TPS542951RSAT

The TPS542951 is a dual, adaptive on-time D-CAP2™ mode synchronous buck converter. It helps system designers complete power bus regulator sets for a variety of end equipment through cost-effective, low component count, and low standby current solutions. The main control loop employs D-CAP2™ mode control, which provides extremely fast transient response without external compensation components. Adaptive on-time control supports seamless transition between PWM mode under heavy load conditions and Eco-mode™ operation under light loads. Eco-mode™ enables the TPS542951 to maintain high efficiency under light load conditions. It is capable of using low ESR and ultra-low ESR ceramic capacitors such as polymer organic semiconductor solid capacitors (POSCAP) or polymer capacitors (SP-CAP). This device provides convenient and efficient operation with input current between 4.5V and 18V. Available in a 4.4mm×5.0mm 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 TPS542951 is a 2A/3A dual synchronous buck converter with two integrated N-channel MOSFETs per channel, operating in D-CAP2™ control mode. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet specific performance levels. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and specialty polymer types. The main control loop of the TPS542951 is an adaptive on-time PWM controller supporting the proprietary D-CAP2™ control mode. D-CAP2™ control combines constant on-time control with internal compensation circuitry to achieve pseudo-fixed frequency and low external component count configurations, suitable for low ESR and ceramic output capacitors. It remains stable even with minimal output ripple. The TPS542951 employs an adaptive on-time control scheme with no dedicated on-board oscillator. By using the input voltage and output voltage to set the on-time timer, it operates at a pseudo-fixed frequency of 700kHz. The on-time is inversely proportional to the input voltage and directly proportional to the output voltage, so the frequency remains constant when the duty cycle is VOx/VINx. The TPS542951 is designed with automatic skip Eco-mode™ to improve light-load efficiency. As the output current decreases from heavy load conditions, the inductor current also decreases, eventually reaching the point where its ripple valley touches zero — the boundary between continuous conduction mode and discontinuous conduction mode.

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 7.0V
• Optimized high-efficiency integrated FETs for low duty cycle applications, 150mΩ (high-side) and 100mΩ (low-side)
• High initial reference accuracy
• Supports constant 2A CH1 and 3A CH2 load current
• Low-side rDS(on) lossless current sensing
• Adjustable soft-start
• Non-sinking pre-bias soft-start
• 700kHz switching frequency
• Cycle-by-cycle overcurrent limit control
• OCL / UVLO / TSD protection
• Hiccup timer for overload protection
• Adaptive gate driver with integrated boost PMOS switch
• Constant OCP due to thermally compensated rDS(on) at 4000ppm/°C
• 16-pin HTSSOP and 16-pin VQFN packages
• Automatic skip Eco-mode™ for high efficiency at light load