Texas Instruments TPS78625KTTR

Overview

TPS78625KTTR from Texas Instruments is a fixed-output 2.5 V, 1.5-A low-dropout linear regulator (LDO) in TO-263-5 (KTT) package, featuring 390 mV dropout at full load, 49 dB PSRR at 10 kHz, and 48 µV_RMS output noise with 0.1 µF NR capacitor - deployed in RF receiver power rails for VCO and ADC biasing.

For engineers reviewing the TPS78625KTTR datasheet, TPS78625KTTR pinout, TPS78625KTTR application, or TPS78625KTTR equivalent, key selection criteria include ultralow noise performance under 1.5-A load, fast 50-µs startup with NR capacitor optimization, thermal derating in TO-263 packages, and compatibility with 1-µF ceramic output capacitance.

Technical Context

The TPS78625KTTR uses a PMOS pass transistor architecture enabling low dropout and reverse-current protection via integrated back diode. Its internal 1.225-V bandgap reference feeds a precision error amplifier that drives the pass element with feedback from the NR/FB pin - configured as NR for fixed-output variants.

Stability is achieved with ≥1-µF ceramic output capacitance and optional 0.001–0.1-µF NR capacitor across the 250-kΩ internal resistor to suppress reference noise. Thermal shutdown activates at ~165°C; recovery occurs below ~140°C.

Key Specifications

Pinout & Package

TPS78625KTTR is housed in a TO-263-5 (KTT) thermally enhanced surface-mount package (10.16 mm × 8.42 mm), with exposed tab electrically connected to GND for optimal heat dissipation into PCB copper planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79625DRBR and LP3878MRX-2.5, the TPS78625KTTR uniquely delivers 48 µV_RMS noise with NR pin flexibility and robust 1.5-A load handling in a thermally optimized TO-263 package - making it the preferred choice for RF and precision analog biasing where noise and thermal margin are critical.

Availability

TPS78625KTTR is available at Aetrix Electronics and suitable for RF receiver power rails, VCO bias supplies, ADC reference buffers, and portable audio codec supplies requiring stable component supply and long-term industrial availability.

Supply support for TPS78625KTTR 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 company specializing in analog and embedded processing technologies, with leadership in power management ICs since the 1980s.

The TPS786 family was designed specifically for noise-sensitive RF and high-resolution analog applications - prioritizing ultralow output noise, high PSRR at RF frequencies, and fast transient response in compact thermally enhanced packages.

FAQ

What is the minimum input voltage required for TPS78625KTTR to regulate 2.5 V at 1.5 A?

The TPS78625KTTR requires a minimum input voltage of 2.89 V to maintain 2.5 V output at 1.5 A load, based on its typical 390-mV dropout voltage. At lower loads or ambient temperatures, dropout decreases - but design margin should assume worst-case 580 mV per datasheet max specification. Input below 2.7 V triggers UVLO shutdown.

Can TPS78625KTTR operate stably with less than 1 µF output capacitance?

No - the TPS78625KTTR requires a minimum of 1 µF ceramic output capacitance for loop stability across all operating conditions. Using smaller values risks oscillation, especially under load transients. The device is optimized for X5R/X7R ceramics with ≤10 mΩ ESR; tantalum or aluminum electrolytics are not recommended due to ESR and aging effects.

How does the NR pin affect startup time in TPS78625KTTR?

The NR pin's RC time constant (250 kΩ × C_NR) directly governs startup delay: with 0.001 µF, startup is ~50 µs; with 0.1 µF, it increases to ~110 µs. This trade-off between noise reduction and speed is intentional - the TPS78625KTTR achieves 48 µV_RMS noise only with ≥0.01 µF NR capacitance, and full spec compliance requires 0.1 µF.

Is the exposed tab of the TPS78625KTTR package electrically connected?

Yes - the exposed tab of the TPS78625KTTR's TO-263-5 (KTT) package is internally connected to the GND pin. It must be soldered to a dedicated PCB ground plane with ≥5×4 thermal vias to achieve the rated R_θJA = 40.7°C/W and prevent thermal shutdown under 1.5-A continuous load at elevated ambient temperatures.

Does TPS78625KTTR support reverse current flow from OUT to IN?

Yes - the TPS78625KTTR's PMOS pass transistor includes an intrinsic body diode that conducts from OUT to IN when V_IN falls below V_OUT, such as during power-down sequencing. This reverse conduction is not current-limited and can discharge output capacitors rapidly; external reverse-blocking circuitry may be needed in systems requiring controlled discharge.