The TPS54331DR device is a 28-V, 3-A, step-down (buck) converter with an integrated high-side n-channel MOSFET. To improve performance during line and load transients, the device implements a constant-frequency,current mode control which reduces output capacitance and simplifies external frequency compensation design.
The TPS54331DR device has a preset switching frequency of 570 kHz.The TPS54331DR device requires a minimum input voltage of 3.5 V for normal operation.
The EN pin has an internal pullup current source that can adjust the input-voltage undervoltage lockout (UVLO) with two external resistors. In addition, the pullup current provides a default condition when the EN pin is floating for the device to operate.
The operating current is 110 μA (typical) when not switching and under no load. When the device is disabled, the supply current is 1 μA (typical).
The integrated 80-mΩ high-side MOSFET allows for high-efficiency power-supply designs with continuous output currents up to 3 A.
The TPS54331DR device reduces the external component count by integrating the boot recharge diode.
The bias voltage for the integrated high-side MOSFET is supplied by an external capacitor on the BOOT to PH pin. The boot capacitor voltage is monitored by an UVLO circuit and turns the high-side MOSFET off when the voltage falls below a preset threshold of 2.1 V (typical). The output voltage can be stepped down to as low as the reference voltage.
By adding an external capacitor, the slow-start time of the TPS54331DR device can be adjustable which enables flexible output filter selection.To improve the efficiency at light load conditions, the TPS54331DR device enters a special pulse skipping Ecomode.when the peak inductor current drops below 160 mA (typical).The frequency foldback reduces the switching frequency during startup and overcurrent conditions to help control the inductor current. The thermal shutdown provides additional protection under fault conditions.
Feature
- 3.5 to 28-V Input Voltage Range
- Adjustable Output Voltage Down to 0.8 V
- Integrated 80-m? High-Side MOSFET Supports up to 3-A Continuous OutputCurrent
- High Efficiency at Light Loads With a Pulse Skipping Eco-mode?
- Fixed 570 kHz Switching Frequency
- Typical 1-μA Shutdown Quiescent Current
- Adjustable Slow-Start Limits Inrush Currents
- Programmable UVLO Threshold
- Overvoltage Transient Protection
- Cycle-by-Cycle Current Limit, Frequency Fold Back, and Thermal ShutdownProtection
- Available in Easy-to-Use SOIC8 Package or Thermally Enhanced SOIC8PowerPAD? Package
- Create aCustom Design with WEBENCH Tools
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DescriptionThe TPS54331 device is a 28-V, 3-A non-synchronous buck converter that integrates a lowRDS(on) high-side MOSFET. To increase efficiency at light loads, a pulseskipping Eco-mode feature is automatically activated. Furthermore, the 1-μA shutdown supply-currentallows the device to be used in battery-powered applications. Current mode control with internalslope compensation simplifies the external compensation calculations and reduces component countwhile allowing the use of ceramic output capacitors. A resistor divider programs the hysteresis ofthe input undervoltage lockout. An overvoltage transient protection circuit limits voltageovershoots during startup and transient conditions. A cycle-by-cycle current-limit scheme,frequency foldback and thermal shutdown protect the device and the load in the event of an overloadcondition. The TPS54331 device is available in an 8-pin SOIC package and 8-pin SO PowerPAD packagethat have been internally optimized to improve thermal performance.
