STD840DN40

Overview

The STD840DN40 is a dual NPN high voltage transistor manufactured using multi-epitaxial planar technology. It integrates two transistors in a single DIP-8 package with separated terminals for mounting flexibility. Key electrical ratings include a collector-emitter voltage (VCEO) of 400 V, a continuous collector current (IC) of 4 A, and a peak collector current (ICM) of 8 A. The device features low saturation voltage (VCE(sat)) of 1 V at IC = 2 A and IB = 0.4 A. Thermal resistance junction-to-case is 2.7 °C/W, with a maximum operating junction temperature of 150 °C.

Feature Summary

• Dual NPN configuration in a single package to simplify circuit design
• High voltage capability with 400 V collector-emitter breakdown
• Low saturation voltage for efficient power switching
• Fast switching speed suitable for high-frequency applications

Applications

• Compact fluorescent lamp (CFL) 220 V mains circuits
• Electronic ballast for fluorescent lighting

Procurement Notes

Verify the specific ordering code and marking against official documentation before procurement. Confirm that the DIP-8 tube packaging aligns with assembly requirements. Ensure thermal management strategies account for the specified junction-to-ambient resistance values under actual PCB mounting conditions. Cross-reference absolute maximum ratings with operational limits to prevent device failure.

Selection Notes

Select this component when a compact solution for high-voltage switching is required. The dual configuration reduces component count compared to discrete transistors. Evaluate thermal performance based on the 3 W dissipation limit at ambient temperature versus 45 W at case temperature. Ensure base drive currents meet the requirements for the specified saturation voltages.

Part Context

The STD840DN40 belongs to STMicroelectronics' portfolio of discrete power transistors designed for industrial and consumer electronics. It utilizes multi-epitaxial planar technology to achieve high voltage blocking capabilities. The device is part of a series aimed at replacing multiple discrete components with integrated solutions to save board space.

Replacement Considerations

Check for direct pin-compatible alternatives within the same manufacturer's lineup offering similar VCEO and IC ratings. Verify that any substitute maintains the DIP-8 package dimensions and thermal characteristics. Ensure the replacement supports the required switching speeds and saturation voltages for the specific application.