LM5642MH/NOPB

Overview

The LM5642MH/NOPB is a high-voltage dual synchronous buck converter switch controller manufactured by Texas Instruments. It features two independent output channels capable of delivering up to 20 A each, with an adjustable output voltage range from 1.3 V to 32.4 V. The device operates at a fixed switching frequency of 200 kHz and supports a maximum duty cycle of 98.9%. Designed for surface-mount installation in an HTSSOP-28 package, it functions within a junction temperature range of -40°C to +125°C. The controller draws a typical operating supply current of 1.1 mA and includes built-in protection features such as overcurrent limiting and soft-start functionality.

Feature Summary

• Dual-channel architecture providing independent synchronous buck control for two separate outputs or combined single-output operation.
• Integrated oscillator synchronization capability allows the switching frequency to align with external system clocks to minimize electromagnetic interference.
• Current-mode control loop ensures rapid transient response and stable regulation across wide input voltage variations.
• Built-in thermal and electrical protection mechanisms including overcurrent limiting and soft-start sequencing.

Applications

• High-reliability communication equipment power supplies requiring efficient DC/DC conversion.
• Electronic computer terminal devices needing compact, lightweight, and high-efficiency power solutions.
• Systems requiring dual voltage rails with synchronized switching to reduce input filter capacitance requirements.

Procurement Notes

Verify that the specific suffix 'X' in related part numbers like LM5642XMH/NOPB denotes extended temperature or reliability grades if required, though standard LM5642MH/NOPB data confirms standard industrial ranges. Confirm package compatibility with HTSSOP-28 footprints during PCB design. Ensure input voltage stays within the 4.5 V to 36 V operational window for proper controller function. Check RoHS compliance documentation for environmental regulations adherence prior to procurement.

Selection Notes

Select this component when dual isolated or non-isolated buck outputs are needed from a single high-voltage source. The 200 kHz frequency balances efficiency and component size effectively. Consider the HTSSOP-28 package for space-constrained designs requiring robust thermal performance. Evaluate the need for oscillator synchronization if system-wide noise reduction is critical. Compare against single-channel controllers if only one output is strictly necessary to optimize cost and board area.

Part Context

This device belongs to the LM5642 series of high-voltage dual synchronous buck converters. It is designed to replace older discrete solutions or single-channel controllers in applications demanding higher current density and improved efficiency. The integration of two controllers on one die allows for phase interleaving, which significantly reduces input ripple current compared to asynchronous designs.

Replacement Considerations

Public confirmed substitute part numbers include LM5642MTC/NOPB and LM5642XMTX/NOPB. Verify package differences; MTC uses TSSOP while MH uses HTSSOP. X-suffix variants may offer extended specifications. Ensure pinout compatibility and thermal characteristics match the existing design constraints before substitution.