Features: ` Low Input (0.7V) and Output (1.8V) Voltage Capability
` Internal Synchronous Rectifier
` High 94% Efficiency
` Fixed Output Voltages: 1.8V, 2.5V, 3V, and 3.3V
` Up to 2MHz Switching Allows Small External Components and Low Output Ripple
` Automatic Pulse Skipping at Light Loads for Extended Battery Life
` Low 70A (typ) Operating Supply Current (Measured at OUT)
` Low 2A Logic-Controlled Shutdown
` True Shutdown Fully Discharges Output to Ground
` Uses Only Small Ceramic Capacitors
` 75ms RESET Output FlagApplication·MP3 Players, Pagers, and CD Players
·PDAs and Organizers
·Digital Still Cameras
·Cordless Phones
·Wireless Mice/Keyboards
·Portable Medical Equipment
·Other Battery-Powered SystemsPinout
SpecificationsBATT, OUT, SHDN to GND .......................................-0.3V to +4.0V
RESET to GND.............................................-0.3V to (VOUT + 0.3V)
PGND to GND ..........................................................-0.3V to +0.3V
Switch Current (ILX, IOUT, IPGND) (Note 1) .................-1A to +1A
Continuous Power Dissipation (TA = +70°C)
8-Pin TDFN (derate 24.4mW/°C above +70°C)........1951.2mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature........................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ..................................+300°C
Note 1: LX has internal clamp diodes to PGND and OUT. Applications that forward bias these diodes should take care not to exceed the IC's package power-dissipation limits.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe MAX1947 is a compact, high-efficiency, step-up DCDC converter that regulates output voltages from 1.8V to 3.3V to power P/DSP cores, memory, and I/O rails in 1-and 2-cell alkaline/NiMH/NiCd battery-powered systems.It features an internal 800mA switch and synchronous rectifier to achieve up to 94% efficiency and to eliminate the need for an external Schottky diode.
High-frequency switching (up to 2MHz) results in low ripple and small external components, while automatic pulse skipping at light loads reduces supply current to just 70A for extended battery life. Maxim's proprietary True Shutdown™ reduces supply current to just 2A and fully discharges the output to ground. The converter is offered in fixed-output voltages of 1.8V, 2.5V, 3.0V,and 3.3V, requiring no feedback or compensation network.A 75ms RESET output flag provides for power-on reset (POR) and undervoltage detection. The MAX1947 is available in a space-saving 8-pin TDFN package.
MAX1947 Data Sheet
