The AD5207 provides a dual-channel, 256-bit, digitally controlled variable resistor (VR) device that performs the same function as a potentiometer or variable electronically adjusted resistor. Each channel of the AD5207 contains a fixed resistor with a tap at one point. The fixed resistance value of the wiper contact is loaded by digital code into the SPI-compatible serial input register. A linear change in the wiper, or between the fixed resistance endpoints, transfers the digital code to the VR latch. Variable resistors provide fully programmable resistance values between terminal and wiper or terminal B and wiper. Fixed B-terminal resistance of 10kΩ, 50kΩ or 100kΩ with a nominal 500 PPM/°C temperature coefficient of ±1% channel-to-channel matching tolerance Unique switching circuitry minimizes the high Fault resistor design and avoid any pre-break or breakbefore make operation. Each VR has its own VR latch, holding its programmed resistance value. These VR latches update the serial-to-parallel shift register internally, which is loaded from a standard 3-wire serial-in digital interface. 10 bits, to make up the data word, are required to clock the serial input register. The first two bits are the address bits. 256 steps of the resistance value represented by the following 8 data bits. The reason for two address bits instead of one is to be compatible with similar products, such as the AD8402, so that drop-in replacement is possible. The address bits determine the CS strobe that the corresponding VR latched data bit is loaded on the positive edge of the return. The serial data output pin on the other end of the serial register allows easy daisy-chaining of multiple VRE applications without additional external decode logic. An internal reset block will force the wiper to the midpoint position in every power-up condition. The SHDN pin forcibly opens a terminal on the circuit, at the same time shorts the wiper B terminal, to achieve a shutdown state of microwatt power. When SHDN is logic high, the previous latch setting puts the wiper at the same resistor setting prior to shutdown. The digital interface is still active during shutdown; code changes can generate new wiper positions when the device is resumed from shutdown. The AD5207 is available in a 1.1mm ultra-thin TSSOP-14 package, which is suitable for PCMCIA applications. All components are guaranteed to operate over the extended industrial temperature range of -40°C to +125°C.