Texas Instruments TPS73633DRBT

Overview

TPS73633DRBT from Texas Instruments is a capacitor-free, NMOS-based low-dropout linear regulator delivering 3.3V at up to 400mA with 75mV typical dropout voltage, reverse current protection, and 30μVRMS output noise (10Hz–100kHz). It operates from 1.7V to 5.5V input and targets noise-sensitive analog circuitry such as VCOs in portable or post-regulation applications.

For engineers reviewing the TPS73633DRBT datasheet, TPS73633DRBT pinout, TPS73633DRBT application, or TPS73633DRBT equivalent, key selection criteria include ultra-low-noise operation without mandatory output capacitance, thermal shutdown/foldback current limiting, and compatibility with battery-powered systems requiring <1μA shutdown current and stable regulation across wide temperature (–40°C to 125°C) and load (0–400mA) ranges.

Technical Context

The TPS73633DRBT employs an NMOS pass transistor with integrated 4MHz charge pump to drive the gate above VOUT, enabling stable regulation down to 1.7V input while maintaining sub-200mV dropout at full load. Its voltage-follower topology eliminates output capacitor stability requirements and delivers near-constant ground pin current across output loads.

It features a dedicated noise-reduction (NR) pin-functionally tied to the internal bandgap reference-allowing external CNR capacitors (e.g., 0.01μF) to reduce output noise to ~8.5×VOUT μVRMS. Reverse leakage is limited to ≤10μA when EN is low and VIN ≤ VOUT, supporting robust power sequencing in multi-rail systems.

Key Specifications

Pinout & Package

The TPS73633DRBT is housed in an 8-pin VSON (DRB) package measuring 3mm × 3mm with exposed thermal pad, optimized for high-power-density PCB layouts and efficient heat dissipation via bottom-side copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LDR and TPS79933DRYR, the TPS73633DRBT uniquely combines capacitor-free operation, 30μVRMS noise, and 75mV dropout-making it irreplaceable for space-constrained, battery-powered analog systems demanding ultra-clean 3.3V rails without layout compromises.

Availability

TPS73633DRBT is available at Aetrix Electronics and suitable for wireless transceivers, portable medical sensors, FPGA I/O banks, and VCO bias supplies requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TPS73633DRBT 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, embedded processing, and power management technologies, with decades of LDO innovation focused on efficiency, precision, and reliability.

The TPS736 family was designed specifically for ultra-low-noise, capacitor-free regulation in portable and RF-intensive applications-emphasizing reverse current blocking, thermal robustness, and seamless integration into space-constrained PCBs.

FAQ

Does the TPS73633DRBT require an output capacitor to maintain stability?

No, the TPS73633DRBT is explicitly designed for capacitor-free operation due to its NMOS voltage-follower topology and internal compensation. Stability is guaranteed with zero output capacitance, though optional COUT improves transient response. This eliminates ESR sensitivity, aging effects, and board space requirements associated with traditional LDOs - a key advantage in miniaturized designs using the TPS73633DRBT.

What is the purpose of the NR pin on the TPS73633DRBT?

The NR (Noise Reduction) pin on the TPS73633DRBT connects directly to the internal bandgap reference node. Adding a capacitor (e.g., 0.01μF) from NR to GND forms a low-pass filter that reduces output noise by ~3.2× - lowering typical 30μVRMS to ~25μVRMS for 3.3V output. This feature is critical for powering VCOs, PLLs, or high-resolution ADCs where spectral purity is essential, and is unique to the TPS73633DRBT among TI's 400mA LDOs.

How does reverse current protection work in the TPS73633DRBT?

The TPS73633DRBT blocks reverse current flow from OUT to IN when the enable pin (EN) is driven low (<0.5V), limiting reverse leakage to ≤10μA across temperature. This is achieved via NMOS topology with controlled gate drive - unlike PMOS LDOs that rely on body diodes. The feature prevents backfeeding in multi-rail systems, protects upstream sources during hot-swap events, and ensures safe power sequencing in battery-backed applications using the TPS73633DRBT.

What thermal performance can be expected from the TPS73633DRBT in its DRB package?

In the 3mm × 3mm VSON (DRB) package, the TPS73633DRBT achieves RθJA = 49.4°C/W (new silicon) with JEDEC-standard 2×2 thermal via array to PCB ground. At 400mA load and 1.7V dropout, power dissipation is ~680mW - resulting in ~34°C junction rise above ambient. This enables reliable operation without heatsinks in compact industrial or medical enclosures, distinguishing the TPS73633DRBT from SOT-23 alternatives with >180°C/W thermal resistance.

Can the TPS73633DRBT be used with input voltages below 3.3V?

Yes - the TPS73633DRBT supports input voltages as low as 1.7V, but regulation requires VIN ≥ VOUT + VDO. With 75mV typical dropout, it maintains 3.3V output down to VIN = 3.375V. Below that, output follows input (dropout mode); however, operation below 3.375V is valid for brown-out detection or partial regulation. This flexibility makes the TPS73633DRBT suitable for Li-ion battery discharge profiles and hybrid power architectures where the TPS73633DRBT serves dual roles.