TPS54308DDCR - 28V 3A Sync Buck Converter | Texas Instruments
MPN: TPS54308DDCR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.53 | $1.53 |
| 10 | $1.41 | $14.10 |
| 100 | $1.17 | $117.00 |
| 500 | $0.97 | $485.00 |
| 1,000 | $0.82 | $820.00 |
| 3,000 | $0.66 | $1,980.00 |
TPS54308DDCR Overview
A synchronous buck converter is a switched-mode DC-DC topology that uses two MOSFETs in a half-bridge configuration, with the low-side switch rectifying the voltage to eliminate the diode drop of a conventional buck, thereby improving efficiency at high step-down ratios. Within the broader power management IC hierarchy, a buck converter sits between linear regulators and isolated converters and is widely used wherever small size and high efficiency are required below about 5-A loads.
Key specifications include 4.5 V to 28 V input range, 3 A continuous output current, 1-V to 18-V adjustable output, 350 kHz typical switching frequency, and FCCM (forced continuous conduction mode) for predictable EMI behavior across all load levels. Additional features include internal compensation, internal 5 ms soft start, and a typical quiescent current suitable for portable and always-on applications.
The device's primary technical advantage is high power density. By integrating high-side and low-side MOSFETs in a small TSOT-23-6 footprint and using internal loop compensation, the TPS54308 minimizes the PCB area required for a complete 3 A point-of-load converter. TI's HotRod flip-chip package construction also reduces parasitic inductance and improves thermal performance for such a small outline.
Typical applications include 12-V and 24-V industrial bus point-of-load regulators, USB power delivery (USB-PD) auxiliary rails, white goods and appliance power supplies, distributed 5-V and 3.3-V POL rails, telecom and networking cards, and general-purpose 5-V to point-of-load conversion. The wide 4.5 V to 28 V input range makes it tolerant of common industrial transients when fed from a protected bus.
When designing with this part, place the input bypass capacitor as close as possible to the PVIN and PGND pins; keep the high-current switching loop small. The feedback resistor divider sets the output voltage and should use 1% or better tolerance to maintain set-point accuracy. The TPS54308 datasheet reference design with 22 µF input and 44 µF output ceramic capacitors typically delivers full 3 A at 25 °C ambient without airflow up to about 24 V input.
This page synthesizes distributor pricing, same-package drop-in alternatives, and practical design notes not collected in the manufacturer datasheet, providing a single decision-making reference for engineers evaluating the TPS54308 family.
Drop-in alternatives for TPS54308DDCR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with TPS54308DDCR (same form factor and footprint) — differing in Package, Switching Frequency, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TPS54302DDCR
✅ Drop-In✓ In Stock
$0.42 / Unit
View Datasheet →TPS54308DDCT
✅ Drop-In📋 Reference alternative (not in catalog)
TPS563249DDCR
✅ Drop-In📋 Reference alternative (not in catalog)
TPS54201DDCR
✅ Drop-In📋 Reference alternative (not in catalog)
AP62300WU-7
✅ Drop-In📋 Reference alternative (not in catalog)
TPS54308DDCR Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Buck (Step-Down) |
| Input Voltage Range | 4.5 V to 28 V |
| Output Voltage Range | 0.6 V to 18 V (Adjustable, typ. 1 V to 18 V listed) |
| Continuous Output Current | 3 A |
| Switching Frequency | 350 kHz (typ, fixed) |
| Operating Mode | Force PWM / FCCM (Continuous) |
| Integrated Switches | 2 (high-side + low-side MOSFETs) |
| Loop Compensation | Internal |
| Soft-Start | 5 ms (internal) |
| Operating Temperature Range | -40 °C to +125 °C (TJ) |
| Package | SOT-23-6 Thin / TSOT-23-6 (DDC) |
| Mounting Type | Surface Mount |
| MSL Level | Level-1-260C-UNLIM |
| RoHS Status | Compliant |
| Enable Control | Active-high EN pin |
| Feedback Reference | 0.6 V (internal) |
TPS54308DDCR Pin Configuration
| Pin 1 | PGND — Power ground (return for internal MOSFETs) |
| Pin 2 | VIN — Input voltage supply (4.5 V to 28 V) |
| Pin 3 | EN — Enable (active-high); pulled up internally |
| Pin 4 | FB — Feedback (sets VOUT via external divider) |
| Pin 5 | VOUT — Output voltage sense (internal bootstrap rail) |
| Pin 6 | GND — Analog/signal ground |
Typical Applications
TPS54308DDCR is suitable for 7 applications: Industrial 24V Point-of-Load Regulator, USB Type-A / Charging Port Auxiliary Rail, White Goods and Appliance Power, Networking and Telecom Card POL Rails, Automotive Infotainment / Body Electronics, Distributed 5V and 3.3V POL Rails, Test and Measurement Bench Supplies.
Industrial 24V Point-of-Load Regulator
The TPS54308DDCR fits 24V industrial bus point-of-load applications because its 4.5V to 28V input range covers the 12V and 24V industrial rails plus surge headroom (up to 28V continuous), and its 3A continuous output supports standard POL rails of 5V, 3.3V, and 1.8V. The device produces a regulated output via external resistor divider; the integrated high-side and low-side MOSFETs eliminate two power-stage components, reducing BOM count. Compared with an LDO, the switching converter dissipates less power at VIN=24V/VOUT=5V (about 89% efficient vs LDO power loss of 19W × 33%), eliminating the need for a bulky heatsink. The TSOT-23-6 (DDC) footprint saves roughly 60% board area vs SOIC-8 alternatives, ideal for dense industrial I/O cards.
Recommended
USB Type-A / Charging Port Auxiliary Rail
The TPS54308DDCR is well suited to USB Type-A charging port auxiliary rails in wall adapters and hubs. Its 4.5V–28V input accepts the rectified high-voltage rail of an AC adapter (5V–24V typical), while its 3A output covers BC1.2 charging currents and 5V auxiliary loads. The FCCM operation ensures predictable EMI across all load conditions, important for USB-IF compliance testing. Compared with a 5V LDO, the switching buck converter's higher efficiency reduces adapter thermal rise and enables smaller form factors. At VIN=12V/VOUT=5V/IOUT=2A, the TPS54308 achieves ~90% efficiency per TI's evaluation data, allowing fanless operation in plastic enclosures.
Recommended
White Goods and Appliance Power
White goods, HVAC controls, and small appliances commonly operate from 12V/24V bus rails and need point-of-load regulation of logic rails. The TPS54308DDCR's TSOT-23-6 (DDC) small footprint, internal compensation, and 5ms internal soft start minimize external parts count, allowing single-layer PCB designs in cost-sensitive appliances. The industrial temperature range (-40°C to +125°C) supports refrigerator and dishwasher control boards. Compared with traditional TO-220 linear regulators, the 350-kHz/3A sync buck achieves ~92% efficiency at full load with no heatsink, eliminating thermal issues in enclosed appliance housings. TI's FCCM switching at 350 kHz falls within EN 55011 conducted EMI limits with the recommended input LC filter.
Recommended
Networking and Telecom Card POL Rails
The TPS54308DDCR is widely used in networking switches, routers, and telecom cards where 12V/24V distribution voltages are stepped down to 3.3V or 1.8V for PHY/MAC ASICs and FPGAs. Its FCCM mode is critical here: under light loads the switching frequency stays constant at 350 kHz, preventing audible-beat tones and conducted EMI spectral drift that complicate system-level CE/UL certifications. Internal compensation eliminates the external C and R feed-forward components required by older controllers, saving roughly 2 components per rail. The 3A continuous output covers the typical ASIC supply bus; the 28V input tolerance protects against transient spikes common to backplane power distribution.
Recommended
Automotive Infotainment / Body Electronics
Although not AEC-Q100 qualified by default, the TPS54308DDCR is found in non-safety automotive infotainment and body electronic POL rails when qualified alternatives are not required. Its 4.5V–28V input covers automotive 12V cold-crank to load-dump transients, and the 3A output supports CAN transceivers, USB hubs, and audio amplifier rails. Compared with a discrete buck using external MOSFETs, the integrated FET approach reduces PCB area by 70% and eliminates gate-drive tuning. FCCM operation is helpful for audio amplifier power rails, where PFM-mode ripple at light load would translate to audible hiss.
Recommended
Distributed 5V and 3.3V POL Rails
The TPS54308DDCR functions as a distributed POL rail in FPGA/MCU-based embedded systems requiring multiple voltage rails. Its small footprint allows placement near the load (point-of-load), reducing trace loss and improving transient response. The TPS54308's 350-kHz FCCM switching provides predictable dynamic behavior when handling step loads from 0.1A to 3A, settling quickly thanks to internal compensation. The device produces lower ripple than PFM-mode alternatives, important for 5V rails feeding ADCs and DACs. TI's 5ms internal soft start controls inrush without adding external capacitor and resistor; the 24V/5V/3A application is one of the most common EVM reference designs.
Recommended
Test and Measurement Bench Supplies
The TPS54308DDCR can be used as a daughter card for bench-style test and measurement supplies where a single board carries multiple POL rails (1.2V, 1.8V, 3.3V, 5V) powered from a 12V/24V bench source. The device's FCCM operation avoids tone-shift noise during spectrum analyzer tests, and its 3A capability covers prototype MCU/FPGA kits that draw 2–2.5A under full loading. The internal 5ms soft start is also gentle on lab power supplies, preventing inrush-trip events. Designers benefit from the small TSOT-23-6 (DDC) footprint, allowing multiple TPS54308 devices to fit on a 35 mm × 50 mm eval board.
Recommended
Recommended Products Summary
Engineering reference data for TPS54308DDCR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TPS54302DDCR | TPS54308DDCT | TPS563249DDCR | TPS54201DDCR | AP62300WU-7 |
|---|---|---|---|---|---|---|
| Package | SOT-23-6 (DDC) | SOT-23-6 (DDC) - same | SOT-23-6 (DDC) - same | SOT-23-6 (DDC) - same | SOT-23-6 (DDC) - same | TSOT-23-6 - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Diodes Incorporated |
| Input Voltage Range | 4.5 V to 28 V | 4.5 V to 18 V | 4.5 V to 28 V | 4.5 V to 16 V | 4.5 V to 28 V | 4.5 V to 18 V |
| Output Current | 3 A | 3 A | 3 A | 3 A | 2 A | 3 A |
| Switching Frequency | 350 kHz | 350 kHz | 350 kHz | 650 kHz | 350 kHz | 1.2 MHz |
| Operating Mode | FCCM (Forced PWM) | FCCM | FCCM | Auto PFM/PWM | FCCM | Auto PFM/PWM |
| Internal Soft Start | 5 ms | 5 ms | 5 ms | 1 ms (typ) | 5 ms | 1 ms |
| Loop Compensation | Internal | Internal | Internal | Internal | Internal | Internal |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
Key Differentiators
- FCCM operation across full load range (vs TPS563249DDCR)
- Wider 28V input range (vs TPS54302DDCR)
- Higher 3A output current in TSOT-23-6 (vs TPS54201DDCR)
- Cross-brand drop-in option at slightly lower voltage (vs AP62300WU-7 (Diodes Incorporated))
Design Notes
Do not lay out the TPS54308DDCR with the input capacitor more than 5 mm from PVIN, otherwise high di/dt switching current will spike the VIN rail and degrade regulation. The PGND pin returns high-current; route this to the input capacitor ground and output capacitor ground via a single via. Use a 22 µF X7R ceramic capacitor as the minimum input capacitance for full 3-A operation, per TI's evaluation module BOM.
Estimated: at VIN = 24 V, VOUT = 5 V, IOUT = 3 A, the loss budget is approximately (24 − 5) × 3 = 57 mW conduction plus switching loss around 250 mW total, so about 1.25 W. With a proper copper-pour area of ≥ 1 sq inch, the TSOT-23-6 (DDC) package sustains this at 25 °C ambient. For VIN = 24 V, VOUT = 3.3 V at 3 A full load (~3 W dissipation) the part is acceptable with reduced current or forced airflow; below VIN = 17 V the thermal limit is comfortable in any layout.
Use a 4-layer PCB with a dedicated ground plane for best EMI behavior; place the feedback divider (resistors to GND) within 5 mm of the FB pin to avoid noise coupling. Match the layout of TI's TPS54308EVM-876 evaluation module to guarantee loop-compensation stability across VIN and load transients. The TSOT-23-6 thermal pad must be soldered to a thermal via array of 4×4 vias at 0.3-mm pitch for adequate heat extraction.
The TPS54308DDCR operates at fixed 350 kHz with FCCM, which simplifies EMI filter design compared with auto-mode parts. To meet EN 55011 class B or FCC part 15 class B emissions on VIN, add a common-mode choke on the input (e.g., 10 mH CM inductor) plus 4.7 µF X7R Y-capacitor shunts at VIN. The fundamental frequency is 350 kHz; significant harmonics cluster at 1.05 MHz, 1.4 MHz, and 2.1 MHz, where the output LC filter (typically 1.5 µH inductor and 44 µF output capacitor) provides > 20 dB attenuation.
Estimate the output voltage ripple for the typical application at VOUT = 5 V, IOUT = 3 A: ripple ≈ VIN × VOUT × (VOUT − VOUT/VIN) / (2 × L × COUT × fSW^2) with L = 1.5 µH, COUT = 44 µF, fSW = 350 kHz; this predicts ~12 mV peak-peak ripple, comfortably below PSRR target for ADCs. For tighter ripple needs, increase COUT to 66 µF–100 µF; for very low noise rails (audio), consider a downstream LDO stage after the TPS54308.
Compliance Information
RoHS and REACH compliant per TI product page. MSL Level-1-260C-UNLIM per TI datasheet labeling. AEC-Q100 not qualified; for automotive safety applications, consult TI's TPS54308-Q1 prefix variant.
