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, come in ultra-small QSOP packages, and require only small, low-profile external components.
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.
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Notebook ComputersPalmtop ComputersPersonal Digital AssistantsPortable Data-Collection Terminals
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1.8V to 20V Battery Input VoltageAutomatic Disable when Display Logic is Shut DownExtremely Small QSOP Package32-Level Internal DACSMBus Serial Interface (MAX1621)Positive or Negative Output Voltage
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VDD to AGND.............................................................-0.3V to 6V
PGND to AGND ..................................................................±0.3V
BATT, LX, LCDON to AGND.......................................-0.3V to 30V
DHI, DLO to PGND.....................................-0.3V to (VDD + 0.3V)
DOUT, FB, POL, POK, REF to AGND.............-0.3V to (VDD + 0.3V)
UP, DN, SHDN to AGND..............................................-0.3V to 6V
SCL, SDA, SUS to AGND.............................................-0.3V to 6V
IDHI ...................................................................................60mA
IDLO..................................................................................-30mA
ILCDON...............................................................................-10mA
Continuous Power Dissipation (TA = +70°C)
QSOP (derate 8.3mW/°C above +70°C) ....................667mW
Operating Temperature Range
MAX1620EEE/MAX1621EEE ............................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Post a Buying Lead
Required Field 
