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19-3067; Rev 1; 2/06
KIT ATION EVALU ILABLE AVA
32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23
General Description
The MAX5471/MAX5472/MAX5474/MAX5475 lineartaper digital potentiometers function as mechanical potentiometers, but replace the mechanics with a simple 3-wire up/down digital interface. These digital potentiometers feature nonvolatile memory (EEPROM) to return the wiper to its previously stored position upon power-up. The MAX5471/MAX5472 are 2-terminal, variable resistors in 6-pin SOT23 packages. The MAX5474/MAX5475 are 3-terminal potentiometers in 8-pin SOT23 packages. The MAX5471/MAX5474 have an end-to-end resistance of 50k, and the MAX5472/MAX5475 have an endto-end resistance of 100k. All of these devices have 32 wiper positions, a low ratiometric temperature coefficient (5ppm/C), and all operate from a single +2.7V to +5.25V supply. Each device is guaranteed over the extended -40C to +85C temperature range.
Features
Wiper Position Stored in Nonvolatile Memory and Recalled Upon Power-Up Tiny SOT23 Package 35ppm/C End-to-End Resistance Temperature Coefficient 5ppm/C Ratiometric Temperature Coefficient 32 Tap Positions Voltage-Divider or Variable-Resistor Potentiometer Configuration 50k and 100k End-to-End Resistance Values 1A (max) Static Supply Current 2.7V to 5.25V Single-Supply Operation 200,000 Wiper Store Cycles 50-Year Wiper Data Retention
MAX5471/MAX5472/MAX5474/MAX5475
Applications
Mechanical Potentiometer Replacement Liquid-Crystal-Display (LCD) Screen Adjustment Audio Volume Control Programmable Filters
Ordering Information
PART MAX5471EZT-T MAX5472EZT-T TEMP RANGE PIN-PACKAGE PKG CODE Z6-1 Z6-1 K8S-3 K8S-3
-40C to +85C 6 Thin SOT23-6 -40C to +85C 6 Thin SOT23-6
MAX5474EKA-T -40C to +85C 8 SOT23-8 MAX5475EKA-T -40C to +85C 8 SOT23-8
Pin Configurations
PART
TOP VIEW
Selector Guide
END-TO-END RESISTANCE (k) 50 100 50 100 TOP MARK ABQN ABQM AEIZ AEIY
MAX5471EZT MAX5472EZT
CS 1 GND 2 U/D 3 6 VDD 5H 4 INC CS 1 VDD 2 GND 3 U/D 4 SOT23-6 8L 7W 6H
MAX5474EKA MAX5475EKA
MAX5471 MAX5472
MAX5474 MAX5475
SOT23-8
5 INC
________________________________________________________________ Maxim Integrated Products
1
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
ABSOLUTE MAXIMUM RATINGS
VDD to GND ...........................................................-0.3V to +6.0V All Other Pins to GND .........-0.3V to the lower of (VDD + 0.3V) or +6.0V Maximum Continuous Current into H, L, and W MAX5471/MAX5474 .....................................................1.3mA MAX5472/MAX5475 .....................................................0.6mA Continuous Power Dissipation (TA = +70C) 6-Pin SOT23 (derate 9.1mW/C above +70C)............727mW 8-Pin SOT23 (derate 8.9mW/C above +70C)............714mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-60C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER DC PERFORMANCE Resolution End-to-End Resistance End-to-End Resistance Temperature Coefficient Ratiometric Resistance Temperature Coefficient Variable-resistor mode (Note 2) Integral Nonlinearity INL Voltage-divider mode (MAX5474/MAX5475) (Note 3) Variable-resistor mode (Note 2) Differential Nonlinearity Full-Scale Error Zero-Scale Error Wiper Resistance RW DIGITAL INPUTS (CS, U/D, INC) (Note 5) Input High Voltage Input Low Voltage Input Current DYNAMIC CHARACTERISTICS Wiper -3dB Bandwidth (Note 6) MAX5471/MAX5474 MAX5472/MAX5475 400 200 kHz VIH VIL IIN VDD < 3.6V VDD 3.6V VDD < 3.6V VDD 3.6V 0.1 0.7 x VDD 2.4 0.3 x VDD 0.8 1 V V A DNL Voltage-divider mode (MAX5474/MAX5475) (Note 3) MAX5474/MAX5475 MAX5474/MAX5475 MAX5474/MAX5475 (Note 4) 600 TCR N MAX5471/MAX5474 MAX5472/MAX5475 32 37.5 75 50 100 35 5 0.5 0.1 0.5 0.1 1.0 0.5 1.0 0.5 -0.5 +0.5 1200 LSB LSB LSB LSB 62.5 125 Tap k ppm/C ppm/C SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.25V, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER CS to INC Setup INC High to U/D Change U/D to INC Setup INC Low Period INC High Period INC Cycle Time INC Inactive to CS Inactive INC Active to CS Inactive CS Deselect Time (Store) Wiper Settling Time Power-Up to Wiper Stable Wiper Store Cycle Data Retention Endurance POWER SUPPLY Supply Voltage Supply Current Static Supply Current VDD IDD ISD Write to memory TA = +25C (Note 9) 0.35 2.70 5.25 400 1 V A A SYMBOL tCI tID tDI tIL tIH tCYC tIC tIK tCPH tIW tPU tWSC TA = +85C TA = +25C TA = +85C 12 50 200,000 50,000 (Note 8) CONDITIONS MIN 50 0 100 50 50 100 100 100 100 1 1 TYP MAX UNITS ns ns ns ns ns ns ns ns ns s s ms Year Store
MAX5471/MAX5472/MAX5474/MAX5475
TIMING CHARACTERISTICS (Figure 1, Note 7)
NONVOLATILE MEMORY RELIABILITY
Note 1: All devices are production tested at TA = +25C and are guaranteed by design and characterization for -40C < TA < +85C. Note 2: The DNL and INL are measured with the potentiometer configured as a variable resistor. For the 3-terminal potentiometers (MAX5474/MAX5475), H is unconnected and L = GND. At VDD = 5.25V, W is driven with a source current of 80A for the 50k configuration, and 40A for the 100k configuration. At VDD = 2.7V, the wiper terminal is driven with a source current of 40A for the 50k configuration, and 20A for the 100k configuration. Note 3: The DNL and INL are measured with the potentiometer configured as a voltage-divider with H = VDD and L = GND (MAX5474/MAX5475 only). The wiper terminal is unloaded. Note 4: The wiper resistance is the worst value measured by injecting the currents given in Note 2 into W with L = GND. RW = (VW - VH) / IW. Note 5: The device draws higher supply current when digital inputs are driven with voltages between 0.3V x VDD and 0.7 x VDD. Drive the digital inputs as close as possible to VDD or GND. (See the Typical Operating Characteristics for the Supply Current vs. Digital Input Voltage graph.) Note 6: Wiper at midscale with a 10pF load. 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 = VDD, L = GND, and the wiper terminal is unloaded and measured with a 10pF oscilloscope probe (see the Typical Operating Characteristics for the Tap-to-Tap Switching Transient). Note 9: Digital inputs CS, U/D, and INC are connected to GND or VDD. See the Typical Operating Characteristics for the Static Supply Current vs. Temperature graph.
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
Typical Operating Characteristics
(VDD = 5.0V, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5471 toc01
STATIC SUPPLY CURRENT vs. TEMPERATURE
MAX5471 toc02
SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE
MAX5471 toc03
0.5 DIGITAL INPUTS = GND OR VDD 0.4 SUPPLY CURRENT (A)
0.5
DIGITAL INPUTS = GND OR VDD
10,000
0.4 SUPPLY CURRENT (A) VDD = 5.0V 0.3
1000 SUPPLY CURRENT (A)
VDD = 5.0V
0.3
100
0.2
0.2 VDD = 3.0V 0.1
10
0.1
1
VDD = 3.0V
0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 SUPPLY VOLTAGE (V)
0 -40 -15 10 35 60 85 TEMPERATURE (C)
0.1 0 1 2 3 4 5 DIGITAL INPUT VOLTAGE (V)
WIPER RESISTANCE vs. TAP POSITION (MAX5474)
MAX5471 toc04
WIPER RESISTANCE vs. TAP POSITION (MAX5475)
MAX5471 toc05
END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE
END-TO-END RESISTANCE % CHANGE 0.15 0.10 0.05 0 -0.05 -0.10 -0.15 -0.20 -40 -15 50k 100k 100k
MAX5471 toc06
600 550 WIPER RESISTANCE () 500 450 400 VDD = 3.0V 350 300 250 200 0 5 10 15 20 25 30 TAP POSITION VDD = 5.0V
600 550 VDD = 3.0V WIPER RESISTANCE () 500 450 VDD = 5.0V 400 350 300 250 200 0 5 10 15 20 25 30 TAP POSITION
0.20 50k
10
35
60
85
TEMPERATURE (C)
W-TO-L RESISTANCE vs. TAP POSITION
MAX5471 toc07
H-TO-GND RESISTANCE vs. TAP POSITION
MAX5471 toc08
TAP-TO-TAP SWITCHING TRANSIENT
INC 5V/div
MAX5471 toc09
100
100
MAX5475 60
H-TO-GND RESISTANCE (k)
W-TO-L RESISTANCE (k)
80
80 MAX5472 60
40 MAX5474 20
40 MAX5471 20
W 100mV/div
MAX5474
MAX5475 CL = 10pF VH = VDD TAP 16 TO TAP 15
0 0 5 10 15 20 25 30 TAP POSITION
0 0 5 10 15 20 25 30 TAP POSITION
400ns/div
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23
Typical Operating Characteristics (continued)
(VDD = 5.0V, TA = +25C, unless otherwise noted.)
MAX5471/MAX5472/MAX5474/MAX5475
WIPER TRANSIENT AT POWER-ON (MAX5474)
MAX5471 toc10
WIPER TRANSIENT AT POWER-ON (MAX5475)
MAX5471 toc11
WIPER RESPONSE vs. FREQUENCY
TAP = 16 CL = 10pF MAX5474
MAX5471toc12
0 -3 WIPER RESPONSE (dB) -6 -9 -12 -15 -18 1
VDD 5V/div
VDD 5V/div
W 1V/div CL = 10pF TAP 16 VH = VDD 1.0s/div
W 1V/div CL = 10pF TAP 16 VH = VDD 1.0s/div
MAX5475
10
100
1000
FREQUENCY (kHz)
RESISTANCE DNL vs. TAP POSITION (MAX5471)
MAX5471 toc13
RESISTANCE INL vs. TAP POSITION (MAX5471)
MAX5471 toc14
RESISTANCE DNL vs. TAP POSITION (MAX5472)
VARIABLE-RESISTOR MODE 0.2 RESISTANCE DNL 0.1 0 -0.1 -0.2 -0.3
MAX5471 toc15
0.3 VARIABLE-RESISTOR MODE 0.2 RESISTANCE DNL 0.1 0 -0.1 -0.2 -0.3 0 5 10 15 20 25 30 TAP POSITION
0.5 VARIABLE-RESISTOR MODE 0.4 RESISTANCE INL 0.3 0.2 0.1 0 -0.1 0 5 10 15 20 25 30 TAP POSITION
0.3
0
5
10
15
20
25
30
TAP POSITION
RESISTANCE INL vs. TAP POSITION (MAX5472)
MAX5471 toc16
RESISTANCE DNL vs. TAP POSITION (MAX5474)
MAX5471 toc17
RESISTANCE INL vs. TAP POSITION (MAX5474)
VOLTAGE-DIVIDER MODE 0.03 0.02 RESISTANCE INL 0.01 0 -0.01 -0.02 -0.03 -0.04
MAX5471 toc18
0.5 VARIABLE-RESISTOR MODE 0.4 RESISTANCE INL 0.3 0.2 0.1 0 -0.1 0 5 10 15 20 25 30 TAP POSITION
0.04 VOLTAGE-DIVIDER MODE 0.03 0.02 RESISTANCE DNL 0.01 0 -0.01 -0.02 -0.03 -0.04 0 5 10 15 20 25 30 TAP POSITION
0.04
0
5
10
15
20
25
30
TAP POSITION
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
Typical Operating Characteristics (continued)
(VDD = 5.0V, TA = +25C, unless otherwise noted.)
RESISTANCE DNL vs. TAP POSITION (MAX5475)
MAX5471 toc19
RESISTANCE INL vs. TAP POSITION (MAX5475)
VOLTAGE-DIVIDER MODE 0.03 0.02 RESISTANCE INL 0.01 0 -0.01 -0.02 -0.03 -0.04
MAX5471 toc20
0.04 VOLTAGE-DIVIDER MODE 0.03 0.02 RESISTANCE DNL 0.01 0 -0.01 -0.02 -0.03 -0.04 0 5 10 15 20 25 30 TAP POSITION
0.04
0
5
10
15
20
25
30
TAP POSITION
Pin Description
PIN MAX5471/ MAX5472 1 2 3 4 5 6 -- -- MAX5474/ MAX5475 1 3 4 5 6 2 7 8 NAME FUNCTION Chip-Select Input. Drive low to change wiper position (W) through INC and U/D. A low-tohigh transition with INC high stores the wiper position in nonvolatile memory. Ground Up/Down Control Input. With U/D low, a high-to-low INC transition decrements the wiper position. With U/D high, a high-to-low INC transition increments the wiper position. Wiper Increment Control Input. With CS low, the wiper position moves in the direction determined by the state of U/D on a high-to-low transition. High Terminal of Resistor. The voltage at H can be greater than or less than the voltage at L. Current can flow into or out of H. Power Supply Wiper Terminal of Resistor Low Terminal of Resistor. The voltage at L can be greater than or less than the voltage at H. Current can flow into or out of L.
CS GND U/D INC H VDD W L
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
WIPER POSITION STORED CS tCI INC tID U/D tIW VW NOTE: VW IS NOT A DIGITAL SIGNAL. IT REPRESENTS A WIPER TRANSITION. tDI tWSC tCYC tIL tIH tIC tCPH tIK WIPER POSITION NOT STORED
Figure 1. Digital Interface and Timing Diagram
Detailed Description
The MAX5471/MAX5472/MAX5474/MAX5475 contain a resistor array with 31 resistive elements (Figures 2 and 3). The MAX5471/MAX5474 have a total end-to-end resistance of 50k, and the MAX5472/MAX5475 have an end-to-end resistance of 100k. The MAX5471/ MAX5472 wiper is connected to the high terminal, and the low terminal is internally connected to ground, making the device a variable resistor. The MAX5474/ MAX5475 allow access to the high, low, and wiper terminals for a standard voltage-divider configuration. The wiper is moved among the 32 tap points through a simple 3-wire interface. Nonvolatile memory allows the wiper position to be stored and recalled to the same point upon power-up.
(state of U/D) can be changed at any time as long as the setup and hold times are met. Since the MAX5471/MAX5472 have the wiper internally connected to H, an increment command increases the resistance between H and GND, and a decrement command decreases the resistance between H and GND. The wiper performs a make-before-break transition, ensuring that there is never an open circuit during a transition from one resistor tap to another. When the wiper is at either end of the resistor array (max/min), additional transitions in the direction of the endpoint do not change the counter value (the wiper does not wrap around).
Storing Wiper Position
The position of the wiper is stored in nonvolatile memory whenever CS transitions low-to-high (rising edge) while INC is high. Upon power-up, the wiper returns to this stored position. By keeping INC low while taking CS high, the serial interface can be disabled and the potentiometer placed in standby without storing the latest wiper position. The factory-default wiper position is midscale. These devices can also be operated like a one-time programmable (OTP) device. Once the desired wiper position is trimmed and stored in nonvolatile memory, disable the serial interface by connecting CS to VDD, and INC to GND. The disabled interface places the device in standby and disallows any changes to the wiper position. In OTP mode, these devices become a fixed 3-terminal potentiometer or a 1-terminal resistor to GND with less than 1A of supply current.
Digital Interface
Logic inputs CS, U/D, and INC control the wiper position and store it in nonvolatile memory (see the Truth Table). The chip-select (CS) input enables the serial interface when low and disables the interface when high. The position of the wiper is stored when CS transitions from low to high and INC is high (see the Storing Wiper Position section). With the serial interface active (CS low), a high-to-low (falling edge) transition on INC moves the wiper position by one resistive element in the direction determined by the state of U/D. If U/D is high, the wiper increments and it increases the resistance between W and L (it decreases the resistance between H and W). If U/D is low, the wiper decrements and it decreases the resistance between W and L (it increases the resistance between H and W). The direction of the wiper
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
Truth Table
CS L L L H U/D L H X X X X X INC X X L H W Decrement Increment No change No change No change Position not stored Position stored
Applications Information
The MAX5471/MAX5472/MAX5474/MAX5475 are intended for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control (where voltage biasing adjusts the display contrast), or programmable filters with adjustable gain and/or cutoff frequency.
Positive LCD Bias Control
Figures 4 and 5 show an application where the voltagedivider or variable resistor is used to make an adjustable, positive LCD-bias voltage. The op amp provides buffering and gain to the resistor-divider network made by the potentiometer (Figure 4) or to a fixed resistor and a variable resistor (Figure 5).
= High-to-low transition. = Low-to-high transition. X = Don't care.
Standby Mode
The MAX5471/MAX5472/MAX5474/MAX5475 are always in standby mode, except during the transition of a logic input or while the wiper position is being stored. When in standby mode, the static supply current is reduced to less than 1A and the resistive terminals (H, W, and L) are unaffected.
Programmable Filter
Figure 6 shows the configuration of a 1st-order programmable filter. The gain of the filter is adjusted by R2, and the cutoff frequency is adjusted by R3. Use the following equations to calculate the gain (G) and the 3dB cutoff frequency (fC): R1 R2 1 fC = 2 x R 3 x C G = 1+
H 6 S32
H 5
S32
MAX5471 MAX5472
VDD GND CS INC U/D 6 2 1 4 3 UP/DOWN COUNTER 32-POSITION DECODER
R31 VDD S31 R30 CS S30 RW INC U/D S3 R2 GND 2 3 1 5 4
MAX5474 MAX5475
R31
S31 R30 S30
UP/DOWN COUNTER
32-POSITION DECODER
RW
7
W
S3 R2 NONVOLATILE MEMORY S2 R1 S1 S1 L 8 R1 S2
NONVOLATILE MEMORY
Figure 2. MAX5471/MAX5472 Functional Diagram 8
Figure 3. MAX5474/MAX5475 Functional Diagram
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
5V H W VOUT R3 VIN 30V C H VOUT
MAX5474 MAX5475
L GND
MAX5471 MAX5472
R1 H
R2
Figure 4. Positive LCD Bias Control Using a Voltage-Divider
GND 5V 30V
MAX5471 MAX5472
Figure 6. Programmable Filter
VOUT H
MAX5471 MAX5472
GND
Chip Information
TRANSISTOR COUNT: 5031 PROCESS: BiCMOS
Figure 5. Positive LCD Bias Control Using a Variable Resistor
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
10
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6L THIN SOT23.EPS
32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
MAX5471/MAX5472/MAX5474/MAX5475
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32-Tap, Nonvolatile, Linear-Taper Digital Potentiometers in SOT23 MAX5471/MAX5472/MAX5474/MAX5475
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
SOT23, 8L.EPS
MARKING
0
0
PACKAGE OUTLINE, SOT-23, 8L BODY
21-0078
G
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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