Datasheet DS1801 (Analog Devices) - 2

DS1801
OPERATION
The DS1801 provides two 65-position potentiometers per package, each having a logarithmic resistive characteristic as shown in Table 1. The DS1801 is controlled by a 3-wire serial interface. The 3-wire serial interface is designed for CPU-controlled applications and allows the potentiometer’s exact wiper position to be read or written. The DS1801 design supports daisy-chaining for multi-device environments. Figure 1 presents a block diagram of the DS1801. As shown, the inputs from the 3-wire serial interface drive a command/control unit. The command/control unit interprets these inputs for control of the two potentiometers. On power-up, the serial port is stable and active within 10 microseconds. The wiper position on power-up will be at position 63, the low end of the potentiometer. Position 64 is the mute level.
RESISTANCE CHARACTERISTICS
Table 1
POSITION OUTPUT LEVEL (dB)
0 0 1 -1 2 -2 3 -3 4 -4 5 -5 63 -63 64(mute) <-90
DS1801 BLOCK DIAGRAM
Figure 1 2 of 10