TPS54339DDAR

D-CAP2™ Mode Enables Fast Transient Response Low Output Ripple and Allows Ceramic Output Capacitor Wide VIN Input Voltage Range: 4.5 V to 23 V Output Voltage Range: 0.76 V to 7 V Highly Efficient Integrated FETs Optimized for Lower Duty Cycle Applications - 140 mΩ (High Side) and 70 mΩ (Low Side) High Efficiency, less than 10 μA at shutdown High Initial Bandgap Reference Accuracy Adjustable Soft Start • Pre-Biased Soft Start 600-kHz Switching Frequency (fSW) Cycle By Cycle Over Current Limit The TPS54339 is an adaptive on-time D-CAP2™ mode synchronous buck converter. The TPS54339 enables system designers to complete the suite of various end-equipment power bus regulators with a cost effective, low component count, low standby current solution. The main control loop for the TPS54339 uses the D-CAP2™ mode control that provides a fast transient response with no external compensation components. The TPS54339 also has a proprietary circuit that enables the device to adopt to both low equivalent series resistance (ESR) output capacitors, such as POSCAP or SP-CAP, and ultralow ESR ceramic capacitors. The device operates from 4.5 V to 23-V VIN input. The output voltage can be programmed between 0.76 V and 7 V. The device also features an adjustable soft start time. The TPS54339 is available in the 8-pin DDA package, and designed to operate from -40°C to 85°C. The TPS54339 is a 3-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs. It operates using D-CAP2™ mode control. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and special polymer types. The main control loop of the TPS54339 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ mode control. D-CAP2™ mode control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low ESR and ceramic output capacitors. It is stable even with virtually no ripple at the output. At the beginning of each cycle, the high-side MOSFET is turned on. This MOSFET is turned off after internal one shot timer expires. This one shot is set by the converter input voltage, VIN, and the output voltage, VO, to maintain a pseudo-fixed frequency over the input voltage range, hence it is called adaptive on-time control. The one-shot timer is reset and the high-side MOSFET is turned on again when the feedback voltage falls below the reference voltage. An internal ramp is added to reference voltage to simulate output ripple, eliminating the need for ESR induced output ripple from D-CAP2™ mode control. TPS54339 uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54339 runs with a pseudo-constant frequency of 600 kHz by using the input voltage and output voltage to set the on-time one-shot timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage; therefore, when the duty ratio is VOUT/VIN, the frequency is constant. The soft start function is adjustable. When the EN pin becomes high, 6 μA current begins charging the capacitor which is connected from the SS pin to GND. Smooth control of the output voltage is maintained during start up.

Applications

• Digital TV Power Supply
• High Definition Blu-ray Disc Players
• Networking Home Terminal
• Digital Set Top Box (STB)