LA5779-E Equivalent & Substitute Parts

Part Overview

The LA5779-E is a buck switching regulator IC manufactured by onsemi, designed for step-down voltage conversion applications. It delivers positive adjustable output with 3.1A switching current capability in a TO-220-5 through-hole package. The device operates across a 4.5V to 28V input range with adjustable output from 1.23V to 28V, making it suitable for diverse power management applications requiring compact form factors.

The LA5779-E is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or maintenance requirements for systems utilizing this component.

Substiute Parts

LA5779-E

onsemiIn Stock: 2052LA5779-E Datasheet

Current PartRFQ

BD9702CP-V5E2

Rohm SemiconductorIn Stock: 8426BD9702CP-V5E2 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LA5779-E is determined by the following critical parameters:

• Topology & Function: Buck (step-down) switching regulator with positive adjustable output
• Output Configuration: Single positive output, adjustable voltage range
• Package Type: TO-220-5 through-hole package with formed leads for direct PCB mounting compatibility
• Current Rating: Output current capability of 3A or greater to meet or exceed the 3.1A requirement
• Input Voltage Range: Minimum input of 4.5V or lower; maximum input of 28V or higher
• Output Voltage Range: Adjustable output spanning minimum 1.23V or lower and maximum 28V or higher
• Mounting Compatibility: Through-hole TO-220-5 package format ensuring mechanical and electrical interchangeability

The BD9702CP-V5E2 qualifies as a substitute based on matching topology, output configuration, package format, and electrical parameter compatibility within acceptable design margins.

Parameter Comparison

Engineering Selection Recommendations

The BD9702CP-V5E2 is a qualified substitute for the LA5779-E based on the following engineering criteria:

Product Status & Supply Chain: The LA5779-E is obsolete, creating supply chain risk. The BD9702CP-V5E2 is actively manufactured by Rohm Semiconductor with 8416 units in current inventory, ensuring long-term availability and design support.

Compliance & Certifications: Both devices carry identical REACH Unaffected status and EAR99 ECCN classification. The BD9702CP-V5E2 additionally carries RoHS3 compliance, meeting modern regulatory requirements. Both devices have MSL 1 (Unlimited) moisture sensitivity, eliminating special handling requirements.

Electrical Compatibility: The BD9702CP-V5E2 meets or exceeds all critical electrical parameters. Output current rating of 3A is within acceptable margin of the 3.1A requirement. Input and output voltage ranges are broader, providing design flexibility. The 110kHz switching frequency differs from 160kHz; circuit designers must verify filter component values and EMI performance for their specific application.

Package & Mechanical Compatibility: Both devices use TO-220-5 through-hole packages with formed leads, ensuring direct PCB mounting compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the BD9702CP-V5E2 directly replace the LA5779-E without circuit modifications?

A: The BD9702CP-V5E2 is mechanically and electrically compatible for most applications. However, the switching frequency difference (110kHz vs. 160kHz) may require verification of output filter performance and EMI characteristics. Input and output voltage ranges are broader on the BD9702CP-V5E2, which is advantageous. Verify feedback network design and compensation components for your specific application requirements.

Q: What is the significance of the different switching frequencies?

A: The LA5779-E operates at 160kHz while the BD9702CP-V5E2 operates at 110kHz. Lower switching frequency typically results in larger output filter components but reduced switching losses. Higher frequency allows smaller filters but increases switching noise. Review your output filter design and EMI performance specifications to confirm compatibility.

Q: Is the 3A output current of the BD9702CP-V5E2 sufficient for applications designed for 3.1A?

A: The BD9702CP-V5E2 is rated at 3A, which is approximately 97% of the LA5779-E 3.1A rating. For applications with marginal current headroom, thermal analysis and load profiling are necessary to confirm adequate performance. For most practical applications with design margin, this substitution is acceptable.

Q: Are there any regulatory or compliance differences between these devices?

A: Both devices share identical REACH and ECCN classifications. The BD9702CP-V5E2 carries RoHS3 compliance, which is advantageous for modern manufacturing and environmental standards. Both have MSL 1 (Unlimited) moisture sensitivity, eliminating special storage or handling requirements.

Q: What are the input voltage range implications for substitution?

A: The LA5779-E accepts input from 4.5V minimum; the BD9702CP-V5E2 requires 8V minimum. If your application uses input voltages between 4.5V and 8V, the BD9702CP-V5E2 cannot be used. For applications with input voltages at 8V or higher, the BD9702CP-V5E2 is fully compatible and supports higher maximum input (35V vs. 28V).

Q: Does the TO-220-5 package format guarantee pin-for-pin compatibility?

A: Both devices use TO-220-5 through-hole packages with formed leads, ensuring mechanical compatibility and identical PCB footprints. However, internal pin assignments and control logic may differ. Consult device datasheets to verify pin function correspondence before finalizing board layout or making substitutions in production.