LT3973HDD-3.3#PBF

Overview

The LT3973HDD-3.3#PBF is a monolithic buck switching regulator manufactured by Analog Devices Inc., designed for high-efficiency DC-to-DC conversion in demanding environments. This specific variant provides a fixed 3.3V output with a maximum current capability of 0.75A, operating within an input voltage range of 4.2V to 42V. It features an adjustable switching frequency ranging from 195kHz to 2.15MHz, allowing optimization for size and efficiency. The device consumes only 2.5µA of quiescent current, ensuring minimal power drain during standby. Packaged in a 10-WFDFN exposed pad surface-mount enclosure, it supports junction temperatures up to 125°C, making it suitable for automotive and industrial applications requiring robust performance under wide thermal and electrical variations.

Feature Summary

• Adjustable switching frequency allows design flexibility between component size and electromagnetic interference levels
• Ultra-low quiescent current consumption minimizes power loss in battery-operated or standby modes
• Wide input voltage range accommodates various supply sources including automotive loads
• Integrated synchronous rectification improves overall conversion efficiency

Applications

• Automotive electronics systems requiring stable 3.3V logic supplies
• Industrial control units and sensors operating in harsh environments
• Battery-powered devices needing extended operational life through low standby current
• General-purpose step-down conversion in space-constrained PCB designs

Procurement Notes

Verify the suffix #PBF indicates lead-free compliance and RoHS adherence when sourcing. Confirm the DD package code corresponds to the 10-WFDFN form factor required for your layout. Ensure the -3.3 designation matches your target output voltage, as other variants exist. Cross-reference the manufacturer part number LT3973HDD-3.3#PBF with authorized distributors to avoid counterfeit components. Check for any specific handling requirements associated with the exposed pad thermal termination.

Selection Notes

Select this component when a fixed 3.3V output is preferred over adjustable versions to simplify external resistor networks. Choose the H-grade variant if automotive qualification and extended temperature ranges are mandatory. Consider the 0.75A limit against peak load demands; higher current needs require different models. The exposed pad package necessitates careful thermal management on the PCB copper plane. Verify that the minimum input voltage of 4.2V aligns with your system's lowest operating condition.

Part Context

This part belongs to the LT3973 family of high-voltage buck regulators from Analog Devices. The family shares core architecture but varies in output configuration (fixed vs. adjustable) and grade (industrial vs. automotive). The HDD suffix denotes the specific 10-WFDFN package type. The -3.3 indicates the fixed output voltage version. Understanding the family context helps in selecting complementary components like inductors and capacitors that match the switching characteristics and current ratings of this specific regulator.

Replacement Considerations

Direct substitutes may include other LT3973 variants with different output voltages if programmability is acceptable. Cross-brand alternatives should match the 42V input rating, 0.75A output, and 10-WFDFN package. Verify pin compatibility and thermal performance before substitution. No direct public substitute part numbers are confirmed for this exact fixed-voltage automotive-grade variant.