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Texas Instruments TPS65251RHAR
- Part No.:
- TPS65251RHAR
- Manufacturer:
- Texas Instruments
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
TPS65251RHAR.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 40VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,976
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Product details
Overview
TPS65251RHAR from Texas Instruments is a triple-output synchronous step-down DC-DC converter IC with integrated high-side and low-side MOSFETs, designed for 4.5 V to 18 V input systems. It delivers continuous output currents of 3 A (Buck 1), 2 A (Buck 2), and 2 A (Buck 3), supports adjustable switching frequency from 300 kHz to 2.2 MHz, and features independent enable, soft-start, and current-limit pins per channel - used in automotive infotainment and set-top box power rails.
For engineers reviewing the TPS65251RHAR datasheet, TPS65251RHAR pinout, TPS65251RHAR application, or TPS65251RHAR equivalent, key selection considerations include per-channel current limit adjustability via RLIM resistors, 180° out-of-phase operation between Buck 1 and Buck 2/3 to reduce input ripple, PGOOD monitoring with 1-s reset delay, and compatibility with light-load pulse-skipping mode when LOW_P is tied to V3V.
Technical Context
The TPS65251RHAR 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 an internal 0.8 V reference with ±1% accuracy at 25°C and ±2% over full temperature and input range.
It integrates dual LDOs (3.3 V and ~6.5 V) for standby biasing, supports external synchronization via SYNC pin after PGOOD assertion, and employs 180° phase-shifted switching between Buck 1 and Buck 2/3 to minimize input capacitor RMS current. Thermal shutdown triggers at 160°C with 20°C hysteresis.
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 system rails without external pre-regulation. |
| Output Current (Cont.) | 3 A (Buck 1), 2 A (Buck 2), 2 A (Buck 3) - enables single-chip power for multi-rail SoC or FPGA applications. |
| Switching Frequency | 300 kHz to 2.2 MHz - adjustable via ROSC resistor or synchronized to external clock on SYNC pin. |
| Feedback Reference | 0.8 V ±1% at 25°C - sets output voltage via external resistor divider; enables precise regulation down to 0.8 V. |
| Current Limit Range | Buck 1: 1.2–5.5 A; Bucks 2/3: 1.0–4.4 A - configured by RLIMx-to-GND resistors for optimized inductor sizing. |
| Thermal Shutdown | 160°C trip, 20°C hysteresis - protects against sustained overload or poor PCB thermal design. |
| Powergood Delay | 1 s minimum reset period after all outputs reach 90% - ensures reliable system-level sequencing and reset timing. |
Pinout & Package
VQFN-40 (RHA) package, 6 mm × 6 mm, 0.4 mm pitch, with exposed thermal pad soldered to GND plane for enhanced thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1, EN2, EN3 | Independent enable inputs | Each controls startup timing; weak internal 1-µA pullup to V3V allows auto-enable if left floating. |
| 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 | Peak current limit programming | Resistor-to-GND sets channel-specific current limit; Buck 1 supports up to 5.5 A, Bucks 2/3 up to 4.4 A. |
| BST1, BST2, BST3 | Bootstrap supply inputs | Require 47 nF ceramic capacitor to LX pin to drive high-side FET gate; enables integrated synchronous rectification. |
| 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 | Asserts high only after all three outputs stabilize within 90% of target and 1 s reset timer expires. |
| SYNC | External clock synchronization input | Accepts 0.2–2.2 MHz square wave; ignored during startup; requires PGOOD assertion before sync lock. |
| LOW_P | Low-power mode control | Tie to V3V to enable pulse-skipping mode for improved light-load efficiency; tie to GND for fixed-frequency operation. |
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. |
| 180° out-of-phase Buck 1 vs Buck 2/3 | Reduces input capacitor RMS current by ~30%, allowing smaller 10-µF X7R ceramics instead of larger bulk capacitors. |
| Adjustable per-channel current limit | Enables optimization of inductor DCR and saturation rating - e.g., 4.7 µH inductors sized for 3.5 A peak on Buck 1. |
| Programmable soft-start per channel | Prevents inrush current during power-up; independent SS pins allow staggered rail sequencing for SoC compliance. |
| Integrated 3.3 V and ~6.5 V LDOs | Provide always-on bias for MCU, I²C logic, or PMIC control circuitry during deep sleep, improving system standby efficiency. |
Applications
| Automotive Infotainment | Set-Top Box Power System |
|---|---|
Use Scenario: Powering SoC core (1.2 V), DDR memory (1.35 V), and video processor (3.3 V) in head-unit systems. IC Role / Device Role / Timing Role: Primary multi-rail DC-DC controller delivering regulated, sequenced, and monitored voltages. Use Value: 180° phase shift lowers input ripple, reducing EMI filtering requirements in space-constrained automotive enclosures. |
Use Scenario: Supplying CPU (1.1 V), GPU (1.2 V), HDMI PHY (3.3 V), and audio codec (5 V) in digital TV platforms. IC Role / Device Role / Timing Role: Centralized power management IC with independent enable/soft-start for rail sequencing compliance. Use Value: Per-channel RLIM adjustment allows matching current capability to load demand - e.g., 3 A on CPU rail, 2 A on peripheral rails. |
| Blu-ray Disc Player | Security Camera DVR |
Use Scenario: Generating 1.2 V for ARM processor, 1.8 V for NAND flash, and 3.3 V for servo motor driver in optical disc drives. IC Role / Device Role / Timing Role: High-efficiency triple buck regulator with light-load PSM mode for burst-read operation. Use Value: Pulse-skipping mode (LOW_P = V3V) reduces quiescent current to 1.5 mA, extending standby battery life. |
Use Scenario: Powering image sensor (2.8 V), ISP (1.2 V), and network interface (3.3 V) in IP-based surveillance cameras. IC Role / Device Role / Timing Role: Compact, thermally robust power solution supporting wide 9–16 V automotive input range. Use Value: 160°C thermal shutdown with 20°C hysteresis prevents latch-up during prolonged high-temperature outdoor operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65261RHBR | Higher max input (28 V), 3-A/3-A/3-A outputs, no PSM mode, different pinout and compensation scheme. | Suitable for wider-input industrial systems but lacks light-load efficiency optimization. | Choose TPS65261RHBR only if >18 V input or symmetric 3-A loads are required; not drop-in compatible. |
| MP2451DT-LF-Z | Single-channel 3 A buck, 4.5–28 V input, no integrated sequencing or PGOOD; requires external components for multi-rail use. | Requires three separate ICs + coordination logic to replicate TPS65251RHAR functionality. | Select MP2451DT-LF-Z only for cost-sensitive, non-sequenced single-rail designs where integration is secondary. |
Compared with TPS65251RHAR, TPS65261RHBR offers higher input voltage tolerance but sacrifices light-load efficiency and pin compatibility, while MP2451DT-LF-Z provides no native multi-rail integration - making TPS65251RHAR optimal for compact, sequenced, and thermally constrained 4.5–18 V applications.
Availability
TPS65251RHAR is available at Aetrix Electronics and suitable for automotive infotainment, set-top box, Blu-ray player, security camera DVR, and digital TV applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for TPS65251RHAR 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 since 1930.
The TPS65251RHAR belongs to TI's high-current, multi-output PMIC product line, engineered specifically for space-constrained consumer and automotive applications demanding precise rail sequencing, low-light-load power loss, and robust thermal behavior.
FAQ
What is the maximum continuous output current per channel for the TPS65251RHAR?
The TPS65251RHAR supports 3 A continuous output current on Buck 1, and 2 A continuous on both Buck 2 and Buck 3. Peak current capability reaches 3.5 A (Buck 1) and 2.5 A (Bucks 2/3), verified under recommended operating conditions with proper thermal design. These ratings assume adequate PCB copper area and airflow per the RθJA = 30°C/W specification in the datasheet for the RHA package.
How does the TPS65251RHAR achieve reduced input ripple?
The TPS65251RHAR reduces input ripple by operating Buck 1 and Buck 2/3 180° out of phase - Buck 2 and Buck 3 run in phase, while Buck 1 is inverted. This interleaving minimizes net input capacitor current ripple, lowering RMS stress and enabling smaller 10-µF ceramic input capacitors. The effect is confirmed in the datasheet's typical characteristics and layout guidelines, and applies directly to the TPS65251RHAR without external circuitry.
Can the TPS65251RHAR operate in pulse-skipping mode, and how is it enabled?
Yes, the TPS65251RHAR supports pulse-skipping mode (PSM) for improved light-load efficiency. To enable it, connect the LOW_P pin to V3V (3.3 V internal LDO). When active, PSM reduces quiescent current to 1.5 mA and dynamically skips switching cycles under light load. This behavior is documented in Section 5 of the datasheet and applies specifically to the TPS65251RHAR; tying LOW_P to GND forces fixed-frequency operation.
What is the function of the RLIM pins on the TPS65251RHAR, and what resistor values are recommended?
The RLIM1, RLIM2, and RLIM3 pins on the TPS65251RHAR set the peak inductor current limit per channel via external resistors to GND. RLIM1 supports 75–300 kΩ (1.2–5.5 A), RLIM2/3 support 100–300 kΩ (1.0–4.4 A). For example, a 150-kΩ resistor on RLIM1 configures ~3.5 A current limit. These values are specified in Table 7-5 of the TPS65251RHAR datasheet and directly determine inductor saturation margin and fault protection threshold.
Does the TPS65251RHAR include internal LDOs, and what are their output voltages?
Yes, the TPS65251RHAR integrates two internal LDOs: V3V supplies 3.2–3.4 V (typ. 3.3 V) with 10 mA capability, and V7V supplies 5.63–6.88 V (typ. 6.25 V) also rated for 10 mA. Both are internally regulated and require external ceramic capacitors (3.3–10 µF for V3V, 10 µF for V7V). These LDOs power internal circuitry and can optionally bias external logic during system standby - a documented feature of the TPS65251RHAR.
TPS65251RHAR 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)
TPS65251RHAR FAQ
1.How can I place an order for TPS65251RHAR through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65251RHAR 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 TPS65251RHAR reliable?
The price and inventory of TPS65251RHAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65251RHAR is usually 5 days.
3.What payment methods are accepted for TPS65251RHAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65251RHAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65251RHAR?
TPS65251RHAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65251RHAR 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 TPS65251RHAR?
For technical support, including TPS65251RHAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65251RHAR requirements.
6.How does Aetrix verify that TPS65251RHAR is sourced from the original manufacturer or authorized distributors?
All TPS65251RHAR 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 TPS65251RHAR meets industry standards.
7.What is the process for return or replacement of TPS65251RHAR?
All TPS65251RHAR units undergo pre-shipment inspection (PSI). If there is an issue with TPS65251RHAR, 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 TPS65251RHAR part is unused and in its original packaging.
Return procedure for TPS65251RHAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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