MAX1621 Datasheet | Maxim Integrated

Description The MAX1620/MAX1621 convert a 1.8V to 20V battery voltage to a positive or negative LCD backplane bias voltage. Backplane bias voltage can be automatically disabled when the display logic voltage is removed, protecting the display. These devices use very little PC board area, e in ultra-small QSOP packages, and require only small, low-profile external ponents. Output voltage can be set to a desired positive or negative voltage range with external resistors, and adjusted over that range with the on-board digital-to-analog converter (DAC) or with a potentiometer. The MAX1620/ MAX1621 include a 5-bit DAC, allowing digital software control of the bias voltage. The MAX1620 uses up/down digital signaling to adjust the DAC, and the MAX1621 uses the System Management Bus (SMBus™) 2-wire serial interface. These devices use a low-cost, external, N-channel MOSFET power switch or NPN transistor, and can be configured for positive or negative output voltages. Operating current is a low 150µA, typically provided from a display’s logic supply of 3.0V to 5.5V. The MAX1620/MAX1621 are available in a 16-pin QSOP package. o 1.8V to 20V Battery Input Voltage o Automatic Disable when Display Logic is Shut Down o Extremely Small QSOP Package o 32-Level Internal DAC o SMBus Serial Interface (MAX1621) o Positive or Negative Output Voltage Features MAX1620/MAX1621 Ordering Information PART MAX1620EEE MAX1621EEE TEMP. RANGE -40°C to +85°C -40°C to +85°C PIN-PACKAGE 16 QSOP 16 QSOP Applications Notebook puters Palmtop puters Personal Digital Assistants Portable Data-Collection Terminals Typical Operating Circuit 2V TO 12V Pin Configuration TOP VIEW DN (SDA) 1 UP (SCL) 2 BATT 3 SHDN (SUS) 4 POK 5 REF 6 POL 7 LCDON 8 16 DHI 15 DLO 14 LX ON/OFF DOWN UP 3V TO 5.5V VDD POL BATT LX DHI DLO PGND 12.5V TO 23.5V OUT SHDN DN UP MAX1620 MAX1621 13 PGND 12 AGND 11 VDD 10 DOUT 9 FB MAX1620 REF AGND POK DOUT FB LCDON ( ) ARE FOR MAX1621 ONLY. QSOP SMBus is a trademark of Intel...