100-tap non-volatile digital pot in 8-uMAX
The DS1804U-100+ is a single-channel, 100-tap digital potentiometer with a linear taper and 100kΩ end-to-end resistance. The wiper position is stored in non-volatile memory, so the setting is retained across power cycles without a host microcontroller re-initializing the part on every boot.
Interface and control logic
The three-wire up/down interface (U/D, INC, CS) increments or decrements the wiper position with each pulse on the INC line while CS is low. This simple serial protocol requires no dedicated SPI or I²C bus — any three GPIO lines on a microcontroller can drive it. The wiper resistance is 400Ω typical, which sets the minimum resistance between the wiper and either end of the resistor string. For a 100kΩ pot, this is a negligible offset in most divider applications.
Package and board integration
The temperature coefficient is 750ppm/°C typical, which means the end-to-end resistance can shift by up to 75Ω per °C. For precision bias or reference applications, this drift should be budgeted into the system error analysis.