Texas Instruments TPS77733D

Overview

TPS77733D from Texas Instruments is a 3.3-V, 750-mA low-dropout (LDO) voltage regulator with integrated open-drain power-on reset (RESET) output and thermal shutdown protection. It features a typical dropout voltage of 260 mV at 750 mA, 85 µA quiescent current, ±2% output voltage tolerance over line/load/temperature, and stable operation with a 10-µF low-ESR output capacitor. It is used in battery-powered microcontroller systems requiring reliable undervoltage detection and clean power sequencing.

For engineers reviewing the TPS77733D datasheet, TPS77733D pinout, TPS77733D application, or TPS77733D equivalent, key selection considerations include its fixed 3.3-V output, SOIC-8 package with exposed thermal pad (D package), RESET timing (200 ms delay), PMOS pass element enabling ultra-low quiescent current independent of load, and compatibility with ceramic, tantalum, and aluminum electrolytic output capacitors (10 µF, 50 mΩ–1.5 Ω ESR).

Technical Context

The TPS77733D employs a PMOS pass transistor architecture that delivers low dropout voltage directly proportional to output current and maintains constant 85 µA quiescent current across 0–750 mA load range. Its internal 1.1834-V reference feeds a precision comparator monitoring regulated output for RESET assertion at 92–98% VO with 0.5% hysteresis.

It operates within −40°C to +125°C junction temperature range, supports input voltages from 4.3 V to 10 V (min VIN = VO + VDO), and integrates thermal shutdown (150°C trip) and current limiting (~1.7 A peak). The RESET output is open-drain, requiring external pull-up, and asserts low during undervoltage conditions after a guaranteed 200 ms timeout.

Key Specifications

Pinout & Package

TPS77733D is housed in an 8-pin SOIC (D) package with exposed thermal pad (GND/HSINK connection on underside). Pin 1 is GND; pins 3 and 4 are parallel IN inputs; pins 5 and 6 are parallel OUT outputs; pin 2 is active-low enable (EN); pin 7 is FB/NC (no connect for fixed-output version); pin 8 is open-drain RESET output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS77733D, TPS76733D offers lower cost but sacrifices integrated RESET and higher dropout, while MCP1703T-3302E/MB trades output current and supervision for extreme quiescent current reduction and smaller footprint - making TPS77733D optimal for 3.3-V MCU systems needing robust power sequencing in SOIC-8.

Availability

TPS77733D is available at Aetrix Electronics and suitable for industrial automation, portable medical devices, and automotive body electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for TPS77733D 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 technologies, with decades of expertise in high-reliability power solutions.

The TPS777xx family was designed specifically for battery-powered and thermally constrained applications demanding ultra-low quiescent current, precise undervoltage monitoring, and robust LDO performance across extended temperature ranges.

FAQ

What is the minimum input voltage required for TPS77733D to maintain regulation?

The minimum input voltage for TPS77733D is determined by its dropout voltage: at 750 mA load, it requires VIN ≥ 3.3 V + 260 mV = 3.56 V (typical). Per datasheet Section 6, the absolute minimum specified VIN is 4.3 V to ensure 2% output accuracy across temperature and line variations - this accounts for worst-case dropout and reference drift. Below 4.3 V, regulation may degrade but the device remains functional until dropout occurs.

Does TPS77733D require an external pull-up resistor on the RESET pin?

Yes, TPS77733D features an open-drain RESET output (pin 8), which must be pulled up externally to a valid logic-high voltage (e.g., 3.3 V or 5 V) using a resistor typically between 4.7 kΩ and 10 kΩ. Without this pull-up, the RESET signal cannot drive high and will remain undefined or float, preventing proper reset signaling to connected microcontrollers or supervisors.

Can TPS77733D operate without an output capacitor?

No, TPS77733D requires a minimum 10-µF output capacitor with ESR between 50 mΩ and 1.5 Ω for loop stability, as specified in the datasheet Application Information section. Omitting the capacitor or using one outside this ESR range risks oscillation, poor transient response, or thermal runaway. Ceramic, tantalum, and aluminum electrolytic types are all acceptable if they meet these criteria.

How does the ENABLE (EN) pin function on TPS77733D?

The EN pin (pin 2) is an active-low enable input: driving it low (≤0.9 V) activates regulation; driving it high (≥1.7 V) places TPS77733D in shutdown mode, reducing quiescent current to 1 µA. During shutdown, the output is high-impedance and RESET is deasserted (open-drain high). EN must never be left floating - tie to GND if unused.

Is TPS77733D pin-compatible with other members of the TPS777xx family?

Yes, all TPS777xx fixed-output variants (e.g., TPS77715D, TPS77718D, TPS77725D, TPS77733D) share identical SOIC-8 (D) package pinouts and electrical interface - only the output voltage differs. This allows direct substitution in existing layouts when changing output voltage requirements, provided input voltage and load current remain within each variant's specifications.