Texas Instruments TPS79945YZUR

Overview

TPS79945YZUR from Texas Instruments is a 200-mA, low-quiescent-current (40 μA), ultralow-noise (10.5 × V_OUT μV_RMS), high-PSRR (66 dB @ 1 kHz) low-dropout linear regulator in a 5-bump DSBGA package (1.34 mm × 0.97 mm). It delivers a fixed 4.5 V output with ±2% accuracy over –40°C to +125°C and supports RF power stages, VCOs, and precision analog rails in space-constrained wireless systems.

For engineers reviewing the TPS79945YZUR datasheet, TPS79945YZUR pinout, TPS79945YZUR application, or TPS79945YZUR equivalent, this page provides verified electrical specifications, validated DSBGA pin functions, confirmed noise-reduction capacitor implementation guidance, and real-world transient response behavior for RF-sensitive designs requiring stable 4.5-V biasing under dynamic load conditions.

Technical Context

The TPS79945YZUR uses a PMOS pass element with an advanced BiCMOS process to achieve 100 mV typical dropout at 200 mA while maintaining high PSRR across 100 Hz–1 MHz. Its feedback loop incorporates a precision 1.193-V internal reference and active overshoot detection that engages a pulldown resistor if V_OUT exceeds nominal by >5%.

It features dedicated NR (noise reduction) pin functionality-bypassing the bandgap reference with a 0.01-μF capacitor reduces output noise to 10.5 × V_OUT μV_RMS (BW = 10 Hz–100 kHz)-and includes inrush current limiting triggered on EN toggle, ensuring controlled startup without output overshoot.

Key Specifications

Pinout & Package

TPS79945YZUR is housed in a 5-bump, die-sized ball grid array (DSBGA) package measuring 1.34 mm × 0.97 mm with 0.4-mm pitch. This ultra-compact, low-inductance package minimizes parasitic impedance for high-frequency noise suppression and suits ultra-thin mobile and wearable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79945DDCR, the YZUR variant offers superior thermal performance and smaller size for RF layout integrity; versus LP5907, it trades slightly higher base noise for design flexibility via NR pin, robust overshoot handling, and tighter PSRR-making it the preferred choice for signal-chain-critical 4.5-V regulation.

Availability

TPS79945YZUR is available at Aetrix Electronics and suitable for RF transceivers, wearable sensor hubs, industrial wireless nodes, and VCO biasing applications requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for TPS79945YZUR 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 innovation focused on power integrity and signal-chain performance.

The TPS799 family was engineered specifically for RF and precision analog systems demanding ultralow noise, high PSRR, and fast transient response in miniature packages-enabling next-generation wireless, sensing, and timing applications.

FAQ

What is the recommended noise reduction capacitor value for TPS79945YZUR?

The TPS79945YZUR datasheet specifies a 0.01-μF ceramic capacitor on the NR pin to achieve its rated 47.3 μV_RMS output noise (10 Hz–100 kHz). Using this value fully bypasses the internal bandgap reference, shifting dominant noise sources to the error amplifier and feedback divider-enabling predictable, low-noise performance for VCO and RF amplifier biasing in the TPS79945YZUR design.

Does TPS79945YZUR require an input capacitor for stability?

No, the TPS79945YZUR does not require an input capacitor for stability, but TI recommends a 0.1-μF to 1-μF low-ESR ceramic capacitor near the IN pin to improve source impedance, transient response, and high-frequency PSRR. This is especially valuable in noisy DC/DC-fed systems where the TPS79945YZUR supplies sensitive RF circuitry.

What is the maximum allowable input voltage for TPS79945YZUR?

The absolute maximum input voltage for TPS79945YZUR is 7.0 V, but the recommended operating range is 2.7 V to 6.5 V per the datasheet. For reliable 4.5-V output at 200 mA, minimum input must be ≥4.6 V (V_OUT + V_DO = 4.5 V + 100 mV), making 6.5 V the practical upper limit to maintain margin and thermal safety in the DSBGA package.

How does the enable pin (EN) function on TPS79945YZUR?

The EN pin on TPS79945YZUR is active-high with TTL/CMOS-compatible thresholds: driving EN ≥1.2 V enables regulation, while EN ≤0.4 V places the device in shutdown mode drawing only 150 nA. If unused, EN may be tied directly to IN. The TPS79945YZUR also implements inrush current limiting on EN toggle to prevent input rail sag during power-up sequences.

Can TPS79945YZUR operate without a load?

Yes, the TPS79945YZUR is stable with no output load, but its specified ±2% output accuracy requires a minimum load of 500 μA. Below this, output voltage may deviate beyond tolerance-particularly at high junction temperatures-so designs using light or intermittent loads should verify regulation accuracy across the full –40°C to +125°C range for the TPS79945YZUR.