Texas Instruments TPS77515D

Overview

TPS77515D from Texas Instruments is a 1.5V fixed-output, 500mA low-dropout (LDO) voltage regulator with open-drain RESET output, PMOS pass element, 169mV typical dropout at 500mA, ±2% output accuracy over line/load/temperature, and 85µA typical quiescent current - used in FPGA core power, DSP I/O rails, and battery-powered microcontroller systems.

For engineers reviewing the TPS77515D datasheet, TPS77515D pinout, TPS77515D application, or TPS77515D equivalent, key selection criteria include RESET timing (200ms delay), thermal shutdown at 150°C, SOIC-8 package compatibility, and stability with 10µF low-ESR output capacitors.

Technical Context

The TPS77515D employs a PMOS pass transistor enabling ultralow, load-independent quiescent current (85µA typ) and dropout voltage directly proportional to output current. Its internal 1.183V reference feeds a precision error amplifier that regulates output via feedback sensing at the OUT pin for fixed versions.

RESET functionality uses an internal comparator monitoring VOUT against 92–98% of nominal voltage with 0.5% hysteresis and a fixed 200ms timeout delay after undervoltage detection - independent of EN control and active only during regulation.

Key Specifications

Pinout & Package

TPS77515D is housed in an 8-pin SOIC (D) package with exposed pad not present; thermal performance rated at 568mW at TA = +25°C, derating 5.68mW/°C above +25°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS77515DR, the TPS77515D offers identical regulation performance in tube packaging for flexibility in small-batch use; versus TPS7A4701RGWR, it trades noise performance for higher current and integrated RESET - making it optimal for digital system power where robust sequencing matters more than sub-µV noise.

Availability

TPS77515D is available at Aetrix Electronics and suitable for FPGA core power, DSP I/O supply, and battery-powered MCU systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for TPS77515D 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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets.

The TPS775xx family was engineered specifically for high-current, low-noise, RESET-enabled power management in space-constrained digital systems - emphasizing fast transient response, ultralow IQ, and robust thermal protection.

FAQ

What is the minimum input voltage required for stable operation of the TPS77515D?

The TPS77515D requires VIN ≥ VOUT + VDO, where VDO is 169mV typical at 500mA. Thus, minimum valid input is 1.5V + 0.169V = 1.669V. However, absolute minimum VIN is specified as 2.7V in the Electrical Characteristics table - meaning the device is not guaranteed to regulate below 2.7V even if dropout math suggests otherwise. Always maintain VIN ≥ 2.7V for full-spec compliance. The TPS77515D remains functional down to 1.669V but may exhibit degraded accuracy or transient response below 2.7V.

Does the TPS77515D require an external pullup resistor on the RESET pin?

Yes, the TPS77515D RESET pin is open-drain and requires an external pullup resistor to a valid logic-high voltage (e.g., 1.8V, 3.3V, or 5V). Typical values range from 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements. Without the pullup, RESET cannot assert a valid high state, breaking power-on reset functionality. The TPS77515D datasheet confirms this in the PIN DESCRIPTIONS table and Figure 24 application circuit.

Can the TPS77515D be used without connecting the EN pin?

Yes, the TPS77515D can operate with EN unconnected only if the application guarantees that the pin remains at a valid logic-low voltage (<0.9V) under all conditions - which is unsafe in noisy environments. TI recommends tying EN directly to GND for default-enable operation. Leaving EN floating risks unintended shutdown due to noise coupling, especially on PCBs with high dv/dt signals nearby. The TPS77515D's EN input leakage is ±1µA, so no current-limiting resistor is needed when grounding.

What output capacitor ESR range is supported by the TPS77515D?

The TPS77515D requires an output capacitor with ESR between 50mΩ and 1.5Ω for stable operation. This range supports common 10µF solid tantalum, aluminum electrolytic, and multilayer ceramic capacitors. Using ESR outside this window - especially below 50mΩ (e.g., some high-grade ceramics) - risks oscillation or poor transient response. The TPS77515D datasheet specifies this explicitly in the APPLICATION INFORMATION section and Figure 22 stability plots.

Is the TPS77515D pin-compatible with other members of the TPS775xx family?

Yes, all TPS775xx fixed-output variants (e.g., TPS77501D, TPS77533D) share identical SOIC-8 pinout, electrical interface, and thermal characteristics - differing only in output voltage and part marking. This allows direct substitution in existing layouts when changing output rails, provided input voltage headroom and load current remain within spec. The TPS77515D's pin mapping matches Table 1 in the datasheet exactly, confirming full mechanical and functional compatibility across the fixed-voltage series.