Texas Instruments TPS77128DGKRG4

Overview

TPS77128DGKRG4 from Texas Instruments is a 2.8-V fixed-output, 150-mA low-dropout (LDO) voltage regulator with integrated open-drain power-on reset output, housed in an 8-pin MSOP (DGK) package. It delivers ultralow 92-µA quiescent current, 115-mV typical dropout at 150 mA (for 3.3-V variant; 2.8-V variant dropout is 150 mV at 150 mA), ±2% output voltage tolerance, and 55-µV_rms output noise without external bypass capacitor. It serves as a precision supply and supervisor for microcontroller core rails in portable instrumentation.

For engineers reviewing the TPS77128DGKRG4 datasheet, TPS77128DGKRG4 pinout, TPS77128DGKRG4 application, or TPS77128DGKRG4 equivalent, key selection considerations include its 220-ms reset delay timing, PMOS pass element architecture enabling load-independent quiescent current, compatibility with 1-µF low-ESR ceramic or 10-µF tantalum output capacitors, and thermal shutdown protection across –40°C to 125°C junction temperature.

Technical Context

The TPS77128DGKRG4 implements a PMOS-based LDO architecture where dropout voltage scales linearly with output current and quiescent current remains constant (92 µA typ) from 0 to 150 mA. Its internal voltage reference (1.1834 V) feeds a high-gain error amplifier that drives the PMOS pass transistor via a stable control loop optimized for fast transient response-demonstrated by <±15 mV load step recovery under 150-mA step changes.

It integrates a dedicated reset supervisor circuit monitoring the regulated output: RESET asserts low when V_OUT falls below 95% of nominal (2.66 V), releases after 220 ms once V_OUT rises above threshold, and features 0.5% hysteresis. The open-drain RESET pin requires an external pullup and supports TTL/CMOS logic interfacing.

Key Specifications

Pinout & Package

TPS77128DGKRG4 is packaged in an 8-pin MSOP (DGK) with exposed thermal pad (not electrically connected). Pin assignments are validated per TI SLVS225D datasheet Figure 1 (TPS771xx top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76328DBVR and TLV70228DBVR, the TPS77128DGKRG4 uniquely combines 150-mA capability, integrated 220-ms reset, and 92-µA IQ in an MSOP-8 footprint-making it the only option among the three that satisfies simultaneous high-current, supervision, and space-constrained requirements.

Availability

TPS77128DGKRG4 is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, wearables with BLE SoC, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for TPS77128DGKRG4 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 headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and logic devices for industrial, automotive, and personal electronics markets.

The TPS771xx family was engineered specifically for battery-powered and space-constrained applications demanding integrated power supervision, low-noise regulation, and high efficiency across wide temperature ranges.

FAQ

What is the maximum input voltage rating for the TPS77128DGKRG4?

The TPS77128DGKRG4 has an absolute maximum input voltage rating of 13.5 V. However, its recommended operating input voltage range is 2.7 V to 10 V. Exceeding 10 V may compromise reliability or violate thermal limits, especially at high ambient temperatures. Always ensure the input voltage remains within the recommended range during normal operation to maintain specified performance and lifetime for the TPS77128DGKRG4.

Does the TPS77128DGKRG4 require an external bypass capacitor for noise reduction?

No, the TPS77128DGKRG4 does not require an external bypass capacitor to achieve its specified 55-µV_rms output noise performance. This low-noise capability is inherent to its internal design and is verified across the 300-Hz to 100-kHz bandwidth with a 10-µF output capacitor. Adding an external bypass capacitor is unnecessary and may even destabilize the control loop if improperly implemented. The TPS77128DGKRG4 achieves this performance without added components, reducing BOM cost and PCB area.

How does the RESET pin on the TPS77128DGKRG4 behave during power-up and brownout conditions?

The RESET pin on the TPS77128DGKRG4 is an open-drain, active-low output. At power-up, RESET remains low until the output reaches 95% of 2.8 V (2.66 V), then stays low for a fixed 220-ms timeout before going high-impedance. During brownout, RESET asserts low again if V_OUT falls below 2.66 V. Hysteresis of 0.5% (≈14 mV) prevents chatter near the threshold. An external pullup resistor (e.g., 10 kΩ to V_CC) is mandatory for proper logic-level signaling in all operating modes of the TPS77128DGKRG4.

Can the TPS77128DGKRG4 operate with a 1-µF ceramic output capacitor?

Yes, the TPS77128DGKRG4 is stable with a 1-µF ceramic output capacitor, provided its ESR falls within the stability region defined in Figures 18 and 20 of the SLVS225D datasheet. For 1-µF ceramics, typical ESR is well below 100 mΩ, satisfying the requirement. This enables compact, low-cost designs-especially valuable in space-constrained applications like wearables. Larger 10-µF tantalum capacitors are also supported, offering additional margin for high-transient scenarios. Both options eliminate need for external compensation in the TPS77128DGKRG4 design.

What is the thermal shutdown threshold and recovery behavior of the TPS77128DGKRG4?

TPS77128DGKRG4 activates thermal shutdown at a junction temperature of 144°C, as specified in the Electrical Characteristics table. Once triggered, the device disables the pass transistor and halts output regulation until the junction temperature falls below the hysteresis threshold (typically ~130°C). During shutdown, quiescent current drops to ≤1 µA. This protection mechanism prevents permanent damage under sustained overload or poor heatsinking. Recovery is automatic and does not require cycling EN or input power-ensuring robust operation in thermally demanding environments for the TPS77128DGKRG4.