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lamaPLC project: Digitales Potentiometer Board Moduls
A digital potentiometer (or “digipot”), such as the Renesas X9C series, is a semiconductor device that replicates the function of a mechanical potentiometer—varying resistance—but replaces the manual knob with digital control signals.
Renesas X9C series
The X9C102, X9C103, X9C104, and X9C503 are digitally controlled (XDCP) potentiometers. The device consists of a resistor array, wiper switches, a control section, and nonvolatile memory. The wiper position is controlled by a three-wire interface.
The potentiometer is implemented using a resistor array composed of 99 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 CS, U/D, and INC inputs. The wiper position can be stored in non-volatile memory and recalled upon subsequent power-up.
The device can be used as a three-terminal potentiometer or a two-terminal variable resistor in a wide variety of applications, from control to signal processing to parameter adjustment.
| Model | Total Resistance (R total) | Step Size (approx.) | Temp.Coefficient | Max Terminal Voltage Differential (ΔV) |
|---|---|---|---|---|
| X9C102 | 1 KΩ | 10.1 Ω | +600 ppm/°C | 4 V |
| X9C103 | 10 KΩ | 101 Ω | +300 ppm/°C | 10 V |
| X9C104 | 100 KΩ | 505 Ω | +300 ppm/°C | 10 V |
| X9C503 | 50 KΩ | 1010 Ω | +300 ppm/°C | 10 V |
- Resolution: 100 Wiper Tap Points (0–99).
- Interface: 3-wire serial (CS, U/D, INC).
- Memory: Non-volatile EEPROM (retains position for 100 years).
- Supply Voltage (Vcc): 5V
- Resistance Tolerance: ±20% end-to-end.
- Typical Wiper Resistance: 40 Ω at 1 mA
Full datasheet: https://www.renesas.com/en/document/dst/x9c102-x9c103-x9c104-x9c503-datasheet
Pinout for the Renesas X9C series module board
The Renesas X9C series module board, commonly known as the X9C103S module, organizes the chip's pins into two separate header rows, making it more convenient to connect with breadboards and microcontrollers such as Arduino. Usually, it includes a 5-pin control header on one side and a 3-pin potentiometer header on the opposite side.
| Header | Pin Label | Name | Function |
|---|---|---|---|
| Control | VCC | Power | Connects to +5V supply. |
| Control | GND | Ground | Circuit common ground. |
| Control | CS | Chip Select | Active LOW. Must be pulled low to enable control. |
| Control | INC | Increment | Negative-edge triggered. Pulses move the wiper. |
| Control | U/D | Up/Down | Direction: HIGH to increase, LOW to decrease. |
| Potentiometer | VH (or H) | High | High-end terminal of the pot (max +5V). |
| Potentiometer | VW (or W) | Wiper | The adjustable “middle” output pin. |
| Potentiometer | VL (or L) | Low | Low-end terminal of the pot (min -5V). |
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