TPS54394RSAT

The TPS54394 is a dual, adaptive on-time D-CAP2™ mode synchronous buck converter. It helps system designers implement a power bus regulator set for various end equipment using a cost-effective, low component count, and low standby current solution. The main control loop employs D-CAP2™ mode control, which provides ultra-fast transient response without requiring external compensation components. Adaptive on-time control enables seamless transition between PWM mode under heavy load conditions and Eco-mode™ operation under light load. Eco-mode™ allows the TPS54394 to maintain high efficiency under light load conditions. It is also compatible with low ESR output capacitors such as polymer organic semiconductor solid capacitors (POSCAP), special polymer capacitors (SP-CAP), and ultra-low ESR ceramic capacitors. The device operates conveniently and efficiently with input voltages ranging from 4.5V to 18V. It is available in a 4.4mm×5mm 16-pin TSSOP (PWP) package and a 4mm×4mm 16-pin VQFN (RSA) package, with a rated ambient operating temperature range of -40°C to 85°C. The TPS54394 is a 3A/3A dual synchronous step-down (buck) converter with two integrated N-channel MOSFETs for each channel. It operates using D-CAP2™ control mode. The fast transient response of D-CAP2™ control reduces the required output capacitance 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 TPS54394 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ control mode. D-CAP2™ 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. TPS54394 uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54394 runs with a pseudo-fixed frequency of 700 kHz by using the input voltage and output voltage to set the on-time timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage, therefore, when the duty ratio is VOx/VINx, the frequency is constant. The TPS54394 is designed with Auto-Skip Eco-mode™ to increase light load efficiency. As the output current decreases from heavy load condition, the inductor current also reduces and eventually comes to the point where its ripple valley touches the zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when zero inductor current is detected.

Applications

• Point-of-load regulation for low-power systems across a wide range of applications
• Digital TV power supplies
• Networked home terminal equipment
• Digital set-top boxes (STB)
• DVD players/recorders
• Game consoles and other devices

Key features

• D-CAP2™ control mode, fast transient response, no external components required for loop compensation, compatible with ceramic output capacitors
• Wide input voltage range: 4.5V to 18V
• Output voltage range: 0.76V to 7V
• Optimized high-efficiency integrated FETs for low duty cycle applications, 90mΩ (high-side) and 60mΩ (low-side)
• High initial reference accuracy
• Supports constant 3A current on both channels
• Low-side rDS(on) low-loss current sensing
• Fixed soft-start time: 1ms
• Non-sinking pre-bias soft-start
• Power Good
• 700kHz switching frequency
• Cycle-by-cycle overcurrent limit control
• Hiccup timer for overload protection
• OCL / UVLO / TSD protection
• Adaptive gate driver with integrated bootstrap PMOS switch
• Constant OCP due to thermally compensated rDS(on) of 4000ppm/℃
• 16-pin HTSSOP and 16-pin VQFN packages
• Automatic skip Eco-mode™ for high efficiency at light loads