Renesas UPD121W25AT1F-E1-AT

Overview

UPD121W25AT1F-E1-AT from Renesas Electronics is a fixed-output 2.5 V, 1.5 A CMOS low-dropout linear regulator in TO-252 (MP-3ZK) package, featuring 1.0 V max dropout at full load, ±2.0% output voltage tolerance at 25°C, and integrated thermal shutdown and over-current protection. It powers large-scale ASICs in digital appliances requiring stable, low-noise local regulation.

For engineers reviewing the UPD121W25AT1F-E1-AT datasheet, UPD121W25AT1F-E1-AT pinout, UPD121W25AT1F-E1-AT application, or UPD121W25AT1F-E1-AT equivalent, key selection criteria include dropout voltage under 1.5 A load, standby current ≤1 μA, compatibility with ≥10 μF laminated ceramic output capacitors, and ON/OFF control interface timing behavior.

Technical Context

This regulator uses a CMOS pass transistor architecture with an internal reference voltage, error amplifier, and constant-current buffer to maintain tight output regulation across load and line variations. Its ON/OFF pin enables external logic-level control of output state, while the ADJ pin is internally tied off for fixed-voltage variants like UPD121W25AT1F-E1-AT.

Thermal shutdown activates when junction temperature exceeds 150°C, and over-current protection limits peak output to 1.0 A during fault conditions. The device operates within −40°C to +85°C ambient and supports input voltages from 3.5 V to 5.5 V for reliable 2.5 V output delivery.

Key Specifications

Pinout & Package

UPD121W25AT1F-E1-AT is housed in a 5-pin TO-252 (MP-3ZK) thermally enhanced surface-mount package with exposed GND fin (Pin 6). Pin 3 is cut and non-functional; Pin 4 is NC for fixed-output variants.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS7A4700RGWR and MCP1703T-2502E/MB, UPD121W25AT1F-E1-AT uniquely delivers 1.5 A at 2.5 V with integrated thermal and over-current protection in a thermally robust TO-252 package - making it suitable for high-power digital loads where reliability under transient stress is critical.

Availability

UPD121W25AT1F-E1-AT is available at Aetrix Electronics and suitable for digital appliance power supply, ASIC core voltage regulation, and portable media player subsystems requiring stable component supply with long-term lifecycle support.

Supply support for UPD121W25AT1F-E1-AT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a Japanese semiconductor manufacturer formed in 2010 through the merger of NEC Electronics and Renesas Technology, specializing in microcontrollers, analog power devices, and timing solutions.

The μPD121WxxA series was designed as a family of high-current CMOS LDO regulators targeting power delivery to large-scale ASICs and digital SoCs in consumer and industrial equipment.

FAQ

What is the minimum input voltage required for stable operation of UPD121W25AT1F-E1-AT?

The minimum input voltage for UPD121W25AT1F-E1-AT is 3.5 V under recommended operating conditions. This ensures the 1.0 V maximum dropout voltage margin maintains 2.5 V output regulation across full 1.5 A load and temperature range. Operation below 3.5 V risks dropout and output collapse, especially at elevated junction temperatures.

Does UPD121W25AT1F-E1-AT require an external resistor network for output voltage setting?

No, UPD121W25AT1F-E1-AT does not require external resistors. It is a fixed-output variant of the μPD121WxxA series with factory-trimmed 2.5 V regulation. Pin 4 (ADJ/NC) is internally disconnected and left unconnected in PCB layout - unlike the adjustable UPD121W00AT1F-E1-AT which requires R1/R2 feedback.

Can UPD121W25AT1F-E1-AT be used with ceramic output capacitors less than 10 μF?

No - the datasheet explicitly requires ≥10 μF laminated ceramic output capacitance for stable operation. Using smaller values risks oscillation due to insufficient phase margin, as confirmed by the ESR stability chart on page 6 of G18852EJ1V0DS. Film or tantalum alternatives are not recommended unless validated per application note G12702E.

What thermal derating applies to UPD121W25AT1F-E1-AT at 85°C ambient?

At TA = 85°C with no heatsink, the maximum continuous output current drops to approximately 0.9 A based on thermal resistance Rth(J-A) = 125°C/W and TJ(max) = 125°C. Derating follows the curve on page 10 of G18852EJ1V0DS; full 1.5 A is only sustainable with adequate PCB copper area or external heatsinking.

Is UPD121W25AT1F-E1-AT compliant with RoHS and lead-free assembly standards?

Yes, UPD121W25AT1F-E1-AT is Pb-free: the product documentation confirms no lead in external electrodes or other parts, and it supports infrared reflow up to 260°C peak temperature per JEDEC J-STD-020. The MP-3ZK package is qualified for lead-free soldering with rosin flux containing ≤0.2 wt% chlorine.