Texas Instruments TPS79401DCQRG4

Overview

TPS79401DCQRG4 from Texas Instruments is a 250mA low-dropout linear regulator in SOT-223-6 package, delivering fixed 1.225V output with ±3% accuracy, 155mV typical dropout at full load, and 60dB PSRR at 10kHz - optimized for noise-sensitive analog circuits in portable RF electronics and smart peripherals.

For engineers reviewing the TPS79401DCQRG4 datasheet, TPS79401DCQRG4 pinout, TPS79401DCQRG4 application, or TPS79401DCQRG4 equivalent, key selection criteria include its fast 500µs start-up (new chip), 71µVRMS output noise (new chip), UVLO threshold of 1.32–1.6V, and compatibility with 1µF minimum COUT ceramic capacitors.

Technical Context

The TPS79401DCQRG4 implements a PMOS pass transistor architecture with undervoltage lockout (UVLO) and active high enable control. It operates across –40°C to +125°C junction temperature, supports input voltages from 2.7V to 5.5V, and maintains regulation with only 1µF output capacitance - eliminating need for large bulk capacitors in space-constrained designs.

Its internal bandgap reference (1.225V nominal) feeds a precision error amplifier driving the pass element. The device features foldback current limiting (320–460mA ICL, 175mA ISC) and thermal shutdown at ~165°C, with active discharge on disable via internal pulldown MOSFET - critical for controlled power-down sequencing in battery-powered systems.

Key Specifications

Pinout & Package

SOT-223-6 package (6.5mm × 7.06mm), thermally enhanced with exposed pad; suitable for manual soldering and automated assembly on standard PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79401DCQRG4, TPS79401DCQ offers identical performance with simplified compliance, while TPS7A2012PDQNR trades pin compatibility and 250mA capability for extreme low-noise and ultra-low-IQ - making the TPS79401DCQRG4 optimal for cost-sensitive, medium-current, noise-critical applications where SOT-223 thermal performance is valued.

Availability

TPS79401DCQRG4 is available at Aetrix Electronics and suitable for smartphone baseband power, RF transceiver bias, industrial sensor signal chains, and USB-C peripheral power requiring stable component supply and long-term lifecycle support.

Supply support for TPS79401DCQRG4 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

Texas Instruments is a global semiconductor leader designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and personal electronics markets.

The TPS794 family targets noise-sensitive analog power domains - specifically engineered for portable RF electronics, high-resolution data acquisition, and fast-transient digital loads where PSRR, low dropout, and fast start-up are critical.

FAQ

What is the output voltage tolerance of the TPS79401DCQRG4?

The TPS79401DCQRG4 delivers a fixed 1.225V output with ±3% accuracy over temperature and load (–40°C to +125°C, 0–250mA). This corresponds to a guaranteed output range of 1.188V to 1.262V under recommended operating conditions, ensuring compatibility with 1.2V core logic and RF bias rails.

Does the TPS79401DCQRG4 require an external noise reduction capacitor?

No - the TPS79401DCQRG4 is the "new chip" variant and does not include a Noise Reduction (NR) pin. Its 71µVRMS output noise (100Hz–100kHz) is achieved without external CNR; legacy versions used NR pins, but this SOT-223 package uses optimized internal design for low noise without added components.

What is the minimum input voltage required for the TPS79401DCQRG4 to regulate 1.225V?

The minimum input voltage for the TPS79401DCQRG4 is determined by dropout: VIN(min) = VOUT + VDO = 1.225V + 155mV = 1.38V (typical). However, the absolute minimum specified VIN is 2.7V per datasheet - meaning the device enters UVLO below 1.32V and will not regulate until VIN exceeds ~1.45V in practice, depending on load and temperature.

Can the TPS79401DCQRG4 be used with a 1µF output capacitor?

Yes - the TPS79401DCQRG4 is stable with a minimum 1µF ceramic output capacitor (0.47µF effective capacitance). This is confirmed in Section 5.3 Recommended Operating Conditions and eliminates need for larger, less reliable tantalum or electrolytic capacitors - reducing cost and footprint in compact designs.

What protection features does the TPS79401DCQRG4 include?

The TPS79401DCQRG4 integrates undervoltage lockout (UVLO), foldback current limiting (320–460mA ICL), short-circuit protection (175mA ISC), thermal shutdown (~165°C), and active discharge on disable. These features protect against input brownout, output overload, PCB shorts, overheating, and uncontrolled power-down - enabling robust operation in unattended embedded systems.