DS1808Z-050+T&R Maxim Integrated Products, DS1808Z-050+T&R Datasheet - Page 4

• Manufacturer Part Number: DS1808Z-050+T&R
• Description: IC POT DUAL LOG HV 50K 16-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of DS1808Z-050+T&R

• Taps: 32
• Resistance (ohms): 45K
• Number Of Circuits: 2
• Temperature Coefficient: 750 ppm/°C Typical
• Memory Type: Volatile
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 4.5 V ~ 5.5 V, ±4.5 V ~ 13.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Resistance In Ohms: 45K
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS1808
OPERATION
The DS1808 is a dual-channel, digitally controlled, logarithmic potentiometer. Each potentiometer has
three accessible terminals, which include H
L, and W. Between each resistor element is a tap-point that is
,
multiplexed to the wiper terminal, W. A block diagram of the DS1808 is shown in Figure 1.
Potentiometer Characteristics
The DS1808 is a volatile device and always powers-up with the wiper positions set to the mute position
(33-decimal) with 90-dB of signal attenuation. The resistor section of the DS1808 is composed of two 32-
position resistor arrays that provide a logarithmic attenuation. The resistor section of the DS1808
provides a typical 50kW end-to-end resistance between the H terminal and the L terminal. The wiper
th
terminal will have a total possible 34 tap positions. The 34
position is considered the mute position and
will provide attenuation in excess of 90dB.
The potentiometers of the DS1808 are closely matched and provide excellent tracking. Interchannel
matching for the device is specified to provide less than 0.5dB. Tap-to-tap tolerances for the device are
specified to provide less than 0.5dB.
Power Supplies
The DS1808 is designed to be powered from dual ±12V supplies. The maximum input signal that can be
placed across the potentiometer sections is ±12V. The device can also be powered using a single +12V
power source. When using the device in a single supply configuration, V
is set to 0V and the maximum
B
potentiometer input signals are restricted to single supply voltage rails.
Controlling the Potentiometers
All writing and reading to the potentiometers is done with the industry standard 2-wire interface, which
includes pins SDA and SCL.
2-WIRE SERIAL PORT OPERATION
The 2-wire serial port interface supports a bi-directional data transmission protocol with device
addressing. A device that sends data on the bus is defined as a transmitter, and a device receiving data as
a receiver. The device that controls the message is called a master. The devices that are controlled by the
master are slaves. The bus must be controlled by a master device that generates the serial clock (SCL),
controls the bus access, and generates the start and stop conditions. The DS1808 operates as a slave on
the two-wire bus. Connections to the bus are made via the open-drain I/O lines SDA and SCL. The
following I/O terminals control the 2-wire serial port: /CE, SDA, SCL, A0, A1, A2. Timing diagrams for
the 2-wire serial port can be found in Figures 2 and 7.
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