MAX879 Datasheet | Maxim Integrated

Description The MAX877/MAX878/MAX879 are pulse-skipping, stepup/step-down DC-DC converters that provide a regulated output from inputs both above and below the output. They require only three external ponents- an inductor (typically 22µH) and two filter capacitors. The MAX877 delivers a regulated 5V output from 2.5V to 6.2V inputs. The MAX878 generates pin-selectable voltages of 3.0V or 3.3V from 1.5V to 6.2V inputs. The MAX879 output can be adjusted from 2.5V to 6V via an external resistor divider from 2.5V to 6.2V inputs. A unique high-power, internal, synchronous rectifier design (Active Rectifier™) enables the devices to regulate in a switched linear mode if the input voltage is higher than the desired output voltage. When the input voltage falls below the output voltage, the MAX877/MAX878/MAX879 will smoothly switch into a pulse-skipping boost mode and step up from input voltages as low as 1V. In shutdown, the active rectifier disconnects the output from the source. This stops the current drain from input to output associated with conventional step-up converters. High-frequency operation (up to 300k Hz) allows the use of small surface-mount inductors. Supply current is 195µA under no load, and only 20µA in shutdown mode. For 1-cell (1V) step-up converters with similar performance and the same pinout, refer to the MAX777/MAX778/MAX779 data sheet. MAX877/MAX878/MAX879 ______________Ordering Information PART MAX877CPA MAX877CSA MAX877C/D MAX877EPA MAX877ESA MAX877MJA TEMP. RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 8 Plastic DIP 8 SO Dice- 8 Plastic DIP 8 SO 8 CERDIP ________________________Applications Two or Three Ni Cd Cells to 3V/3.3V Conversion Three or Four Alkaline Cells to 5V Conversion One Lithium Cell to 3V/3.3V Conversion Pagers Palmtop and Notebook puters Battery-Powered and Hand-Held Instruments Ordering Information continued on last page. - Contact factory for dice specifications....