MAX640 MAXIM [Maxim Integrated Products], MAX640 Datasheet
MAX640
Available stocks
Related parts for MAX640
MAX640 Summary of contents
Page 1
... PWM converters). The result is high efficiency over a wide range of loads. The MAX639/MAX640/MAX653 input range 11.5V, and the devices provide lower preset output volt- ages of 5V, 3.3V, and 3V, respectively. Or, the output can be user-adjusted to any voltage from 1.3V to the input voltage ...
Page 2
... Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS ( for the MAX639 for the MAX640/MAX653, I unless otherwise noted.) PARAMETER ...
Page 3
... High-Efficiency, Low I ELECTRICAL CHARACTERISTICS (continued) ( for the MAX639 for the MAX640/MAX653, I unless otherwise noted.) PARAMETER Switch On-Resistance Switch Leakage V+ = 11.5V, V VFB Bias Current VFB = 2V VFB Dual-Mode Trip Point MAX6_ _C VFB Threshold MAX6_ _E/M LBI Bias Current ...
Page 4
... High-Efficiency, Low I , Step-Down DC-DC Converters Q _____________________________Typical Operating Characteristics (continued) (Circuit of Figure 3, internal feedback 100µH, T EFFICIENCY vs. OUTPUT CURRENT 100 L = 100 MAX639 MAX640 4.3V MAX653 10m 100m 10 100 1 OUTPUT CURRENT (A) MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE 250 L = 100 H MAX640 ...
Page 5
... OUTPUT CURRENT (mA) MAX640/MAX653 START-UP TIME vs. OUTPUT CURRENT 40 MEASURED FROM THE RISING EDGE SHDN TO (V OUT = 3.0V)(MAX653). THE OR (V OUT 30 START-UP TIME DIFFERENCE BETWEEN THE MAX640 AND THE MAX653 IS NEGLIGIBLE 470 5. OUTPUT CURRENT (mA) _______________________________________________________________________________________ , Step-Down DC-DC Converters Q = +25°C, unless otherwise noted.) ...
Page 6
High-Efficiency, Low I , Step-Down DC-DC Converters Q _____________________________Typical Operating Characteristics (continued) (Circuit of Figure 3, internal feedback 100µH, T MAX653 LOAD-TRANSIENT RESPONSE 1ms/div A: I 0mA TO 100mA, 50mA/div LOAD 100mV/div, AC COUPLED ...
Page 7
... Dual-Mode Feedback Pin. When VFB is grounded, the internal voltage divider sets the output VFB (MAX639), 3.3V (MAX640 (MAX653). For adjustable operation, connect VFB to an external volt- age divider. Shutdown Input — active low. When pulled below 0.8V, the LX power switch stays off, shutting down SHDN the regulator ...
Page 8
... Figure 3 shows the MAX639/MAX640/MAX653 block dia- gram and a typical connection in which 9V is converted to 5V (MAX639), 3.3V (MAX640), or 3.0V (MAX653). The sequence of events in this application is as follows: INPUT, +5.5V TO +11.5V (MAX639), +3.8V TO +11.5V (MAX640), +3.5V TO +11.5V (MAX653) ...
Page 9
... The low-battery comparator remains active in shutdown mode. Bringing SHDN below 0.8V places the MAX639/ MAX640/MAX643 in shutdown mode. LX becomes high impedance, and the voltage at VOUT falls to zero. The time required for the output to rise to its nominal regu- lated voltage when brought out of shutdown (start-up time) depends on the inductor value, input voltage, and load current (see the Start-Up Time vs ...
Page 10
... If the ON capacitor (Table 1). , the ON In most MAX639/MAX640/MAX653 circuits, the current in the external diode (D1, Figure 3) changes abruptly from zero to its peak value each time LX switches off. To avoid excessive losses, the diode must have a fast turn-on time. For low-power circuits with peak currents less than 100mA, signal diodes such as the 1N4148 perform well ...
Page 11
... For battery-powered applications, where the signal ground does not have to correspond to the power-supply ground, the circuit in Figure 6 generates 5V (MAX639), 3.3V (MAX640 (MAX653) from a pair of AA batter- ies. Connect the V and connect the output to your system’s ground input. This configuration has the added advantage of reduced on resistance, since the IC’ ...
Page 12
... Information (continued) PART TEMP. RANGE MAX640CPA 0°C to +70°C MAX640CSA 0°C to +70°C MAX640C/D 0°C to +70°C MAX640EPA -40°C to +85°C MAX640ESA -40°C to +85°C MAX640MJA -55°C to +125°C MAX653CPA 0°C to +70°C MAX653CSA 0°C to +70°C MAX653C/D 0°C to +70°C MAX653EPA -40° ...