Texas Instruments TLV74128PDQNR

Overview

TLV74128PDQNR from Texas Instruments is a 150-mA, low-dropout linear regulator (LDO) with foldback current limit, designed for power-sensitive portable electronics. It delivers fixed 2.8 V output with ±1% accuracy over –40°C to +125°C, 230 mV dropout at 150 mA, and 50 µA quiescent current - enabling stable operation with only 1-µF ceramic output capacitance in battery-powered MSP430 microcontroller supply rails.

For engineers reviewing the TLV74128PDQNR datasheet, TLV74128PDQNR pinout, TLV74128PDQNR application, or TLV74128PDQNR equivalent, key selection criteria include its active output discharge capability (P-version), UVLO behavior, thermal shutdown threshold (158°C), and compatibility with low-ESR ceramic capacitors in space-constrained SOT-23 and X2SON packages.

Technical Context

The TLV74128PDQNR employs a PMOS pass transistor architecture to achieve ultra-low dropout and inherent reverse-voltage protection via its body diode. Its internal foldback current limit reduces output current as VOUT collapses during short-circuit events, limiting typical short-circuit current to 40 mA while maintaining thermal cycling between 140°C reset and 158°C shutdown thresholds.

It integrates undervoltage lockout (UVLO) that disables regulation until VIN exceeds minimum operating voltage, and an active pulldown circuit (120 Ω to GND) on the OUT pin during shutdown - enabling rapid discharge of output capacitance without external components. EN pin logic is active-high with 0.9 V turn-on and 0.4 V turn-off thresholds.

Key Specifications

Pinout & Package

TLV74128PDQNR is packaged in a 4-pin X2SON (DQN) with 1.00 mm × 1.00 mm body size and exposed thermal pad electrically tied to GND - requiring PCB thermal pad connection for optimal power dissipation (RθJB = 174.7°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV74128PDQNR, TLV74228PDQNR trades protection and efficiency for higher current, while TPL7407LPDQNR is functionally unrelated - making TLV74128PDQNR the sole fit for compact, protected 2.8 V LDO applications demanding low IQ and active discharge.

Availability

TLV74128PDQNR is available at Aetrix Electronics and suitable for wearable sensor nodes, MSP430 microcontroller supplies, and portable audio DAC applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TLV74128PDQNR 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 company specializing in analog and embedded processing technologies, with leadership in power management ICs and low-power signal chain solutions.

The TLV741P family was engineered for battery-powered portable devices requiring ultra-low quiescent current, fast transient response, and integrated protection - targeting PDAs, handheld audio, WLAN cards, and microcontroller-based edge nodes.

FAQ

What is the output voltage tolerance of TLV74128PDQNR across temperature and load?

The TLV74128PDQNR provides ±1% DC output accuracy over –40°C to +125°C junction temperature and 0–150 mA load range. At TJ = 25°C, tolerance tightens to ±1%; over full temperature range, it remains within ±1.5% for VOUT ≥ 1.2 V - verified per Electrical Characteristics table in SBVS309A datasheet. This ensures reliable operation for precision analog and low-voltage logic rails.

Does TLV74128PDQNR support active output discharge, and how does it work?

Yes, TLV74128PDQNR includes active output discharge via an internal 120 Ω pulldown resistor connected between OUT and GND when EN is driven LOW. This feature rapidly discharges external output capacitance without requiring external MOSFETs or resistors. Discharge time depends on COUT and parallel load resistance, per τ = 120·RL/(120 + RL)·COUT - enabling clean power-down sequencing in portable systems.

What is the minimum input voltage required for TLV74128PDQNR to regulate 2.8 V at full load?

At 150 mA load and TJ = –40°C to +85°C, TLV74128PDQNR requires VIN ≥ 3.03 V to maintain regulation (2.8 V + 230 mV dropout). The absolute minimum input is 1.4 V, but regulation is only guaranteed above VOUT + VDO. Below that, the device enters dropout mode - where VOUT ≈ VIN – VDO - with degraded PSRR and transient response.

Can TLV74128PDQNR be used with ceramic capacitors smaller than 1 µF?

No - the TLV74128PDQNR is specified and characterized for stable operation with ≥1 µF ceramic output capacitance (X5R/X7R dielectric). Using smaller values risks instability, excessive overshoot/undershoot during load transients, and potential oscillation. Input capacitance of 0.1–1 µF is recommended but not mandatory for stability; output capacitance is mandatory at ≥1 µF.

How does the foldback current limit behave during a short-circuit event on TLV74128PDQNR?

During output short-circuit, TLV74128PDQNR's foldback current limit reduces output current as VOUT collapses - limiting typical short-circuit current to 40 mA. This prevents destructive power dissipation in the PMOS pass element. If thermal shutdown triggers (at ~158°C), the device cycles between current limit and cooldown (~140°C reset), protecting itself without external intervention.