Texas Instruments TPS71721DCKR

Overview

TPS71721DCKR from Texas Instruments is a fixed-output, low-noise, high-PSRR linear regulator delivering 2.1 V at up to 150 mA with 170 mV typical dropout, 30 µV_RMS output noise (100 Hz–100 kHz), and 70 dB PSRR at 1 kHz - designed for powering noise-sensitive analog and RF circuits in portable electronics.

For engineers reviewing the TPS71721DCKR datasheet, TPS71721DCKR pinout, TPS71721DCKR application, or TPS71721DCKR equivalent, key selection criteria include ultra-low ground current (45 µA typ), SC-70-5 package footprint, noise reduction capacitor support (0.01 µF NR pin), thermal shutdown (160°C), and guaranteed ±3% output accuracy over –40°C to 125°C.

Technical Context

The TPS71721DCKR uses a PMOS pass device with an advanced BiCMOS process to achieve fast startup, low noise, and excellent transient response. Its high-gain error amplifier enables 70 dB PSRR at 1 kHz and maintains stability with only 1 µF ceramic output capacitance.

It integrates undervoltage lockout (UVLO rising threshold 2.45 V), active-high enable with TTL/CMOS-compatible logic levels (VEN(high) ≥1.2 V), and internal current limiting (200–575 mA). The NR pin provides dedicated filtering of bandgap reference noise, reducing output spectral noise density by up to 8× when using 0.01 µF.

Key Specifications

Pinout & Package

TPS71721DCKR is housed in a 5-pin SC-70 (DCK) package measuring 2.00 mm × 1.25 mm, optimized for space-constrained portable PCBs. Thermal performance is characterized by R_θJA = 279.2°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS71721DCKR, TPS71722DCKR offers identical performance at 2.2 V and is pin-compatible, while TPS7A20215DCKR improves noise and I_Q but changes enable behavior and increases BOM cost - making TPS71721DCKR optimal for cost-sensitive, 2.1 V–specific legacy designs requiring proven reliability.

Availability

TPS71721DCKR is available at Aetrix Electronics and suitable for camera sensor power, mobile handset RF biasing, and wireless connectivity modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for TPS71721DCKR 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 LDO design expertise for high-reliability applications.

The TPS717 family targets portable, battery-powered systems demanding ultra-low noise, high PSRR, and minimal board area - specifically engineered for camera modules, smartphones, and wireless edge devices where power integrity directly impacts signal fidelity.

FAQ

What is the maximum input voltage rating for the TPS71721DCKR?

The TPS71721DCKR has an absolute maximum input voltage of 7 V, but its recommended operating range is 2.5 V to 6.5 V. Exceeding 6.5 V may trigger the internal undervoltage lockout or cause reliability degradation. For sustained operation, VIN should remain within the recommended range, especially under thermal stress or high load conditions.

Does the TPS71721DCKR require an external noise reduction capacitor?

Yes - the TPS71721DCKR uses the NR pin to achieve its specified 30 µV_RMS output noise. A 0.01 µF ceramic capacitor must be connected between NR and GND. Omitting it degrades noise performance to ~95×V_OUT µV_RMS. The quick-start circuit fully charges this capacitor within 135 µs, ensuring fast startup without compromising noise.

Can the TPS71721DCKR operate with zero output load?

Yes - the TPS71721DCKR remains stable and regulated with no output load due to its low-current mode circuitry, which maintains loop gain at near-zero current. This makes it suitable for applications like optical sensors or wake-on-interrupt circuits where the load is intermittently disconnected without risking oscillation or output overshoot.

What is the thermal shutdown behavior of the TPS71721DCKR?

The TPS71721DCKR activates thermal shutdown at approximately 160°C junction temperature and resets at ~140°C. During cycling, output is disabled until cooling occurs. Continuous thermal cycling indicates insufficient heatsinking or excessive power dissipation - design margin should keep T_J ≤125°C under worst-case load and ambient conditions to ensure long-term reliability.

Is the TPS71721DCKR pin-compatible with other variants in the TPS717 family?

Yes - all SC-70-5 packaged TPS717xxDCKR variants (e.g., TPS71718, TPS71725) share identical pinout and footprint. However, output voltage, NR pin functionality, and FB/NR pin assignment differ between fixed and adjustable versions. TPS71721DCKR is pin-compatible only with other fixed-output DCKR variants, not with TPS71701 (adjustable) or WSON-packaged versions.