay (HSD) designed for driving ground-referenced loads in automotive and industrial power distribution systems. It features 16 mΩ R_DS(on), 30 A continuous output current, 36 V maximum supply voltage, integrated proportional current sense (K ≈ 4400), and comprehensive protection including thermal shutdown (T_TSD = 150–200 °C), undervoltage/overvoltage shutdown, short-circuit current limiting, and reverse battery protection. It is used in body control modules for headlight, fan, and pump switching.

For engineers reviewing the VN920-B5 datasheet, VN920-B5 pinout, VN920-B5 application, or VN920-B5 equivalent, key selection criteria include its SO-16L package thermal performance (R_thj-amb = 65 °C/W on 0.5 cm² Cu), CMOS-compatible input logic (V_IL = 1.25 V, V_IH = 3.25 V), analog current sense accuracy (±10% ratio drift over −40 to +150 °C), and ISO 7637-1 Pulse 5a transient immunity up to +86.5 V.

Technical Context

The VN920-B5 integrates ST's VIPower M0-3 BCD technology to combine high-voltage DMOS power stage with smart bipolar-CMOS control circuitry. Its active V_CC clamp (41–55 V) and demagnetization clamp (V_demag = V_CC − 41 V) enable robust inductive load switching. Protection logic includes independent detection circuits for overtemperature (TTSD), overvoltage (VOV), undervoltage (VUSD), and loss-of-ground-each triggering automatic latch-off with thermal hysteresis (Thyst = 7–15 °C).

Current sensing uses an internal transconductance amplifier delivering I_SENSE = I_OUT/K, where K varies from 3300 to 6000 depending on I_OUT and temperature. The sense output (CSENSE pin) provides real-time analog feedback with 500 µs delay (t_DSENSE) and supports external resistor-based scaling (e.g., R_SENSE = 3.9 kΩ yields V_SENSE ≈ 4 V at 10 A). Input logic is fully compatible with 3.3 V/5 V microcontrollers and includes 0.5 V hysteresis for noise immunity.

Key Specifications

Pinout & Package

Package: SO-16L (16-pin small-outline integrated circuit, 10.1 × 10.65 mm body, 1.27 mm pitch, 1.37 mm height). Thermal performance optimized for surface-mount assembly on 0.5 cm² of 35 µm Cu on FR-4 (R_thj-amb = 65 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side driver applications.

Compared with VN920-B5, STVN820B5 trades current capability for cost and thermal simplicity, while BTS724G offers comparable switching but lacks integrated reverse-battery handling and tighter current sense stability-making VN920-B5 optimal for new BCM designs demanding full diagnostic coverage and compact SO-16L layout.

Availability

VN920-B5 is available at Aetrix Electronics and suitable for automotive body control modules, industrial motor starters, and 24 V commercial vehicle power distribution systems requiring stable component supply, long lifecycle support, and AEC-Q100-compliant sourcing.

Supply support for VN920-B5 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 vertical manufacturing and broad automotive qualification expertise.

VN920-B5 belongs to ST's VIPower family of intelligent power switches, engineered specifically for automotive power distribution and load driving where functional safety, diagnostic capability, and ruggedness against harsh electrical environments are mandatory.

FAQ

What is the recommended PCB layout for thermal performance in SO-16L?

For optimal thermal performance, mount VN920-B5 on a single-sided FR-4 board with ≥0.5 cm² of 35 µm-thick copper connected to all V_CC and OUTPUT pins. Use thermal vias under the exposed pad (if present) and avoid isolating copper areas. ST specifies R_thj-amb = 65 °C/W under these conditions-critical for sustaining 30 A continuous current without derating.

How does the current sense output interface with a microcontroller ADC?

CSENSE delivers a current (not voltage) proportional to load current: I_SENSE = I_OUT/K. To convert to voltage, connect a precision pull-up resistor (e.g., 3.9 kΩ to V_CC)-yielding ~4 V at 10 A. The output impedance is <400 Ω in overtemperature, ensuring minimal loading error. No external op-amp is needed for basic diagnostics.

Does VN920-B5 require external components for ISO 7637-1 Pulse 5a compliance?

No external TVS diode is required for ISO 7637-1 Pulse 5a (+86.5 V, 400 ms) due to its integrated active V_CC clamp (V_clamp = 41–55 V) and internal energy handling (E_MAX = 352 mJ). However, a load-dump suppressor (D_ld) is recommended if V_CC transients exceed 41 V or if the application demands >352 mJ clamping margin.

Can VN920-B5 drive inductive loads without external freewheeling diodes?

Yes-the device integrates an active demagnetization clamp (V_demag = V_CC − 41 V) that safely dissipates inductive kickback energy during turn-off. This eliminates the need for external flyback diodes in most automotive solenoid and relay applications, though external snubbers may still be used for EMI reduction in sensitive systems.