Rainbow Electronics MAX5479 - Manual

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 I
2 C-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: 10k
Ω (MAX5477), 50kΩ
(MAX5478), or 100k Ω (MAX5479). The nominal resistor
temperature coefficient is 35ppm/°C end-to-end and
5ppm/°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
♦ 35ppm/°C End-to-End Resistance Temperature
Coefficient
♦ 5ppm/°C Ratiometric Temperature Coefficient
♦ Fast 400kbps I
2 C
†
-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
MAX5477/MAX5478/MAX5479
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
________________________________________________________________ Maxim Integrated Products 1
MAX5477
MAX5478
MAX5479
8-BIT
SHIFT
REGISTER
POR
16-BIT
LATCH
16-BIT
NV
MEMORY
SDA
SCL
WP
A0
A1
A2
8 256
POSITION
DECODER
8
8
256
256
POSITION
DECODER
256
HA
WA
LA
HB
WB
LB
V DD
GND
I 2 C
INTERFACE
Ordering Information/Selector Guide
Functional Diagram
19-3379; Rev 2; 12/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Pin Configurations appear at end of data sheet.
†Purchase of I 2 C components from Maxim Integrated
Products, Inc. or one of its sublicensed Associated
Companies, conveys a license under the Philips I
2 C Patent
Rights to use these components in an I 2 C system, provided
that the system conforms to the I 2 C Standard Specification as
defined by Philips.
PART TEMP RANGE PIN-PACKAGE
END-TO-END
RESISTANCE (k Ω)
TOP
MARK
PACKAGE CODE
MAX5477ETE* -40°C to +85°C 16 Thin QFN 10 ABO T1633F-3
MAX5477EUD* -40°C to +85°C 14 TSSOP 10 — —
MAX5478ETE* -40°C to +85°C 16 Thin QFN 50 ABP T1633F-3
MAX5478EUD -40°C to +85°C 14 TSSOP 50 — —
MAX5479ETE* -40°C to +85°C 16 Thin QFN 100 ABQ T1633F-3
MAX5479EUD -40°C to +85°C 14 TSSOP 100 — —
*Future product—contact factory for availability.