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Texas Instruments TPS65251RHA
- Part No.:
- TPS65251RHA
- Manufacturer:
- Texas Instruments
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
TPS65251RHA.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 40VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,002
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Product details
Overview
TPS65251RHA from Texas Instruments is a triple-output synchronous step-down DC/DC converter IC with integrated high- and low-side MOSFETs, supporting 4.5 V to 18 V input, 0.8 V ±1% reference, 3 A continuous output on Buck 1, and 2 A on Bucks 2 and 3 - used in multi-rail power systems for set-top boxes and automotive infotainment.
For engineers reviewing the TPS65251RHA datasheet, TPS65251RHA pinout, TPS65251RHA application, or TPS65251RHA equivalent, key selection considerations include per-channel enable/soft-start control, adjustable current limit via RLIM pins, 300 kHz–2.2 MHz switching frequency setting, and 180° out-of-phase operation between Buck 1 and Buck 2 to reduce input ripple.
Technical Context
The TPS65251RHA implements peak current-mode control across all three buck channels, enabling stable loop compensation with simple RC networks on COMP pins and built-in slope compensation to prevent subharmonic oscillation. Each channel features independent feedback (FBx), soft-start (SSx), enable (ENx), and current-limit (RLIMx) pins for configurable sequencing and protection.
It supports dual operating modes: constant-frequency PWM (via ROSC resistor or SYNC pin) and light-load pulse-skipping mode (PSM) activated by pulling LOW_P high to V3V. Buck 1 operates 180° out of phase with Buck 2, while Buck 2 and Buck 3 run in phase - minimizing input capacitor RMS current and EMI in multi-output designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 18 V - supports 5 V, 9 V, 12 V, and 15 V intermediate bus systems without external pre-regulation. |
| Output Current (Buck 1) | 3 A continuous, 3.5 A peak - enables powering high-current SoCs or FPGAs from single-channel output. |
| Output Current (Bucks 2 & 3) | 2 A continuous, 2.5 A peak each - suitable for I/O rails, memory, and peripheral supplies. |
| Feedback Reference | 0.8 V ±1% - allows precise output regulation down to 0.8 V and scalable up to near VIN using resistor dividers. |
| Switching Frequency | 300 kHz to 2.2 MHz - adjustable via ROSC pin resistor or synchronized externally via SYNC pin for EMI reduction. |
| Thermal Resistance | RθJA = 30 °C/W - enables 3.5 W dissipation at ΔT = 105 °C with standard PCB layout and thermal pad grounding. |
| ESD Rating | ±2000 V HBM - meets industrial handling requirements without special ESD precautions during assembly. |
Pinout & Package
VQFN-40 (RHA) package, 6 mm × 6 mm, 0.4 mm pitch, with exposed thermal pad connected to GND - optimized for high-power density and thermal performance in space-constrained applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1, EN2, EN3 | Individual enable inputs | Active-high logic control with internal 1 µA pullup to V3V; adding capacitor enables programmable delayed startup (≈1.67 ms/nF). |
| SS1, SS2, SS3 | Soft-start charge nodes | 5 µA internal current source charges external capacitor; 4.7 nF yields ~1 ms soft-start time per channel. |
| RLIM1, RLIM2, RLIM3 | Current limit programming inputs | Resistor-to-GND sets peak inductor current: Buck 1 (1.2–5.5 A), Bucks 2/3 (1–4.4 A). |
| BST1, BST2, BST3 | Bootstrap supply terminals | Connect 47 nF ceramic capacitor to respective LX pin to generate gate drive voltage for integrated high-side FETs. |
| FB1, FB2, FB3 | Feedback inputs | Monitor output voltage via resistor divider; 0.8 V reference enables adjustable output from 0.8 V to near VIN. |
| PGOOD | Open-drain power-good indicator | Asserted high after all outputs reach ≥90% of target and 1 s reset timer expires; pulled low if any output drops below 85%. |
| SYNC | External clock synchronization input | Accepts 0.2–2.2 MHz external clock; ignored during startup; requires PGOOD assertion before sync lock. |
| ROSC | Oscillator frequency set input | Resistor-to-GND selects internal switching frequency (e.g., 230 kΩ → 800 kHz); used when SYNC is not active. |
Key Features
| Feature | Design Value |
|---|---|
| Triple synchronous buck with integrated FETs | Eliminates need for 6 external power MOSFETs and associated gate drivers - reduces BOM count and layout complexity. |
| Per-channel enable, soft-start, and current limit | Enables independent power sequencing, inrush control, and optimized inductor selection per rail - critical for FPGA/SoC boot integrity. |
| 180° out-of-phase Buck 1/Buck 2 operation | Reduces input capacitor RMS current by up to 30% compared to in-phase operation - lowers input cap size and cost. |
| Light-load pulse-skipping mode (PSM) | Reduces quiescent current from 20 mA to 1.5 mA when LOW_P = high - extends standby time in always-on consumer devices. |
| Integrated 3.3 V and 6.5 V LDOs (V3V/V7V) | Provides bias rails for MCU, logic, and enable circuitry - allows full shutdown of buck converters during deep sleep. |
Applications
| Set-Top Box Power Management | Automotive Infotainment System |
|---|---|
Use Scenario: Multi-rail power delivery for SoC core, DDR memory, and display interface in cable/satellite receivers. IC Role / Device Role / Timing Role: Primary PMIC supplying 1.2 V (core), 1.8 V (memory), and 3.3 V (I/O) rails with coordinated sequencing and PGOOD monitoring. Use Value: Single-chip solution eliminates discrete regulators and simplifies compliance with tight EMI limits via phase-shifted switching. |
Use Scenario: Powering head-unit processor, audio codec, and touch controller in 12 V automotive systems. IC Role / Device Role / Timing Role: High-input-voltage triple buck delivering 1.1 V (CPU), 2.5 V (audio), and 5 V (USB) with cold-crank tolerance down to 4.5 V. Use Value: Wide VIN range and hiccup-mode overcurrent protection ensure robust operation during load-dump and cranking events. |
| Blu-ray Disc Player | Security Camera DVR |
Use Scenario: Compact power system for laser diode driver, video decoder, and HDMI transmitter in optical disc players. IC Role / Device Role / Timing Role: Synchronous buck regulator providing 3.3 V (logic), 1.2 V (decoder), and 7.5 V (laser bias) with independent soft-start to avoid brownout during disc spin-up. Use Value: Adjustable current limit and per-rail enable allow dynamic power scaling during playback vs. standby states. |
Use Scenario: Outdoor IP camera with PoE-powered DVR requiring efficient multi-voltage conversion and thermal resilience. IC Role / Device Role / Timing Role: Triple buck supplying 1.8 V (sensor), 3.3 V (processor), and 5 V (network PHY) with thermal shutdown at 160 °C and 20 °C hysteresis. Use Value: Integrated thermal protection and low-power mode extend operational life in unventilated enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-buck power management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65261RSL | Higher input range (4.5–28 V), 3 A/2 A/2 A outputs, but no PSM mode and fixed 500 kHz/1 MHz options only. | Lacks light-load efficiency optimization; better suited for industrial systems where constant-frequency EMI control is prioritized over standby power. | Select TPS65261RSL when input voltage may exceed 18 V or deterministic EMI filtering is required over variable-frequency operation. |
| MP2451DT-LF-Z | Single-channel 3 A buck, 4.5–28 V input, no integrated sequencing or multi-rail coordination - requires external logic for multi-output use. | Not functionally equivalent: lacks triple-output architecture, PGOOD, or per-channel enable/soft-start - used only as building block in custom PMIC designs. | Choose MP2451DT-LF-Z only when designing modular power trees with independent control and higher VIN margin than TPS65251RHA supports. |
Compared with TPS65251RHA, TPS65261RSL offers extended input voltage and simpler frequency control but sacrifices light-load efficiency and flexible sequencing; MP2451DT-LF-Z provides higher VIN headroom but requires significant external circuitry to replicate even basic TPS65251RHA functionality.
Availability
TPS65251RHA is available at Aetrix Electronics and suitable for set-top box, automotive infotainment, and security camera DVR applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for TPS65251RHA 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 IC design and high-volume manufacturing.
The TPS65251RHA belongs to TI's multi-output DC/DC converter product line, engineered specifically for compact, high-efficiency power delivery in consumer and automotive multimedia systems with strict thermal and EMI constraints.
FAQ
What is the maximum input voltage rating for the TPS65251RHA?
The TPS65251RHA has an absolute maximum input voltage rating of 20 V on VIN, VIN1, VIN2, and VIN3 pins, with transient withstand capability up to 23 V for <10 ns pulses. Its recommended operating input range is 4.5 V to 18 V - making it suitable for 12 V automotive and industrial bus systems with cold-crank and load-dump margins.
How does the TPS65251RHA implement power sequencing between its three buck channels?
The TPS65251RHA enables independent power sequencing via dedicated EN1, EN2, and EN3 pins. Delayed startup is achieved by adding ceramic capacitors to these pins (≈1.67 ms delay per nF). The PGOOD pin asserts only after all three outputs reach ≥90% regulation and a 1-second reset timer expires - ensuring system-level power integrity before host processor release.
Can the TPS65251RHA operate in pulse-skipping mode, and how is it enabled?
Yes, the TPS65251RHA supports pulse-skipping mode (PSM) for improved light-load efficiency. It is enabled by connecting the LOW_P pin to V3V (3.3 V internal rail). In this mode, quiescent current drops from 20 mA to 1.5 mA, significantly reducing standby power - ideal for always-on consumer devices like set-top boxes and DVRs.
What is the purpose of the ROSC and SYNC pins on the TPS65251RHA?
The ROSC pin sets the internal oscillator frequency (300 kHz–2.2 MHz) via an external resistor to ground. The SYNC pin allows external clock synchronization within the same frequency range. SYNC is ignored during startup and only takes effect after PGOOD assertion - enabling deterministic EMI reduction in noise-sensitive systems without compromising startup reliability.
How is current limit configured for each buck channel in the TPS65251RHA?
Each buck channel (Buck 1, Buck 2, Buck 3) has a dedicated RLIM pin (RLIM1, RLIM2, RLIM3) that accepts an external resistor to ground. RLIM1 supports 75–300 kΩ (1.2–5.5 A limit), while RLIM2/RLIM3 accept 100–300 kΩ (1–4.4 A limit). This allows precise, per-rail current limiting to match inductor saturation ratings and optimize thermal design.
TPS65251RHA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 40-VFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 3
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 18V
- Current - Output:
- 3A, 2A
- Frequency - Switching:
- 300kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-VQFN (6x6)
TPS65251RHA FAQ
1.How can I place an order for TPS65251RHA through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65251RHA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TPS65251RHA reliable?
The price and inventory of TPS65251RHA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65251RHA is usually 5 days.
3.What payment methods are accepted for TPS65251RHA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65251RHA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65251RHA?
TPS65251RHA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65251RHA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TPS65251RHA?
For technical support, including TPS65251RHA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65251RHA requirements.
6.How does Aetrix verify that TPS65251RHA is sourced from the original manufacturer or authorized distributors?
All TPS65251RHA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TPS65251RHA meets industry standards.
7.What is the process for return or replacement of TPS65251RHA?
All TPS65251RHA units undergo pre-shipment inspection (PSI). If there is an issue with TPS65251RHA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TPS65251RHA part is unused and in its original packaging.
Return procedure for TPS65251RHA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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