19-3371; Rev 0; 7/04
KIT
ATION
EVALU
BLE
AVAILA
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
General Description
Features
♦
Wiper Position Stored in Nonvolatile Memory
(EEPROM) and Recalled Upon Power-Up or
Interface Command
♦
3mm x 3mm x 0.8mm TDFN Package
♦
35ppm/°C End-to-End Resistance Temperature
Coefficient
♦
5ppm/°C Ratiometric Temperature Coefficient
♦
50kΩ, 100kΩ, and 200kΩ Resistor Values
♦
5MHz SPI-Compatible Serial Interface
♦
500nA (typ) Static Supply Current
♦
Single-Supply Operation: +2.7V to +5.25V
♦
256 Tap Positions
♦
±0.5 LSB DNL in Voltage-Divider Mode
♦
±0.5 LSB INL in Voltage-Divider Mode
SPI is a trademark of Motorola, Inc.
MAX5422/MAX5423/MAX5424
The MAX5422/MAX5423/MAX5424 nonvolatile, linear-
taper, digital potentiometers perform the function of a
mechanical potentiometer, but replace the mechanics
with a simple 3-wire SPI™-compatible digital interface.
Each device performs the same function as a discrete
potentiometer 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. The 3-wire SPI-compatible serial interface
allows communication at data rates up to 5MHz, mini-
mizing board space and reducing interconnection com-
plexity in many applications.
The MAX5422/MAX5423/MAX5424 provide three nomi-
nal resistance values: 50kΩ (MAX5422), 100kΩ
(MAX5423), or 200kΩ (MAX5424). The nominal resistor
temperature coefficient is 35ppm/°C end-to-end and
only 5ppm/°C ratiometric. This makes the devices ideal
for applications requiring a low-temperature-coefficient
variable resistor, such as low-drift, programmable gain-
amplifier circuit configurations.
The MAX5422/MAX5423/MAX5424 are available in a
3mm x 3mm 8-pin TDFN package, and are specified
over the extended -40°C to +85°C temperature range.
Applications
Mechanical Potentiometer Replacement
Low-Drift Programmable Gain Amplifiers
Audio Volume Control
Liquid-Crystal Display (LCD) Contrast Control
Low-Drift Programmable Filters
Pin Configuration
TOP VIEW
V
DD
SCLK
DIN
CS
1
2
3
4
8
H
W
L
GND
Functional Diagram
H
8-BIT
SHIFT
REGISTER
8
8
256-
256
POSITION
DECODER
MAX5422
MAX5423
MAX5424
7
6
5
V
DD
GND
8-BIT
LATCH
W
L
CS
SCLK
DIN
SPI
INTERFACE
POR
8-BIT
NV
MEMORY
TDFN (3mm x 3mm)
MAX5422
MAX5423
MAX5424
Ordering Information/Selector Guide
PART
MAX5422ETA
MAX5423ETA
MAX5424ETA
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
END-TO-END
RESISTANCE (kΩ)
50
100
200
PIN-PACKAGE
8 TDFN-EP*
8 TDFN-EP*
8 TDFN-EP*
TOP MARK
AIJ
AII
AIH
*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.
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
MAX5422/MAX5423/MAX5424
ABSOLUTE MAXIMUM RATINGS
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
MAX5422......................................................................±1.3mA
MAX5423......................................................................±0.6mA
MAX5424......................................................................±0.3mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin TDFN (derate 24.4mW/°C above +70°C) .........1951mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°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. Typical values are at V
DD
= +5.0V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Resolution
Integral Nonlinearity
Differential Nonlinearity
End-to-End Resistance
Temperature Coefficient
Ratiometric Resistance
Temperature Coefficient
MAX5422
Full-Scale Error
MAX5423
MAX5424
MAX5422
Zero-Scale Error
MAX5423
MAX5424
DC PERFORMANCE (VARIABLE-RESISTOR MODE)
Integral Nonlinearity
(Note 2)
INL
V
DD
= 3V
V
DD
= 5V
V
DD
= 3V, MAX5422, -40°C
≤
T
A
≤
+85°C,
guaranteed monotonic
Differential Nonlinearity
(Note 2)
DNL
V
DD
= 3V, MAX5422, 0°C
≤
T
A
≤
+85°C,
guaranteed monotonic
V
DD
= 3V, MAX5423
V
DD
= 3V, MAX5424
V
DD
= 5V
DC PERFORMANCE (RESISTOR CHARACTERISTICS)
Wiper Resistance
Wiper Capacitance
End-to-End Resistance
R
W
C
W
MAX5422
MAX5423
MAX5424
37.5
75
150
V
DD
= 3V to 5.25V (Note 3)
325
10
50
100
200
62.5
125
250
kΩ
675
Ω
pF
-1.0
-1.0
±3.0
±1.5
+2.0
+1.2
±1.0
±1.0
±1.0
LSB
SYMBOL
N
INL
DNL
TC
R
(Note 1)
(Note 1)
35
5
-0.6
-0.3
-0.15
0.7
0.35
0.18
LSB
LSB
CONDITIONS
MIN
256
±0.5
±0.5
TYP
MAX
UNITS
Taps
LSB
LSB
ppm/°C
ppm/°C
DC PERFORMANCE (VOLTAGE-DIVIDER MODE)
LSB
2
_______________________________________________________________________________________
256-Tap, Nonvolatile, SPI-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. Typical values are at V
DD
= +5.0V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
DIGITAL INPUTS (CS, DIN, SCLK)
V
DD
= 3.4V to 5.25V
Input High Voltage (Note 4)
V
IH
V
DD
< 3.4V
V
DD
= 2.7V to 5.25V (Note 4)
±0.1
5
MAX5422
Wiper -3dB Bandwidth (Note 5)
MAX5423
MAX5424
NONVOLATILE MEMORY RELIABILITY
Data Retention
Endurance
POWER SUPPLY
Supply Voltage
Standby Current
Programming Current
V
DD
I
DD
I
PG
Digital inputs = V
DD
or GND, T
A
= +25°C
During nonvolatile write to memory; digital
inputs = V
DD
or GND (Note 6)
2.70
0.5
200
5.25
1
400
V
µA
µA
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
50
200,000
50,000
Years
Stores
100
50
25
kHz
2.4
0.7 x
V
DD
0.8
±1
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5422/MAX5423/MAX5424
Input Low Voltage
Input Leakage Current
Input Capacitance
DYNAMIC CHARACTERISTICS
V
IL
I
IN
C
IN
V
µA
pF
TIMING CHARACTERISTICS
(V
DD
= +2.7V to +5.25V, H = V
DD
, L = GND, T
A
= -40°C to +85°C. Typical values are at V
DD
= +5.0V, T
A
= +25°C, unless otherwise
noted. See Figure 1.) (Note 7)
PARAMETER
ANALOG SECTION
MAX5422
Wiper Settling Time (Note 8)
DIGITAL SECTION
SCLK Frequency
SCLK Clock Period
SCLK Pulse-Width High
SCLK Pulse-Width Low
CS
Fall to SCLK Rise Setup
SCLK Rise to
CS
Rise Hold
DIN to SCLK Setup
f
SCLK
t
CP
t
CH
t
CL
t
CSS
t
CSH
t
DS
200
80
80
80
0
50
5
MHz
ns
ns
ns
ns
ns
ns
t
S
MAX5423
MAX5424
400
600
1000
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
3
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
MAX5422/MAX5423/MAX5424
TIMING CHARACTERISTICS (continued)
(V
DD
= +2.7V to +5.25V, H = V
DD
, L = GND, T
A
= -40°C to +85°C. Typical values are at V
DD
= +5.0V, T
A
= +25°C, unless otherwise
noted. See Figure 1.) (Note 7)
PARAMETER
DIN Hold after SCLK
SCLK Rise to
CS
Fall Delay
CS
Rise to SCLK Rise Hold
CS
Pulse-Width High
Write NV Register Busy Time
SYMBOL
t
DH
t
CS0
t
CS1
t
CSW
t
BUSY
CONDITIONS
MIN
0
20
80
200
12
TYP
MAX
UNITS
ns
ns
ns
ns
ms
Note 1:
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 2:
The DNL and INL are measured with the potentiometer configured as a variable resistor. H is unconnected and L = GND.
For the 5V condition, the wiper terminal is driven with a source current of 80µA for the 50kΩ configuration, 40µA for the
100kΩ configuration, and 20µA for the 200kΩ configuration. For the 3V condition, the wiper terminal is driven with a source
current of 40µA for the 50kΩ configuration, 20µA for the 100kΩ, and 10µA for the 200kΩ configuration.
Note 3:
The wiper resistance is measured using the source currents given in Note 2. For operation to V
DD
= 2.7V, see Maximum
Wiper Resistance vs. Temperature in the
Typical Operating Characteristics.
Note 4:
The device draws higher 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 5:
Wiper at midscale with a 10pF load (DC measurement). L = GND; an AC source is applied to H; and the W output is mea-
sured. A 3dB bandwidth occurs when the AC W/H value is 3dB lower than the DC W/H value.
Note 6:
The programming current operates only during power-up and NV writes.
Note 7:
Digital timing is guaranteed by design and characterization, and is not production tested.
Note 8:
Wiper-settling time is the worst-case 0% to 50% rise-time measured between consecutive wiper positions. H = V
DD
, L =
GND, and the wiper terminal is unloaded and measured with a 10pF oscilloscope probe.
Typical Operating Characteristics
(V
DD
= 5.0V, T
A
= +25°C, unless otherwise noted.)
DNL vs. TAP POSITION
MAX5422 toc01
INL vs. TAP POSITION
MAX5422 toc02
WIPER RESISTANCE vs. TAP POSITION
V
DD
= 2.7V
I
SRC
= 50μA
MAX5422 toc03
0.25
0.20
0.15
0.10
DNL (LSB)
VOLTAGE-DIVIDER MODE
0.25
0.20
0.15
0.10
INL (LSB)
0.05
0
-0.05
-0.10
-0.15
-0.20
-0.25
VOLTAGE-DIVIDER MODE
700
600
RESISTANCE (Ω)
500
400
300
200
100
0.05
0
-0.05
-0.10
-0.15
-0.20
-0.25
0
32
64
96
128 160 192 224 256
TAP POSITION
0
32
64
96
128 160 192 224 256
0
0
32
64
96
128 160 192 224 256
TAP POSITION
TAP POSITION
4
_______________________________________________________________________________________
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
Typical Operating Characteristics (continued)
(V
DD
= 5.0V, T
A
= +25°C, unless otherwise noted.)
MAX5422/MAX5423/MAX5424
WIPER TRANSIENT AT POWER-ON
MAX5422 toc04
END-TO-END RESISTANCE %
CHANGE vs. TEMPERATURE
END-TO-END RESISTANCE % CHANGE
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-40
-15
10
35
60
85
MAX5422toc05
STANDBY SUPPLY CURRENT
vs. TEMPERATURE
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
V
DD
= 3.0V
V
DD
= 2.7V
60
85
TEMPERATURE (°C)
V
DD
= 5.25V
V
DD
= 4.0V
MAX5422 toc06
1.0
V
DD
1V/div
1.0
W
1V/div
C
L
= 10pF
TAP = 128
H = V
DD
4μs/div
TEMPERATURE (°C)
MAXIMUM WIPER RESISTANCE
vs. TEMPERATURE
MAX5422 toc07
SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
MAX5422 toc08
700
600
V
DD
= 2.7V
RESISTANCE (Ω)
500
400
300
200
100
0
-40
-15
10
35
60
V
DD
= 3.0V
V
DD
= 4.5V
V
DD
= 5.25V
600
500
SUPPLY CURRENT (µA)
400
300
200
100
0
85
0
1
2
3
4
5
TEMPERATURE (°C)
DIGITAL INPUT VOLTAGE (V)
THD+N RESPONSE
1:1 RATIO
20Hz TO 20kHz BANDPASS
MAX5422 toc09
100
10
1
THD+N (%)
INL vs. TAP POSITION
(MAX5422)
VARIABLE-RESISTOR MODE
V
DD
= 2.7V
I
SRC
= 50μA
MAX5422 toc10
2.0
1.5
1.0
0.1
0.01
0.001
INL (LSB)
10
100
1k
FREQUENCY (Hz)
10k
100k
0.5
0
-0.5
0.0001
-1.0
0
32
64
96
128 160 192 224 256
TAP POSITION
_______________________________________________________________________________________
5
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