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Texas Instruments TPS65261-1RHBT
- Part No.:
- TPS65261-1RHBT
- Manufacturer:
- Texas Instruments
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
TPS65261-1RHBT.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 32VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,747
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Product details
Overview
TPS65261-1RHBT from Texas Instruments is a monolithic triple synchronous step-down DC/DC converter delivering 3-A, 2-A, and 2-A output currents across three independent buck channels. It operates from a 4.5-V to 18-V input supply, features a 0.6-V ±1% feedback reference, supports adjustable switching frequency from 250 kHz to 2 MHz via ROSC pin, and implements forced continuous conduction mode (FCCM) for low-noise operation in consumer networking and surveillance power rails.
For engineers reviewing the TPS65261-1RHBT datasheet, TPS65261-1RHBT pinout, TPS65261-1RHBT application, or TPS65261-1RHBT equivalent, this page delivers verified electrical parameters, validated thermal performance (RθJA = 31.6°C/W), confirmed FCCM light-load behavior, and precise pin-level circuit roles - all essential for pre-compliance power architecture validation in set-top boxes and wireless routers.
Technical Context
The TPS65261-1RHBT uses constant-frequency peak-current-mode control with dedicated loop compensation pins (COMP1–COMP3) and independent soft-start/tracking inputs (SS1–SS3). Its 180° phase shift between Buck1 and Buck2/Buck3 reduces input ripple and eases filter design.
Buck1 integrates a 100-mΩ high-side and 65-mΩ low-side MOSFET; Buck2/Buck3 each integrate 140-mΩ/95-mΩ FETs. The device includes V7V LDO (6.3-V output, 175-mA limit) for gate driver bias, PGOOD open-drain monitoring, and RESET signal for input power failure detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input voltage range | 4.5 V to 18 V - supports common intermediate bus rails (5 V, 9 V, 12 V, 15 V) without external pre-regulation |
| Output current capability | 3 A / 2 A / 2 A - enables single-chip power delivery for multi-rail SoC systems (e.g., CPU + memory + I/O) |
| Feedback reference voltage | 0.6 V ±1% - enables precise output regulation down to 0.6 V and stable margining across temperature (±0.002 V drift) |
| Switching frequency range | 250 kHz to 2 MHz - allows optimization of efficiency vs. size: 600 kHz typical for balanced EMI and thermal performance |
| Light-load operation mode | Forced Continuous Conduction Mode (FCCM) - eliminates audible noise and RF interference in sensitive RF front-end applications |
| Thermal shutdown threshold | 160°C trip point with 20°C hysteresis - ensures safe recovery after transient overload without manual reset |
| Junction-to-ambient thermal resistance | 31.6°C/W (RθJA, RHB package) - defines maximum power dissipation (≈3.2 W at 85°C ambient) before derating |
Pinout & Package
RHB package is a 32-pin, 5-mm × 5-mm, 0.5-mm pitch VQFN with exposed thermal pad. Soldering the thermal pad to PCB ground plane is mandatory for achieving rated RθJA = 31.6°C/W and sustained 3-A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1, EN2, EN3 | Independent enable inputs for Buck1–Buck3 | Float to enable; internal 3.6-µA pullup allows simple resistor-divider UVLO adjustment per channel |
| FB1, FB2, FB3 | Kelvin feedback sensing inputs | Direct connection to resistor divider outputs enables accurate remote-sense regulation and minimizes layout-induced error |
| SS1, SS2, SS3 | Soft-start and tracking inputs | 5-µA internal current source enables programmable ramp time with capacitor; supports power sequencing with external voltage reference |
| ROSC | Oscillator frequency programming | Resistor to ground sets switching frequency (e.g., 73.2 kΩ → 600 kHz); tolerance directly impacts timing accuracy |
| PGOOD | Open-drain power-good indicator | Asserts high only when all three outputs are within ±5% regulation and startup sequence completes |
| RESET | Open-drain power-failure signal | Asserts low when input voltage drops below VDIV threshold (1.23 V typical), enabling system brownout response |
| BST1–BST3 | Bootstrap supply terminals | Capacitor (47 nF recommended) between BSTx and LXx provides gate drive voltage for high-side FETs; UVLO protects against boot capacitor discharge |
| LX1–LX3 | Switching node connections | High dv/dt nodes requiring tight layout to PGND; voltage swing spans from ~−0.8 V to PVINx; drives external inductors |
| PGND1–PGND3 | Power ground returns | Must be routed separately from AGND and tied near respective input capacitors to minimize ground bounce and EMI |
| AGND | Analog ground reference | Common return for FB/COMP/SS pins; must be isolated from high-current PGND paths and connected to VIN bypass capacitor negative terminal |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent buck regulators | Enables discrete rail control: Buck1 (3 A) for core logic, Buck2/Buck3 (2 A each) for memory and I/O - no cross-regulation coupling |
| 180° phase-shifted clocking | Reduces RMS input current ripple by >40% versus in-phase operation, allowing smaller input bulk capacitance (e.g., 2×10 µF instead of 4×10 µF) |
| Integrated V7V LDO | 6.3-V, 175-mA regulated supply powers internal gate drivers and control logic - eliminates need for external bias rail |
| FCCM light-load operation | Maintains fixed 600-kHz switching under all loads - prevents frequency modulation artifacts in RF-sensitive receivers and ADC references |
| Monotonic startup into pre-biased outputs | Prevents reverse current flow during hot-plug or partial system power-up - critical for field-upgradable embedded gateways |
Applications
| DTV Power Management | Home Gateway Router |
|---|---|
Use Scenario: Dual-tuner digital TV platform requiring isolated 1.2-V CPU core, 3.3-V interface, and 1.8-V memory rails with strict EMI limits. IC Role / Device Role / Timing Role: Primary triple-output PMIC supplying sequenced, low-noise DC rails to SoC and peripherals. Use Value: FCCM mode eliminates switching frequency variation that could interfere with QAM demodulation; 180° phase shift cuts input capacitor count by 50%. | Use Scenario: Multi-band Wi-Fi 6 gateway with ARM-based processor, Ethernet PHY, and USB 3.0 controller needing coordinated power-up timing. IC Role / Device Role / Timing Role: Central power controller managing rail enable sequencing, power-good handshaking, and brownout detection. Use Value: Dedicated ENx/SSx pins allow independent delay programming; RESET output triggers graceful firmware shutdown on AC adapter loss. |
| Surveillance Camera System | POS Terminal Power |
Use Scenario: IP camera with image sensor, ISP, and PoE-powered Ethernet interface operating from 12-V input with thermal constraints. IC Role / Device Role / Timing Role: High-efficiency triple buck delivering 1.1-V sensor core, 1.8-V ISP, and 3.3-V PHY rails under ambient temperatures up to 70°C. Use Value: RθJA = 31.6°C/W and thermal shutdown (160°C) ensure reliable operation in sealed enclosures; PGOOD confirms all rails before sensor initialization. | Use Scenario: Retail point-of-sale terminal with display, barcode scanner, and contactless payment module sharing a 12-V wall adapter. IC Role / Device Role / Timing Role: Single-package solution generating 5-V display backlight, 3.3-V logic, and 1.2-V secure element rails with fault reporting. Use Value: Integrated overcurrent protection (256-cycle hiccup wait) prevents latch-up during short-circuit events on peripheral ports; VDIV-based RESET enables battery backup switchover. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65261RHBT | Uses Pulse Skipping Mode (PSM) at light load; 0.6-V reference identical; same RHB package and pinout | Higher light-load efficiency but introduces variable-frequency noise - unsuitable for RF or precision analog circuits | Select TPS65261RHBT only when >90% efficiency at 10-mA load is prioritized over EMI control |
| TPS65270PWP | Triple 3-A/3-A/2-A buck; wider 4.5–32-V input; no integrated V7V LDO; HTSSOP-48 package | Supports higher input voltages (e.g., 24-V industrial buses); requires external 7-V bias rail; larger footprint | Choose TPS65270PWP when input exceeds 18 V or total output current >7 A is required |
Compared with TPS65261-1RHBT, the TPS65261RHBT trades FCCM's EMI stability for PSM's light-load efficiency, while the TPS65270PWP expands input range and output current at the cost of added external components and board area - making TPS65261-1RHBT optimal for compact, noise-sensitive 12-V consumer electronics.
Availability
TPS65261-1RHBT is available at Aetrix Electronics and suitable for DTV, home gateway, and surveillance camera applications requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.
Supply support for TPS65261-1RHBT 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 manufacturing.
The TPS6526x product line was engineered specifically for multi-rail consumer and networking equipment, integrating high-current buck stages, sequencing control, and robust protection in a space-constrained VQFN package.
FAQ
What is the key functional difference between TPS65261-1RHBT and TPS65261RHBT?
The TPS65261-1RHBT operates in Forced Continuous Conduction Mode (FCCM) at all load levels, ensuring fixed-frequency switching for predictable EMI filtering and noise immunity. In contrast, the TPS65261RHBT enters Pulse Skipping Mode (PSM) under light load, improving efficiency but introducing variable-frequency artifacts. Both share identical pinout, package, and 0.6-V reference, but FCCM makes TPS65261-1RHBT preferable for RF-sensitive applications like wireless routers and surveillance cameras where spectral purity matters.
How does the TPS65261-1RHBT achieve input ripple reduction across its three buck channels?
The TPS65261-1RHBT reduces input ripple by operating Buck1 180° out-of-phase with Buck2 and Buck3 (which run in-phase). This phase interleaving cancels fundamental input current harmonics, lowering RMS input current by up to 42% compared to in-phase operation. As a result, designers can use fewer or smaller input ceramic capacitors - for example, two 10-µF X7R caps instead of four - without violating ripple voltage specifications. This benefit is inherent to the TPS65261-1RHBT's internal oscillator architecture and requires no external configuration.
Can the TPS65261-1RHBT safely start up into pre-biased output capacitors?
Yes, the TPS65261-1RHBT supports monotonic startup into pre-biased outputs. Its peak-current-mode control and internal current-limit architecture prevent reverse current flow during power-up when output rails already hold residual voltage. This behavior is confirmed in the datasheet's Detailed Description section and is critical for hot-plug scenarios in modular gateways or field-upgradable DTV platforms. No external diodes or sequencing controllers are needed - the feature is built into the TPS65261-1RHBT's control loop design.
What is the role of the V7V pin on the TPS65261-1RHBT, and how must it be decoupled?
On the TPS65261-1RHBT, the V7V pin outputs a regulated 6.3-V supply (±5%) used internally to bias the high-side gate drivers and analog control circuitry. It must be decoupled with a 10-µF ceramic capacitor connected directly from V7V to power ground, placed as close as possible to the pin. Failure to install this capacitor causes gate drive instability, erratic switching, and potential thermal shutdown. The V7V LDO delivers up to 175 mA, eliminating the need for an external 7-V bias rail - a key integration advantage of the TPS65261-1RHBT over discrete controller solutions.
How does the TPS65261-1RHBT indicate power failure on the input supply?
The TPS65261-1RHBT monitors input voltage via the VDIV pin, which compares the divided input to an internal 1.23-V threshold. When the scaled input falls below this level, the open-drain RESET pin asserts low after a 12–16 cycle deglitch (≈20 µs at 600 kHz). This signal can directly trigger microcontroller NMI or initiate controlled shutdown sequences. Unlike PGOOD, RESET responds exclusively to input collapse - not output faults - making it ideal for detecting AC adapter disconnection or PoE power loss in surveillance and gateway applications using the TPS65261-1RHBT.
TPS65261-1RHBT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 32-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):
- 0.6V
- Voltage - Output (Max):
- 18V
- Current - Output:
- 3A, 2A
- Frequency - Switching:
- 250kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-VQFN (5x5)
TPS65261-1RHBT FAQ
1.How can I place an order for TPS65261-1RHBT through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65261-1RHBT 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 TPS65261-1RHBT reliable?
The price and inventory of TPS65261-1RHBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65261-1RHBT is usually 5 days.
3.What payment methods are accepted for TPS65261-1RHBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65261-1RHBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65261-1RHBT?
TPS65261-1RHBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65261-1RHBT 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 TPS65261-1RHBT?
For technical support, including TPS65261-1RHBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65261-1RHBT requirements.
6.How does Aetrix verify that TPS65261-1RHBT is sourced from the original manufacturer or authorized distributors?
All TPS65261-1RHBT 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 TPS65261-1RHBT meets industry standards.
7.What is the process for return or replacement of TPS65261-1RHBT?
All TPS65261-1RHBT units undergo pre-shipment inspection (PSI). If there is an issue with TPS65261-1RHBT, 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 TPS65261-1RHBT part is unused and in its original packaging.
Return procedure for TPS65261-1RHBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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