DS1808 Dual Log Digital Potentiometer www.maxim-ic.com FEATURES PIN ASSIGNMENT Two 32-position log-tapers 60dB attenuation range: 16 V GND 1 DD 1dB per step (12 taps) V A2 15 2dB per step (12 taps) 2 CC A1 3dB per step (8 taps) SCL 3 14 90dB low-end attenuation V SDA B 4 13 2-Wire Interface Control CE A0 12 5 Power Supply: Dual 12V W 6 W0 11 Maximum Voltage Across Potentiometers: L0 H1 7 10 V 8 Standard Resistance Value: 45k H0 9 L1 Packages: 16-Pin SOIC o o 16-Pin SOIC (150-mil) Operating Temperature: -40 C to +85 C ORDERING INFORMATION PIN DESCRIPTION DS1808Z-050 16-Pin SOIC -40C to V - +12V Supply CC +85C 45k V - -12V Supply (substrate bias) B V - 5V Digital Supply DD DS1808Z-050/T&R 16-Pin SOIC -40C to H , H - High-end Terminals 0 1 +85C 45k L , L - Low-end Terminals 0 1 W , W - Wiper Terminals 0 1 SDA - 2-Wire Serial Data Input/Output SCL - 2-Wire Clock Input /CE - 2-Wire Interface Enable GND - Ground A0, A1, A2 - Address Pins DESCRIPTION The DS1808 is a dual-channel, digitally controlled, log-taper potentiometer. Each potentiometer is comprised of 32 wiper terminal positions plus a mute position. The device has three accessible potentiometer terminals that include the high-side terminal (H), the low-side terminal (L), and the wiper terminal (W). The resolution of the DS1808 is shown in Figure 8 and represents 1dB per step for the first 12 taps, 2dB per step for the next 12 taps and 3dB per step for the bottom 8 taps, providing a total attenuation range of 60dB. The mute position of the DS1808 provides greater than 90dB of attenuation. The wiper position on the resistor ladder is selected via a 6-bit register, whose value is controlled by the industry-standard 2-wire interface. The interface consists of two control signals: SDA and SCL. The DS1808 is available in a standard 45k resistor value. The DS1808 is specified to operate over the o o industrial temperature range (-40 C to +85 C) and is available in the 16-pin SOIC package. The DS1808 was designed for low-cost, stereo volume control applications. The device is specified to operate from 12V 10% supplies and accept a maximum input signal range of 12V. 1 of 17 072601DS1808 DS1808 BLOCK DIAGRAM Figure 1 W W 1 0 0dB 0dB H H 0 1 60dB 60dB L L 1 0 >90dB >90dB Address Lines SDA A0 A2 Control Logic CE SCL V (+12V Supply) CC Power Supply V (-12V Supply) GND B VDD (5V Supply) PIN DESCRIPTIONS V Power Supply Terminal. This pin acts as the positive rail. The DS1808 will support positive supply CC voltages ranging from 5 to 13.2 volts. When V V is less than 8 volts the series wiper resistance will CC B increase up to 1k . The value of V should never exceed V . DD CC V Substrate Bias Supply. This pin acts as a negative rail. The DS1808 will support negative voltages B ranging from 0 to -13.2 volts. When V V is less than 8 volts the series wiper resistance will increase CC B up to 1k . V DC Supply Terminal. 5V DC voltage supply. The value of V should never exceed V . DD DD CC GND Ground Terminal. SDA 2-wire serial data interface. The serial data pin is for serial data transfer to and from the DS1808. The pin is open drain and may be wire-ORed with other open drain or open collector interfaces. SCL 2-wire serial clock interface. The serial clock input is used to clock data into the DS1808 on rising edges and clock data out on falling edges. /CE Port Enable Pin. When active (/CE=0), the port inputs SDA and SCL are recognized by the device. If inactive (/CE=1), the port input pins SDA and SCL are disabled making 2-wire communication impossible. 2 of 17