STMicroelectronics VN771K

Overview

VN771K from STMicroelectronics is a quad-channel smart power solid-state relay integrating two VIPower™ M0-3 high-side switches and two OMNIFET II low-side switches in a single SO-28 package. It delivers linear current limitation (9 A typical), 95 mΩ on-resistance per bridge side, 36 V max supply voltage, and integrated open-load/over-temperature diagnostics via open-drain status flag - enabling full H-bridge DC motor control with fault feedback.

For engineers reviewing the VN771K datasheet, VN771K pinout, VN771K application, or VN771K equivalent, key selection considerations include dual high-side thermal shutdown behavior, low-side clamping voltage (VCC−48 V), status timing under overload (≤20 µs delay), and SO-28 thermal resistance (20 °C/W junction-to-case).

Technical Context

The VN771K implements a monolithic three-chip architecture: one die for dual high-side switching with built-in thermal shutdown and current limiter blocks, and two separate OMNIFET II low-side dies featuring linear current limitation, overvoltage clamping, and auto-protection logic. All channels operate across −40 °C to 150 °C case temperature range with undervoltage (4 V typ) and overvoltage (36 V) protection thresholds.

Diagnostic functionality is centralized on a shared open-drain STATUS pin that reports open-load (in both on/off states), over-temperature (>150 °C shutdown threshold), and short-circuit events. Fault detection on low-side switches is inferred by monitoring input pin voltage during thermal intervention, while high-side status reflects combined channel health with 0.5 V max low-level output at 1.6 mA sink current.

Key Specifications

Pinout & Package

Package: SO-28 (Small Outline, 28-pin, surface-mount, standard JEDEC MS-013AC). Exposed pad variant not specified; thermal path relies on PCB copper area per Figure 49.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel smart power switch applications.

Compared with STSPIN840 and TPS27082L, the VN771K uniquely combines dual high-side + dual low-side topology, shared STATUS diagnostics, and linear current limiting in SO-28 - making it the only option supporting full-bridge DC motor control with minimal external components and deterministic fault response.

Availability

VN771K is available at Aetrix Electronics and suitable for automotive power window systems, industrial conveyor motor drives, medical infusion pumps, and robotics joint actuators requiring stable component supply and long-lifecycle support.

Supply support for VN771K 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 analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The VN771K belongs to ST's VIPower™ smart-power family, engineered specifically for robust, integrated H-bridge motor control in safety-critical 12–24 V systems where thermal resilience, fault visibility, and board-space efficiency are mandatory.

FAQ

What is the maximum continuous current per channel under forced-air cooling?

The VN771K supports 9 A typical continuous current per channel at T_c = 25 °C with adequate PCB copper (≥6 cm²) and ambient airflow. Derating begins above 25 °C case temperature per Figure 24; at 100 °C case, max current drops to ~5.5 A due to thermal foldback. No external heatsink is required if PCB layout follows ST's SO-28 thermal guidelines (Figure 47).

How does open-load detection work in off-state versus on-state?

In off-state, open-load is detected when V_OL exceeds 2.5 V (typ) at the DRAIN pin - indicating no current path to ground. In on-state, detection triggers when load current falls below 100 mA (typ) while INPUT is asserted - confirming motor disconnection or winding break. Both conditions assert the STATUS pin within 1000 µs (off) or 200 µs (on).

Can the VN771K drive inductive loads without external flyback diodes?

Yes. The low-side switches integrate active clamp circuits that limit turn-off voltage to V_CC−48 V (typ), safely absorbing inductive energy from loads up to 6 mH. This eliminates need for external freewheeling diodes in most 24 V DC motor applications, though external TVS may still be advised for extreme transients beyond datasheet limits.

Is the DIAGNOSTIC pin compatible with 3.3 V microcontrollers?

Yes. The open-drain DIAGNOSTIC pin operates with any pull-up voltage from 3.3 V to 5 V. Its leakage current is ≤10 µA (Table 9), and low-level output voltage is ≤0.5 V at 1.6 mA sink - ensuring reliable logic-low recognition by 3.3 V I/O even under worst-case conditions.