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Texas Instruments TPS54478RTET
- Part No.:
- TPS54478RTET
- Manufacturer:
- Texas Instruments
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
TPS54478RTET.pdf
- Description:
- IC REG BUCK ADJ 4A 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:430
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Product details
Overview
TPS54478RTET from Texas Instruments is a 2.95-V to 6-V input, 4-A synchronous step-down DC/DC converter with integrated high- and low-side 30-mΩ MOSFETs, 0.6-V ±1% reference over –40°C to +150°C, hiccup current limit protection, and 200-kHz to 2-MHz adjustable switching frequency. It delivers regulated 1.2-V, 1.8-V, or 2.5-V outputs for FPGA core rails in telecom infrastructure.
For engineers reviewing the TPS54478RTET datasheet, TPS54478RTET pinout, TPS54478RTET application, or TPS54478RTET equivalent, key selection considerations include its WQFN-16 (3 mm × 3 mm) thermal pad package, RT/CLK synchronization capability, PWRGD open-drain power-good signal with 2% hysteresis, and pre-bias startup support for reliable system sequencing.
Technical Context
The TPS54478RTET implements constant-frequency peak-current-mode control with internal slope compensation to prevent subharmonic oscillation across 0–100% duty cycle. Its error amplifier features dual transconductance modes (225 μA/V normal, ≥77 μA/V during soft-start) and compares VSENSE against either the 0.6-V reference or SS/TR voltage.
It integrates BOOT capacitor charge management with BOOT-PH UVLO at 2.2 V, enabling near-100% duty-cycle operation. The device uses an internal PLL on the RT/CLK pin to synchronize switching to external clocks and provides hiccup-mode overcurrent protection after 512 fault cycles, holding off for 16,384 cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.95 V to 6 V - supports single-cell Li-ion, 3.3-V, and 5-V intermediate bus rails without external LDO pre-regulation. |
| Continuous Output Current | 4 A - sustains full load with ≤49.1°C/W junction-to-ambient thermal resistance in RTE package at TA = 25°C. |
| Reference Voltage Accuracy | 0.600 V ±1% (–40°C to +150°C) - enables precise output regulation for ASIC/FPGA core supplies requiring tight tolerance. |
| Switching Frequency Range | 200 kHz to 2 MHz - selectable via RT resistor or external clock; higher frequencies reduce inductor size (e.g., 1-MHz design uses ≤1.0-μH inductors). |
| Quiescent Current | 525 μA typical - minimizes no-load power loss in always-on subsystems; drops to 2.5 μA in shutdown mode. |
| Current Limit Threshold | 5.2 A to 8.2 A (VIN = 6 V) - cycle-by-cycle limiting plus hiccup mode prevents thermal runaway during sustained overload. |
| Power-Good Accuracy | ±2% hysteresis (93–107% of VREF) - ensures robust detection of valid output voltage for processor reset sequencing. |
Pinout & Package
TPS54478RTET is housed in a thermally enhanced 3-mm × 3-mm, 16-pin WQFN (RTE) package with exposed thermal pad (Pin 17) that must be soldered to PCB ground plane via multiple vias for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 1, 2, 16) | Input supply connection | Accepts 2.95–6 V; multiple pins reduce trace IR drop and improve high-current path integrity. |
| PH (Pins 10, 11, 12) | Switch node | Connects to inductor; shared high-side source / low-side drain node-requires tight layout to minimize EMI and ringing. |
| BOOT (Pin 13) | High-side gate drive supply | Requires 0.1-μF X7R/X5R ceramic capacitor to PH; UVLO disables high-side FET if BOOT-PH < 2.2 V. |
| VSENSE (Pin 6) | Feedback input | Compares output divider voltage to 0.6-V reference; 7-nA input bias enables use of high-value resistors for light-load efficiency. |
| COMP (Pin 7) | Error amplifier output | Drives external RC compensation network; gm = 225 μA/V enables stable loop response with standard Type-II/III networks. |
| EN (Pin 15) | Enable / UVLO control | Pull below 1.21 V to disable; internal 2.76-μA hysteresis current allows resistor-divider UVLO adjustment above 2.6 V. |
| RT/CLK (Pin 8) | Frequency setting / sync input | Resistor-to-GND sets fSW (200 kHz–2 MHz); accepts external clock (300–2000 kHz) with 75-ns pulse width min. |
| SS/TR (Pin 9) | Soft-start / tracking control | Capacitor sets ramp time; dual-slope charging (45 μA / 2.2 μA) avoids minimum-on-time limitation during startup. |
| PWRGD (Pin 14) | Open-drain power-good flag | Asserts low when VOUT deviates >±2% from target; 56–120-Ω on-resistance supports direct MCU GPIO interfacing. |
| GND (Pins 3, 4) | Power ground return | Must connect directly to thermal pad; separates power and analog ground paths to reduce noise coupling into VSENSE. |
| AGND (Pin 5) | Analog ground reference | Electrically isolated from GND at PCB level; ties to local ground near VSENSE/COMP to stabilize feedback loop. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 30-mΩ MOSFETs | Enables >90% efficiency at 4-A load (e.g., 94% @ 1.8 V/3 A, VIN = 5 V, fSW = 1 MHz), eliminating external switch losses and layout complexity. |
| Hiccup overcurrent protection | Enters 16,384-cycle shutdown after 512 consecutive current-limit events-prevents thermal damage while allowing automatic recovery after fault clears. |
| Pre-bias startup capability | Monotonically ramps output from precharged rail without reverse current flow, ensuring safe power-up in multi-rail systems with staggered sequencing. |
| Synchronization to external clock | PLL on RT/CLK pin locks switching edge to system clock falling edge-eliminates beat frequencies and simplifies EMI filtering in synchronized power domains. |
| Adjustable undervoltage lockout | EN pin supports resistor-divider programming of rising/falling UVLO thresholds (e.g., 4.2 V rise / 4.0 V fall), preventing brownout operation in battery-powered designs. |
Applications
| Telecom Point-of-Load Regulation | Industrial FPGA Core Supply |
|---|---|
|
Use Scenario: Powers 1.2-V core rail of Xilinx Kintex-7 FPGA in 5G baseband unit with strict ripple & transient requirements. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering 4-A continuous current; regulates output using VSENSE feedback and COMP-based current-mode loop. Use Value: Integrated MOSFETs and 2-MHz capability enable compact 12-mm² solution; hiccup protection prevents latch-up during antenna SWR faults. |
Use Scenario: Supplies 1.8-V I/O bank of Intel Cyclone V SoC in programmable logic controller with extended temperature range. IC Role / Device Role / Timing Role: Step-down converter with SS/TR pin used for power-rail tracking with auxiliary 3.3-V supply. Use Value: ±1% reference and 2% PWRGD hysteresis ensure deterministic reset assertion; WQFN thermal pad maintains TJ < 125°C at 70°C ambient. |
| Optical Transceiver Module | Networking ASIC Bias Rail |
|
Use Scenario: Generates 2.5-V analog bias for 100G coherent DSP in CFP2 optical module with minimal board space. IC Role / Device Role / Timing Role: High-density DC/DC converter operating at 1.5 MHz to shrink filter components; EN pin tied to system supervisor for controlled enable. Use Value: 525-μA quiescent current extends standby time; BOOT UVLO ensures reliable 100% duty cycle during low-VIN brownout conditions. |
Use Scenario: Provides 0.85-V core supply to Broadcom BCM88312 switch ASIC in enterprise switch line card. IC Role / Device Role / Timing Role: Synchronous buck with RT/CLK synchronized to system timing reference to suppress conducted EMI in backplane environment. Use Value: Pin compatibility with TPS54418 allows reuse of validated layout; PWRGD signal feeds ASIC's POR circuit for deterministic initialization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54418RTVT | Same 4-A rating and WQFN-16 package, but fixed 500-kHz fSW (no RT/CLK sync), lower 2.95–6-V input range, and no hiccup mode-uses foldback current limit. | Lacks external clock synchronization and hiccup recovery; suitable only where fixed frequency and simpler protection suffice. | Choose TPS54418RTVT only if system clock sync and robust overload recovery are not required-reduces BOM count by eliminating RT resistor. |
| MP2347DJ-LF-Z | 4-A monolithic buck with 4.5–28-V input, 300-kHz–2.2-MHz fSW, but no PWRGD, no pre-bias startup, and 1.5% reference accuracy vs. TPS54478RTET's 1%. | Targets wider-input industrial rails; lacks power-good signaling and monotonic startup needed for FPGA/ASIC sequencing. | Select MP2347DJ-LF-Z for cost-sensitive 12-V intermediate bus apps where sequencing and precision are secondary to input voltage range. |
Compared with TPS54478RTET, TPS54418RTVT sacrifices synchronization and hiccup protection for simplicity, while MP2347DJ-LF-Z trades precision and sequencing features for broader input range-making TPS54478RTET optimal for high-reliability, multi-rail telecom and computing power delivery.
Availability
TPS54478RTET is available at Aetrix Electronics and suitable for telecom infrastructure, industrial FPGA power systems, and optical transceiver modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for TPS54478RTET 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, embedded processing, and power management technologies with over 50 years of innovation in high-reliability power conversion.
The TPS54478RTET belongs to TI's SWIFT™ synchronous buck converter family, designed specifically for high-density, high-efficiency point-of-load regulation in networking, telecom, and computing applications demanding precision, thermal resilience, and system-level integration.
FAQ
What is the recommended input capacitor for TPS54478RTET in a 5-V input, 1.8-V/4-A application?
For TPS54478RTET with 5-V input and 1.8-V/4-A output, TI recommends a minimum 47-μF X5R/X7R ceramic capacitor with ≤5-mΩ ESL placed within 3 mm of VIN and GND pins. A parallel 10-μF capacitor improves high-frequency decoupling. Total input capacitance must sustain 4-A load transients without dropping below 2.95 V; layout must minimize loop area to reduce EMI.
Does TPS54478RTET support forced continuous conduction mode (FCCM) or only pulse-skipping at light loads?
TPS54478RTET operates exclusively in pulse-skipping mode at light loads-there is no FCCM or diode-emulation mode. Its current-mode architecture automatically skips switching cycles when inductor current falls to zero, reducing light-load quiescent current to ~525 μA. This behavior is inherent to the control scheme and cannot be disabled.
Can the TPS54478RTET be used to generate a negative output voltage?
No, TPS54478RTET is a synchronous buck converter optimized for positive step-down operation only. Its internal architecture-including bootstrap gate drive, PH node topology, and VSENSE reference polarity-does not support inverting or negative-output configurations. For negative rails, use a dedicated inverting controller or charge-pump IC.
How does the hiccup current limit in TPS54478RTET differ from standard cycle-by-cycle limiting?
TPS54478RTET combines cycle-by-cycle current limiting (active each switching cycle) with hiccup mode: after 512 consecutive current-limit events, it disables switching for 16,384 cycles before retrying. This prevents thermal runaway during sustained shorts while allowing automatic recovery-unlike latch-off protection which requires external reset.
Is the TPS54478RTET pin-compatible with any other TI buck converters besides TPS54418?
Yes, TPS54478RTET is pin-compatible with TPS54418RTVT in the same WQFN-16 (RTE) package. Both share identical pin functions, layout, and thermal pad configuration-enabling drop-in replacement where hiccup protection and RT/CLK sync are not required. No other TI buck converters share this exact pinout.
TPS54478RTET Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SWIFT™
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.95V
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 4.5V
- Current - Output:
- 4A
- Frequency - Switching:
- 200kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (3x3)
TPS54478RTET FAQ
1.How can I place an order for TPS54478RTET through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS54478RTET 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 TPS54478RTET reliable?
The price and inventory of TPS54478RTET are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS54478RTET is usually 5 days.
3.What payment methods are accepted for TPS54478RTET?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS54478RTET transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS54478RTET?
TPS54478RTET orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS54478RTET 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 TPS54478RTET?
For technical support, including TPS54478RTET datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS54478RTET requirements.
6.How does Aetrix verify that TPS54478RTET is sourced from the original manufacturer or authorized distributors?
All TPS54478RTET 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 TPS54478RTET meets industry standards.
7.What is the process for return or replacement of TPS54478RTET?
All TPS54478RTET units undergo pre-shipment inspection (PSI). If there is an issue with TPS54478RTET, 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 TPS54478RTET part is unused and in its original packaging.
Return procedure for TPS54478RTET:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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