Rainbow Electronics DS2890 - Manual (Page 2)

DS2890
2 of 28
PIN DESCRIPTION
SIGNAL
NAME
TYPE FUNCTION
1-WIRE I/O 1-Wire bus interface. Open drain, requires external pull-up resistor. Range:
2.8V – 6.0V. See HARDWARE CONFIGURATION for pull-up resistor
recommendations.
RH
I/O High end terminal of potentiometer resistor element. Range: 0V – 11.0V.
Range independent of 1-Wire or V
DD
supply levels as well as the voltage
levels applied to the other potentiometer terminals.
RL
I/O Low end terminal of potentiometer resistor element. Range: 0V – 11.0V.
Range independent of 1-Wire or V
DD
supply levels as well as the voltage
levels applied to the other potentiometer terminals.
WIPER
I/O Potentiometer wiper terminal. Range 0V – 11.0V. Range independent of
1-Wire or V
DD
supply levels as well as the voltage levels applied to the other
potentiometer terminals.
V
DD PWR Auxiliary power supply input. Range: 2.8V – 6.0V
GND
PWR Ground
DESCRIPTION
The DS2890 is a linear taper digitally controlled potentiometer with 256 wiper positions. Device
operation, including wiper position, is controlled over the single contact 1-Wire bus for the ultimate in
electrical interface simplicity. With a wide 0–11 volt working voltage range for the potentiometer
terminals, the DS2890 is ideal for a broad range of industrial and control applications. Potentiometer
terminal voltage is independent of device supply voltage as well as the voltage applied to the other
potentiometer terminals. Communication with the DS2890 follows the standard Dallas Semiconductor
1-Wire protocol and can be accomplished with minimal hardware such as a single port pin of a
microcontroller. Multiple DS2890 devices can reside on a common 1-Wire bus and be operated
independently of each other. Each DS2890 has its own unalterable 64-bit ROM registration number that
is factory lasered into the chip. The registration number guarantees unique identification for absolute
traceability and is used to address the device in a multi-drop 1-Wire Network environment. The DS2890
will respond to a 1-Wire Conditional Search command if the potentiometer wiper is set at the power-on
default position. This feature enables the bus master to easily determine whether a potentiometer has
gone through a power-on reset and needs to be re-configured with a required wiper position setting. The
DS2890 supports two power modes: a) 1-Wire only mode in which device power is supplied parasitically
from the 1-Wire and b) V
DD
mode where power is supplied from an external supply With a V
DD
supply
the device can support both a potentiometer and variable resistor configuration. When operating in a 1-
Wire only power mode the device supports only a variable resistor configuration.