MAX5477 Ver la hoja de datos (PDF) - Maxim Integrated
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MAX5477 Datasheet PDF : 16 Pages
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Dual, 256-Tap, Nonvolatile, I2C-Interface,
Digital Potentiometers
Detailed Description
The MAX5477/MAX5478/MAX5479 contain two resistor
arrays with 255 elements in each array. The MAX5477
has a total end-to-end resistance of 10kΩ, the
MAX5478 has an end-to-end resistance of 50kΩ, and
the MAX5479 has an end-to-end resistance of 100kΩ.
The MAX5477/MAX5478/MAX5479 provide access to
the high, low, and wiper terminals for a standard volt-
age-divider configuration. Connect H_, L_, and W_ in
any desired configuration as long as their voltages
remain between GND and VDD.
A simple 2-wire I2C-compatible serial interface moves
the wiper among the 256 tap points (Figure 2). A non-
volatile memory stores the wiper position and recalls
the stored wiper position upon power-up. The non-
volatile memory is guaranteed for 50 years for wiper
data retention and up to 200,000 wiper store cycles.
Analog Circuitry
The MAX5477/MAX5478/MAX5479 consist of two resistor
arrays with 255 resistive elements; 256 tap points are
accessible to the wipers, along the resistor string
between H_ and L_. The wiper tap point is selected by
programming the potentiometer through the I2C inter-
face. An address byte, a command byte, and 8 data bits
program the wiper position for each potentiometer. The
H_ and L_ terminals of the MAX5477/MAX5478/
MAX5479 are similar to the two end terminals of a
mechanical potentiometer. The MAX5477/MAX5478/
MAX5479 feature power-on reset circuitry that loads the
wiper position from the nonvolatile memory at power-up.
Table 1. Slave Addresses
ADDRESS INPUTS
A2
A1
A0
GND
GND
GND
GND
GND
VDD
GND
VDD
GND
GND
VDD
VDD
GND
VDD
GND
VDD
VDD
GND
VDD
VDD
GND
VDD
VDD
VDD
SLAVE ADDRESS
0101000
0101001
0101010
0101011
0101100
0101101
0101110
0101111
H_
256-POSITION
DECODER
S256
R255
S255
R254
S254
RW
W_
S3
R2
WIPER
CODE 02h
S2
R1
S1
L_
Figure 2. Potentiometer Configuration
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