Texas Instruments TPS65231A2DCAR

Overview

TPS65231A2DCAR from Texas Instruments is a highly integrated power management IC (PMIC) for digital set-top boxes, featuring one adjustable PWM buck controller (3.3–6.1 V, 500 kHz), two synchronous step-down regulators (0.9–3.3 V, 1 MHz, 3-A each), dual 1-A USB power switches with overcurrent protection, and a dual-input supply voltage supervisor with brownout and thermal warning flags. It operates from a 10.8–22-V input and targets satellite STB and xDSL modem main power rails.

For engineers reviewing the TPS65231A2DCAR datasheet, TPS65231A2DCAR pinout, TPS65231A2DCAR application, or TPS65231A2DCAR equivalent, key selection considerations include its triple-buck architecture with independent enable sequencing, I²C/parallel control flexibility, integrated 1-A USB switches with fault flagging, and real-time thermal/brownout monitoring via open-drain nBOR/nHOT.

Technical Context

The TPS65231A2DCAR implements three independent voltage-mode DC-DC converters: BUCK1 is a high-voltage PWM controller with external FET drive (LDRV/HDRV), while BUCK2 and BUCK3 are fully integrated synchronous buck regulators with internal MOSFETs (R_DS(ON) = 32 mΩ low-side / 36 mΩ high-side), 1-MHz switching, and Type III compensation. All three support soft-start via shared SS pin and programmable current limiting using external TRIP resistor.

Control is configurable via parallel I/O (EN_BCKx, EN_USBx) or I²C interface (address selectable via I2C_ADD pin); I²C mode enables register-based fault status readback (STATUS1), dynamic output adjustment, and interrupt-driven diagnostics via USBFLAG2/nINT. The SVS monitors VMON1 (3.3-V rail) and VMON2 (user-scaled rail), asserting nRST ≥180 ms on undervoltage and pulling nBOR/nHOT low at VIN < 9.3 V or junction temperature ≥120 °C.

Key Specifications

Pinout & Package

TPS65231A2DCAR is housed in a 48-pin HTSSOP (DCA) package with exposed thermal pad, optimized for high-power density and efficient heat transfer in compact STB PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power management IC applications.

Compared with TPS65230A2DCAR, the TPS65231A2DCAR provides double USB current capacity (1 A vs. 0.5 A) for full-speed peripheral support, while TPS65217CZQW trades USB switching for battery management and analog functions-making it incompatible for mains-powered STB applications.

Availability

TPS65231A2DCAR is available at Aetrix Electronics and suitable for digital set-top box, xDSL modem, DVD player, home gateway, and wireless router applications requiring stable component supply, long-term lifecycle assurance, and consistent thermal performance across industrial temperature ranges.

Supply support for TPS65231A2DCAR 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 for consumer and communications infrastructure.

The TPS65231A2DCAR belongs to TI's dedicated power management IC family for broadband and digital entertainment systems, engineered to consolidate multiple voltage rails, USB power delivery, and intelligent supply monitoring into a single thermally robust package for cost-sensitive, high-volume STB and modem platforms.

FAQ

What is the maximum output current supported by each buck regulator in the TPS65231A2DCAR?

The TPS65231A2DCAR supports up to 3 A continuous output current on both BUCK2 and BUCK3 channels, with internal MOSFETs rated at 32 mΩ (low-side) and 36 mΩ (high-side). BUCK1 is a controller-only stage and requires external FETs; its current capability depends on the selected external components. All three buck stages include cycle-by-cycle overcurrent protection and hiccup-mode fault recovery.

How does the TPS65231A2DCAR handle power-up sequencing between its three buck regulators?

The TPS65231A2DCAR supports flexible power-up sequencing via EN_BCK1, EN_BCK2, and EN_BCK3 pins. When pulled directly to V3P3, regulators start in default order: BUCK1 → BUCK2 → BUCK3, with ≥2.5-ms minimum delay between ramps. Custom sequencing is achieved by adding RC networks to individual enable pins-each 1-nF capacitor introduces ~0.2-ms delay. In I²C mode, sequencing is controlled by writing to the ENABLE register with identical timing constraints.

Can the TPS65231A2DCAR be used without an I²C host controller?

Yes, the TPS65231A2DCAR operates fully in parallel I/O mode. When the USBFLAG2/nINT pin is pulled to ≤3.3 V, I²C is disabled and all functions-including BUCK enable/disable, USB switch control, and fault flagging-are managed solely through dedicated EN_ and FLAG pins. No I²C pull-ups, address configuration, or firmware driver is required for basic operation.

What is the purpose of the nBOR/nHOT pin on the TPS65231A2DCAR, and how does it behave?

The nBOR/nHOT pin on the TPS65231A2DCAR is an open-drain output that asserts low under two independent conditions: (1) brownout (VIN < 9.3 V) or (2) thermal warning (junction temperature ≥120 °C). It remains low for ≥180 ms after supply recovery or cooling, giving the host processor time to execute safe shutdown. Unlike the interrupt pin, nBOR/nHOT state is not cleared by I²C reads-it resets only when the underlying fault condition clears.

Does the TPS65231A2DCAR support ceramic output capacitors for all buck regulators?

Yes, the TPS65231A2DCAR's BUCK2 and BUCK3 regulators are designed for stability with ceramic output capacitors, requiring minimum 10 µF (BUCK2/BUCK3) and 22 µF (BUCK1) capacitance. Each uses Type III compensation and supports low-ESR ceramics (≤50 mΩ), reducing board area and eliminating electrolytic capacitor aging concerns. Layout guidelines recommend placing capacitors close to PHx and PGND pins to minimize loop inductance.