TPL0102

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SLIS134C – MARCH 2011 – REVISED SEPTEMBER 2015

8 Detailed Description

8.1 Overview

The TPL0102 has two linear-taper digital potentiometers with 256 wiper positions and an end-to-end resistance

of 100 k

Ω. Each potentiometer can be used as a three-terminal potentiometer or as a two-terminal rheostat. The

two potentiometers can both be used in Voltage Divider Mode, Rheostat Mode, or Shutdown Mode at the same

time, or any combination of those modes. For example, potentiometer A can be used in Voltage Divider Mode

and potentiometer B can be used in Voltage Divider Mode, or potentiometer A can be used in Voltage Divider

Mode and potentiometer B can be used in Rheostat Mode. The two potentiometers are functionally independent

of one another.

The High (H) and Low (L) terminals of the TPL0102 are equivalent to the fixed terminals of a mechanical

potentiometer. The H and L terminals do not have any polarity restrictions (H can be at a higher voltage than L,

or L can be at a higher voltage than H). The position of the wiper (W) terminal is controlled by the value in the

Wiper Resistance (WR) 8-bit register. When the WR register contains all zeroes (zero-scale), the wiper terminal

is closest to its L terminal. As the value of the WR register increases from all zeroes to all ones (full-scale), the

wiper moves monotonically from the position closest to L terminal to the position closest to the H terminal. At the

same time, the resistance between W and L increases monotonically, whereas the resistance between W and H

decreases monotonically.

The TPL0102 has non-volatile memory (EEPROM) which can be used to store the wiper position. When the

device is powered down, the last value stored in the Initial Value Register (IVR) will be maintained in the non-

volatile memory. When power is restored, the contents of the IVR are automatically recalled and loaded into the

corresponding WR register to set the wipers . The internal registers of the TPL0102 can be accessed using the

register can be written to directly without first writing to the IVR, depending upon the setting of the volatile

memory (VOL) in the ACR (Access Control Register). If the WR register is written to directly without writing to the

IVR as well, this results in the wiper position changing to a desired position, but the position will not be stored in

memory and will not be reloaded upon powering up the device.

With one TPL0102, a variable resistor with 512 settings can be used since there are two potentiometers in one

TPL0102. In order to achieve this, the two potentiometers should be in Rheostat Mode and wired so that terminal

L of potentiometer B is tied to terminal W of potentiometer A. This will provide 512 settings between terminal L of

potentiometer A and terminal W of potentiometer B.

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