DS1801 Dual Audio Taper Potentiometer www.dalsemi.com FEATURES PIN ASSIGNMENT Ultra-low power consumption Operates from 3V or 5V supplies GND 1 14 VCC Two digitally controlled, 65-position COUT 2 13 CLK potentiometers including mute RST 3 12 D Logarithmic resistive characteristics (1 dB ZCEN 4 11 AGND per step) W0 5 10 H1 Zero-crossing detection eliminates noise L0 6 9 L1 caused by wiper movement H0 7 8 W1 Serial port provides means for setting and reading both potentiometers wipers DS1801 14-Pin PDIP (300-mil) 14-pin PDIP, 16-pin SOIC, and 14-pin DS1801 14-Pin TSSOP (173-mil) TSSOP packages Operating Temperature Range: - Industrial: -40C to +85C GND 1 16 VCC Software mute Resistance available: 45 k COUT 2 15 CLK RST 3 14 D PIN DESCRIPTION ZCEN 4 13 NC L0, L1 - Low End of Resistor NC 5 12 AGND H0, H1 - High End of Resistor W0 6 11 H1 W0,W1 - Wiper End of Resistor L0 7 10 L1 V - 3V or 5V Power Supply Input CC H0 8 9 W1 RST - Serial Port Reset Input D - Serial Port Data Input DS1801S 16-PIN SOIC (300-mil) CLK - Serial Port Clock Input See Mech. Drawings Section GND - Digital Ground AGND - Analog Ground ZCEN - Zero-Crossing Detect Input C - Cascade Output OUT NC - No Connect DESCRIPTION The DS1801 is a dual audio taper potentiometer having logarithmic resistive characteristics over the device range. Each potentiometer provides 65 wiper positions with a 1 dB increment per step and device mute. The 3-wire serial interface, using a CPU, provides the user the ability of reading or writing exact wiper positions of the two potentiometers. Additionally, the part contains a zero-crossing detection feature that minimizes noise resulting from wiper transitions. Packages for the part include a 14-pin PDIP, 16-pin SOIC, and 14-pin TSSOP. 1 of 10 030300DS1801 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 potentiometers 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) 00 1-1 2-2 3-3 4-4 5-5 63 -63 64(mute) <-90 DS1801 BLOCK DIAGRAM Figure 1 2 of 10