19-3379; Rev 5; 11/11
KIT
ATION
EVALU
BLE
AVAILA
Dual, 256-Tap, Nonvolatile,
I
2
C-Interface, Digital Potentiometers
Features
o
Power-On Recall of Wiper Position from
Nonvolatile Memory
o
EEPROM Write Protection
o
Tiny 3mm x 3mm x 0.8mm Thin QFN Package
o
70ppm/°C End-to-End Resistance Temperature
Coefficient
o
10ppm/°C Ratiometric Temperature Coefficient
o
Fast 400kbps I
2
C-Compatible Serial Interface
o
1µA (max) Static Supply Current
o
Single-Supply Operation: +2.7V to +5.25V
o
256 Tap Positions per Potentiometer
o
±0.5 LSB DNL in Voltage-Divider Mode
o
±1 LSB INL in Voltage-Divider Mode
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 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 TQFN and 14-pin 4.4mm x
5mm TSSOP packages. These devices operate over
the extended -40°C to +85°C temperature range.
MAX5477/MAX5478/MAX5479
Functional Diagram
V
DD
GND
HA
8-BIT
SHIFT
REGISTER
8
16-BIT
LATCH
8
256
POSITION
DECODER
256
WA
POR
SDA
SCL
WP
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
A0
A1
A2
MAX5477
MAX5478
MAX5479
LB
Pin Configurations appear at end of data sheet.
Ordering Information/Selector Guide
PART
MAX5477ETE+T
MAX5477EUD+
MAX5478ETE+T
MAX5478EUD+
MAX5479ETE+T
MAX5479EUD+
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
-40°C to +85°C
PIN-PACKAGE
16 TQFN-EP*
14 TSSOP
16 TQFN-EP*
14 TSSOP
16 TQFN-EP*
14 TSSOP
END-TO-END
RESISTANCE (k )
10
10
50
50
100
100
TOP MARK
ABO
—
ABP
—
ABQ
—
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP
= Exposed pad.
________________________________________________________________
Maxim Integrated Products
1
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 TQFN (derate 17.5mW/°C above +70°C) .......1398mW
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
Soldering Temperature (reflow) .......................................+260°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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TQFN
Junction-to-Ambient Thermal Resistance (θ
JA
) ........57.2°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ................40°C/W
TSSOP
Junction-to-Ambient Thermal Resistance (θ
JA
) ......100.4°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ................30°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
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 2)
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 4)
INL
V
DD
= 3V
V
DD
= 5V
MAX5477
Differential Nonlinearity (Note 4)
DNL
MAX5478
MAX5479
±1
±1
±1
LSB
±3
±1.5
LSB
TC
R
INL
DNL
(Note 3)
(Note 3)
R0 and R1 set to same code (all codes)
70
10
-4
-0.6
-0.3
4
0.6
0.3
LSB
LSB
SYMBOL
CONDITIONS
MIN
256
±1
±0.5
±1
TYP
MAX
UNITS
Taps
LSB
LSB
LSB
ppm/°C
ppm/°C
DC PERFORMANCE (VOLTAGE-DIVIDER MODE)
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 2)
PARAMETER
Dual Code Matching
SYMBOL
CONDITIONS
R0 and R1 set to same code
(all codes), V
DD
= 3V or 5V
R
W
C
W
MAX5477
End-to-End Resistance
DIGITAL INPUTS
Input High Voltage (Note 6)
Input Low Voltage
Output Low Voltage
WP Pullup Resistance
Input Leakage Current
Input Capacitance
DYNAMIC CHARACTERISTICS
Crosstalk
HA = 1kHz (0 to V
DD
), LA = GND,
LB = GND, measure WB
MAX5477
3dB Bandwidth (Note 7)
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
, T
A
= +25°C (Note 8)
Supply Current
I
DD
Normal operation,
digital inputs at GND or
V
DD
, T
A
= +25°C
WP = GND
WP = V
DD
2.70
250
15
0.5
5.25
400
20.6
1
µA
V
MAX5478
MAX5479
THD+N
H_ = 1V
RMS
, f = 1kHz, L_ = GND,
measure W_
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
-75
400
100
50
0.003
%
kHz
dB
V
IH
V
IL
V
OL
I
WP
I
LEAK
5
V
DD
= 3.4V to 5.25V
V
DD
< 3.4V
(Note 6)
I
SINK
= 3mA
255
±1
2.4
0.7 x V
DD
0.8
0.4
V
V
V
k
µA
pF
R
HL
MAX5478
MAX5479
7.5
37.5
75
(Note 5)
325
10
10
50
100
12.5
62.5
125
k
MIN
TYP
MAX
±3
UNITS
LSB
MAX5477/MAX5478/MAX5479
DC PERFORMANCE (RESISTOR CHARACTERISTICS)
Wiper Resistance
Wiper Capacitance
675
pF
NONVOLATILE MEMORY RELIABILITY
50
200,000
50,000
Years
Stores
_______________________________________________________________________________________
3
Dual, 256-Tap, Nonvolatile, I
2
C-Interface,
Digital Potentiometers
MAX5477/MAX5478/MAX5479
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 9 and 10)
PARAMETER
ANALOG SECTION
MAX5477
Wiper Settling Time (Note 11)
DIGITAL SECTION
SCL Clock Frequency
Setup Time for START Condition
Hold Time for START Condition
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
f
SCL
t
SU:STA
t
HD:STA
t
HIGH
t
LOW
t
SU:DAT
t
HD:DAT
t
R
t
F
t
SU:STO
t
BUF
t
SP
C
B
(Note 12)
(Note 13)
Minimum power-up rate = 0.2V/µs
0.6
1.3
50
400
12
0.6
0.6
0.6
1.3
100
0
0.9
300
300
400
kHz
µs
µs
µs
µs
ns
µs
ns
ns
µs
µs
ns
pF
ms
t
WS
MAX5478
MAX5479
325
500
1000
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 2:
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 3:
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 4:
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 5:
The wiper resistance is measured using the source currents given in Note 3.
Note 6:
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 7:
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 8:
The programming current exists only during power-up and EEPROM writes.
Note 9:
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 10:
Digital timing is guaranteed by design and characterization, and is not production tested.
Note 11:
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 12:
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 13:
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)
MAX5477/78/79 toc01
SUPPLY CURRENT
vs. TEMPERATURE
MAX5477/78/79 toc1a
WIPER RESISTANCE
vs. INPUT CODE
WP = GND
450
400
WIPER RESISTANCE (Ω)
350
300
250
200
150
100
50
MAX5477/78/79 toc02
1.0
WP = V
DD
0.8
SUPPLY CURRENT (µA)
15
V
CC
= 5V
13
SUPPLY CURRENT (µA)
500
0.6
V
CC
= 5V
0.4
V
CC
= 3V
0.2
11
9
V
CC
= 3V
7
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
5
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
0
32
64
96
128 160 192 224 256
INPUT CODE
TAP-TO-TAP SWITCHING TRANSIENT
MAX5477/78/79 toc03
TAP-TO-TAP SWITCHING TRANSIENT
MAX5477/78/79 toc04
TAP-TO-TAP SWITCHING TRANSIENT
MAX5477/78/79 toc05
SDA
2V/div
SDA
2V/div
SDA
2V/div
W_
50mV/div
MAX5477
C
L
= 10pF
H_ = V
DD
FROM TAP 00 TO TAP 04
200ns/div
W_
20mV/div
MAX5478
C
L
= 10pF
H_ = V
DD
FROM TAP 00 TO TAP 04
1µs/div
MAX5479
C
W_
= 10pF
H_ = V
DD
FROM TAP 00 TO TAP 04
400ns/div
W_
20mV/div
WIPER TRANSIENT AT POWER-ON
MAX5477/78/79 toc06
WIPER TRANSIENT AT POWER-ON
MAX5477/78/79 toc07
WIPER TRANSIENT AT POWER-ON
MAX5477/78/79 toc08
V
DD
2V/div
V
DD
2V/div
V
DD
2V/div
W_
1V/div
W_
1V/div
MAX5477
TAP = 128
2µs/div
4µs/div
MAX5478
TAP = 128
2µs/div
W_
1V/div
MAX5479
TAP = 128
_______________________________________________________________________________________
5
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