19-3379; Rev 2; 12/04
Dual, 256-Tap, Nonvolatile, I
2
C-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 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: 10kΩ (MAX5477), 50kΩ
(MAX5478), or 100kΩ (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.
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
MAX5477/MAX5478/MAX5479
♦
256 Tap Positions per Potentiometer
♦
±0.5 LSB DNL in Voltage-Divider Mode
♦
±1 LSB INL in Voltage-Divider Mode
Functional Diagram
V
DD
GND
HA
8-BIT
SHIFT
REGISTER
8
16-BIT
LATCH
8
256
POSITION
DECODER
256
WA
POR
SDA
SCL
WP
A0
A1
A2
I
2
C
INTERFACE
16-BIT
NV
MEMORY
LA
HB
8
256
POSITION
DECODER
256
WB
Applications
Mechanical Potentiometer Replacement
Low-Drift Programmable-Gain Amplifiers
Volume Control
Liquid-Crystal Display (LCD) Contrast Control
MAX5477
MAX5478
MAX5479
LB
†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.
Ordering Information/Selector Guide
PART
MAX5477ETE*
MAX5477EUD*
MAX5478ETE*
MAX5478EUD
MAX5479ETE*
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 Thin QFN
14 TSSOP
16 Thin QFN
14 TSSOP
16 Thin QFN
END-TO-END
RESISTANCE (kΩ)
10
10
50
50
100
100
TOP
MARK
ABO
—
ABP
—
ABQ
—
PACKAGE CODE
T1633F-3
—
T1633F-3
—
T1633F-3
—
MAX5479EUD
-40°C to +85°C
14 TSSOP
*Future
product—contact factory for availability.
Pin Configurations appear at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
MAX5477/MAX5478/MAX5479
ABSOLUTE MAXIMUM RATINGS
SDA, SCL, V
DD
to GND .........................................-0.3V to +6.0V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Maximum Continuous Current into H_, L_, and W_
MAX5477......................................................................±5.0mA
MAX5478......................................................................±1.3mA
MAX5479......................................................................±0.6mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin Thin QFN (derate 17.5mW/°C above +70°C) 1399mW
14-Pin TSSOP (derate 9.1mW/°C above +70°C) .........727mW
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= +2.7V to +5.25V, H_ = V
DD
, L_ = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
= +5V, T
A
=
+25°C.) (Note 1)
PARAMETER
Resolution
Integral Nonlinearity
Differential Nonlinearity
Dual Code Matching
End-to-End Resistance
Temperature Coefficient
Ratiometric Resistance
Temperature Coefficient
MAX5477
Full-Scale Error
MAX5478
MAX5479
MAX5477
Zero-Scale Error
MAX5478
MAX5479
DC PERFORMANCE (VARIABLE-RESISTOR MODE)
Integral Nonlinearity (Note 3)
INL
V
DD
= 3V
V
DD
= 5V
V
DD
= 3V, MAX5477, guaranteed
monotonic
Differential Nonlinearity (Note 3)
DNL
V
DD
= 3V, MAX5478
V
DD
= 3V, MAX5479
V
DD
= 5V
Dual Code Matching
R0 and R1 set to same code
(all codes), V
DD
= 3V or 5V
R
W
C
W
MAX5477
End-to-End Resistance
R
HL
MAX5478
MAX5479
7.5
37.5
75
(Note 4)
325
10
10
50
100
12.5
62.5
125
kΩ
±3
±1.5
±1
±1
±1
±1
±3
LSB
LSB
LSB
TC
R
INL
DNL
(Note 2)
(Note 2)
R0 and R1 set to same code (all codes)
35
5
-3
-0.6
-0.3
3
0.6
0.3
LSB
LSB
SYMBOL
CONDITIONS
MIN
TYP
256
±1
±0.5
±1
MAX
UNITS
Taps
LSB
LSB
LSB
ppm/°C
ppm/°C
DC PERFORMANCE (VOLTAGE-DIVIDER MODE)
DC PERFORMANCE (RESISTOR CHARACTERISTICS)
Wiper Resistance
Wiper Capacitance
675
Ω
pF
2
_______________________________________________________________________________________
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +5.25V, H_ = V
DD
, L_ = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
= +5V, T
A
=
+25°C.) (Note 1)
PARAMETER
DIGITAL INPUTS
Input High Voltage (Note 5)
Input Low Voltage
Output Low Voltage
WP Pullup Resistance
Input Leakage Current
Input Capacitance
DYNAMIC CHARACTERISTICS
Crosstalk
3dB Bandwidth (Note 6)
Total Harmonic Distortion Plus
Noise
Data Retention
Endurance
POWER SUPPLY
Power-Supply Voltage
V
DD
Writing to EEPROM, digital inputs at
GND or V
DD
(Note 7)
Normal operation, digital WP = GND
inputs at GND or V
DD
WP = V
DD
2.70
250
15
0.5
5.25
400
20.6
1
µA
V
THD+N
HA = 1kHz (0 to V
DD
), LA = GND,
LB = GND, measure WB
MAX5478
MAX5479
H_ = 1V
RMS
, f = 1kHz, L_ = GND,
measure W_
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
-80
100
50
0.003
dB
kHz
%
V
IH
V
IL
V
OL
I
WP
I
LEAK
5
V
DD
= 3.4V to 5.25V
V
DD
< 3.4V
(Note 5)
I
SINK
= 3mA
255
±1
2.4
0.7 x V
DD
0.8
0.4
V
V
V
kΩ
µA
pF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5477/MAX5478/MAX5479
NONVOLATILE MEMORY RELIABILITY
50
200,000
50,000
Years
Stores
Supply Current
I
DD
TIMING CHARACTERISTICS
(V
DD
= +2.7V to +5.25V, H_ = V
DD
, L_ = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
= +5V,
T
A
= +25°C. See Figure 1.) (Notes 8 and 9)
PARAMETER
ANALOG SECTION
Wiper Settling Time (Note 10)
DIGITAL SECTION
SCL Clock Frequency
Setup Time for START Condition
Hold Time for START Condition
f
SCL
t
SU:STA
t
HD:STA
0.6
0.6
400
kHz
µs
µs
t
WS
MAX5478
MAX5479
500
1000
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
3
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
MAX5477/MAX5478/MAX5479
TIMING CHARACTERISTICS (continued)
(V
DD
= +2.7V to +5.25V, H_ = V
DD
, L_ = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
= +5V,
T
A
= +25°C. See Figure 1.) (Notes 8 and 9)
PARAMETER
SCL High Time
SCL Low Time
Data Setup Time
Data Hold Time
SDA, SCL Rise Time
SDA, SCL Fall Time
Setup Time for STOP Condition
Bus Free Time Between STOP
and START Condition
Pulse Width of Spike Suppressed
Capacitive Load for Each Bus
Line
Write NV Register Busy Time
SYMBOL
t
HIGH
t
LOW
t
SU:DAT
t
HD:DAT
t
R
t
F
t
SU:STO
t
BUF
t
SP
C
B
(Note 11)
(Note 12)
Minimum power-up rate = 0.2V/µs
0.6
1.3
50
400
12
CONDITIONS
MIN
0.6
1.3
100
0
0.9
300
300
TYP
MAX
UNITS
µs
µs
ns
µs
ns
ns
µs
µs
ns
pF
ms
Note 1:
All devices are production tested at T
A
= +25°C and are guaranteed by design and characterization for -40°C < T
A
< +85°C.
Note 2:
The DNL and INL are measured with the potentiometer configured as a voltage-divider with H_ = V
DD
and L_ = GND. The
wiper terminal is unloaded and measured with a high-input-impedance voltmeter.
Note 3:
The DNL and INL are measured with the potentiometer configured as a variable resistor. H_ is unconnected and L_ =
GND. For V
DD
= +5V, the wiper is driven with 400µA (MAX5477), 80µA (MAX5478), or 40µA (MAX5479). For V
DD
= +3V,
the wiper is driven with 200µA (MAX5477), 40µA (MAX5478), or 20µA (MAX5479).
Note 4:
The wiper resistance is measured using the source currents given in Note 3.
Note 5:
The devices draw current in excess of the specified supply current when the digital inputs are driven with voltages between
(V
DD
- 0.5V) and (GND + 0.5V). See Supply Current vs. Digital Input Voltage in the
Typical Operating Characteristics.
Note 6:
Wiper at midscale with a 10pF load (DC measurement). L_ = GND, an AC source is applied to H_, and the W_ output is
measured. A 3dB bandwidth occurs when the AC W_/H_ value is 3dB lower than the DC W_/H_ value.
Note 7:
The programming current exists only during power-up and EEPROM writes.
Note 8:
The SCL clock period includes rise and fall times (t
R
= t
F
). All digital input signals are specified with t
R
= t
F
= 2ns and
timed from a voltage level of (V
IL
+ V
IH
) / 2.
Note 9:
Digital timing is guaranteed by design and characterization, and is not production tested.
Note 10:
This is measured from the STOP pulse to the time it takes the output to reach 50% of the output step size (divider mode). It
is measured with a maximum external capacitive load of 10pF.
Note 11:
An appropriate bus pullup resistance must be selected depending on board capacitance. Refer to the I
2
C-bus specifica-
tion document linked to this web address: www.semiconductors.philips.com/acrobat/literature/9398/39340011.pdf
Note 12:
The idle time begins from the initiation of the STOP pulse.
4
_______________________________________________________________________________________
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
Typical Operating Characteristics
(V
DD
= +5V, H_ = V
DD
, L_ = GND, T
A
= +25°C, unless otherwise noted.)
MAX5477/MAX5478/MAX5479
SUPPLY CURRENT
vs. TEMPERATURE
MAX5477/78/79 toc01
WIPER RESISTANCE
vs. INPUT CODE
450
400
WIPER RESISTANCE (Ω)
350
300
250
200
150
100
50
0
MAX5477/78/79 toc02
TAP-TO-TAP SWITCHING TRANSIENT
MAX5477/78/79 toc03
1.0
0.9
0.8
SUPPLY CURRENT (µA)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
-15
10
35
60
V
DD
= 3V
V
DD
= 5V
500
SDA
2V/div
W_
20mV/div
MAX5478
C
L
= 10pF
H_ = V
DD
FROM TAP 00 TO TAP 04
0
32
64
96
128 160 192 224 256
1µs/div
85
TEMPERATURE (°C)
INPUT CODE
TAP-TO-TAP SWITCHING TRANSIENT
MAX5477/78/79 toc04
WIPER TRANSIENT AT POWER-ON
MAX5477/78/79 toc05
WIPER TRANSIENT AT POWER-ON
MAX5477/78/79 toc06
SDA
2V/div
V
DD
2V/div
V
DD
2V/div
MAX5479
C
W_
= 10pF
H_ = V
DD
FROM TAP 00 TO TAP 04
400ns/div
W_
20mV/div
MAX5478
TAP = 128
4µs/div
W_
1V/div
MAX5479
TAP = 128
2µs/div
W_
1V/div
INTEGRAL NONLINEARITY
vs. CODE (VDM MODE)
MAX5477/78/79 toc07
DIFFERENTIAL NONLINEARITY
vs. CODE (VDM MODE)
MAX5477/78/79 toc08
INTEGRAL NONLINEARITY
vs. CODE (VRM MODE)
MAX5478
0.2
0.1
INL (LSB)
0
-0.1
-0.2
-0.3
MAX5477/78/79 toc09
0.3
MAX5478
0.2
0.1
0
-0.1
-0.2
-0.3
0
32
64
96
0.3
MAX5478
0.2
0.1
DNL (LSB)
0
-0.1
-0.2
-0.3
0.3
INL (LSB)
128 160 192 224 256
CODE
0
32
64
96
128 160 192 224 256
CODE
0
32
64
96
128 160 192 224 256
CODE
_______________________________________________________________________________________
5
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