The MAX649/MAX651/MAX652 BiCMOS, step-down DCDC switching controllers provide high efficiency over three decades of load current. A unique, current-limited pulse-frequency-modulated (PFM) control scheme gives these devices 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). The result is high efficiency over loads ranging from 10mA to more than 2.5A.
These devices use miniature external components. Their high switching frequency (up to 300kHz) allows for less than 9mm diameter surface-mount inductors.
The MAX649/MAX651/MAX652 have dropout voltages less than 1V and accept input voltages up to 16.5V. Output voltages are preset at 5V (MAX649), 3.3V (MAX651), and 3V (MAX652). These controllers can also be adjusted to any voltage from 1.5V to the input voltage by using two resistors.
These step-down controllers drive external P-channel MOSFETs at loads greater than 10W. If less power is required, use the MAX639/MAX640/MAX653 step-down converters with on-chip FETs, which allow up to a 225mA load current.
|
|
|
5V-to-3.3V Green PC ApplicationsHigh-Efficiency Step-Down RegulationMinimum-Component DC-DC ConvertersBattery-Powered Applications
|
More than 90% Efficiency (10mA to 1.5A Loads)More than 12.5W Output Power100µA Max Quiescent Supply Current5µA Max Shutdown Supply Current Less than 1.0V Dropout Voltage16.5V Max Input Voltage5V (MAX649), 3.3V (MAX651), 3V (MAX652), or Adjustable Output Voltage Current-Limited Control SchemeUp to 300kHz Switching Frequency
|
Supply Voltage, V+ to GND........................................-0.3V, +17V
REF, SHDN, FB, CS, EXT, OUT ..........................-0.3V, (V+ + 0.3V)
Continuous Power Dissipation (TA = +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW
SO (derate 5.88mW/°C above +70°C)..........................471mW
CERDIP (derate 8.00mW/°C above +70°C)...................640mW
Operating Temperature Ranges
MAX649C_A, MAX65_C_A ....................................0°C to +70°C
MAX649E_A, MAX65_E_A .................................-40°C to +85°C
MAX649MJA, MAX65_MJA ................................-55°C to +125°C
Storage Temperature Range ..........................-65°C to +160°C
Lead Temperature (soldering, 10sec) ............................+300°C
Post a Buying Lead
Required Field 
