MAX5477_06 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – Dual, 256-Tap, Nonvolatile, I2C-Interface, Digital Potentiometers

19-3379; Rev 4; 1/06
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Dual, 256-Tap, Nonvolatile,
I²C-Interface, Digital Potentiometers
General Description
The MAX5477/MAX5478/MAX5479 nonvolatile, dual,
linear-taper, digital potentiometers perform the function
of a mechanical potentiometer, but replace the
mechanics with a simple 2-wire digital interface. Each
device performs the same function as a discrete poten-
tiometer or variable resistor and has 256 tap points.
The devices feature an internal, nonvolatile EEPROM
used to store the wiper position for initialization during
power-up. A write-protect feature prevents accidental
overwrites of the EEPROM. The fast-mode I²C-compati-
ble serial interface allows communication at data rates
up to 400kbps, minimizing board space and reducing
interconnection complexity in many applications. Three
address inputs allow a total of eight unique address
combinations.
The MAX5477/MAX5478/MAX5479 provide three nomi-
nal resistance values: 10kΩ (MAX5477), 50kΩ
(MAX5478), or 100kΩ (MAX5479). The nominal resistor
temperature coefficient is 70ppm/°C end-to-end and
10ppm/°C ratiometric. The low temperature coefficient
makes the devices ideal for applications requiring a low-
temperature-coefficient variable resistor, such as low-
drift, programmable gain-amplifier circuit configurations.
The MAX5477/MAX5478/MAX5479 are available in 16-
pin 3mm x 3mm x 0.8mm thin QFN and 14-pin 4.4mm x
5mm TSSOP packages. These devices operate over
the extended -40°C to +85°C temperature range.
Applications
Mechanical Potentiometer Replacement
Low-Drift Programmable-Gain Amplifiers
Volume Control
Liquid-Crystal Display (LCD) Contrast Control
Features
♦ Power-On Recall of Wiper Position from
Nonvolatile Memory
♦ EEPROM Write Protection
♦ Tiny 3mm x 3mm x 0.8mm Thin QFN Package
♦ 70ppm/°C End-to-End Resistance Temperature
Coefficient
♦ 10ppm/°C Ratiometric Temperature Coefficient
♦ Fast 400kbps I²C-Compatible Serial Interface
♦ 1µA (max) Static Supply Current
♦ Single-Supply Operation: +2.7V to +5.25V
♦ 256 Tap Positions per Potentiometer
♦ ±0.5 LSB DNL in Voltage-Divider Mode
♦ ±1 LSB INL in Voltage-Divider Mode
Functional Diagram
VDD
HA
8-BIT
GND
SHIFT ⁸
REGISTER
16-BIT
LATCH
8
256
256
POSITION
DECODER
WA
POR
LA
SDA
I²C
SCL
INTERFACE
16-BIT
NV
MEMORY
8
256
256
HB
WP
POSITION
WB
DECODER
A0
MAX5477
LB
A1
MAX5478
A2
MAX5479
Ordering Information/Selector Guide
PART
TEMP RANGE
PIN-PACKAGE
MAX5477ETE*
-40°C to +85°C 16 Thin QFN
MAX5477EUD
-40°C to +85°C 14 TSSOP
MAX5478ETE*
-40°C to +85°C 16 Thin QFN
MAX5478EUD
-40°C to +85°C 14 TSSOP
MAX5479ETE*
-40°C to +85°C 16 Thin QFN
MAX5479EUD
-40°C to +85°C 14 TSSOP
*Future product—contact factory for availability.
Pin Configurations appear at end of data sheet.
END-TO-END
RESISTANCE (kΩ)
10
10
50
50
100
100
TOP
MARK
ABO
—
ABP
—
ABQ
—
PACKAGE CODE
T1633F-3
U14-1
T1633F-3
U14-1
T1633F-3
U14-1
________________________________________________________________ Maxim Integrated Products 1
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