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19-1997; Rev 0; 4/01
Dual, 256-Tap, Up/Down Interface, Digital Potentiometers
General Description
The MAX5450-MAX5455 are a family of dual digital potentiometers that perform the same function as a mechanical potentiometer or variable resistor. The MAX5451/MAX5453/MAX5455 have two 3-terminal potentiometers and the MAX5450/MAX5452/MAX5454 have two 2-terminal variable resistors. The MAX5450- MAX5455 operate from a +2.7V to +5.5V single-supply voltage and use an ultra-low supply current of 0.1A. These devices consist of two fixed resistors each with 256 digitally-controlled wiper contacts. The convenient power-on reset (POR) sets the wiper to midscale position at power-up and the easy-to-use up/down interface allows glitchless switching between resistor taps. Six inputs control the 14-pin MAX5451/ MAX5453/MAX5455 potentiometers. Four inputs control the 10-pin MAX5450/MAX5452/MAX5454 variable resistors. The MAX5450-MAX5455 are ideal for applications requiring digitally-controlled resistors. Three resistance values are available: 10k, 50k, and 100k. An endto-end resistor temperature coefficient of 35ppm/C and a ratiometric temperature coefficient of 5ppm/C make the MAX5450-MAX5455 excellent choices for adjustable gain circuit requiring low-temperature drift The MAX5450-MAX5455 are available in 10-pin MAX and 14-pin TSSOP packages. Each device is guaranteed over the extended-industrial temperature range (-40C to +85C).
Features
o Small-Footprint Packages 10-Pin MAX (MAX5450/MAX5452/MAX5454) 14-Pin TSSOP (MAX5451/MAX5453/MAX5455) o 256-Tap Positions o Independent Up/Down Potentiometer Controls (MAX5451/MAX5453/MAX5455) o Ultra-Low 0.1A Supply Current o +2.7V to +5.5V Single-Supply Operation o Low 35ppm/C End-to-End Temperature Coefficient o Power-On Reset Sets Wiper to Midscale (Position 127) o Glitchless Switching Between the Resistor Taps o 10k, 50k, 100k Resistance Values
MAX5450-MAX5455
Ordering Information
PART MAX5450EUB MAX5451EUD MAX5452EUB MAX5453EUD MAX5454EUB MAX5455EUD TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 10 MAX 14 TSSOP 10 MAX 14 TSSOP 10 MAX 14 TSSOP R (k) 10 10 50 50 100 100
Applications
Mechanical Potentiometer Replacement Low-Drift Programmable-Gain Amplifier (PGA) Volume Control LCD Screen Adjustment Adjustable Voltage References Adjustable Linear Regulators Programmable Filters, Delays, Time Constants Impedance Matching
Pin Configurations
TOP VIEW
CS1 1 U/D VDD W1 L1 2 3 4 5
10 CS2 9 INC GND W2 L2
CS1 1 U/D1 U/D2 2 3
14 CS2 13 INC1 12 INC2
MAX5450 MAX5452 MAX5454
8 7 6
VDD 4 W1 5 H1 6 L1 7
MAX5451 MAX5453 MAX5455
11 GND 10 W2 9 8 H2 L2
MAX
TSSOP
________________________________________________________________ Maxim Integrated Products
1
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
ABSOLUTE MAXIMUM RATINGS
VDD to GND ..............................................................-0.3V to +6V CS_, INC_, and U/D_ to GND...................................-0.3V to +6V H_, L_, W_ to GND ......................................-0.3V to (VDD +0.3V) Maximum Continuous Current into H_, L_, and W_............1mA Continuous Power Dissipation (TA = +70C) 10-Pin MAX (derate 6.94mW/C above +70C) ..........555mW 14-Pin TSSOP (derate 9.1mW/C above +70C) ..........727mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C 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 +5.5V, VH = VDD, VL = 0; TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +5V, TA = +25C, unless otherwise noted.)
PARAMETER Resolution Integral Nonlinearity (Notes 1 and 2) Differential Nonlinearity (Notes 1 and 2) End-to-End Resistor Tempco Ratiometric Resistor Tempco MAX5451 Full-Scale Error MAX5453 MAX5455 MAX5451 Zero-Scale Error DC PERFORMANCE (Variable Resistor Mode) Resolution Integral Nonlinearity (Notes 1 and 3) N VDD = +5V INL VDD = +3V Differential Nonlinearity (Notes 1 and 3) DNL VDD = +5V VDD = +3V VDD = +5V VDD = +3V 10 MAX5450, MAX5451 End-To-End Resistance RHL MAX5452, MAX5453 MAX5454, MAX5455 6.5 32 60 10 50 100 12.5 62.5 125 k 225 550 MAX5450, MAX5451 MAX5452-MAX5455 MAX5450, MAX5451 MAX5452-MAX5455 8 3 1 4.5 2 1 1 LSB LSB Bits MAX5453 MAX5455 SYMBOL N INL DNL TCR VDD = +5V VDD = +3V VDD = +5V VDD = +3V 35 5 -8 -1.6 -0.8 +8 +1.6 +0.8 LSB LSB CONDITIONS MIN 8 1 1 1 1 TYP MAX UNITS Bits LSB LSB ppm/C ppm/C
DC PERFORMANCE (Voltage-Divider Mode, MAX5451/MAX5453/MAX5455 Only)
DC PERFORMANCE (Resistor Characteristics) Wiper Resistance (Note 4) Wiper Capacitance RW CW pF
2
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.5V, VH = VDD, VL = 0; TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +5V, TA = +25C, unless otherwise noted.)
PARAMETER DIGITAL INPUTS (Note 5) Input High Voltage Input Low Voltage Input Leakage Current Input Capacitance TIMING CHARACTERISTICS (Analog) MAX5451 Wiper-Settling Time (Note 6) tIW MAX5453 MAX5455 TIMING CHARACTERISTICS (Digital, Note 7, Figure 1) Maximum INC Frequency CS to INC Setup Time CS to INC Hold Time INC Low Period INC High Period U/D to INC Setup U/D to INC Hold POWER SUPPLIES Supply Voltage Supply Current VDD IDD CS = INC = U/D = VDD or GND VDD = +5V VDD = +2.7V 2.7 0.7 0.1 5.5 2 V A fMAX tCI tIC tIL tIH tDI tID 7 25 0 25 25 50 0 MHz ns ns ns ns ns ns 0.5 1.2 1.8 s 5 VIH VIL 0.7 x VDD 0.3 x VDD 1.0 V V A pF SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5450-MAX5455
Note 1: Linearity is defined in terms of the H_ to L_ code-dependent resistance. Note 2: The DNL and INL are measured with the potentiometer configured as a voltage divider with H_ = VDD and L_ = GND. The wiper terminal is unloaded and measured with an ideal voltmeter. Note 3: The DNL and INL are measured with the potentiometer configured as a variable resistor. For the 3-terminal potentiometers (MAX5451/MAX5453/MAX5455), H_ is unconnected and L_ = GND. For the 2-terminal potentiometers (MAX5450/MAX5452/MAX5454), L_ = GND. At VDD = +5V, the wiper terminal is driven with a source current of 400A for the 10k configuration, 80A for the 50k configuration, and 40A for the 100k configuration. At VDD = +3V, 200A/40A/20A for 10k/50k/100k configuration, respectively. Note 4: The wiper resistance is the worst value measured by injecting the currents given in Note 3 into W_ with L_ = GND. RW_ = (VW_ - VH_) / IW_. Note 5: Device draws higher supply current when digital inputs are driven with voltages between 0.3 x VDD and 0.7 x VDD. (See Supply Current vs. Digital Input Voltage in the Typical Operating Characteristics.) Note 6: 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 Tap-To-Tap Switching Transient in the Typical Operating Characteristics). Note 7: Digital timing is guaranteed by design.
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
Typical Operating Characteristics
(VDD = +5V, TA = +25C, unless otherwise noted.)
WIPER RESISTANCE vs. WIPER VOLTAGE (10k)
MAX5450/5 toc01
WIPER RESISTANCE vs. WIPER VOLTAGE (50k)
MAX5450/5 toc02
WIPER RESISTANCE vs. WIPER VOLTAGE (100k)
MAX5450/5 toc03 MAX5450/5 toc09 MAX5450/5 toc06
300 280 WIPER RESISTANCE () 260 240 220 200 180 160 0 VDD = +5V VDD = +3V
380 360 340 WIPER RESISTANCE () 320 300 280 260 240 220 200 180 160 VDD = +5V VDD = +3V
400 380 WIPER RESISTANCE () 360 340 320 300 280 260 240 220 200 180 160 VDD = +5V VDD = +3V
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 WIPER VOLTAGE (V)
WIPER RESISTANCE vs. WIPER POSITION (10k)
MAX5450/5 toc04
WIPER RESISTANCE vs. WIPER POSITION (50k)
45 W-TO-L RESISTANCE (k) 40 35 30 25 20 15 10 5 0
MAX5450/5 toc05
WIPER RESISTANCE vs. WIPER POSITION (100k)
100 90 W-TO-L RESISTANCE (k) 80 70 60 50 40 30 20 10 0
10 9 W-TO-L RESISTANCE (k) 8 7 6 5 4 3 2 1 0 0 32 64 96
50
128 160 192 224 256
0
32
64
96
128 160 192 224 256
0
32
64
96
128 160 192 224 256
WIPER POSITION
WIPER POSITION
WIPER POSITION
VARIABLE RESISTOR DNL vs. WIPER POSITION (10k)
MAX5450/5 toc07
VARIABLE RESISTOR INL vs. WIPER POSITION (MAX5451)
0.40 0.30 INL (LSB) 0.20 0.10 0.00 -0.10
MAX5450/5 toc08
VARIABLE RESISTOR DNL vs. WIPER POSITION (50k)
0.06 0.05 0.04 DNL (LSB) 0.03 0.02 0.01 0.00 -0.01 -0.02 -0.03
0.20
0.50
0.15
DNL (LSB)
0.10
0.05
0.00 -0.20 -0.05 0 32 64 96 128 160 192 224 256 WIPER POSITION -0.30 0 32 64 96 128 160 192 224 256 WIPER POSITION
0
32
64
96
128 160 192 224 256
WIPER POSITION
4
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers
Typical Operating Characteristics (continued)
(VDD = +5V, TA = +25C, unless otherwise noted.)
VARIABLE RESISTOR INL vs. WIPER POSITION (MAX5453)
MAX5450/5 toc10
MAX5450-MAX5455
VARIABLE RESISTOR DNL vs. WIPER POSITION (100k)
MAX5450/5 toc11
VARIABLE RESISTOR INL vs. WIPER POSITION (MAX5455)
0.10 0.05 INL (LSB) 0.00 -0.05 -0.10 -0.15 -0.20
MAX5450/5 toc12
0.04 0.02 0.00 -0.02 INL (LSB) -0.04 -0.06 -0.08 -0.10 -0.12 -0.14 -0.16 0 32 64 96
0.12 0.11 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00 -0.01 -0.02 0 32 64 96 128 160 192 224
0.15
128 160 192 224 256
DNL (LSB)
256
0
32
64
96
128
160 192 224
256
WIPER POSITION
WIPER POSITION
WIPER POSITION
VOLTAGE-DIVIDER DNL vs. WIPER POSITION (10k)
MAX5450/5 toc13
VOLTAGE-DIVIDER INL vs. WIPER POSITION (10k)
MAX5450/5 toc14
VOLTAGE-DIVIDER DNL vs. WIPER POSITION (50k)
0.07 0.06 0.05 DNL (LSB) 0.04 0.03 0.02 0.01 0.00 -0.01
MAX5450/5 toc15
0.08 0.07 0.06 0.05 DNL (LSB) 0.04 0.03 0.02 0.01 0.00 -0.01 -0.02 0 32 64 96 128 160 192 224
0.15 0.10 0.05 INL (LSB) 0.00 -0.05 -0.10 -0.15 -0.20
0.08
256
0
32
64
96
128
160 192 224
256
-0.02 0 32 64 96 128 160 192 224 256 WIPER POSITION
WIPER POSITION
WIPER POSITION
VOLTAGE-DIVIDER INL vs. WIPER POSITION (50k)
MAX5450/5 toc16
VOLTAGE-DIVIDER DNL vs. WIPER POSITION (100k)
MAX5450/5 toc17
VOLTAGE-DIVIDER INL vs. WIPER POSITION (100k)
0.10 0.05 INL (LSB) 0.00 -0.05 -0.10 -0.15 -0.20
MAX5450/5 toc18
0.15 0.10 0.05
0.08 0.07 0.06 0.05 DNL (LSB) 0.04 0.03 0.02 0.01 0.00
0.15
INL (LSB)
0.00 -0.05 -0.10 -0.15 -0.20 0 32 64 96 128 160 192 224 256 WIPER POSITION
-0.01 -0.02 0 32 64 96 128 160 192 224 256 WIPER POSITION 0 32 64 96 128 160 192 224 256
WIPER POSITION
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
Typical Operating Characteristics (continued)
(VDD = +5V, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5450/5 toc19
MAX5450/5 toc20
1.4 DIGITAL INPUTS + VDD 1.2 1.0 IDD (A) 0.8 0.6 0.4 0.2 0 0 1 2 3 VDD (V) 4 5 6
1 VDD = 5V 0.1 IDD (mA) VDD = 3V 0.01
0.8 SUPPLY CURRENT (A)
VDD = +5V
0.6
0.4 VDD = +3V 0.2
0.001 0.0001 0 1 2 3 4 5 DIGITAL INPUT VOLTAGE (V) 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 TEMPERATURE (C)
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 -0.25 -40 -20 0 20 40 60 80 10k 100k 50k 100k INC_ 5V/div 10k 50k
MAX5450/5 toc22
TAP-TO-TAP SWITCHING TRANSIENT
MAX5450/5 toc23
0.20
W 10mV/div
MAX5455 MAX5453 MAX5451
1s/div
TEMPERATURE (C)
6
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MAX5450/5 toc21
SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
1.0
Dual, 256-Tap, Up/Down Interface, Digital Potentiometers
Pin Description
PIN MAX5451 MAX5453 MAX5455 1 MAX5450 MAX5452 MAX5454 1 NAME FUNCTION
MAX5450-MAX5455
CS1
Chip-Select Input of Resistor 1. Drive low to change wiper position W1 through INC and U/D. Up/Down Control Input. With U/D low, a high-to-low INC transition decrements wiper position. With U/D high, a high-to-low INC transition increments wiper position. Up/Down Control Input of Resistor 1. With U/D1 low, a high-to-low INC1 transition decrements wiper position W1. With U/D1 high, a high-to-low INC1 transition increments wiper position W1. Up/Down Control Input of Resistor 2. With U/D2 low, a high-to-low INC2 transition decrements wiper position W2. With U/D2 high, a high-to-low INC2 transition increments wiper position W2. Power Supply Wiper Terminal of Resistor 1 High Terminal of Resistor 1 Low Terminal of Resistor 1 Low Terminal of Resistor 2 High Terminal of Resistor 2 Wiper Terminal of Resistor 2 Ground Wiper Increment Control Input. With CS1 low, a high-to-low transition increments (U/D high) or decrements (U/D low) wiper position W1. This applies similarly for CS2 and W2. Wiper Increment Control Input. With CS2 low, a high-to-low transition increments (U/D2 high) or decrements (U/D2 low) wiper position W2. Wiper Increment Control Input. With CS1 low, a high-to-low transition increments (U/D1 high) or decrements (U/D1 low) wiper position W1. Chip-Select Input of Resistor 2. Drive low to change wiper position W2 through INC and U/D.
--
2
U/D
2
--
U/D1
3 4 5 6 7 8 9 10 11 --
-- 3 4 -- 5 6 -- 7 8 9
U/D2 VDD W1 H1 L1 L2 H2 W2 GND INC
12 13 14
-- -- 10
INC2 INC1 CS2
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
CS_
tCI INC_
tIL
tIC
tIH tDI
U/D_
tID tIW
W_
Figure 1. Digital Interface and Timing diagram
Detailed Description
The MAX5450-MAX5455 contain two independent resistor arrays each with 255-resistive elements. 256tap points are accessible to the wiper along the resistor arrays between H and L (Figure 2). Power-on reset circuitry sets the wiper to midscale (position 127) at power-up. Logic inputs CS, U/D, and INC determine the wiper position of the MAX5450-MAX5455. With CS low and U/D high, a high-to-low (falling edge) transition on INC, increments the internal counter, which increases the resistance between W and L. When both CS and U/D are low, a high-to-low INC transition decrements the internal counter, decreasing the resistance between W and L (Figure 1). The wiper performs a make-beforebreak 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 (max/min) of the resistor array, additional transitions in the direction of the endpoint will not change the counter value (the counter will not wrap around). The MAX5450/MAX5452/MAX5454 are similar to the MAX5451/MAX5453/MAX5455 except for internal connections. The MAX5450/MAX5452/MAX5454 internally connect INC1 to INC2, U/D1 to U/D2, W1 to H1, and W2 to H2 (Figures 3 and 4). The internal connections configure the MAX5450/MAX5452/MAX5454 to be variable resistors.
Applications Information
The MAX5450-MAX5455 are ideal for adjustable voltage or adjustable gain circuits where accurate adjustable resistances are required.
Adjustable Current to Voltage Converter
Figure 5 shows the MAX5450/MAX5452/MAX5454 with a MAX4250 low-noise op amp to fine-tune a current to voltage converter. The physical sizes of both devices minimize circuit space.
Adjustable Gain Amplifier
Figures 6a and 6b shows the MAX5450-MAX5455 digitally adjusting the gain of the MAX4493 general-purpose, dual supply op amp. Figure 6a shows the MAX5450/MAX5452/MAX5454 variable resistor in series with a resistor to ground to form the adjustable gain control. Figure 6b shows the MAX5451/MAX5453/ MAX5455 as a 3-terminal potentiometer. In these applications the low 5ppm/C ratiometric tempco allows for a very stable adjustable gain over temperature.
Adjustable Linear Regulator
In Figure 7, the MAX5450/MAX5452/MAX5454 is shown digitally adjusting the output voltage of the MAX8866 dual linear regulator. In this circuit, the MAX5450/ MAX5452/MAX5454 is connected in series with a resistor to ground to form the adjustable feedback stage. The 8-bit MAX5450/MAX5452/MAX5454 allows precise tuning of the output voltage.
8
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
H W1 CS1 S256 R255 INC U/D
UP/DOWN COUNTER
POSITION DECODER
L1 R254 S255 VDD GND
POWER-ON RESET
MAX5450 MAX5452 MAX5454
W2
CS2 S254 W
UP/DOWN COUNTER
POSITION DECODER
L2 R2 S3
R1 S2 S1 L
Figure 3. MAX5450/MAX5452/MAX5454 Simplified Functional Diagram
Figure 2. Simplified Digital Potentiometer Resistor Array
R3
H1
W
VDD
CS1 INC1 U/D1
R2
UP/DOWN COUNTER POSITION DECODER W1
MAX5450 MAX5452 MAX5454
R1 L
L1 VDD GND
POWER-ON RESET
IS
VOUT MAX4250 VOUT R = R3 1 + 2 + R2 R1 IS
MAX5451 MAX5453 MAX5455
H2
(
)
CS2 INC2 U/D2 UP/DOWN COUNTER POSITION DECODER W2
Figure 5. Adjustable Current to Voltage Converter
L2
Figure 4. MAX5451/MAX5453/MAX5455 Simplified Functional Diagram
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9
Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
VCC
OUT1 VOUT1 VOUT2 W1 MAX8866 MAX5450 MAX5452 MAX5454 IN SHDN1 SET1 SET2 W2
VIN VOUT MAX4493
OUT2
VEE
W
V+
L1
L2
MAX5450 MAX5452 MAX5454
SHDN2
GND
L
Figure 7. Adjustable Dual Linear Regulator Figure 6a. Variable Resistor Adjustable-Gain Amplifier
VCC
Truth Table
CS U/D X L H L H INC X W O O O - + H
VOUT MAX4493
VIN
L L L L
VEE
X = Don't care
W
O = Previous State - = Decrement + = Increment
= High-to-Low Transition = Low-to-High Transition
H
L
Chip Information
MAX5451 MAX5453 MAX5455
TRANSISTOR COUNT: 9680 PROCESS: CMOS
Figure 6b. Potentiometer Adjustable-Gain Amplifier
10
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Dual, 256-Tap, Up/Down Interface, Digital Potentiometers
Package Information
10LUMAX.EPS
MAX5450-MAX5455
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11
Dual, 256-Tap, Up/Down Interface, Digital Potentiometers MAX5450-MAX5455
Package Information (continued)
TSSOP,NO PADS.EPS
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) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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