RP111L331B-TR Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The RP111L331B-TR is an active linear voltage regulator IC manufactured by Nisshinbo Micro Devices Inc. This positive fixed output regulator delivers 500mA at 3.3V with a maximum dropout voltage of 0.32V at full load current. The device is housed in a 6-XFDFN exposed pad package and is designed for surface mount applications requiring low-noise, regulated power delivery in compact form factors.

Equivalent and substitute parts are identified to provide design flexibility, support supply chain continuity, and accommodate varying procurement requirements across manufacturing environments. Substitutes maintain functional equivalence within the specified electrical and mechanical parameters of this product category.

Substiute Parts

RP111L331B-TR

Nisshinbo Micro Devices Inc.In Stock: 658RP111L331B-TR Datasheet

Current PartRFQ

LD39050PU33R

STMicroelectronicsIn Stock: 8613LD39050PU33R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the RP111L331B-TR are identified based on strict equivalence across the following critical parameters:

Output Voltage & Current: Substitute parts must deliver a fixed 3.3V output at 500mA minimum current capacity.

Package Compatibility: Substitute parts must use 6-pin DFN surface mount packages with exposed pad configurations. The RP111L331B-TR uses 6-XFDFN (DFN1212-6) and acceptable substitutes use 6-VDFN (3x3) packages, both supporting identical pinout and thermal characteristics for direct board-level replacement.

Electrical Performance: Substitute parts must operate within the input voltage range, maintain acceptable dropout voltage performance, and provide equivalent or superior protection features (Over Current, Over Temperature).

Regulatory Compliance: Substitute parts must maintain RoHS compliance and active product status to ensure long-term availability and supply chain reliability.

Operating Temperature: Substitute parts must support the minimum operating range of -40°C to 85°C; extended temperature ranges are acceptable.

The LD39050PU33R from STMicroelectronics meets all substitution criteria and is classified as a direct functional equivalent.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: RP111L331B-TR

The RP111L331B-TR remains the primary component choice when Nisshinbo Micro Devices supply is available. This device is active, RoHS compliant, and delivers superior PSRR performance (75dB at 1kHz) and lower dropout voltage (0.32V), making it optimal for noise-sensitive applications.

Substitute Selection: LD39050PU33R

The LD39050PU33R from STMicroelectronics is a qualified substitute when RP111L331B-TR availability is constrained. This device is active and ROHS3 compliant, ensuring regulatory compliance and long-term supply continuity. The LD39050PU33R provides extended operating temperature range (-40°C to 125°C), lower quiescent current (50µA vs. 125µA), and enhanced protection features including short circuit protection and Power Good output. The slightly higher dropout voltage (0.4V vs. 0.32V) and lower PSRR (65dB ~ 62dB) are acceptable trade-offs in applications where these parameters are not critical design constraints.

Both devices use compatible 6-pin DFN surface mount packages with exposed pads, supporting direct board-level substitution without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the LD39050PU33R directly replace the RP111L331B-TR on the PCB?

A: Yes. Both devices use 6-pin DFN surface mount packages with exposed pad configurations. The pinout and thermal pad placement are compatible, allowing direct substitution without PCB layout changes.

Q: What are the key electrical differences between these parts?

A: The LD39050PU33R has a higher maximum input voltage (5.5V vs. 5.25V), slightly higher dropout voltage (0.4V vs. 0.32V at 500mA), lower quiescent current (50µA vs. 125µA), and lower PSRR (65dB ~ 62dB vs. 75dB at 1kHz). Both deliver identical 3.3V output at 500mA.

Q: Which part should I use for noise-sensitive applications?

A: The RP111L331B-TR is preferred for applications requiring superior noise rejection due to its higher PSRR (75dB at 1kHz) and lower dropout voltage. The LD39050PU33R is suitable for applications where PSRR performance above 62dB is acceptable.

Q: Are both parts RoHS compliant?

A: Yes. The RP111L331B-TR is RoHS compliant, and the LD39050PU33R is ROHS3 compliant. Both meet current regulatory requirements.

Q: What is the operating temperature difference?

A: The RP111L331B-TR operates from -40°C to 85°C. The LD39050PU33R extends the upper limit to 125°C, providing broader thermal operating range for high-temperature environments.

Q: Does the LD39050PU33R offer additional features?

A: Yes. The LD39050PU33R includes Power Good output and short circuit protection in addition to the over current and over temperature protection found in the RP111L331B-TR.

Q: What is the quiescent current difference and why does it matter?

A: The LD39050PU33R draws 50µA quiescent current compared to 125µA for the RP111L331B-TR. Lower quiescent current reduces standby power consumption, which is beneficial in battery-powered or always-on applications.

Q: Are both parts available in the same packaging format?

A: Both use 6-pin DFN surface mount packages with exposed pads. The RP111L331B-TR uses DFN1212-6 (6-XFDFN), and the LD39050PU33R uses 6-DFN (3x3) (6-VDFN). These packages are mechanically and electrically compatible for direct substitution.