Texas Instruments TPS71721DCKT

Overview

TPS71721DCKT from Texas Instruments is a fixed-output, 2.1 V, 150-mA low-dropout linear regulator in SC-70-5 package, featuring 70 dB PSRR at 1 kHz, 170 mV typical dropout at full load, and 30 µV_RMS output noise (100 Hz–100 kHz). It delivers stable power to noise-sensitive analog and RF circuits in space-constrained portable devices.

For engineers reviewing the TPS71721DCKT datasheet, TPS71721DCKT pinout, TPS71721DCKT application, or TPS71721DCKT equivalent, key selection criteria include ultra-low noise performance with optional NR capacitor support, high-bandwidth PSRR across 100 Hz–1 MHz, sub-200 mV dropout at 150 mA, ±3% output accuracy over temperature/load, and compatibility with 1-µF ceramic output capacitance.

Technical Context

The TPS71721DCKT employs a PMOS pass device and advanced BiCMOS process to achieve fast startup, low ground current (45 µA typical), and excellent transient response without requiring minimum load. Its error amplifier features high gain and bandwidth to sustain 70 dB PSRR at 1 kHz while maintaining stability with only 1 µF output capacitance.

A dedicated noise reduction (NR) pin enables external 0.01 µF capacitor connection to filter bandgap reference noise, reducing output noise to 30 µV_RMS; a quick-start circuit charges this capacitor within 160 µs. The device integrates undervoltage lockout (UVLO), thermal shutdown (160°C trip), and current limiting (≥200 mA) for robust system-level protection.

Key Specifications

Pinout & Package

TPS71721DCKT is housed in a 5-pin SC-70 (DCK) package measuring 2.00 mm × 1.25 mm, optimized for ultra-compact PCB layouts in mobile and wearable applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL71721PDBVR and MCP1702T-2102E/MB, the TPS71721DCKT uniquely balances 30 µV_RMS noise, 70 dB PSRR, 1 µF stability, and SC-70 footprint - making it optimal for space-constrained, noise-sensitive analog subsystems where both performance and size are critical.

Availability

TPS71721DCKT is available at Aetrix Electronics and suitable for camera sensor power, mobile phone baseband supplies, Bluetooth® audio codecs, and wearable health monitors requiring stable component supply across high-mix, low-volume production runs.

Supply support for TPS71721DCKT 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 connectivity technologies, with decades of LDO design expertise for portable and industrial applications.

The TPS717 family was engineered specifically for ultra-low-noise, high-PSRR power delivery in battery-powered RF and imaging systems - prioritizing small footprint, fast transient response, and minimal quiescent current without sacrificing regulation accuracy.

FAQ

What is the maximum input voltage rating for the TPS71721DCKT?

The TPS71721DCKT has an absolute maximum input voltage of 7 V, with recommended operating range from 2.5 V to 6.5 V. Exceeding 7 V risks permanent damage; operation above 6.5 V violates recommended conditions and may degrade PSRR or increase dropout voltage beyond specifications. The TPS71721DCKT must maintain VIN ≥ VOUT + VDO (≥2.27 V) to regulate properly.

Does the TPS71721DCKT require an external noise reduction capacitor to achieve its specified 30 µV_RMS output noise?

Yes - the TPS71721DCKT achieves 30 µV_RMS output noise (100 Hz–100 kHz) only when a 0.01 µF ceramic capacitor is connected between the NR pin and ground. Without this capacitor, noise rises to 95 × VOUT µV_RMS (≈200 µV_RMS for 2.1 V). The NR pin is high-impedance, so low-leakage ceramics are required; the quick-start circuit fully charges this capacitor in ~160 µs.

Can the TPS71721DCKT operate without any output load?

Yes - the TPS71721DCKT is explicitly designed to remain stable at 0 mA output current. Its low-current mode circuit boosts loop gain under no-load conditions, preventing output voltage drift or oscillation. This eliminates the need for dummy loads in always-on sensor or standby circuits, directly supporting ultra-low-power wearable and IoT designs using the TPS71721DCKT.

What thermal protection behavior does the TPS71721DCKT exhibit under overload conditions?

The TPS71721DCKT activates thermal shutdown at approximately 160°C junction temperature, disabling the output until junction temperature cools to ~140°C. This hysteresis prevents rapid cycling; however, sustained operation near thermal limit degrades reliability. For safe continuous use, keep T_J ≤125°C via proper PCB copper area or thermal vias - the DCK package has R_θJA = 279.2°C/W, requiring careful thermal design when delivering 150 mA at high ambient temperatures.

Is the TPS71721DCKT pin-compatible with other members of the TPS717 family?

Yes - all TPS717x DCK (SC-70-5) variants share identical pinout: Pin 1 = IN, Pin 2 = GND, Pin 3 = EN, Pin 4 = NR, Pin 5 = OUT. This allows drop-in replacement across output voltages (0.9 V to 5 V) without PCB changes. However, NR functionality applies only to fixed-output versions; adjustable variants (e.g., TPS71701) use Pin 4 as FB and require external resistor dividers instead of a noise capacitor.