19-2462; Rev 2; 3/05
KIT
ATION
EVALU
BLE
AVAILA
One-Time Programmable, Linear-Taper
Digital Potentiometers
General Description
Features
♦
Wiper Position Stored After One-Time Fuse
Programming
♦
User-Defined Power-On Reset Position
♦
35ppm/°C End-to-End Temperature Coefficient
and 5ppm/°C Ratiometric Temperature Coefficient
♦
32 Tap Positions
♦
Tiny 8-Pin Thin QFN and µMAX Packages
♦
Ultra-Low 1.5µA (max) Static Supply Current
♦
2.7V to 5.5V Single-Supply Operation
♦
Wiper Position Programmed Through Simple
2-Wire Serial Interface
♦
10kΩ, 50kΩ, and 100kΩ End-to-End Resistances
MAX5427/MAX5428/MAX5429
The MAX5427/MAX5428/MAX5429 linear-taper digital
potentiometers function as mechanical potentiometers,
but replace the mechanics with a simple 2-wire digital
interface. These digital potentiometers are unique in that
they have an optional one-time programmable feature
that either sets the wiper’s power-on reset (POR) posi-
tion to a user-defined value, or the wiper can be set and
the interface disabled to prevent further adjustment.
The MAX5427 has an end-to-end resistance of 100kΩ,
the MAX5428 a resistance of 50kΩ, and the MAX5429 a
resistance of 10kΩ. All these devices have 32 wiper
positions, operate from a single 2.7V to 5.5V supply, and
use less than 1.5µA (max) static supply current.
The MAX5427/MAX5428/MAX5429 are available in
8-pin thin QFN and µMAX
®
packages. Each device is
guaranteed over the extended temperature range of
-40°C to +85°C.
Ordering Information
PART
MAX5427EUA
MAX5427ETA
MAX5428EUA
MAX5428ETA
MAX5429EUA
MAX5429ETA
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
8 µMAX
8 Thin QFN-EP*
8 µMAX
8 Thin QFN-EP*
8 µMAX
8 Thin QFN-EP*
R (kΩ)
100
100
50
50
10
10
Applications
Mechanical Potentiometer Replacement
Products Using One-Time Factory Calibration
Pin Configurations
TOP VIEW
W
CS
V
DD
GND
1
2
3
4
MAX5427
MAX5428
MAX5429
8
7
6
5
H
L
U/D
V
PP
*EP
= Exposed paddle.
Functional Block Diagram
H
8
V
DD
3
4
S
32
MAX5427
MAX5428
MAX5429
R
31
µMAX
GND
S
31
R
30
*
W
CS
V
DD
GND
1
2
3
4
MAX5427
MAX5428
MAX5429
*
8
7
6
5
H
CS
L
2
6
UP/DOWN
COUNTER
U/D
U/D
32-
POSITION
DECODER
R
2
S
30
S
3
R
W
1
W
V
PP
V
PP
5
ONE-TIME
PROGRAM
BLOCK
R
1
S
2
QFN
*EXPOSED PADDLE. CONNECTED TO GND.
S
1
7
L
µMax is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
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.
One-Time Programmable, Linear-Taper
Digital Potentiometers
MAX5427/MAX5428/MAX5429
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ...........................................................-0.3V to +6.0V
V
PP
to GND..........................................................-0.3V to +12.0V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Input and Output Latchup Immunity...............................±200mA
Maximum Continuous Current into H, L, and W
MAX5427 .................................................................±1.5mA
MAX5428 .................................................................±1.5mA
MAX5429 .................................................................±2.0mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW
8-Pin QFN-EP (derate 24.4mW/°C above +70°C)......1951mW
Operating Temperature Range ...........................-40°C to +85°C
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 5.5V, V
PP
= GND, V
H
= V
DD
, V
L
= GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
=
5.0V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
DC PERFORMANCE
Resolution
MAX5427
End-to-End Resistance
End-to-End Resistance Tempco
Ratiometric Resistance Tempco
Integral Nonlinearity
Differential Nonlinearity
Full-Scale Error
Zero-Scale Error
Wiper Resistance
DIGITAL INPUTS (CS, U/D)
Input High Voltage
Input Low Voltage
Input Current
Input Capacitance
TIMING CHARACTERISTICS
(Note 2)
U/D Mode to
CS
Setup
CS
Hold to U/D Mode
U/D Step Hold to
CS
U/D Step Low Time
t
CU
t
CI
t
IC
t
IL
Figures 2, 3
Figures 2, 3
Figures 2, 3
Figures 2, 3
50
50
0
100
ns
ns
ns
ns
V
IH
V
IL
I
IN
C
IN
±0.1
5
0.7
x
V
DD
0.3
x
V
DD
±1
V
V
µA
pF
R
W
INL
DNL
TC
R
MAX5427/MAX5428
MAX5429
Potentiometer configuration, no load,
Figure 1
Potentiometer configuration, no load,
Figure 1
Potentiometer configuration, no load,
Figure 1
Potentiometer configuration, no load,
Figure 1
MAX5427 I
W
= 20µA; MAX5428 I
W
= 40µA;
MAX5429 I
W
= 200µA
100
MAX5428
MAX5429
32
75
37.5
7.5
100
50
10
35
5
10
±1
±1
-0.5
+0.5
240
125
62.5
12.5
ppm/°C
ppm/°C
LSB
LSB
LSB
LSB
Ω
kΩ
Taps
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
One-Time Programmable, Linear-Taper
Digital Potentiometers
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 2.7V to 5.5V, V
PP
= GND, V
H
= V
DD
, V
L
= GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
DD
=
5.0V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
U/D Step High Time
Wiper Switching Time
V
PP
Rising Edge to
CS
Falling
Edge
CS
Falling Edge to V
PP
Falling
Edge
CS
Step Low Time
CS
Step High Time
V
PP
Falling Edge to
CS
Rising
Edge
U/D Frequency
Power-Up Time
SYMBOL
t
IH
t
IW
t
PC
t
CP
t
CL
t
CH
t
PH
f
U/DMAX
t
UP
(Note 3)
100kΩ variable resistor configuration,
C
L
= 10pF, Figure 1
100kΩ potentiometer configuration,
C
L
= 10pF, Figure 1
2.7
(Note 4)
T
A
< +50°C
T
A
≥
+50°C
V
PP
= 11V
10.45
11
5
1
µs
0.25
Figures 2, 3
C
L
= 0pF, Figures 2, 3
Figure 4
Figure 4
Figure 4
Figure 4
Figure 4
1
5
5
5
1
5
1
CONDITIONS
MIN
100
100
TYP
MAX
UNITS
ns
ns
ms
ms
ms
ms
ms
MHz
ms
MAX5427/MAX5428/MAX5429
Output Settling Time
t
SETTLE
POWER SUPPLY
Supply Voltage
Static Supply Current
Programming Voltage
Programming Current
V
DD
I
DD
V
PP
I
PP
5.5
1.5
11.55
11.55
V
µA
V
mA
Note 1:
Note 2:
Note 3:
Note 4:
All devices are production tested at T
A
= +25°C and are guaranteed by design for T
A
= -40°C to +85°C.
Digital timing is guaranteed by design, not production tested.
Power-up time is the period of time from when the power supply is applied until the serial interface is ready for writing.
Digital inputs
CS
and U/D are connected to GND or V
DD
.
POTENTIOMETER
CONFIGURATION
H
VARIABLE-RESISTOR
CONFIGURATION
H
W
L
L
Figure 1. Potentiometer/Variable-Resistor Configuration
_______________________________________________________________________________________
3
One-Time Programmable, Linear-Taper
Digital Potentiometers
MAX5427/MAX5428/MAX5429
Typical Operating Characteristics
(V
DD
= 5.0V, T
A
= +25°C, unless otherwise noted.)
END-TO-END RESISTANCE PERCENT
CHANGE vs. TEMPERATURE
MAX5427-29 toc02
WIPER RESISTANCE vs. WIPER VOLTAGE
MAX5427 toc01
W-TO-L RESISTANCE
vs. TAP POSITION
90
W-TO-L RESISTANCE (kΩ)
80
70
60
50
40
30
20
10
MAX5429
MAX5427
MAX5428
MAX5427-29 toc03
160
0.3
END-TO-END RESISTANCE CHANGE (%)
0.2
0.1
MAX5429
0
-0.1
MAX5427
-0.2
-0.3
MAX5428
100
WIPER RESISTANCE (Ω)
140
V
DD
= 3.3V
120
100
V
DD
= 5.0V
80
0
1
2
3
4
5
WIPER VOLTAGE (V)
0
-40
-15
10
35
60
85
0
5
10
15
20
25
30
TEMPERATURE (°C)
TAP POSITION
SUPPLY CURRENT vs. TEMPERATURE
MAX5427-29 toc04
TAP-TO-TAP SWITCHING TRANSIENT
MAX5427-29 toc05
WIPER TRANSIENT AT POWER-ON
MAX5427-29 toc06
0.30
0.25
SUPPLY CURRENT (µA)
0.20
0.15
0.10
0.05
0
-40
-15
10
35
60
V
DD
= 3.3V
V
DD
= 5.0V
U/D
2V/div
V
DD
2V/div
OUTPUT
W
100mV/div
C
L
= 10pF
85
100ns/div
OUTPUT
W
1V/div
2µs/div
TEMPERATURE (°C)
R-DNL ERROR vs. INPUT CODE
(MAX5427)
MAX5427-29 toc07
R-INL ERROR vs. INPUT CODE
(MAX5427)
MAX5427-29 toc08
R-DNL ERROR vs. INPUT CODE
(MAX5428)
0.015
0.010
R-DNL (LSB)
0.005
0
-0.005
-0.010
-0.015
-0.020
MAX5427-29 toc09
0.020
0.015
0.010
R-DNL (LSB)
0.005
0
-0.005
-0.010
-0.015
-0.020
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
0.10
0.08
0.06
0.04
R-INL (LSB)
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.10
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
0.020
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
4
_______________________________________________________________________________________
One-Time Programmable, Linear-Taper
Digital Potentiometers
Typical Operating Characteristics (continued)
(V
DD
= 5.0V, T
A
= +25°C, unless otherwise noted.)
R-INL ERROR vs. INPUT CODE
(MAX5428)
MAX5427-29 toc10
MAX5427/MAX5428/MAX5429
R-DNL ERROR vs. INPUT CODE
(MAX5429)
MAX5427-29 toc11
R-INL ERROR vs. INPUT CODE
(MAX5429)
0.08
0.06
0.04
R-INL (LSB)
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.10
MAX5427-29 toc12
0.10
0.08
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.10
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
R-INL (LSB)
0.025
0.020
0.015
0.010
R-DNL (LSB)
0.005
0
-0.005
-0.010
-0.015
-0.020
-0.025
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
0.10
0
5
10
15
20
25
30
INPUT CODE (DECIMAL)
Pin Description
PIN
1
2
3
4
5
6
7
8
NAME
W
CS
V
DD
GND
V
PP
U/D
L
H
FUNCTION
Wiper Connection
Chip-Select Input. A high-to-low
CS
transition determines the mode: increment if U/D is high, or
decrement if U/D is low.
CS
is also used for one-time programming (see the
One-Time Programming
section).
Power-Supply Voltage
Ground
Programming Voltage for One-Time Programming. Connect V
PP
to 10V supply when one-time
programming the device. For normal operation, connect to ground or let float.
Up/Down Control Input. With
CS
low, a low-to-high transition increments or decrements the wiper
position.
Low Terminal of Resistor
High Terminal of Resistor
Detailed Description
The MAX5427/MAX5428/MAX5429 are 100kΩ/50kΩ/
10kΩ (end-to-end resistance) digitally controlled poten-
tiometers. They have 32 tap positions that are accessible
to the wiper along the resistor array between H and L.
The wiper (W) position is adjusted sequentially through
the tap positions using a simple 2-wire interface. These
digital potentiometers have an optional one-time pro-
grammable feature that sets the POR position of the
wiper. The 2-wire interface can then be disabled, perma-
nently preventing unwanted adjustment.
Digital Interface Operation
The MAX5427/MAX5428/MAX5429 have two modes of
operation when the serial interface is active: increment
mode and decrement mode. The serial interface is only
active when
CS
is low.
The
CS
and U/D inputs control the position of the wiper
along the resistor array. When
CS
transitions from high
to low, the part goes into increment mode if U/D is high
(Figure 2), and into decrement mode if U/D is low
(Figure 3). Once the mode is set, the device remains in
that mode until
CS
goes high. A low-to-high transition at
the U/D increments or decrements the wiper position
depending on the current mode.
When the
CS
input transitions to high (when serial inter-
face is inactive) and U/D is low, the wiper increments or
decrements one position in accordance with the state
of U/D when
CS
went low. If U/D is high when
CS
tran-
sitions to high, the wiper remains in the same position.
5
_______________________________________________________________________________________
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