The TPS54335A is a 3-amp, synchronous step-down (buck) regulator. It accepts input voltages from 4.5 V up to 28 V. It uses an internal high-side MOSFET (128 mΩ) and low-side MOSFET (84 mΩ) to deliver up to 3 A of output current with high efficiency .

Electrical Specifications
• Input voltage range: 4.5 V to 28 V 
• Output current: up to 3 A 
• Reference voltage: 0.8 V. External resistor divider sets the output, e.g. VOUT = 0.8 V × (1 + R7/R8)
• Quiescent (shutdown) current: 2 µA 

Key Features
• Eco-mode operation reduces switching frequency under light loads. It lowers switching losses and improves light-load efficiency .
• Fixed 340 kHz switching frequency. Frequency can be adjusted externally from about 300 kHz to 1.3 MHz via a single resistor .
• Cycle-by-cycle current limiting on the high-side MOSFET protects against overload. Low-side sourcing and sinking limits prevent reverse currents and runaway. A hiccup-mode restart occurs if an overcurrent persists .
• Undervoltage lockout (UVLO) is adjustable via the EN pin threshold. A typical threshold sits near 4.3 V with hysteresis to prevent chatter .
• Thermal shutdown guards the device when junction temperature exceeds safe limits.

Design Considerations
• Layout must keep input decoupling capacitors close to the VIN and ground pins. This minimizes loop inductance and reduces noise.
• Compensation network (type II or type III) is external. Follow the TI evaluation-module schematic for component values to achieve stability across load and line variations.
• Use a thermally enhanced package (e.g. SON or VSON). Tie the exposed pad to a ground plane for heat dissipation.

Typical Application
A common design uses TPS54335A to step 12 V down to 5 V at up to 3 A. Designers choose a 47 µH inductor and low-ESR input/output capacitors. They set R7 and R8 for the desired output and use the EN pin to implement soft-start or UVLO control.

This regulator suits distributed power rails in automotive, industrial controls, telecom, and battery-powered systems. Its integrated MOSFETs and Eco-mode operation help minimize external parts and maintain efficiency across a wide load range.