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Texas Instruments TPS65261RHBT
- Part No.:
- TPS65261RHBT
- Manufacturer:
- Texas Instruments
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
TPS65261RHBT.pdf
- Description:
- IC REG BCK ADJ 3A/2A TRPL 32VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:697
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Product details
Overview
TPS65261RHBT 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, pulse-skipping mode (PSM) for light-load efficiency, and 180° phase-shifted switching between Buck1 and Buck2/Buck3 to minimize input ripple. It is used in DTV power rails requiring tight regulation and sequenced startup.
For engineers reviewing the TPS65261RHBT datasheet, TPS65261RHBT pinout, TPS65261RHBT application, or TPS65261RHBT equivalent, this page delivers verified technical context, validated pin functions, confirmed thermal and electrical specifications, and real-world application implementation details - all specific to the RHB (VQFN-32) package and PSM-mode operation of TPS65261RHBT.
Technical Context
The TPS65261RHBT implements constant-frequency peak-current-mode control with independently configurable soft-start, enable, and loop compensation per channel. Its 250 kHz–2 MHz switching frequency is set via an external resistor on ROSC, and its 180° phase shift between Buck1 and the in-phase Buck2/Buck3 pair reduces input capacitor RMS current and EMI.
It integrates a 6.3 V internal LDO (V7V) for gate driver bias, supports monotonic startup into pre-biased loads, and includes dedicated overcurrent protection with hiccup-mode recovery (256-cycle wait, 8192-cycle restart), thermal shutdown at 160°C with 20°C hysteresis, and input undervoltage lockout with adjustable thresholds via ENx pins.
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 currents | 3 A / 2 A / 2 A - enables single-chip power delivery for multi-rail SoC or FPGA core/I/O/memory supplies. |
| Feedback reference | 0.6 V ±1% - enables precise output voltage setting down to 0.6 V with minimal divider error impact. |
| Switching frequency | 250 kHz to 2 MHz - allows optimization of efficiency vs. size: lower frequencies improve light-load PSM efficiency; higher frequencies shrink inductors/capacitors. |
| Thermal shutdown | 160°C trip, 20°C hysteresis - ensures safe operation under sustained overload or poor PCB thermal design. |
| Quiescent current (shutdown) | 9.2 µA - minimizes system standby power in always-on applications like home gateways. |
| Power-good accuracy | ±2.5% threshold window (92.5–107.5% of VREF) with deglitch timing - prevents false resets during transient load steps. |
Pinout & Package
RHB package is a 32-pin VQFN (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad requiring solder connection to PCB ground plane for optimal thermal performance (RθJA = 31.6°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN1 / EN2 / EN3 | Independent enable inputs | Float to enable; internal 3.6 µA pull-up allows simple UVLO adjustment via resistor divider on each channel. |
| FB1 / FB2 / FB3 | Feedback sensing inputs | Kelvin-connected to output resistive dividers; referenced to 0.6 V for accurate regulation across temperature and load. |
| LX1 / LX2 / LX3 | Switching node outputs | Drive external inductors; voltage swing spans diode-drop below GND to PVINx; requires low-ESR ceramic capacitors near each LX-PGND pair. |
| BST1 / BST2 / BST3 | Bootstrap supply terminals | Connect 47 nF capacitor to respective LX pin to sustain high-side MOSFET gate drive; monitored for UVLO recharging. |
| PGOOD | Open-drain power-good indicator | Asserts high only when all three outputs are within ±2.5% regulation and sequencing completes - used for system enable or reset coordination. |
| ROSC | Oscillator frequency programming | External resistor to GND sets switching frequency; 73.2 kΩ yields 600 kHz typical - critical for EMI filtering and efficiency trade-offs. |
| MODE | Power sequence control | High enables automatic staggered startup/shutdown (1024-cycle delay between bucks); simplifies firmware-free sequencing in DTV and routers. |
| V7V | Internal LDO output | 6.3 V ±5% regulated supply for gate drivers and internal logic; requires 10 µF ceramic capacitor to PGND for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Pulse Skipping Mode (PSM) | Enables >85% efficiency at 10 mA load on Buck1 (1.2 V), reducing standby power in always-on consumer electronics. |
| 180° phase-shifted clocking | Reduces input ripple current by ~30% versus in-phase operation, allowing smaller bulk input capacitors and lower EMI filter cost. |
| Dedicated soft-start pins (SS1–SS3) | Each channel's 5 µA internal current source enables independent soft-start timing via external capacitor - eliminates cross-talk during rail ramp-up. |
| Integrated bootstrap circuitry | Eliminates need for external charge pumps; automatic LX-driven recharging maintains 100% duty cycle capability as long as BST–LX > 2.1 V. |
| Pre-biased load startup | Guarantees monotonic output rise even when output capacitors are pre-charged - essential for hot-swap and FPGA configuration sequencing. |
Applications
| DTV Power Management | Home Gateway SoC Supply |
|---|---|
Use Scenario: Powering main SoC, DDR memory, and USB PHY in digital television platforms with strict standby power limits. IC Role / Device Role / Timing Role: Triple-buck regulator providing 1.2 V (core), 3.3 V (I/O), and 1.8 V (memory) with synchronized startup and PSM-enabled low-power idle mode. Use Value: Eliminates discrete DC/DC solutions, reduces BOM count by 3×, and achieves <25 mW total quiescent loss in standby via 9.2 µA shutdown current. |
Use Scenario: Delivering clean, sequenced rails to ARM-based gateway processors handling Wi-Fi 6, Ethernet, and voice processing. IC Role / Device Role / Timing Role: Central power controller managing 1.1 V CPU, 1.8 V RAM, and 3.3 V peripheral rails with MODE-pin-activated automatic power-up sequence. Use Value: Removes need for external sequencer IC or firmware-controlled GPIO timing, cutting layout area by 40% and enabling faster time-to-market. |
| Wireless Router Baseband | Surveillance Camera DSP Core |
Use Scenario: Supplying baseband processor, RF transceiver, and PoE interface in dual-band wireless access points. IC Role / Device Role / Timing Role: High-efficiency triple converter operating from 12 V PoE input, with phase-shifted clocks minimizing conducted EMI on sensitive RF sections. Use Value: Achieves >92% peak efficiency at full load while meeting FCC Class B conducted emissions without added ferrite beads or shielding. |
Use Scenario: Powering image signal processor, ISP memory, and video encoder in IP cameras with ambient temperature up to 70°C. IC Role / Device Role / Timing Role: Thermally robust buck regulator with 160°C shutdown and 20°C hysteresis, supporting continuous operation in enclosed enclosures. Use Value: Maintains stable 1.0 V core and 1.8 V I/O rails under thermal stress, avoiding unexpected resets during extended night-vision 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 |
|---|---|---|---|
| TPS65261-1RHBT | Uses forced continuous conduction mode (FCCM) instead of PSM; higher light-load noise but tighter output voltage ripple. | Suitable for noise-sensitive analog/RF sections where PSM-induced frequency variation is unacceptable. | Select TPS65261-1RHBT when EMI filtering priority outweighs standby power savings. |
| TPS65263RHBR | Same 3-A/2-A/2-A rating but adds integrated LDOs (3.3 V/200 mA, 1.8 V/200 mA); higher pin count (40-pin VQFN); no PSM mode. | Used where auxiliary low-noise rails are needed alongside main buck outputs - e.g., sensor interfaces or audio codecs. | Choose TPS65263RHBR only if auxiliary LDOs eliminate need for separate linear regulators in the BOM. |
Compared with TPS65261RHBT, the TPS65261-1RHBT trades 15–20% higher light-load efficiency for lower output ripple, while TPS65263RHBR adds integration at the cost of larger footprint and fixed operational mode - making TPS65261RHBT optimal for cost- and power-sensitive DTV and gateway designs requiring PSM.
Availability
TPS65261RHBT is available at Aetrix Electronics and suitable for DTV, home gateway, and wireless router applications requiring stable component supply, long-term industrial lifecycle support, and guaranteed traceable sourcing.
Supply support for TPS65261RHBT 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 family was designed specifically for multi-rail consumer and networking equipment - delivering high integration, sequencing flexibility, and PSM efficiency in compact VQFN packages for space-constrained DTV, set-top box, and access point applications.
FAQ
What is the maximum input voltage rating for the TPS65261RHBT?
The TPS65261RHBT has an absolute maximum input voltage rating of 20 V on PVIN1, PVIN2, PVIN3, and VIN pins. However, its recommended operating input voltage range is strictly 4.5 V to 18 V per datasheet Section 6.3. Exceeding 18 V may cause premature device failure or violate safety margins, even if below the 20 V absolute limit. Always maintain input transients within this 18 V ceiling for reliable TPS65261RHBT operation.
Does the TPS65261RHBT support power sequencing between its three buck channels?
Yes, the TPS65261RHBT supports automatic power sequencing when the MODE pin is pulled high. In this mode, it staggers startup with a 1024-cycle delay between channels (≈1.7 ms at 600 kHz), ensuring Buck1 powers first, followed by Buck2 and Buck3. This eliminates external sequencing ICs in DTV and gateway designs. The TPS65261RHBT also supports independent enable control via EN1/EN2/EN3 for custom sequencing.
How does the PSM mode in the TPS65261RHBT improve efficiency at light loads?
The TPS65261RHBT enters Pulse Skipping Mode (PSM) automatically below ~200 mA load per channel, disabling switching cycles until output voltage droops beyond regulation. This eliminates switching losses, raising efficiency from ~65% (in FCCM) to >85% at 10 mA on Buck1. PSM is exclusive to TPS65261RHBT - not present in the TPS65261-1RHBT variant - making it ideal for standby power optimization in always-on devices.
What thermal performance can be expected from the TPS65261RHBT in a standard 4-layer PCB layout?
In a typical 4-layer board with 1 oz copper, 200 mm² thermal pad copper pour, and no airflow, the TPS65261RHBT achieves a junction-to-ambient thermal resistance (RθJA) of 31.6°C/W. At full 3-A/2-A/2-A load with 12 V input, power dissipation is ~2.1 W, resulting in ≈66°C junction rise above ambient. This stays well below the 125°C max operating junction temperature, confirming robust thermal margin for TPS65261RHBT in consumer-grade enclosures.
Can the TPS65261RHBT safely start up into pre-biased output capacitors?
Yes, the TPS65261RHBT is explicitly designed for monotonic startup into pre-biased loads. Its current-mode architecture and controlled gate drive prevent reverse current flow during ramp-up. When output capacitors are pre-charged to 1.2 V, 3.3 V, or 1.8 V, the TPS65261RHBT initiates soft-start without overshoot or latch-up - a critical feature for hot-plug systems and FPGA configuration where rails must power up cleanly after partial discharge.
TPS65261RHBT 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)
TPS65261RHBT FAQ
1.How can I place an order for TPS65261RHBT through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS65261RHBT 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 TPS65261RHBT reliable?
The price and inventory of TPS65261RHBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS65261RHBT is usually 5 days.
3.What payment methods are accepted for TPS65261RHBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS65261RHBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS65261RHBT?
TPS65261RHBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS65261RHBT 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 TPS65261RHBT?
For technical support, including TPS65261RHBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS65261RHBT requirements.
6.How does Aetrix verify that TPS65261RHBT is sourced from the original manufacturer or authorized distributors?
All TPS65261RHBT 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 TPS65261RHBT meets industry standards.
7.What is the process for return or replacement of TPS65261RHBT?
All TPS65261RHBT units undergo pre-shipment inspection (PSI). If there is an issue with TPS65261RHBT, 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 TPS65261RHBT part is unused and in its original packaging.
Return procedure for TPS65261RHBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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