LP3966ESX-3.3 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP3966ESX-3.3 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 3.3V output at 3A in a TO-263 (DDPAK-5) surface mount package. This device is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement planning. The regulator integrates over-current, over-temperature, and short-circuit protection with an enable control feature, operating across the industrial temperature range of -40°C to 125°C.

Substiute Parts

LP3966ESX-3.3

Texas InstrumentsIn Stock: 2072LP3966ESX-3.3 Datasheet

Current PartRFQ

LP3853ESX-3.3/NOPB

Texas InstrumentsIn Stock: 10410LP3853ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3856ESX-3.3/NOPB

Texas InstrumentsIn Stock: 1489LP3856ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3873ESX-3.3/NOPB

Texas InstrumentsIn Stock: 1916LP3873ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3963ESX-3.3

Texas InstrumentsIn Stock: 1533LP3963ESX-3.3 Datasheet

Parametric EquivalentRFQ

LP3963ESX-3.3/NOPB

National SemiconductorIn Stock: 1478LP3963ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3966ESX-3.3/NOPB

National SemiconductorIn Stock: 2042LP3966ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP3966ESX-3.3 are identified based on strict electrical and mechanical parameter matching within the linear voltage regulator category. The substitution criteria are:

Primary Matching Parameters:

• Output voltage: 3.3V fixed
• Output current capability: 3A
• Maximum input voltage: 7V
• Package type: TO-263 (DDPAK-5) surface mount
• Protection features: Over-current, over-temperature, short-circuit protection
• Control feature: Enable function
• Operating temperature range: -40°C to 125°C

Secondary Considerations:

• Voltage dropout characteristics (1.2V @ 3A or lower)
• Quiescent current and supply current specifications
• Product status and RoHS compliance

All identified substitutes meet the primary electrical and mechanical requirements. Differences in quiescent current, dropout voltage, and product status are noted for engineering evaluation.

Parameter Comparison

Engineering Selection Recommendations

For Active Production Designs: LP3853ESX-3.3/NOPB and LP3856ESX-3.3/NOPB are preferred substitutes. Both are active products with ROHS3 compliance, lower quiescent current (4 mA vs. 9 mA), and improved dropout voltage performance (0.6V @ 3A vs. 1.2V @ 3A). These characteristics provide superior power efficiency and thermal performance in new designs.

For Dropout Voltage Matching: LP3873ESX-3.3/NOPB maintains the same 1.2V dropout specification as the original LP3966ESX-3.3, making it suitable for designs where dropout voltage is a critical constraint. This part is active and ROHS3 compliant.

For Compliance-Sensitive Applications: LP3853ESX-3.3/NOPB, LP3856ESX-3.3/NOPB, and LP3873ESX-3.3/NOPB all carry ROHS3 compliance certification, addressing regulatory requirements for new product development.

For Legacy System Support: LP3963ESX-3.3 and LP3963ESX-3.3/NOPB provide electrical equivalence with the original part. LP3963ESX-3.3 is designated Last Time Buy, indicating limited future availability. LP3966ESX-3.3/NOPB (National Semiconductor variant) maintains full parameter equivalence and is currently active.

Frequently Asked Questions (FAQ)

Q: Can LP3853ESX-3.3/NOPB or LP3856ESX-3.3/NOPB be used as direct replacements for LP3966ESX-3.3?

A: Yes, both parts are direct electrical and mechanical substitutes. They deliver the same 3.3V output at 3A in the identical TO-263 (DDPAK-5) package. The primary advantage is improved performance: lower quiescent current (4 mA vs. 9 mA) and reduced dropout voltage (0.6V @ 3A vs. 1.2V @ 3A). Both are active products with ROHS3 compliance.

Q: What is the difference between LP3853ESX-3.3/NOPB and LP3856ESX-3.3/NOPB?

A: Both parts are electrically and mechanically identical. The difference lies in packaging: LP3853ESX-3.3/NOPB is supplied in Cut Tape (CT) and Digi-Reel format, while LP3856ESX-3.3/NOPB is supplied in Tape & Reel (TR). Select based on procurement and assembly requirements.

Q: Why should I consider LP3873ESX-3.3/NOPB instead of LP3853ESX-3.3/NOPB?

A: LP3873ESX-3.3/NOPB matches the original dropout voltage specification (1.2V @ 3A) and quiescent current (9 mA). If your circuit design depends on these specific parameters, LP3873ESX-3.3/NOPB maintains full compatibility. However, LP3853ESX-3.3/NOPB offers superior efficiency with lower quiescent current and dropout voltage.

Q: Is LP3963ESX-3.3 still available for new designs?

A: LP3963ESX-3.3 is designated Last Time Buy, indicating limited future availability. For new designs, select from active products: LP3853ESX-3.3/NOPB, LP3856ESX-3.3/NOPB, or LP3873ESX-3.3/NOPB.

Q: What is the significance of the /NOPB suffix?

A: The /NOPB suffix indicates the part is supplied without plumbum (lead-free), meeting RoHS compliance requirements. Parts without this suffix may contain lead and are subject to different regulatory restrictions.

Q: Are all substitute parts pin-compatible with LP3966ESX-3.3?

A: Yes. All substitute parts use the TO-263 (DDPAK-5) package with identical pinout and thermal tab configuration, ensuring direct PCB compatibility without layout modifications.

Q: Which substitute offers the best power efficiency?

A: LP3853ESX-3.3/NOPB and LP3856ESX-3.3/NOPB provide the lowest quiescent current (4 mA) and dropout voltage (0.6V @ 3A), resulting in superior power efficiency compared to the original LP3966ESX-3.3 specification.