HCPL-6431

Logic Output Optoisolators Overview

The HCPL-6431 is a high-reliability, Class H, dual-channel hermetically sealed optocoupler manufactured by Broadcom Limited. It utilizes a 20-pad Leadless Ceramic Chip Carrier (LCCC) package and complies with MIL-PRF-38534 standards. The device integrates AlGaAs light-emitting diodes with high-gain photodetectors featuring hysteresis thresholds for noise immunity. It supports a data rate of 40 Mbit/s and offers a common-mode rejection ratio of 500 V/µs. The isolation voltage is rated at 1500 Vdc, with an operating temperature range from -55°C to +125°C. Each channel includes a three-state output capable of directly driving data buses.

Logic Output Optoisolators Feature Summary

• Hermetically sealed construction in a 20-pad LCCC package ensuring high reliability for military and aerospace applications.
• Dual-channel design with integrated AlGaAs LEDs and photodetectors providing high-speed signal transmission.
• Three-state output configuration allows direct interfacing with data buses without additional pull-up components.
• Hysteresis threshold on detectors provides differential mode noise immunity and minimizes output signal jitter.

Logic Output Optoisolators Applications

• Military and aerospace equipment requiring high reliability
• Medical systems demanding strict isolation standards
• High-speed logic isolation interfaces
• Industrial automation control systems

Logic Output Optoisolators Procurement Notes

Verify the specific ordering suffix to confirm package type and lead content, as the standard LCCC variant contains lead and is not RoHS compliant. Ensure the procurement source is an authorized distributor or manufacturer agent to guarantee authenticity, given the component's compliance with MIL-PRF-38534 Class H and K standards. Check for QML-38534 certification status if required for defense contracts. Confirm availability of the 20-pin LCCC package versus other variants like DIP, as pinout and physical dimensions differ significantly between packages.

Logic Output Optoisolators Selection Notes

Select this component when hermetic sealing and extreme temperature stability are critical requirements. The dual-channel architecture is suitable for isolating parallel data lines or bidirectional communication buses. Consider the 40 Mbit/s speed limit for high-frequency digital isolation needs. The three-state output simplifies circuit design for bus-driven applications. Verify that the 1500 Vdc isolation rating meets the system's safety requirements. Ensure the PCB layout accommodates the 20-pad LCCC footprint or select an alternative package if space constraints exist.

Logic Output Optoisolators Part Context

This device belongs to the HCPL-64xx series of high-speed optocouplers designed for robust performance in harsh environments. It is part of Avago/Broadcom's portfolio of qualified microcircuits adhering to military specifications. The series emphasizes consistency across channels due to identical chip characteristics and assembly processes. It serves as a replacement for pulse transformers in certain isolation applications, offering superior noise immunity and compact form factor compared to magnetic solutions.

Logic Output Optoisolators Replacement Considerations

Direct replacements must match the 20-pin LCCC hermetic package and MIL-PRF-38534 qualification. Generic non-hermetic optocouplers lack the required environmental resilience. Verify compatibility with TTL, STTL, LSTTL, and HCMOS logic levels. Ensure the substitute maintains the 500 V/µs CMTI and 1500 Vdc isolation ratings. Cross-reference datasheets for pin-to-pin compatibility and thermal management requirements.

Logic Output Optoisolators FAQ

Does the HCPL-6431 support bidirectional data transmission?

Yes, the dual-channel design allows for independent signal paths, supporting bidirectional communication when configured appropriately with external circuitry.

What is the maximum operating temperature for this device?

The HCPL-6431 is rated for operation up to +125°C, making it suitable for high-temperature industrial and aerospace environments.

How does the hysteresis threshold improve performance?

The hysteresis threshold on the photodetector provides approximately 0.25 mA of differential mode noise immunity, reducing the likelihood of output signal jitter in noisy environments.