My Inquiry
My Account
Texas Instruments TPS65251-3RHAR
- Part No.:
- TPS65251-3RHAR
- Manufacturer:
- Texas Instruments
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
TPS65251-3RHAR.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 40VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,458
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
TPS65251-3RHAR from Texas Instruments is a triple-output synchronous buck DC/DC converter IC for multi-rail power management in 4.5–18 V input systems. It integrates three high-current buck regulators (3 A/2 A/2 A continuous), supports 300 kHz–2.2 MHz adjustable switching frequency, features independent enable/soft-start/current-limit pins per channel, and delivers precise 0.8 V to VIN–1 V output regulation - used in automotive infotainment and broadcast video systems requiring tight sequencing and low-noise rail generation.
For engineers reviewing the TPS65251-3RHAR datasheet, TPS65251-3RHAR pinout, TPS65251-3RHAR application, or TPS65251-3RHAR equivalent, this page provides verified specifications, validated pin functions, confirmed thermal and electrical performance data, and real-world implementation context for multi-buck power architecture design.
Technical Context
The TPS65251-3RHAR implements peak current-mode control with integrated high-side and low-side MOSFETs per buck stage (RDS(on) = 95 mΩ/50 mΩ for Buck 1; 120 mΩ/80 mΩ for Buck 2 & 3), enabling fast transient response and simplified RC compensation. Its 180° out-of-phase operation between Buck 1 and Buck 2/3 reduces input ripple, while dedicated ROSC and SYNC pins allow either resistor-set autonomous oscillation or external clock synchronization.
Each buck channel includes independent ENx, SSx, RLIMx, FBx, and COMPx terminals, supporting programmable start-up sequencing, adjustable soft-start time (via 5 µA internal current source), and user-defined current limit (via external resistor). The device integrates two LDOs (3.3 V and 6.5 V) and a factory-configured active-high PGOOD with 256 ms reset delay specific to the -3 variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input voltage range | 4.5 V to 18 V - supports wide-range industrial and automotive supplies without pre-regulation |
| Buck 1 continuous current | 3 A - sufficient for main SoC core rails in set-top boxes and DTV platforms |
| Buck 2 & 3 continuous current | 2 A each - powers peripheral I/O, memory, and interface circuits |
| Switching frequency range | 300 kHz to 2.2 MHz - enables optimization of efficiency vs. size using 0.47–4.7 µH inductors |
| Output voltage range | 0.8 V to VIN – 1 V - supports 1.2 V, 1.8 V, 3.3 V, and 5 V rails via external resistor divider |
| PGOOD reset delay | 256 ms - factory-set timing for controlled system boot sequencing in broadcast video applications |
| Thermal resistance θJA | 32.7 °C/W - requires minimum 4-layer PCB with thermal pad grounding for full-load operation at 125°C ambient |
Pinout & Package
VQFN-40 (RHA) package, 6.0 mm × 6.0 mm body, 0.4 mm pitch, exposed thermal pad connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1 / EN2 / EN3 | Independent enable inputs | Active-high logic; weak internal 1-µA pull-up to V3V allows auto-enable; capacitor-to-ground adds ~1.67 ms/nF delay for sequencing |
| SS1 / SS2 / SS3 | Soft-start control inputs | 5 µA internal current source charges external capacitor; 4.7 nF yields ~1 ms ramp time per channel |
| RLIM1 / RLIM2 / RLIM3 | Current limit programming inputs | Resistor-to-ground sets peak inductor current: Buck 1 (100–300 kΩ → 3–3.5 A), Buck 2/3 (1.1–5.1 kΩ → 1.2–2.5 A) |
| FB1 / FB2 / FB3 | Feedback inputs | 0.8 V reference; connects to resistor divider for precise output voltage setting (±1% typical at 25°C) |
| PGOOD | Open-drain power-good output | Asserted high after all outputs reach ≥90% nominal and 256 ms reset timer expires; pulled low if any output drops ≤85% |
| ROSC | Oscillator frequency set | Resistor-to-ground selects switching frequency (e.g., 230 kΩ → 800 kHz); required even when SYNC is used |
| SYNC | External clock input | Accepts 0.2–2.2 MHz square wave; ignored during startup; synchronizes only after PGOOD assertion |
| BST1 / BST2 / BST3 | Bootstrap supply inputs | Connect 47 nF X7R ceramic capacitor between BSTx and corresponding LXx for high-side gate drive |
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 RMS input ripple by up to 40%, allowing smaller input capacitors and lower EMI filter cost |
| Independent per-channel enable and soft-start | Enables precise power-up sequencing across multiple voltage domains without external controllers |
| Adjustable current limit via RLIM pins | Permits optimization of inductor selection for cost, size, and thermal trade-offs in each rail |
| PFM/PWM auto-mode transition | Maintains <2% output ripple at light loads while improving standby efficiency over fixed-frequency operation |
| Integrated 3.3 V and 6.5 V LDOs | Provides always-on bias rails for MCU, I²C, and monitoring circuitry during buck converter sleep modes |
Applications
| Set-Top Box Power Management | Automotive Infotainment System |
|---|---|
Use Scenario: Multi-rail power delivery for SoC (1.2 V core), DDR memory (1.8 V), and HDMI PHY (3.3 V) in cable/satellite STBs. IC Role / Device Role / Timing Role: Primary PMIC providing sequenced, regulated, and monitored DC outputs with PGOOD-driven system reset. Use Value: Single-chip solution replaces discrete buck + LDO combinations, reducing board area by >35% and eliminating external sequencing logic. | Use Scenario: Powering head-unit display processor, audio codec, and CAN interface in 12 V automotive systems. IC Role / Device Role / Timing Role: Centralized buck regulator managing cold-crank tolerant 4.5–18 V input and delivering isolated, soft-started rails. Use Value: 256 ms PGOOD delay ensures stable microcontroller boot before peripheral initialization; built-in UVLO prevents brownout resets. |
| Digital Video Recorder (DVR) | Security Camera Processing Unit |
Use Scenario: Supplying dual-core ARM processor (1.1 V), image signal processor (1.8 V), and PoE interface (5 V) in DVR enclosures. IC Role / Device Role / Timing Role: High-efficiency triple-buck controller with thermal shutdown (160°C trip) and hiccup-mode fault recovery. Use Value: 32.7 °C/W θJA enables full 3 A/2 A/2 A load in compact enclosures; PFM mode extends battery backup runtime. | Use Scenario: Powering CMOS image sensor, video encoder ASIC, and IR LED driver in outdoor IP cameras. IC Role / Device Role / Timing Role: Sequenced power source with independent EN/SS pins ensuring clean sensor initialization before encoder activation. Use Value: Per-channel current limiting protects against short-circuited sensor rails; 180° phase shift minimizes conducted EMI on shared input traces. |
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 |
|---|---|---|---|
| TPS65251-1RHAR | Identical architecture and pinout; differs only in PGOOD reset delay (1000 ms vs. 256 ms) | Suitable for systems requiring longer power-good hold-off before firmware execution | Select when extended system reset window is needed for FPGA configuration or bootloader handoff |
| TPS65251-2RHAR | Same silicon and package; PGOOD reset delay is 32 ms (vs. 256 ms for -3) | Better suited for fast-boot consumer electronics where minimal boot latency is critical | Choose for portable media players or streaming sticks needing rapid wake-from-sleep response |
Compared with TPS65251-1RHAR and TPS65251-2RHAR, the TPS65251-3RHAR offers a mid-range 256 ms PGOOD assertion delay - balancing robust power sequencing against boot speed, making it optimal for broadcast video and automotive infotainment where deterministic timing is required but not ultra-fast.
Availability
TPS65251-3RHAR is available at Aetrix Electronics and suitable for set-top box, automotive infotainment, and digital video recorder applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for TPS65251-3RHAR 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 automotive-grade reliability validation.
The TPS65251 family is engineered for multi-rail consumer and automotive power systems - delivering high-current, low-noise, and thermally robust DC/DC conversion in compact QFN packages with flexible sequencing and protection features.
FAQ
What is the PGOOD reset delay timing for TPS65251-3RHAR?
The TPS65251-3RHAR has a factory-configured PGOOD reset delay of 256 ms. This timing begins after all three buck outputs reach ≥90% of their nominal voltages and remains asserted until the delay expires. It is distinct from the TPS65251-1RHAR (1000 ms) and TPS65251-2RHAR (32 ms) variants. The 256 ms value is fixed and non-adjustable in the TPS65251-3RHAR.
Can TPS65251-3RHAR operate with input voltage below 4.5 V?
No. The TPS65251-3RHAR has a guaranteed operating input range of 4.5 V to 18 V. Its VIN undervoltage lockout (UVLO) activates at 4.1 V (falling) and releases at 4.22 V (rising), with 110 µs deglitch. Operation below 4.5 V violates recommended conditions and may cause unstable regulation or unmonitored shutdown. For sub-4.5 V systems, consider TI's TPS65261 or similar low-input PMICs.
How is the switching frequency set on TPS65251-3RHAR?
The switching frequency of TPS65251-3RHAR is set using an external resistor connected from the ROSC pin to GND. A 230 kΩ resistor yields 800 kHz; values from 50 kΩ to 600 kΩ support 0.3–2.2 MHz. Even when using the SYNC pin for external clock synchronization, the ROSC resistor must be installed and set to ~70% of the sync frequency to ensure oscillator stability during sync loss events.
Does TPS65251-3RHAR support pre-biased output startup?
Yes. The TPS65251-3RHAR supports pre-biased output startup - its current-mode control architecture and internal soft-start circuitry prevent reverse current flow during startup into pre-charged outputs. This capability is confirmed in the functional description and timing diagrams of the datasheet, enabling safe use in hot-swap or multi-source power systems where output capacitors may retain residual voltage.
What thermal derating applies to TPS65251-3RHAR at 85°C ambient?
At 85°C ambient temperature, the TPS65251-3RHAR junction temperature must remain ≤125°C. With θJA = 32.7 °C/W, maximum allowable power dissipation is (125 – 85) / 32.7 ≈ 1.22 W. Full 3 A/2 A/2 A load exceeds this; therefore, derating is required - e.g., limiting Buck 1 to ≤2.2 A and Buck 2/3 to ≤1.5 A each on standard 4-layer FR4 with thermal pad grounded. Thermal simulation or testing under actual airflow is recommended.
TPS65251-3RHAR 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):
- 17V
- 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)
TPS65251-3RHAR FAQ
1.How can I place an order for TPS65251-3RHAR through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65251-3RHAR 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 TPS65251-3RHAR reliable?
The price and inventory of TPS65251-3RHAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65251-3RHAR is usually 5 days.
3.What payment methods are accepted for TPS65251-3RHAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65251-3RHAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65251-3RHAR?
TPS65251-3RHAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65251-3RHAR 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 TPS65251-3RHAR?
For technical support, including TPS65251-3RHAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65251-3RHAR requirements.
6.How does Aetrix verify that TPS65251-3RHAR is sourced from the original manufacturer or authorized distributors?
All TPS65251-3RHAR 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 TPS65251-3RHAR meets industry standards.
7.What is the process for return or replacement of TPS65251-3RHAR?
All TPS65251-3RHAR units undergo pre-shipment inspection (PSI). If there is an issue with TPS65251-3RHAR, 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 TPS65251-3RHAR part is unused and in its original packaging.
Return procedure for TPS65251-3RHAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TPS65251-3RHAR Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
