ISL90728UIE627ZL Digital Potentiometer ICs ISL90728 IND 6LD SC7 3 SNGL VOLATIL128E SC70-6

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ISL90728UIE627ZL Digital Potentiometer ICs ISL90728 IND 6LD SC7 3 SNGL VOLATILE 128

The Intersil ISL 90727 and ISL 90728 are digitally controlled
potentiometers (XDCPTM). Each device consists of a resistor
array, wiper switches, and a control section. The wiper
position is controlled by an 12c BusTM.
The potentiometer is implemented by a resistor array
composed of 127 resistive elements and a wiper switching
network. Between each element and at either end are tap
points accessible to the wiper terminal. The position of the
wiper element is controlled by the SDA and SCL inputs.

Features
●Volatile Solid-State Potentiometer
2c Serial Bus Interface
●DCP Terminal Voltage, 2.7V to 5.5V
●Low Tempco
- Rheostat - 45 ppm/°C Typical
- Divider- 15 ppm/°C Typical
●128 Wiper Tap Points
- Wiper Resistance 702 Typ at Vcc = 3.3V
●Low Power CMOS
- Active Current, 200μA Max
- Standby Current, 500nA Max
●Available RTOTAL Values = 50kL2, 10kQ
●Power-on Preset to Midscale

Packaging
-6Ld SC-70
●Pb-Free (RoHS Compliant)

Applications
●Mechanical Potentiometer Replacement
●Transducer Adjustment of Pressure, Temperature,
Position, Chemical, and Optical Sensors
●RF Amplifier Biasing
●LCD Brightness and Contrast Adjustment
●Gain Control and Offset Adjustment

Principles of Operation
The ISL90727 and ISL 90728 are integrated circuits
incorporating one DCP with its associated registers and an 2c
serial interface providing direct communication between a host
and the potentiometer.

DCP Description
The DCP is implemented with a combination of resistor elements
and CMOS switches. The physical ends of the DCP are
equivalent to the fixed terminals of a mechanical potentiometer
(RH and RL pins). The Rw pin of the DCP is connected to
intermediate nodes, and is equivalent to the wiper temminal ofa
mechanical potentiometer. The position of the wiper terminal
within the DCP is controlled by a 7-bit volatile Wiper Register
(WR). The DCP has its own WR. When the WR of the DCP
contains all zeroes (WR<6:0> = 00h), its wiper terminal (Rw) is
dlosest to its "Low" terminal (R ). When the WR of the DCP
contains all ones (WR<6:0> = 7Fh), its wiper terminal (Rw) is
dlosest to its "High" terminal (RH). As the value of the WR
increases from all zeroes (00h) to all ones (127 decimal), the
wiper moves monotonically from the position closest to RL to the
position closest to RH. At the same time, the resistance between
Rw and RL increases monotonically, while the resistance
between RH and Rw decreases monotonically. RL is connected
to the GND pin of the device, so the wiper movement will always
be relativeto R.
While the ISL90727 and ISL90728 are being powered up, the
WR is reset to 40h (64 decimal), which locates Rw roughly at
the center between RL and RH.
The WR and IVR can be read or written directly using the 12c
serial interface as described in the following sections.