DS2890 - 1-Wire Digital Potentiometer

NAME SYNOPSIS FAMILY CODE SPECIAL PROPERTIES chargepump wiper STANDARD PROPERTIES ALARMS DESCRIPTION DS2890 ADDRESSING DATASHEET SEE ALSO AVAILABILITY AUTHOR

NAME

DS2890 − 1-Wire Digital Potentiometer

SYNOPSIS

Variable resistance

2C [.]XXXXXXXXXXXX[XX][/[ chargepump | wiper | ]]

read-write, yes-no
State of the chargepump in the chip (0 = off 1 = on). Only available if external power is available (hence not in the TO-92 packaging) at pin Vdd.
When chargepump is on, the wiper resistance will range between Rh and Rl relatively linearly.
When chargepump is off, the wiper resistance (to ground) will range relatively linearly (to 100kOhms).

wiper

read-write, unsigned integer
Value of the variable element, 0 to 255. The actual interpretation of wiper depands on the chargepump state, but in general 0 is low and 255 is high.

STANDARD PROPERTIES

ALARMS

The device condition that will cause individual DS2890s to participate in a Conditional Search is a wiper position located at the power-on default setting (00h). This feature enables the bus master to easily determine whether a potentiometer has gone through a power-on reset and needs to be re-configured with a required wiper position setting.

DESCRIPTION

DS2890

The D2890 (3) allows variable resistance under 1-wire control. Possible uses are analog feedback mechanisms (sound pitch, light level).

Although there are provisions in the datasheet for different DS2890 configurations (non-linear wiper ranges, multiple wipers, different resistance scales) non are in production. To simplify implementation, this driver assumes the standard DS2890 design.