STMicroelectronics VN31-12-E

Overview

VN31-12-E from STMicroelectronics is a high-side smart power solid-state relay designed for automotive ISO-compliant load switching, featuring 31 A continuous output current at Tc = 85 °C, 60 V drain-source breakdown voltage, 0.03 Ω on-state resistance at 25 °C, 5 V logic-compatible input, and open-drain diagnostic output. It drives grounded resistive or inductive loads in engine control units, body electronics, and lighting modules.

For engineers reviewing the VN31-12-E datasheet, VN31-12-E pinout, VN31-12-E application, or VN31-12-E equivalent, key selection criteria include thermal shutdown threshold (140 °C), inductive demagnetization clamp (–18 V), open-load detection timing (5–10 ms), under-voltage lockout (5 V), and ISO 7637-2 Pulse 5 Level II surge immunity without external components.

Technical Context

The VN31-12-E integrates a VIPower MOSFET with embedded protection logic and diagnostics. Its high-side architecture enables direct battery-switching of grounded loads, while internal thermal sensing triggers automatic shutdown at 140 °C and reset at 125 °C. The device implements fast inductive demagnetization via active –18 V clamp during turn-off, reducing dissipation by controlling energy recovery.

Diagnostic functionality includes open-load detection in both ON and OFF states, overtemperature flagging, and short-to-VCC indication-all delivered through an open-drain status output with configurable filtering (5–10 ms). Input hysteresis (0.5 V) and internal 6 V VIH clamp ensure robust noise immunity in automotive environments.

Key Specifications

Pinout & Package

The VN31-12-E uses the PENTAWATT vertical package (Order Code suffix "-E"), a 5-pin through-hole power package with isolated heatsink tab. Pin 1 = GND, Pin 2 = IN, Pin 3 = V_CC, Pin 4 = OUT, Pin 5 = STATUS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STVN32-12-E and BTS50085-1TAD, the VN31-12-E delivers superior surge immunity (60 V vs. 40 V), higher continuous current (31 A), and simpler analog interface-making it optimal for cost-sensitive, thermally demanding high-power automotive switches where discrete diagnostics suffice.

Availability

VN31-12-E is available at Aetrix Electronics and suitable for engine control units, body control modules, and lighting control systems requiring stable component supply across extended automotive temperature ranges and long production lifecycles.

Supply support for VN31-12-E 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 rigorous AEC-Q100 qualification processes.

The VN31 belongs to ST's VIPower M0-3 high-side driver product line, engineered specifically for ISO 16750-2 and ISO 7637-2 compliant automotive power switching-emphasizing ruggedness, integrated diagnostics, and thermal resilience in under-hood environments.

FAQ

What is the maximum inductive load energy the VN31-12-E can safely demagnetize?

The VN31-12-E achieves safe demagnetization for inductive loads up to 1 mH at 11.5 A, producing a typical clamp voltage of –18 V. Its internal circuit limits peak reverse voltage to –24 V, preventing MOSFET avalanche. Energy handling depends on switching frequency and thermal environment-designers must verify junction temperature rise using the provided P_dem formula and R_thj-case = 1.2 °C/W.

Does the VN31-12-E require external components for ISO 7637-2 Pulse 5 Level II compliance?

No external components are required for ISO 7637-2 Pulse 5 Level II (46.5 V) compliance-the device withstands this transient internally. For Level III (60 V), ST recommends adding a 150 Ω resistor between Pin 1 (GND) and chassis ground plus a 1000 µF capacitor between Pin 3 (V_CC) and ground-only when load resistance is ≤20 Ω.

How does the open-load detection behave during PWM switching?

The open-load filter (t_1(on)/t_1(off) = 1–10 ms) remains active during PWM operation. If load disconnection occurs for ≥5 ms within a PWM cycle, the STATUS pin asserts low. Brief interruptions (<5 ms) are ignored-ensuring reliable detection without false alarms during normal PWM edge transitions or contact bounce.

Can the VN31-12-E be used with 24 V commercial vehicle systems?

Yes-the VN31-12-E supports V_CC up to 26 V and meets ISO 7637-2 Pulse 5 Level II at 46.5 V, making it suitable for 24 V truck/bus systems. However, continuous current derating applies above 13 V: at 24 V and T_c = 85 °C, max I_OUT drops to ~18 A due to increased conduction loss and thermal constraints.