LA5797MC-BH Equivalent & Substitute Parts

Part Overview

The LA5797MC-BH is a charge pump switching regulator IC manufactured by onsemi, designed for positive adjustable voltage regulation in step-up applications. This device features a single adjustable output with input voltage range of 7.5V to 28V and operates at a switching frequency of 140kHz. The component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

LA5797MC-BH

onsemiIn Stock: 3983LA5797MC-BH Datasheet

Current PartRFQ

LT1109CS8-12#TRPBF

Analog Devices Inc.In Stock: 1212LT1109CS8-12#TRPBF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LA5797MC-BH is determined by the following critical parameters:

• Package Compatibility: Both devices must use 8-SOIC (0.154", 3.90mm Width) surface mount packaging to ensure PCB layout compatibility
• Functional Classification: Step-up (boost) topology with positive output configuration
• Output Configuration: Single output with adjustable or fixed voltage capability
• Voltage Operating Range: Input and output voltage specifications must accommodate the application requirements
• Switching Frequency: Operating frequency in the 120kHz–140kHz range ensures comparable performance characteristics
• Synchronous Rectifier: Non-synchronous topology matching

The LT1109CS8-12#TRPBF from Analog Devices Inc. qualifies as a substitute based on matching package type, step-up topology, positive output configuration, single output design, and compatible switching frequency. Both devices operate in the same thermal range and share identical MSL classification.

Parameter Comparison

Engineering Selection Recommendations

The LT1109CS8-12#TRPBF is available as an active product with ROHS3 compliance, providing supply chain continuity for applications currently using the obsolete LA5797MC-BH. Both devices share identical package geometry and MSL classification, enabling direct PCB footprint compatibility.

Key considerations for selection:

• Voltage Range Differences: The LT1109CS8-12#TRPBF operates with a narrower input range (5V–20V) compared to the LA5797MC-BH (7.5V–28V). Applications requiring the full 28V input capability must evaluate alternative solutions
• Output Voltage: The LT1109CS8-12#TRPBF provides a fixed 12V output, whereas the LA5797MC-BH offers adjustable output from 7.5V to 28V. Fixed output operation may require circuit redesign
• Operating Temperature: The LT1109CS8-12#TRPBF operates from 0°C to 70°C, which is narrower than the LA5797MC-BH range of -25°C to 90°C. Applications requiring extended low-temperature operation must account for this limitation
• Regulatory Compliance: The LT1109CS8-12#TRPBF meets ROHS3 requirements, supporting modern regulatory frameworks

Frequently Asked Questions (FAQ)

Q: Can the LT1109CS8-12#TRPBF directly replace the LA5797MC-BH without circuit modifications?

A: Direct replacement is not possible due to output voltage differences. The LA5797MC-BH provides adjustable output (7.5V–28V), while the LT1109CS8-12#TRPBF delivers fixed 12V output. Circuit redesign is required if the application requires adjustable voltage or output voltages outside the 12V specification.

Q: Are the packages physically compatible?

A: Yes. Both devices use 8-SOIC (0.154", 3.90mm Width) surface mount packaging, ensuring identical PCB footprint compatibility and pin spacing.

Q: What are the input voltage limitations when substituting?

A: The LT1109CS8-12#TRPBF accepts input voltage from 5V to 20V. Applications requiring input voltages above 20V or below 5V cannot use this substitute without additional circuit modifications.

Q: Does the LT1109CS8-12#TRPBF meet environmental specifications for low-temperature applications?

A: The LT1109CS8-12#TRPBF operates from 0°C to 70°C. Applications requiring operation below 0°C or above 70°C must use alternative components, as the LA5797MC-BH supports -25°C to 90°C.

Q: What is the significance of the different topologies (Charge Pump vs. Boost)?

A: Both topologies perform step-up voltage conversion with positive output. The charge pump topology uses capacitive energy transfer, while the boost topology uses inductive energy transfer. Both achieve the same functional outcome in step-up applications with compatible electrical characteristics for this substitution.

Q: Is the LT1109CS8-12#TRPBF available in the same packaging format?

A: The LT1109CS8-12#TRPBF is supplied in Tape & Reel (TR) format, which is standard for production environments. The LA5797MC-BH packaging format was not specified in the original documentation.