Texas Instruments TPS79433DCQRG4

Overview

TPS79433DCQRG4 from Texas Instruments is a 3.3 V fixed-output, 250 mA low-dropout linear regulator in SOT-223-6 package, featuring 145 mV typical dropout at full load, 64 dB PSRR at 10 kHz (new chip), and fast 500 µs start-up time. It delivers stable, low-noise power for noise-sensitive analog circuits in portable RF electronics and embedded systems.

For engineers reviewing the TPS79433DCQRG4 datasheet, TPS79433DCQRG4 pinout, TPS79433DCQRG4 application, or TPS79433DCQRG4 equivalent, key selection criteria include its fixed 3.3 V output, SOT-223 thermal performance (R_θJB = 25.3 °C/W), enable-controlled shutdown (<1 µA I_SHDN), and compatibility with ≥1 µF ceramic output capacitors.

Technical Context

The TPS79433DCQRG4 implements a PMOS pass transistor architecture with undervoltage lockout (UVLO) activation at 1.32–1.6 V and active discharge on disable via internal pulldown MOSFET. Its feedback loop is internally compensated for stability with ≥1 µF C_OUT, eliminating need for external compensation components.

It operates across –40°C to +125°C junction temperature, supports input voltages from 2.7 V to 5.5 V, and integrates foldback current limiting (320–460 mA I_CL, 175 mA I_SC) plus thermal shutdown at ~165°C with hysteresis.

Key Specifications

Pinout & Package

SOT-223-6 package (6.5 mm × 7.06 mm) with exposed thermal pad; optimized for PCB heat dissipation (R_θJB = 25.3 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79433DCQRG4, TPS79433DCQRG4 offers superior PSRR and noise performance versus MCP1703T-3302E/MB, and higher output current versus TPS79633DCQR - making it optimal for 250 mA, noise-critical, enable-controlled applications where thermal performance matters.

Availability

TPS79433DCQRG4 is available at Aetrix Electronics and suitable for smartphone baseband power, industrial sensor nodes, and home theater audio DAC applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TPS79433DCQRG4 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 and broad automotive/industrial qualification.

The TPS794 family targets noise-sensitive portable and embedded systems requiring fast transient response, low dropout, and integrated enable/UVLO - optimized for RF, audio, and precision analog signal chains.

FAQ

What is the minimum input voltage required for TPS79433DCQRG4 to regulate 3.3 V output?

The minimum input voltage is determined by the dropout voltage: V_IN(MIN) = V_OUT + V_DO. For TPS79433DCQRG4, typical dropout is 145 mV at 250 mA, so minimum input is 3.445 V. Absolute minimum VIN per spec is 2.7 V, but regulation only occurs above V_OUT + V_DO. The TPS79433DCQRG4 datasheet specifies V_IN ≥ 2.7 V, with functional regulation requiring VIN ≥ 3.445 V under full load.

Does TPS79433DCQRG4 require an external noise reduction capacitor?

No. The TPS79433DCQRG4 is a "new chip" revision and does not use the NR pin - it is internally disconnected (NC). Noise reduction is achieved via internal design and optional feed-forward capacitor (10–100 nF) between IN and OUT. External CNR is legacy-only; the TPS79433DCQRG4 achieves 33 µV_RMS noise with standard 10 nF C_FF and 10 µF C_OUT.

Can TPS79433DCQRG4 be used without the enable pin connected?

Yes. The EN pin is active-high and can be tied directly to IN for always-on operation. When left floating, the TPS79433DCQRG4 may behave unpredictably due to noise coupling; TI recommends either connecting EN to IN or using a pull-up resistor to IN. The TPS79433DCQRG4 draws <1 µA in shutdown, so enabling via EN is optional but recommended for power-gated systems.

What output capacitor value is required for stability with TPS79433DCQRG4?

The TPS79433DCQRG4 is stable with ≥1 µF ceramic output capacitance (minimum effective value). TI recommends 2.2 µF for best transient response, especially when using the optional feed-forward capacitor. The TPS79433DCQRG4 does not require ESR-based damping, and stability is maintained across 0.47–10 µF range per datasheet Section 5.3.

Is thermal pad connection mandatory for TPS79433DCQRG4 in SOT-223-6 package?

Yes. The thermal pad (exposed copper on bottom of SOT-223-6) must be soldered to a PCB copper pour for thermal performance. The TPS79433DCQRG4's R_θJB = 25.3 °C/W assumes proper thermal pad connection; omitting it degrades junction-to-board resistance by >30%, risking thermal shutdown under 250 mA load at elevated ambient temperatures. The TPS79433DCQRG4 datasheet explicitly states thermal pad connection is required for specified thermal metrics.