LP8345CDT-3.3/NOPB Equivalent & Substitute Parts

Part Overview

The LP8345CDT-3.3/NOPB is a linear voltage regulator IC from Texas Instruments designed to deliver a fixed 3.3V output at 500mA in a TO-252-3 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The device provides positive fixed output regulation with integrated over-current and over-temperature protection.

Substiute Parts

LP8345CDT-3.3/NOPB

Texas InstrumentsIn Stock: 1155LP8345CDT-3.3/NOPB Datasheet

Current PartRFQ

LP38691DT-3.3/NOPB

Texas InstrumentsIn Stock: 2954LP38691DT-3.3/NOPB Datasheet

MFR RecommendedRFQ

LF33CDT-TR

STMicroelectronicsIn Stock: 27804LF33CDT-TR Datasheet

MFR RecommendedRFQ

MIC5237-3.3YU

Microchip TechnologyIn Stock: 4039MIC5237-3.3YU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the LP8345CDT-3.3/NOPB is determined by the following critical parameters:

• Fixed output voltage of 3.3V
• Output current capability of 500mA
• Surface mount packaging compatible with TO-252-3 footprint
• Positive fixed output configuration
• Single regulator topology
• ROHS3 compliance

The three substitute parts listed below meet these core electrical and mechanical requirements. Variations in input voltage rating, dropout voltage, quiescent current, and operating temperature range are secondary parameters that may influence selection based on specific application constraints.

Parameter Comparison

Engineering Selection Recommendations

LP38691DT-3.3/NOPB is the primary substitute from Texas Instruments. It maintains the same manufacturer lineage and identical input voltage rating (10V max) as the original part. This device is in active production status and ROHS3 compliant. The dropout voltage increases marginally from 0.5V to 0.55V, and the operating temperature range extends to -40°C, providing broader environmental coverage.

LF33CDT-TR from STMicroelectronics is a direct functional equivalent with enhanced input voltage tolerance (16V max) and superior PSRR performance (80dB). It maintains the same TO-252-3 package footprint and includes both over-current and over-temperature protection. This part is in active production and ROHS3 compliant. The higher quiescent current (1 mA) may be a consideration in low-power applications.

MIC5237-3.3YU from Microchip Technology provides the highest level of protection with integrated reverse polarity protection in addition to over-current and over-temperature functions. It operates at 16V maximum input and features 75dB PSRR. The package is TO-263-4 (D2PAK), which differs from the TO-252-3 footprint of the original part and requires PCB layout modification. This part is in active production and ROHS3 compliant.

Frequently Asked Questions (FAQ)

Q: Can LP38691DT-3.3/NOPB be used as a direct replacement for LP8345CDT-3.3/NOPB?

A: Yes. Both parts share identical output voltage (3.3V), output current (500mA), input voltage rating (10V max), and TO-252-3 package. The LP38691DT-3.3/NOPB is in active production status, making it the recommended primary substitute.

Q: What is the difference between the TO-252-3 and TO-263-4 packages?

A: TO-252-3 (DPAK) and TO-263-4 (D2PAK) are different surface mount packages with different footprints and lead configurations. The MIC5237-3.3YU uses TO-263-4, requiring PCB redesign if substituting for the original TO-252-3 package. The LP38691DT-3.3/NOPB and LF33CDT-TR maintain the TO-252-3 footprint.

Q: Why does the LF33CDT-TR have a higher input voltage rating (16V vs 10V)?

A: The LF33CDT-TR from STMicroelectronics is designed with a higher maximum input voltage specification. This provides greater design margin in applications with variable input supplies but does not affect compatibility in circuits designed for 10V maximum input.

Q: What is the significance of the dropout voltage difference between these parts?

A: Dropout voltage determines the minimum input-to-output voltage differential required for regulation. The LP8345CDT-3.3/NOPB specifies 0.5V dropout, while substitutes range from 0.55V to 0.7V. In applications with tight input voltage margins, the lower dropout voltage of the original part may be preferred, but the differences are typically negligible in standard designs.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The LP38691DT-3.3/NOPB, LF33CDT-TR, and MIC5237-3.3YU are all ROHS3 compliant, matching the compliance status of the original LP8345CDT-3.3/NOPB.

Q: Which substitute offers the best performance for low-power applications?

A: The LP38691DT-3.3/NOPB maintains the lowest quiescent current specification at 55 µA, closely matching the original part's 50 µA. The LF33CDT-TR specifies 1 mA quiescent current, which may impact battery-powered designs. The MIC5237-3.3YU does not specify quiescent current in the provided data.

Q: Can MIC5237-3.3YU be used without PCB modification?

A: No. The MIC5237-3.3YU uses a TO-263-4 package, which has a different footprint than the TO-252-3 package of the original part. PCB layout modification is required for this substitution.