Overview
The TPS54308DDCT from Texas Instruments is a high-performance, synchronous step-down (buck) converter designed to handle a wide input voltage range and high output current. This device is integrated with two n-channel MOSFETs, an 85-mΩ high-side MOSFET and a 40-mΩ low-side MOSFET, enabling continuous output currents up to 3 A. The TPS54308 operates in force continuous conduction mode (FCCM) during light load conditions, maintaining a constant switching frequency of 350 kHz. This feature is particularly beneficial for applications requiring tight control over the switching frequency and output voltage ripple. The device also includes internal loop compensation, a 5-ms soft-start function, and various protection mechanisms such as overcurrent, overvoltage, and thermal shutdown.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage Range | 4.5 | - | 28 | V |
| Output Current | - | - | 3 | A |
| Switching Frequency | 255 | 350 | 445 | kHz |
| High-Side MOSFET Rds(on) | 85 | - | - | mΩ |
| Low-Side MOSFET Rds(on) | 40 | - | - | mΩ |
| Quiescent Current (Non-Switching) | - | 300 | - | μA |
| Shutdown Current | - | 2 | - | μA |
| Operating Junction Temperature | -40 | - | 150 | °C |
| Thermal Shutdown Temperature | - | 165 | - | °C |
| Package Type | - | - | SOT-23(6) | - |
Key Features
- Wide Input Voltage Range: 4.5 V to 28 V
- Integrated MOSFETs: 85-mΩ high-side and 40-mΩ low-side MOSFETs for high efficiency
- Fixed Switching Frequency: 350 kHz
- Force Continuous Conduction Mode (FCCM): Maintains switching frequency during light load conditions
- Internal Loop Compensation: Minimizes external component count
- Internal Soft Start: 5-ms soft-start time to reduce inrush currents
- Protection Mechanisms: Overcurrent, overvoltage, and thermal shutdown protection
- Small Footprint: SOT-23(6) package for high power density
Applications
- Distributed Power Systems: 12-V and 24-V power-bus supplies
- Consumer Electronics: Audio equipment, set-top boxes, DTV, printers
- Industrial Applications: White goods, industrial power supplies
- Automotive Systems: Car audio power supplies
Q & A
- What is the input voltage range of the TPS54308?
The input voltage range is from 4.5 V to 28 V.
- What is the maximum continuous output current of the TPS54308?
The maximum continuous output current is 3 A.
- What is the switching frequency of the TPS54308?
The switching frequency is fixed at 350 kHz.
- What type of MOSFETs are integrated into the TPS54308?
The device includes an 85-mΩ high-side MOSFET and a 40-mΩ low-side MOSFET.
- What is the quiescent current when the device is not switching?
The quiescent current is typically 300 μA when the device is not switching.
- What is the shutdown current of the TPS54308?
The shutdown current is typically 2 μA.
- What protection mechanisms are built into the TPS54308?
The device includes overcurrent, overvoltage, and thermal shutdown protection.
- What is the operating junction temperature range of the TPS54308?
The operating junction temperature range is from -40°C to 150°C.
- What package type is the TPS54308 available in?
The device is available in a SOT-23(6) package.
- How does the TPS54308 handle light load conditions?
The device operates in force continuous conduction mode (FCCM) during light load conditions, maintaining a constant switching frequency.
