Rainbow-electronics MAX653 Manual do Utilizador Página 1

________________________________________________________________Maxim Integrated Products1_______________General DescriptionThe MAX639/MAX640/MAX653 s

MAX639/MAX640/MAX653Step 3: L = 50 / IPEAK. L will be in µH. Do not use aninductor of less than 100µH.Step 4: Make sure that IPEAKdoes not exceed 0.6A

capacitor, even when the switch is off. This will usually notbe a problem for a 5V output at room temperature, sincethe diode’s reverse leakage curren

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters_Ordering Information (continued)_______________________

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters2 ______________________________________________________

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters________________________________________________________

010MAX640OUTPUT VOLTAGE RIPPLE vs.INPUT VOLTAGE25100MAX639-10V+ (V)OUTPUT VOLTAGE RIPPLE (mV)7751503 4 5 6 8 9 11 12IOUT = 25mAL = 100µH12550L = 220µH

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters________________________________________________________

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters6 ______________________________________________________

MAX639/MAX640/MAX6535V/3.3V/3V/Adjustable, High-Efficiency, Low IQ, Step-Down DC-DC Converters________________________________________________________

MAX639/MAX640/MAX653Figure 2 shows what happens to the ideal circuit ofFigure 1 if the switch turns on with a 66% duty cycle andV+ = 3/2 VOUT. The ind

Low-Battery DetectorThe low-battery detector compares the voltage on theLBI input with the internal 1.28V reference. LBO goeslow whenever the input vo