Texas Instruments TPS25821DSSR

Overview

TPS25821DSSR from Texas Instruments is a USB Type-C 1.5-A source controller and integrated high-side power switch for Downstream Facing Port (DFP) applications. It monitors CC1/CC2 to detect sink attachment, advertises current capability (STD or 1.5 A), enables VBUS with 64-mΩ R_DS(on), and signals status via open-drain SINK, POL, and FAULT outputs. Designed for USB 2.0 host ports and data-less charging systems where VCONN is not required.

For engineers reviewing the TPS25821DSSR datasheet, TPS25821DSSR pinout, TPS25821DSSR application, or TPS25821DSSR equivalent, key selection considerations include its 1.7-A ±7% current limit accuracy, 1.5-µs overcurrent response, ±8-kV CC-line ESD rating, thermal shutdown thresholds at 135°C and 155°C, and WSON-12 package with exposed thermal pad.

Technical Context

The TPS25821DSSR implements USB Type-C Rel. 1.3-compliant DFP logic without VCONN support-distinguishing it from the TPS25820. It uses dual CC pins to detect sink attachment, determine cable orientation (via POL output), and broadcast current capability (controlled by CHG pin). Its internal 64-mΩ high-side MOSFET delivers up to 1.5 A with fast 1.5-µs overcurrent response and built-in discharge resistance (400–600 Ω) on OUT.

Operation relies on external 100-kΩ reference resistor on REF pin to set current-limit threshold. All status outputs (FAULT, SINK, POL) are open-drain and require pull-up to IN. The device draws only 1.0 µA typical quiescent current when no sink is attached, and supports UVLO (4.1 V nominal turn-on) and dual-stage thermal protection (135°C switch disable, 155°C full shutdown).

Key Specifications

Pinout & Package

TPS25821DSSR is housed in a 3.0 mm × 2.0 mm, 12-pin WSON package (DSS) with an exposed thermal pad on the bottom for enhanced heat dissipation. Pin numbering follows top-view layout with Pin 1 at top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB Type-C source controller applications.

Compared with TPS25820DSSR, TPS25821DSSR removes VCONN circuitry to reduce cost and complexity for USB 2.0-only designs; compared with TPS65987DQJ, it eliminates MCU, PD stack, and voltage regulation - delivering a lean, hardware-only solution for basic 1.5-A Type-C sourcing.

Availability

TPS25821DSSR is available at Aetrix Electronics and suitable for USB 2.0 host ports, compact wall chargers, and charging cradles requiring stable component supply, long-term lifecycle assurance, and full USB-IF compliance support.

Supply support for TPS25821DSSR 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 connectivity technologies with decades of USB interface expertise and broad automotive/industrial qualification.

The TPS258xx product line delivers highly integrated, standards-compliant USB Type-C source controllers targeting cost-sensitive, firmware-free DFP implementations in consumer, computing, and industrial equipment.

FAQ

What is the primary function of the TPS25821DSSR in a USB Type-C system?

The TPS25821DSSR serves as a fully autonomous USB Type-C Downstream Facing Port (DFP) source controller. It monitors CC1 and CC2 lines to detect sink attachment, advertises current capability (STD or 1.5 A) via CHG pin, enables VBUS through its integrated 64-mΩ high-side switch, and reports status via SINK, POL, and FAULT outputs - all without requiring firmware or external microcontroller intervention. This makes TPS25821DSSR ideal for fixed-function USB 2.0 host ports and data-less charging applications.

Does the TPS25821DSSR support VCONN power delivery?

No, the TPS25821DSSR does not support VCONN power delivery. Unlike the TPS25820DSSR, it omits the internal VCONN current-limiting switch and associated control logic. This design choice reduces cost and complexity for applications where VCONN is unnecessary - such as USB 2.0 host ports, wall chargers, and charging cradles that do not use electronically marked cables. The TPS25821DSSR remains fully compliant with USB Type-C Rel. 1.3 for DFP functionality excluding VCONN discharge requirements.

How does the TPS25821DSSR handle overcurrent conditions?

The TPS25821DSSR responds to overcurrent with a 1.5-µs typical current-limit activation time, holding output current at 1.7 A ±7% during sustained overload. If the condition persists, thermal protection engages: at 135°C, the VBUS switch disables while CC monitoring remains active; at 155°C, full shutdown occurs. The FAULT pin asserts low after a 5.6-ms deglitch period and remains asserted until the fault clears for 5.6 ms. This two-tiered response prevents false triggering while ensuring robust protection - a key design feature of the TPS25821DSSR.

What external components are required for basic operation of the TPS25821DSSR?

For basic operation, the TPS25821DSSR requires only three external components: a 100-kΩ ±0.5% resistor between REF and GND (to set current limit and discharge timing), a 100-kΩ pull-up resistor from FAULT to IN (for open-drain logic level translation), and appropriate decoupling capacitors (e.g., 1-µF ceramic near IN and OUT). No external FETs, gate drivers, or microcontrollers are needed - the TPS25821DSSR integrates all essential DFP control and power switching functions into a single WSON-12 package.

Can the TPS25821DSSR be used in USB Power Delivery (PD) systems?

No, the TPS25821DSSR is not a USB Power Delivery (PD) controller and does not support PD communication, variable voltage negotiation (e.g., 9 V, 15 V, 20 V), or dual-role port (DRP) functionality. It is designed exclusively for fixed 5-V USB Type-C source applications compliant with USB Type-C Rel. 1.3 - supporting only STD (500 mA/900 mA) and 1.5-A current advertisements on the CC line. For PD-capable systems, a dedicated PD controller such as the TPS65987DQJ is required; the TPS25821DSSR remains optimal for simpler, lower-cost 5-V-only implementations.