Texas Instruments TPS7A7833PWPT

Overview

TPS7A7833PWPT from Texas Instruments is a 120-mA, non-isolated smart AC/DC linear voltage regulator with integrated 4:1 switched-capacitor stage and LDO. It delivers a fixed 3.3 V output from ≥18 V_RMS AC input (e.g., 120 V_RMS/60 Hz), achieves up to 75% efficiency, maintains 15 mW typical standby power, and provides power-fail detection (PFD) and power-good (PG) indicators. It targets electricity meters and tamper-resistant AC-powered sensors.

For engineers reviewing the TPS7A7833PWPT datasheet, TPS7A7833PWPT pinout, TPS7A7833PWPT application, or TPS7A7833PWPT equivalent, key selection considerations include its AC-input compatibility (full/half-bridge), 3.3 V fixed output accuracy (±1%), 120 mA load capability, thermal shutdown (162°C), and absence of external magnetics - critical for IEC 61000-4-8 compliance in metering.

Technical Context

The TPS7A7833PWPT integrates an actively clamped full/half-bridge rectifier, a 4:1 switched-capacitor charge pump (f_SC = 200 kHz), and a precision LDO. Its architecture reduces input current by 4× versus passive cap-drop, enabling smaller CS capacitors (as low as 1 µF) and minimizing shunt losses.

It supports dual supply modes: AC-input via AC+/AC− pins (with external CS/RS) or DC-input directly to SCIN (≥17 V for 3.3 V output). Power-fail detection uses resistor-divider–based analog threshold (V_{IT(PFD,FALLING)} = 1.17–1.25 V), while PG asserts when V_{LDO_OUT} exceeds 90.16–93.84% of nominal.

Key Specifications

Pinout & Package

TPS7A7833PWPT is housed in a 14-pin HTSSOP (PWP) package measuring 5.00 mm × 6.50 mm with exposed thermal pad. The package requires soldering the thermal pad to a large-area ground plane for optimal thermal performance (R_θJB = 24.2°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AC/DC linear regulator applications.

Compared with TPS7A7825PWPT and TPS7A7850PWPT, the TPS7A7833PWPT offers optimal balance for modern 3.3 V microcontrollers - delivering tighter regulation tolerance (±1%), lower quiescent current than 5 V variant, and broader compatibility with IoT radios and low-voltage sensors than the 2.5 V version.

Availability

TPS7A7833PWPT is available at Aetrix Electronics and suitable for electricity meters, smart thermostats, garage door controllers, and smoke detectors requiring stable component supply, long-term lifecycle support, and traceable sourcing for safety-critical deployments.

Supply support for TPS7A7833PWPT 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 conversion ICs.

The TPS7A78 family was designed specifically for non-isolated, magnetic-free AC/DC conversion in utility metering and building automation - prioritizing ultra-low standby power, IEC-compliant robustness, and simplified bill-of-materials.

FAQ

What is the minimum AC input voltage supported by the TPS7A7833PWPT?

The TPS7A7833PWPT requires a minimum AC input of 18 V_RMS to ensure reliable startup and regulation. This is enforced by the internal UVLO_SCIN circuit, which has a rising threshold of 17 V on the SCIN pin - corresponding to ≥18 V_RMS after rectification and clamping. Operation below this level may result in unstable output or failure to regulate. The TPS7A7833PWPT datasheet specifies this as a hard operating condition, not a recommendation.

Can the TPS7A7833PWPT operate from a DC source instead of AC?

Yes, the TPS7A7833PWPT supports DC-only operation via the SCIN pin, with a recommended input range of 17 V to 23 V for 3.3 V output. In this mode, the AC+ and AC− pins must be grounded, and the internal bridge rectifier is bypassed. The TPS7A7833PWPT maintains full regulation, power-good signaling, and thermal protection - making it ideal for DC backup or hybrid AC/DC systems.

How does the power-fail detection (PFD) pin work on the TPS7A7833PWPT?

The PFD pin on the TPS7A7833PWPT is an analog input that compares a resistor-divided VSCIN voltage against an internal 1.24 V reference. When the divided voltage falls below 1.17–1.25 V (V_{IT(PFD,FALLING)}), the open-drain PF pin pulls low. The TPS7A7833PWPT includes 110 mV hysteresis to prevent oscillation during marginal line conditions - a key differentiator from comparator-based alternatives.

What capacitor values are required for stable operation of the TPS7A7833PWPT?

The TPS7A7833PWPT requires four critical external capacitors: CSCIN ≥22 µF (bulk input), CSC1/CSC2 ≥1 µF each (X5R, 16 V and 10 V rated), and CLDO_OUT ≥0.68 µF (X5R, placed near LDO_OUT). These values are specified in the Recommended Operating Conditions table and validated across temperature and load. Using undersized or wrong-dielectric caps risks startup failure, ripple increase, or thermal instability.

Is the TPS7A7833PWPT pin-compatible with other variants in the TPS7A78 family?

Yes, all TPS7A78 variants - including TPS7A7825PWPT, TPS7A7833PWPT, and TPS7A7850PWPT - share identical 14-pin HTSSOP (PWP) packaging, pinout, and footprint. The only differences are output voltage and associated internal reference scaling; no PCB layout change is needed when migrating between them. This enables single-design flexibility across 2.5 V, 3.3 V, and 5.0 V system requirements.