Texas Instruments TPS65250RHA

Overview

TPS65250RHA from Texas Instruments is a triple-output synchronous buck converter IC with integrated high-side/low-side FETs, designed for xDSL/xPON modems and home gateways. It delivers 3 A (Buck 1), 2 A (Buck 2), and 2 A (Buck 3) across a 4.5–18 V input range, features a 0.8 V ±1% reference, adjustable 300 kHz–2.2 MHz switching frequency, and on-chip dying gasp storage/release circuitry optimized for 20 V storage voltage and 10.5 V release threshold.

For engineers reviewing the TPS65250RHA datasheet, TPS65250RHA pinout, TPS65250RHA application, or TPS65250RHA equivalent, this device supports precise power rail sequencing via independent EN/SS pins, current-limit tuning via external RLIM resistors, soft-start timing control with ceramic capacitors, and system-level dying gasp coordination through GASP and STRG terminals - all in a thermally enhanced 40-pin QFN (6 mm × 6 mm, RHA).

Technical Context

The TPS65250RHA integrates three current-mode controlled synchronous buck regulators with independent enable, soft-start, compensation, and current-limit configuration. Buck 1 uses lower R_DS(on) (95 mΩ HS / 50 mΩ LS) for high-current loads, while Bucks 2 and 3 share higher R_DS(on) (120 mΩ HS / 80 mΩ LS) and operate 180° out-of-phase with Buck 1 to minimize input ripple.

Its dedicated dying gasp circuit includes on-die charge control (IPRECHARGE_LIMIT = 0.1–0.15 A), storage voltage regulation up to 20.1 V, and dump-mode current limiting (ISTORAGE_LIMIT = 2–3 A), with GASP flag signaling active discharge to host processors. The low-power mode (LOW_P pin) reduces quiescent current from 20 mA to 1.5 mA when asserted.

Key Specifications

Pinout & Package

TPS65250RHA is housed in a 40-pin QFN package (6 mm × 6 mm, 0.4 mm pitch, RHA suffix), featuring an exposed thermal pad for enhanced heat dissipation. Pin numbering follows standard DCA layout with AGND/GND tie-down and power pad connected to system ground.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-buck PMIC applications.

Compared with TPS65250RHA, TPS65261RHBR omits dying gasp functionality but offers identical buck performance and lower unit cost, while MP8859GD-Z adds I²C flexibility at the expense of increased system complexity for backup operation.

Availability

TPS65250RHA is available at Aetrix Electronics and suitable for xDSL modems, home gateways, and wireless routers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for production programs.

Supply support for TPS65250RHA 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 and embedded processing technologies, with decades of expertise in power management ICs for communications infrastructure.

The TPS65250RHA belongs to TI's high-integration PMIC product line targeting broadband access equipment, engineered specifically to replace discrete DC/DC stages while adding system-level features like dying gasp coordination and low-power mode.

FAQ

What is the maximum storage voltage supported by the TPS65250RHA dying gasp circuit?

The TPS65250RHA supports a maximum storage voltage of 20.1 V ±5% on the STRG pin, as specified in the electrical characteristics table. This value is derived from the internal charge pump architecture and must remain below ~2×VIN – 1.5 V to ensure safe operation. The circuit actively regulates STRG to this target during precharge, enabling efficient energy accumulation for brownout hold-up without oversized capacitors.

How does the TPS65250RHA achieve input ripple reduction across its three buck converters?

The TPS65250RHA reduces input ripple by operating Buck 2 and Buck 3 in-phase with each other while running 180° out-of-phase with Buck 1. This interleaving minimizes net input current variation, allowing smaller input bulk capacitance and relaxed EMI filtering requirements. The phase relationship is fixed in silicon and requires no external configuration - it is inherent to the internal oscillator architecture.

Can the TPS65250RHA operate without external synchronization, and what is the frequency tolerance?

Yes, the TPS65250RHA operates autonomously using its internal oscillator when the SYNC pin is grounded. The switching frequency is set by an external resistor on the ROSC pin, with a typical accuracy of ±10% across temperature and process variation. For example, a 230 kΩ resistor yields ~800 kHz, and the full range spans 300 kHz to 2.2 MHz depending on ROSC value.

What is the role of the LOW_P pin on the TPS65250RHA, and how does it affect quiescent current?

The LOW_P pin on the TPS65250RHA enables a hardware-controlled low-power mode that reduces total quiescent current from 20 mA (normal operation) to 1.5 mA. When driven high (≥1.55 V), it disables non-essential bias circuits while maintaining regulation on all three outputs. This feature is critical for extending hold-up time in battery-backed or energy-harvesting gateway applications.

How is the current limit adjusted for each buck channel on the TPS65250RHA?

Each buck channel on the TPS65250RHA uses a dedicated RLIM pin (RLIM1–RLIM3) to set peak inductor current via an external resistor to ground. Buck 1 supports 1–4 A (75–300 kΩ), while Bucks 2 and 3 support 1–3 A (100–300 kΩ). The relationship is monotonic and documented in Figures 33–35 of the datasheet, enabling precise inductor selection based on saturation current.