Texas Instruments TPS77450DGKR

Overview

TPS77450DGKR from Texas Instruments is a 5.0-V fixed-output, 250-mA low-dropout (LDO) voltage regulator with integrated open-drain power-good (PG) output, housed in an 8-pin MSOP (DGK) package. It delivers ultralow 92-µA quiescent current, 200-mV typical dropout at full load, ±2% output voltage tolerance over line/load/temperature, and 55-µV_rms output noise without external filtering - enabling stable, low-noise power for precision analog and battery-sensitive applications.

For engineers reviewing the TPS77450DGKR datasheet, TPS77450DGKR pinout, TPS77450DGKR application, or TPS77450DGKR equivalent, key selection criteria include its active-high PG function (82% trip threshold), PMOS pass element architecture, thermal shutdown protection, compatibility with 1-µF tantalum or 10-µF ceramic output capacitors, and support for fast transient response in compact space-constrained designs.

Technical Context

The TPS77450DGKR uses a PMOS pass transistor to achieve low dropout and load-independent quiescent current. Its internal 1.183-V reference feeds a high-gain error amplifier that drives the pass device, enabling tight regulation and fast load transient recovery (e.g., <1 mV droop under 250-mA step).

Power-good monitoring is implemented via a dedicated comparator comparing V_OUT against 82% of nominal output; PG asserts low when V_OUT falls below this threshold and releases after hysteresis (0.5% VO) and stabilization. The EN pin provides TTL-compatible active-low enable control, reducing quiescent current to ≤3 µA in shutdown.

Key Specifications

Pinout & Package

TPS77450DGKR is packaged in an 8-pin MSOP (DGK) with exposed thermal pad (not electrically connected). Pin functions are validated per TI SLVS281E Rev E (July 2001): pins 1–4 are FB/SENSE, PG, EN, GND; pins 5–6 are dual IN inputs; pins 7–8 are dual OUT outputs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS77450DGKR, TPS79550DBVR trades integrated PG for smaller footprint and lower cost, while MCP1825-5002E/DB offers double the current but requires redesign for enable logic and external supervision - making TPS77450DGKR optimal for space-constrained systems needing guaranteed power sequencing with minimal external components.

Availability

TPS77450DGKR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable medical sensors, automotive body control units, and test & measurement signal sources requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for TPS77450DGKR 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 power management ICs, with decades of expertise in high-reliability power regulation.

The TPS774xx family was designed specifically for battery-powered and space-constrained systems requiring precise, low-noise, sequenced 5-V (or other fixed) regulation with integrated power-good signaling - targeting portable instrumentation, industrial automation, and automotive sub-systems.

FAQ

What is the minimum input voltage required for stable operation of the TPS77450DGKR?

The minimum input voltage for the TPS77450DGKR is calculated as V_OUT + V_DO(max). With a 5.0-V output and maximum dropout of 330 mV (per datasheet Table 7), VI(min) = 5.33 V. However, the recommended operating condition specifies VI ≥ 6.0 V for 5.0-V output to ensure margin across temperature and load - confirmed in the "Recommended Operating Conditions" table on page 7 of SLVS281E.

Does the TPS77450DGKR require an external pullup resistor on the PG pin?

Yes, the TPS77450DGKR PG pin is an open-drain output and requires an external pullup resistor to a valid logic-high voltage (e.g., 3.3 V or 5 V). Typical values range from 10 kΩ to 100 kΩ. Without this resistor, PG cannot assert high-impedance state and will remain floating, preventing proper power-good detection in host systems.

Can the TPS77450DGKR operate with a 1-µF ceramic output capacitor?

No - the TPS77450DGKR requires either a 1-µF low-ESR tantalum capacitor or a ≥10-µF ceramic capacitor, as specified in Figures 18–21 of SLVS281E. A 1-µF ceramic typically has insufficient ESR and may cause instability; only 1-µF tantalum (with appropriate ESR range) or ≥10-µF X5R/X7R ceramic meets the stability criteria across temperature and load.

What is the thermal shutdown threshold of the TPS77450DGKR?

The TPS77450DGKR thermal shutdown junction temperature is 144°C, as specified in the Electrical Characteristics table (page 7, SLVS281E). Once triggered, the device shuts down until junction temperature falls below the hysteresis threshold (~130°C), then resumes regulation automatically - protecting against sustained overload or poor heatsinking conditions.

How does the power-good (PG) function behave during startup and brownout events?

At startup, PG remains low until V_OUT reaches 82% of 5.0 V (4.1 V), then transitions to high-impedance (open-drain pulled high by external resistor). During brownout, PG pulls low when V_OUT drops below 4.1 V and stays low until V_OUT recovers above 4.1 V plus 0.5% hysteresis (≈4.125 V), ensuring glitch-free sequencing - per timing diagram on page 5 of SLVS281E.