The MAX1649CPA+ is a 5V, high efficiency, low-dropout, step-down DC-DC controller in 8 pin DIP package. This switching controller provides high efficiency over loads ranging from 1mA to more than 2.5A. A unique, current limited pulse frequency modulated (PFM) control scheme gives this device the benefits of pulse width modulation (PWM) converters (high efficiency at heavy loads), while using only 100μA of supply current (vs. 2mA to 10mA for PWM converters). Dropout performance down to 300mV is provided by a high switch duty cycle (96.5%) and a low current sense threshold (110mV). A high switching frequency (up to 300KHz) allows this device to use miniature external components. It has dropout voltages less than 0.3V at 500mA and accepts input voltages up to 16V and output voltage is preset at 5V. It can also be adjusted to any voltage from 1.5V to the input voltage by using two resistors. It is used in high-efficiency step-down regulation, 5V to 3.3V green PC applications and PDAs.
Supply voltage range is 3V to 16V
Operating temperature range from 0°C to 70°C
More than 90% efficiency (10mA to 1.5A loads)
More than 12.5W output power
Max quiescent supply current is 100μA at V+ = 16V, SHDN <= 0.4V (operating, switch off)
Max shutdown supply current is 5μA at V+ = 10V, SHDN >= 1.6V (shutdown)
Current-limited control scheme
EXT rise time & EXT fall time is 25ns at CEXT = 0.001μF, V+ = 12V
