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Texas Instruments TPS65251RHAT
- Part No.:
- TPS65251RHAT
- Manufacturer:
- Texas Instruments
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
TPS65251RHAT.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 40VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:966
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Product details
Overview
TPS65251RHAT 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 and delivering up to 3 A (Buck 1), 2 A (Buck 2), and 2 A (Buck 3) continuous output current. It features adjustable switching frequency (300 kHz–2.2 MHz), per-channel enable/soft-start/current-limit control, and power-good monitoring - used in multi-rail power systems for set-top boxes and automotive infotainment.
For engineers reviewing the TPS65251RHAT datasheet, TPS65251RHAT pinout, TPS65251RHAT application, or TPS65251RHAT equivalent, key selection considerations include channel-specific current limits (set via RLIM pins), 180° out-of-phase operation between Buck 1 and Buck 2/3 to reduce input ripple, PSM mode activation via LOW_P pin, and VQFN-40 (6 mm × 6 mm) thermal performance with RθJA = 30°C/W.
Technical Context
The TPS65251RHAT 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 uses independent feedback (FBx), soft-start (SSx), and current-limit (RLIMx) pins for system-level optimization.
It supports flexible timing architecture: internal oscillator frequency set by ROSC resistor or synchronized externally via SYNC pin after PGOOD assertion; Buck 1 operates 180° out of phase with Buck 2 and 3 (which run in phase), minimizing input capacitor RMS current. The device integrates two LDOs (V3V and V7V) for biasing and enables light-load efficiency via pulse-skipping mode when LOW_P is tied to V3V.
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 architectures without external pre-regulation. |
| Output Current (Cont.) | 3 A (Buck 1), 2 A (Buck 2), 2 A (Buck 3) - enables single-chip power for SoC + memory + peripheral rails in compact designs. |
| Switching Frequency | 300 kHz to 2.2 MHz - adjustable via ROSC resistor or external SYNC clock; allows trade-off between efficiency (lower fSW) and size (higher fSW). |
| Feedback Reference | 0.8 V ±1% - precise reference enables accurate output regulation down to 0.8 V with external resistor divider. |
| Thermal Resistance | RθJA = 30°C/W - validated for 6 mm × 6 mm VQFN package with standard PCB layout, supporting >2 W dissipation at ΔT = 60°C. |
| Current Limit Range | Buck 1: 1.2–5.5 A; Buck 2/3: 1–4.4 A - set via external RLIM resistors (75–300 kΩ), enabling inductor optimization for cost and size. |
| Power-Good Logic | Open-drain PGOOD with active-high polarity - asserts only after all three outputs reach ≥90% of target and 1 s reset timer expires. |
Pinout & Package
VQFN-40 (RHA) package, 6.00 mm × 6.00 mm body, 0.4 mm pitch, exposed thermal pad soldered to ground plane for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1, EN2, EN3 | Enable inputs (active-high) | Independent channel startup control; weak internal 1-µA pullup to V3V enables auto-enable if left floating. |
| SS1, SS2, SS3 | Soft-start timing inputs | 5 µA internal current source charges external capacitor; 4.7 nF yields ~1 ms soft-start time per channel. |
| RLIM1, RLIM2, RLIM3 | Peak current limit setting | Resistor-to-ground sets overcurrent threshold - Buck 1 supports higher current range than Buck 2/3. |
| BST1, BST2, BST3 | Bootstrap supply inputs | Connect 47 nF ceramic capacitor between BSTx and LXx to drive high-side FET gate above VIN. |
| FB1, FB2, FB3 | Feedback voltage inputs | Monitor output via resistor divider; 0.8 V reference enables precise regulation from 0.8 V to near VIN. |
| PGOOD | System power-good indicator | Open-drain output asserted only when all three outputs are within regulation and sequencing completed. |
| SYNC | External clock synchronization input | Accepts 0.2–2.2 MHz external clock; ignored during startup, active only after PGOOD assertion. |
| LOW_P | Low-power mode control | Active-high input enabling pulse-skipping mode (PSM) to reduce quiescent current to 1.5 mA under light load. |
Key Features
| Feature | Design Value |
|---|---|
| Triple synchronous buck with integrated FETs | Eliminates need for 6 external MOSFETs and associated gate drivers - reduces BOM count and layout complexity. |
| Per-channel enable, soft-start, and current limit | Enables precise power sequencing, inrush control, and inductor optimization - critical for multi-rail SoC applications. |
| 180° out-of-phase Buck 1 vs. Buck 2/3 | Reduces input ripple current by up to 50%, allowing smaller input capacitors and lower EMI filter cost. |
| Adjustable PSM mode | Quiescent current drops from 20 mA to 1.5 mA when LOW_P = high - extends standby time in always-on consumer devices. |
| V3V and V7V internal LDOs | Provide dedicated 3.3 V and ~6.5 V bias rails for MCU, logic, and analog circuitry - eliminates need for external LDOs. |
Applications
| Set-Top Box Power Management | Automotive Infotainment System |
|---|---|
|
Use Scenario: Powering main SoC core (1.2 V), DDR memory (1.5 V or 1.35 V), and HDMI PHY (3.3 V) from 12 V vehicle battery. IC Role / Device Role / Timing Role: Primary triple-rail PMIC delivering regulated, sequenced, and monitored voltages with hiccup-mode fault protection. Use Value: Single-chip solution replaces discrete buck controllers + external FETs, reducing board area by >35% and enabling ASIL-B compatible power sequencing. |
Use Scenario: Supplying processor, display interface, audio codec, and CAN transceiver in head-unit design with 9–16 V unregulated input. IC Role / Device Role / Timing Role: Central power management IC providing independent enable/soft-start for rail isolation and thermal derating during high ambient temperature. Use Value: 125°C junction rating and thermal shutdown with 20°C hysteresis ensure reliable operation in under-dash environments without forced cooling. |
| Blu-ray Disc Player | Security Camera DVR |
|
Use Scenario: Generating 1.1 V (CPU), 1.8 V (memory), and 3.3 V (optical drive motor control) from 12 V AC/DC adapter. IC Role / Device Role / Timing Role: High-efficiency multi-output regulator with PSM mode to meet Energy Star standby power requirements (<300 mW). Use Value: Pulse-skipping mode reduces no-load input current to 1.5 mA, meeting <0.5 W standby consumption targets without auxiliary flyback. |
Use Scenario: Powering image sensor, video encoder ASIC, and network PHY in outdoor IP camera with wide-input 12 V PoE or battery supply. IC Role / Device Role / Timing Role: Robust triple-buck converter with UVLO (4.22 V), OVP (109%), and hiccup-mode overload protection for field-deployed reliability. Use Value: Adjustable current limits (via RLIM) allow matching inductor saturation current to actual load profile - preventing false trips during motion-triggered burst loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-buck PMIC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65261-1RSLR | Higher max input (28 V), fixed 1.2/1.8/3.3 V outputs, no per-channel current limit adjustment. | Lacks RLIM/SS/EN flexibility; suited for fixed-voltage, cost-sensitive designs without sequencing needs. | Choose when output voltages are static and board space is constrained - but not for programmable rail tuning. |
| MP2451DT-LF-Z | Single-channel 3 A buck, 4.5–26 V input, no integrated sequencing or PGOOD - requires external logic for multi-rail use. | Requires three separate ICs + coordination circuitry to replicate TPS65251RHAT functionality. | Select only for incremental upgrades to existing single-rail layouts where adding channels is impractical. |
Compared with TPS65261-1RSLR and MP2451DT-LF-Z, the TPS65251RHAT uniquely delivers per-channel programmability (frequency, soft-start, current limit), integrated sequencing, and true triple-buck integration - making it optimal for new designs requiring flexibility, compactness, and robust power supervision.
Availability
TPS65251RHAT 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 TPS65251RHAT 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with over 90 years of innovation history.
The TPS65251RHAT belongs to TI's high-current, multi-rail PMIC product line designed specifically for consumer and automotive applications demanding compact, efficient, and highly configurable power solutions for SoC-based systems.
FAQ
What is the maximum continuous output current per channel for the TPS65251RHAT?
The TPS65251RHAT supports 3 A continuous output current on Buck 1, and 2 A continuous on both Buck 2 and Buck 3. These ratings assume proper thermal management using the exposed thermal pad and recommended PCB copper area. Peak currents reach 3.5 A (Buck 1) and 2.5 A (Buck 2/3), verified per electrical characteristics in the official datasheet SLVSAA4G.
How does the TPS65251RHAT achieve reduced input ripple in multi-buck configurations?
The TPS65251RHAT reduces input ripple by operating Buck 1 180° out of phase with Buck 2 and Buck 3 (which run in phase). This interleaving minimizes RMS input capacitor current - confirmed in the datasheet's Detailed Description section (8.3.3) and Typical Characteristics plots. The effect is most pronounced when channel loads are balanced, lowering required input capacitance and EMI filtering cost.
Can the TPS65251RHAT be synchronized to an external clock, and what are the timing constraints?
Yes, the TPS65251RHAT accepts external synchronization via the SYNC pin across 0.2–2.2 MHz. However, synchronization activates only after PGOOD is asserted - it is ignored during startup. The external clock must also exceed the internal oscillator frequency to reliably override it, as specified in Section 8.3.2 of the SLVSAA4G datasheet. For reliable lock, TI recommends keeping external clock duty cycle between 40% and 60%.
What is the function of the LOW_P pin on the TPS65251RHAT, and how does it affect efficiency?
The LOW_P pin on the TPS65251RHAT enables pulse-skipping mode (PSM) when pulled high to V3V. In PSM, the device skips switching cycles under light load, reducing quiescent current from 20 mA to 1.5 mA - directly improving standby efficiency. This behavior is documented in Section 5 and Figure 3 of the SLVSAA4G datasheet, and is factory-configurable for active-high polarity.
How is output voltage accuracy maintained across temperature and load for the TPS65251RHAT?
The TPS65251RHAT maintains output voltage accuracy via a precision 0.8 V ±1% internal reference (measured at TJ = 25°C) and ±2% total tolerance over full input (4.5–18 V), load (10–90% IOUT), and temperature (–40°C to 125°C) ranges. Line regulation is 0.5% VOUT and load regulation is 0.5% VOUT/A, as specified in Section 7.5 of SLVSAA4G - enabling stable rail generation without post-regulation.
TPS65251RHAT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 40-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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)
TPS65251RHAT FAQ
1.How can I place an order for TPS65251RHAT through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65251RHAT 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 TPS65251RHAT reliable?
The price and inventory of TPS65251RHAT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65251RHAT is usually 5 days.
3.What payment methods are accepted for TPS65251RHAT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65251RHAT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65251RHAT?
TPS65251RHAT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65251RHAT 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 TPS65251RHAT?
For technical support, including TPS65251RHAT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65251RHAT requirements.
6.How does Aetrix verify that TPS65251RHAT is sourced from the original manufacturer or authorized distributors?
All TPS65251RHAT 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 TPS65251RHAT meets industry standards.
7.What is the process for return or replacement of TPS65251RHAT?
All TPS65251RHAT units undergo pre-shipment inspection (PSI). If there is an issue with TPS65251RHAT, 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 TPS65251RHAT part is unused and in its original packaging.
Return procedure for TPS65251RHAT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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