Texas Instruments TPS74901DRCRM3

Overview

TPS74901DRCRM3 from Texas Instruments is a 3A, ultra-low-dropout linear regulator with programmable soft-start, designed for high-accuracy point-of-load regulation in server and networking power rails. It supports adjustable output from 0.8V to 3.6V, operates with input as low as 0.8V (using VBIAS), delivers 1% output accuracy over line/load/temperature (new chip), and features an open-drain power-good signal for supply sequencing in multi-rail systems.

For engineers reviewing the TPS74901DRCRM3 datasheet, TPS74901DRCRM3 pinout, TPS74901DRCRM3 application, or TPS74901DRCRM3 equivalent, key selection criteria include its 120mV typical dropout at 3A, VSON-10 package thermal performance (RθJB = 19.5°C/W), stability with ≥2.2µF ceramic output capacitance, and compatibility with fast-transient FPGA/DSP core supplies requiring monotonic start-up and precise voltage tracking.

Technical Context

The TPS74901DRCRM3 uses an NMOS pass transistor architecture powered by a dedicated VBIAS rail (2.7–5.5V), enabling stable regulation at ultra-low VIN–VOUT differentials and eliminating capacitor-dependent loop compensation. Its internal 0.8V reference and precision error amplifier achieve ±0.3% typical output accuracy across –40°C to +125°C junction temperature.

Soft-start is implemented via external capacitor on the SS pin, generating a controlled, monotonic VOUT ramp; the PG output asserts high-impedance only when VOUT exceeds 90% of nominal and remains above thermal/UVLO thresholds. Enable logic includes 50mV hysteresis and 20µs deglitching to prevent false triggering during slow-ramping control signals.

Key Specifications

Pinout & Package

TPS74901DRCRM3 is housed in a 10-pin VSON package (3mm × 3mm × 1mm) with exposed thermal pad. The package requires soldering the thermal pad to a PCB ground plane for optimal thermal performance (RθJB = 19.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS74901DRCRM3, TPS74801DRCT trades programmability and monitoring for lower BOM count in fixed-rail designs, while TPS7A8300RGWR offers tighter accuracy at the expense of dropout performance and bias flexibility-making TPS74901DRCRM3 optimal for high-efficiency, multi-rail server core regulation with strict sequencing demands.

Availability

TPS74901DRCRM3 is available at Aetrix Electronics and suitable for network attached storage, rack servers, network interface cards, and merchant power supply auxiliary rails requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS74901DRCRM3 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 specializing in analog and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.

The TPS74901 product line targets high-performance, multi-rail server and networking infrastructure, delivering ultra-low-dropout regulation with programmable soft-start and sequencing capability for FPGA, ASIC, and CPU core supplies.

FAQ

What is the minimum input voltage required for TPS74901DRCRM3 to regulate 1.0V output?

The TPS74901DRCRM3 can regulate down to 0.8V output with VIN as low as 0.8V when VBIAS ≥ 2.7V is supplied. For 1.0V output, minimum VIN is 1.0V + VDO; with 120mV typical dropout at 3A, VIN ≥ 1.12V suffices. VBIAS must be ≥ VOUT + VDO(VBIAS) ≈ 1.0V + 1.45V = 2.45V (min 2.7V per spec), ensuring stable operation and fast transients.

Does TPS74901DRCRM3 require an external pull-up resistor on the PG pin?

Yes, TPS74901DRCRM3 requires an external pull-up resistor (10kΩ to 1MΩ) from PG to a supply ≤5.5V. The PG pin is open-drain and only drives low when VOUT falls below 90% of nominal or during shutdown. Without the pull-up, PG cannot assert high-impedance state, breaking sequencing functionality. TI recommends 100kΩ for noise immunity and fast rise time.

How does the VBIAS pin improve transient response in TPS74901DRCRM3?

The VBIAS pin powers the internal reference, error amplifier, and control circuitry independently of VIN. This decoupling prevents VIN droop during load transients from modulating the reference or control loop, resulting in faster recovery (typical <10µs) and reduced output deviation. In tests at 1A load step, VBIAS operation cuts undershoot by >40% versus VIN-only biasing.

Can TPS74901DRCRM3 operate without connecting the SS pin?

Yes, TPS74901DRCRM3 operates with SS pin floating, defaulting to ~100µs soft-start ramp time. However, leaving SS unconnected forfeits inrush current control and risks violating input capacitor surge ratings during cold start. For systems with >1000µF output capacitance or sensitive upstream converters, a 1nF–4.7nF capacitor on SS is strongly recommended to extend ramp time and limit peak inrush.

What thermal derating applies to TPS74901DRCRM3 at 85°C ambient temperature?

With RθJB = 19.5°C/W and max TJ = 125°C, TPS74901DRCRM3 supports full 3A output up to ambient temperatures where power dissipation stays within thermal limits. At 85°C ambient, max allowable power loss is (125–85)/19.5 ≈ 2.05W. For 1.2VOUT/3A operation (VDO ≈ 120mV), PLOSS = 0.36W - well within margin. No derating is needed below 100°C ambient with proper thermal pad soldering.