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19-3562; Rev 1; 6/05
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
General Description
The MAX5494-MAX5499 10-bit (1024-tap), dual, nonvolatile, linear-taper, programmable voltage-dividers and variable resistors perform the function of a mechanical potentiometer, but replace the mechanics with a 3-wire SPITM-compatible serial interface. The MAX5494/MAX5495 are dual, 3-terminal, programmable voltage-dividers; the MAX5496/MAX5497 are dual, 2-terminal variable resistors; and the MAX5498/ MAX5499 include one 2-terminal variable resistor and one 3-terminal programmable voltage-divider. The MAX5494-MAX5499 feature an internal, nonvolatile, electrically erasable programmable read-only memory (EEPROM) that stores the wiper position for initialization during power-up. The 3-wire SPI-compatible serial interface allows communication at data rates up to 7MHz. The MAX5494-MAX5499 are ideal for applications requiring digitally controlled potentiometers. End-to-end resistance values of 10k and 50k are available with a 35ppm/C end-to-end temperature coefficient. The ratiometric temperature coefficient is 5ppm/C for each channel, making these devices ideal for applications requiring low-temperature-coefficient programmable voltagedividers such as low-drift, programmable-gain amplifiers. The MAX5494-MAX5499 operate with either a single power supply (+2.7V to +5.25V) or dual power supplies (2.5V). The devices consume 400A (max) of supply current when writing data to the nonvolatile memory and 1.5A (max) of standby supply current. The devices are available in space-saving (5mm x 5mm x 0.8mm), 16-pin TQFN package and are specified over the extended (-40C to +85C) temperature range.
Features
Wiper Position Stored in Nonvolatile Memory and Recalled Upon Power-Up 16-Pin, 5mm x 5mm x 0.8mm TQFN Package 35ppm/C End-to-End Resistance Temperature Coefficient 5ppm/C Ratiometric Temperature Coefficient 10k and 50k End-to-End Resistor Values 3-Wire SPI-Compatible Serial Interface Reliability (TA = +85C) 50,000 Wiper Store Cycles 50 Years Wiper Data Retention 1.5A (max) Standby Current Single +2.7V to +5.25V Supply Operation Dual 2.5V Supply Operation
MAX5494-MAX5499
Pin Configurations
GND W1
TOP VIEW
12 DIN 13 N.C. 14 N.C. 15 SCLK 16 1 CS INTERFACE
11
10
H1 9 8 7 VSS N.C. N.C. VDD
MAX5494 MAX5495
L1
6 5
W2
N.C. 14 N.C. 15
INTERFACE
Gain and Offset Adjustment LCD Contrast Adjustment Pressure Sensors Low-Drift Programmable-Gain Amplifiers Mechanical Potentiometer Replacement Volume Control
5mm x 5mm x 0.8mm TQFN
D.N.C. 9 8 7 VSS N.C. N.C. VDD GND W1 L1 10
12 DIN 13
11
Ordering Information
PART MAX5494ETE MAX5495ETE TEMP RANGE PINPACKAGE PKG CODE T1655-2 T1655-2
SCLK 16
MAX5496 MAX5497
H2
L2
Applications
2
3
4
6 5
-40C to +85C 16 TQFN-EP* -40C to +85C 16 TQFN-EP*
1 CS
2 W2
3 L2
4 D.N.C.
*EP = Exposed pad. Ordering Information continued at end of data sheet. Selector Guide appears at end of data sheet. SPI is a trademark of Motorola, Inc.
5mm x 5mm x 0.8mm TQFN
Pin Configurations continued at end of data sheet. 1
________________________________________________________________ Maxim Integrated Products
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.
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
ABSOLUTE MAXIMUM RATINGS
VDD to GND ...........................................................-0.3V to +6.0V VSS to GND............................................................-6.0V to +0.3V VDD to VSS .............................................................-0.3V to +6.0V H1, H2, L1, L2, W1, W2 to VSS.........(VSS - 0.3V) to (VDD + 0.3V) CS, SCLK, DIN to GND ..............................-0.3V to (VDD + 0.3V) Maximum Continuous Current into H_, L_, and W_ MAX5494/MAX5496/MAX5498 ....................................5.0mA MAX5495/MAX5497/MAX5499 ....................................1.0mA Maximum Current Into Other Pins .................................50.0mA Continuous Power Dissipation (TA = +70C) 16-Pin TQFN (derate 20.8mW/C above +70C) ....1666.7mW 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, VSS = GND = 0, VH_ = VDD, VL_ = 0, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C.) (Note 1)
PARAMETER Resolution Integral Nonlinearity (Note 2) Differential Nonlinearity (Note 2) End-to-End Resistance Temperature Coefficient Ratiometric Temperature Coefficient Full-Scale Error Zero-Scale Error Wiper Capacitance End-to-End Resistance Channel-to-Channel Division Ratio Matching FSE ZSE CW RHL MAX5494/MAX5498 MAX5495/MAX5499 VDD = 3V, midcode: 512 MAX5494 MAX5495 7.5 37.5 MAX5494/MAX5498 MAX5495/MAX5499 MAX5494/MAX5498 MAX5495/MAX5499 -4 -4 0 0 SYMBOL N INL DNL TCR VDD = 2.7V VDD = 5V VDD = 2.7V VDD = 5V 35 5 -2.5 -0.75 3.3 1.45 60 10 50 0.05 0.15 6.3 k MAX5495/MAX5499, W_ at 15 code, H_ and L_ shorted to VSS, measure resistance from W_ to H_ (Figures 4 and 5) 25 12.5 62.5 0 0 5 5 CONDITIONS MIN 10 2 2 1 1 TYP MAX UNITS Bits LSB LSB ppm/C ppm/C LSB LSB pF k %
DC PERFORMANCE (MAX5494/MAX5495/MAX5498/MAX5499 Programmable Voltage-Divider)
MAX5494/MAX5498, W_ at 15 code, H_ and L_ shorted to VSS, measure resistance from W_ to H_ (Figures 4 and 5) Resistance from W_ to L_ and H_
2
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.25V, VSS = GND = 0, VH_ = VDD, VL_ = 0, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C.) (Note 1)
PARAMETER Resolution Integral Nonlinearity (Note 3) SYMBOL N VDD = 2.7V INL_R VDD = 3V VDD = 5V VDD = 2.7V Differential Nonlinearity (Note 3) Variable-Resistor Temperature Coefficient Wiper Resistance Wiper Capacitance Full-Scale Wiper-to-End Resistance Zero-Scale Resistor Error DNL_R VDD = 3V VDD = 5V TCVR RW CWR RW-L RZ MAX5496/MAX5498 MAX5497/MAX5499 Code = 0 MAX5494/MAX5498 MAX5495/MAX5499 MAX5496/MAX5498, Code >128 VDD = 3V to 5.25V MAX5497/MAX5499, Code >200 7.5 37.5 VDD = 3V to 5.25V; code = 128 to 1024 VDD 3V (Note 4) -1 -1 -4 -4 CONDITIONS MIN 10 -1.6 -1.4 -1.3 +0.45 +0.4 +0.35 35 50 60 10 50 70 110 0.1 % 0.15 12.5 62.5 +1 +1 ppm/C pF k LSB +4 +4 LSB TYP MAX UNITS Bits DC PERFORMANCE (MAX5496-MAX5499 Variable Resistor)
MAX5494-MAX5499
Two-Channel Resistance Matching DIGITAL INPUTS (CS, SCLK, DIN) (Note 5)
Single-supply operation Input High Voltage VIH Dual-supply operation Single-supply operation Input Low Voltage VIL Dual-supply operation
VDD = 3.6V to 5.25V VDD = 2.7V to 3.6V With respect to GND, VDD = 2.5V, VSS = -2.5V VDD = 2.7V to 5.25V With respect to GND, VDD = 2.5V, VSS = -2.5V
2.4 0.7 x VDD 2.0
V
0.8 V 0.6 1 5 A pF
Input Leakage Current Input Capacitance DYNAMIC CHARACTERISTICS Wiper -3dB Bandwidth
IIN CIN Wiper at code 495 (01111 01111), 10pF load at wiper
MAX5494/MAX5498 MAX5495/MAX5499
250 kHz 50
BW
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.25V, VSS = GND = 0, VH_ = VDD, VL_ = 0, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MAX5494/MAX5498; VDD = 3V; wiper at code 495; 10kHz, 1VRMS signal is applied at H_; 10pF load at wiper Total Harmonic Distortion THD MAX5495/MAX5499; VDD = 3V; wiper at code 495; 10kHz, 1VRMS signal is applied at H_; 10pF load at wiper CH2 = 11111 11111, CH1 = 01111 01111, CW_ = 10pF, VH1 = VDD = +2.5V, VL1 = VSS = -2.5V, measure VW1 with VW2 = 5VP-P at f = 1kHz 0.03 MIN TYP 0.026 % MAX UNITS
Analog Crosstalk
-93
dB
NONVOLATILE MEMORY RELIABILITY Data Retention Endurance POWER SUPPLIES Single-Supply Voltage Dual-Supply Voltage Average Programming Current Peak Programming Current Standby Current IDD VDD VDD VSS IPG VSS = GND = 0 GND = 0 (VDD - VSS) 5.25V During nonvolatile write only; digital inputs = VDD or GND During nonvolatile write only; digital inputs = VDD or GND Digital inputs = VDD or GND, TA = +25C 2.70 2.50 -2.5 220 4 0.6 1.5 5.25 5.25 -0.2 400 V V A mA A TA = +85C TA = +25C TA = +85C 50 200,000 50,000 Years Stores
4
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
TIMING CHARACTERISTICS
(VDD = +2.7V to +5.25V, VSS = GND = 0, VH_ = VDD, VL_ = 0, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = +5.0V, TA = +25C.) (Note 1)
PARAMETER ANALOG SECTION Wiper Settling Time (Note 6) tS MAX5494/MAX5498 MAX5495/MAX5499 5 22 7 140 60 60 60 0 40 0 15 60 150 12 s SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5494-MAX5499
SPI-COMPATIBLE SERIAL INTERFACE (Figure 6) 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 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 fSCLK tCP tCH tCL tCSS tCSH tDS tDH tCS0 tCS1 tCSW tBUSY MHz ns ns ns ns ns ns ns ns ns ns ms
Note 1: 100% production tested at TA = +25C and TA = +85C. Guaranteed by design to TA = -40C. Note 2: The DNL and INL are measured for the voltage-divider with H_ = VDD and L_ = VSS. The wiper terminal (W_) is unloaded and measured with a high-input-impedance voltmeter. Note 3: The DNL and INL are measured with L_ = VSS = 0. For VDD = 5V, the wiper terminal is driven with a current source of IW = 80A for the 50k device and IW = 400A for the 10k device. For VDD = 3V, the wiper terminal is driven with a current source of IW = 40A for the 50k device and IW = 200A for the 10k device. Note 4: The wiper resistance is measured using the source currents given in Note 3. Note 5: The device draws higher supply current when the digital inputs are driven with voltages between (VDD - 0.5V) and (GND + 0.5V). See the Supply Current vs. Digital Input Voltage graph in the Typical Operating Characteristics. Note 6: Wiper settling test condition uses the voltage-divider with a 10pF load on W_. Transition code from 0 to 495 and measure the time from CS going high to the wiper voltage settling to within 0.5% of its final value.
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5
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Typical Operating Characteristics
(VDD = +5.0V, VSS = 0, TA = +25C, unless otherwise noted.)
DIFFERENTIAL NONLINEARITY vs. CODE (VARIABLE RESISTOR)
MAX5494 toc01
INTEGRAL NONLINEARITY vs. CODE (VARIABLE RESISTOR)
MAX5494 toc02
MAXIMUM DIFFERENTIAL NONLINEARITY vs. SUPPLY VOLTAGE (VARIABLE RESISTOR)
0.8 0.6 0.4 DNL (LSB) 0.2 0 -0.2 -0.4 -0.6 -0.8
MAX5494 toc03
1.0 0.8 0.6 0.4 DNL (LSB) VDD = 3V
1.5 VDD = 3V 1.0 0.5 INL (LSB) 0 -0.5 -1.0 -1.5
1.0
0.2 0 -0.2 -0.4 -0.6 -0.8 -1.0 0 128 256 384 512 640 768 896 1024 CODE
-1.0 0 128 256 384 512 640 768 896 1024 CODE 2.5 3.0 3.5 4.0 4.5 5.0 VDD (V)
MAXIMUM INTEGRAL NONLINEARITY vs. SUPPLY VOLTAGE (VARIABLE RESISTOR)
MAX5494 toc04
DIFFERENTIAL NONLINEARITY vs. CODE (VOLTAGE-DIVIDER)
MAX5494 toc05
INTEGRAL NONLINEARITY vs. CODE (VOLTAGE-DIVIDER)
VDD = 3V 1.0 0.5 INL (LSB) 0 -0.5 -1.0 -1.5
MAX5494 toc06
1.0 0.5 0 -0.5 -1.0 -1.5 -2.0 2.5 3.0 3.5 4.0 4.5
1.0 0.8 0.6 0.4 DNL (LSB) 0.2 0 -0.2 -0.4 -0.6 -0.8 -1.0 VDD = 3V
1.5
INL (LSB)
5.0
0
128 256 384 512 640 768 896 1024 CODE
0
128 256 384 512 640 768 896 1024 CODE
VDD (V)
WIPER RESISTANCE vs. CODE (VARIABLE RESISTOR)
70 60 40 RWL (k) 40 30 20 10 10 0 0 128 256 384 512 640 768 896 1024 CODE 0 0 30 20
MAX5494 toc07
END-TO-END RESISTANCE vs. CODE (MAX5497/MAX5499)
MAX5494 toc08
END-TO-END RESISTANCE vs. CODE (MAX5496/MAX5498)
MAX5494 toc09
80
60 50
12 10 8 RWL (k) 6 4 2 0
50 RW ()
128 256 384 512 640 768 896 1024 CODE
0
128 256 384 512 640 768 896 1024 CODE
6
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Typical Operating Characteristics (continued)
(VDD = +5.0V, VSS = 0, TA = +25C, unless otherwise noted.)
WIPER RESISTANCE vs. WIPER VOLTAGE (VARIABLE RESISTOR)
MAX5494 toc10
END-TO-END RESISTANCE (RHL) % CHANGE vs. TEMPERATURE (VOLTAGE-DIVIDER)
MAX5494 toc11
WIPER-TO-END RESISTANCE (RWL) % CHANGE vs. TEMPERATURE (VARIABLE RESISTOR)
WIPER-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 CODE IS 11 1111 1111
MAX5494 toc12
22 CODE IS 00 0000 0000 21 20 RW () 19 18 17 16 0 1 2 3 4 5 WIPER VOLTAGE (V) VDD = 5V
1.0 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
1.0
85
TEMPERATURE (C)
TEMPERATURE (C)
STANDBY SUPPLY CURRENT vs. TEMPERATURE
MAX5494 toc13
DIGITAL SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE
MAX5494 toc14
RATIOMETRIC TEMPERATURE COEFFICIENT vs. CODE
180 RATIOMETRIC TEMPCO (ppm/C) 160 140 120 100 80 60 40 20 10k 50k VOLTAGE-DIVIDER VDD = 3V TA = -40C TO +85C
MAX5494 toc15
1.5
VDD = 5.25V
10,000
200
VDD = 5V
1.2
1000
IDD (A)
0.6
IDD (A)
0.9
100
10
0.3
1
0 -40 -15 10 35 60 85 TEMPERATURE (C)
0.1 0 1 2 3 4 5 DIGITAL INPUT VOLTAGE (V)
0 0 128 256 384 512 640 768 896 1024 CODE
VARIABLE RESISTOR TEMPERATURE COEFFICIENT vs. CODE
MAX5494 toc16
TAP-TO-TAP SWITCHING TRANSIENT (MAX5494/MAX5498)
MAX5494 toc17
TAP-TO-TAP SWITCHING TRANSIENT (MAX5495/MAX5499)
CS 2V/div
MAX5494 toc18
700 600 500 TCVR (ppm/C) 400 300 200 50k 100 0 0 10k
VDD = 3V TA = -40C TO +85C
CS 2V/div
VW_ 20mV/div H_ = VDD L_ = GND FROM CODE 01111 11111 TO CODE 10000 00000 CW_ = 10pF 1s/div H_ = VDD L_ = GND FROM CODE 01111 11111 TO CODE 10000 00000 CW_ = 10pF 4s/div
VW_ 20mV/div
128 256 384 512 640 768 896 1024 CODE
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7
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Typical Operating Characteristics (continued)
(VDD = +5.0V, VSS = 0, TA = +25C, unless otherwise noted.)
CROSSTALK
MAX5494 toc19
CROSSTALK vs. FREQUENCY
CW_ = 10pF CODE = 01111 01111 -20 CROSSTALK (dB) -40 -60 -80 -100 -120
MAX5494 toc20
VW2 2V/div
0
VW1 20mV/div VH2 = VDD VL2 = VL1 = VH1 = GND CW_ = 10pF 400ns/div
MAX5494/MAX5498 MAX5495/MAX5499
0.01
0.1
1
10
100
1000
FREQUENCY (kHz)
THD+N vs. FREQUENCY (MAX5494/MAX5498)
CW_ = 10pF CODE = 01111 01111
MAX5494 toc21
THD+N vs. FREQUENCY (MAX5495/MAX5499)
CW_ = 10pF CODE = 01111 01111 1
MAX5494 toc22
10
10
1
THD+N (%)
THD+N (%)
0.1
0.1
0.01
0.01
0.001
0.001
0.0001 0.01 0.1 1 FREQUENCY (kHz) 10 100
0.0001 0.01 0.1 1 FREQUENCY (kHz) 10 100
WIPER RESPONSE vs. FREQUENCY (MAX5494/MAX5498)
MAX5494 toc23
WIPER RESPONSE vs. FREQUENCY (MAX5495/MAX5499)
MAX5494 toc24
0 CW_ = 10pF
0
-5
-5
CW_ = 10pF
GAIN (dB)
CW_ = 30pF -15
GAIN (dB)
-10
-10 CW_ = 30pF
-15
-20 CODE = 01111 01111 0.1 1 10 FREQUENCY (kHz) 100 1000
-20 CODE = 01111 01111 0.1 1 10 FREQUENCY (kHz) 100 1000
-25
-25
8
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
Pin Descriptions
PIN MAX5494/ MAX5495 1 2 3 4 5 6, 7,14,15 MAX5496/ MAX5497 1 2 3 -- 5 6, 7,14,15 MAX5498/ MAX5499 1 2 3 -- 5 6, 7,14,15 NAME FUNCTION Active-Low Chip-Select Input. Drive CS low to enable the serial interface. Drive CS high to disable the serial interface and put the device in standby mode. Wiper Terminal 2 Low Terminal 2 High Terminal 2 Positive Power-Supply Input. 2.7V VDD 5.25V. Bypass with a 0.1F capacitor from VDD to GND as close to the device as possible No Connection. Not internally connected. Negative Power-Supply Input. Single-supply operation: VSS = GND = 0. Dual-supply operation: -2.5V VSS -0.2V (VSS can vary as long as (VDD - VSS) 5.25V). Bypass with a 0.1F capacitor from VSS to GND as close to the device as possible. High Terminal 1 Low Terminal 1 Wiper Terminal 1 Ground Serial-Data Input. The data at DIN synchronously loads into the serial shift register on each SCLK rising edge. Serial-Clock Input . SCLK clocks in the data when CS is low. Do Not Connect. Leave unconnected for proper operation. Exposed Pad. Externally connect EP to VSS to provide a low thermal resistance path from the IC junction to the PC board or leave unconnected.
MAX5494-MAX5499
CS W2 L2 H2 VDD N.C.
8
8
8
VSS
9 10 11 12 13 16 -- EP
-- 10 11 12 13 16 4, 9 EP
9 10 11 12 13 16 4 EP
H1 L1 W1 GND DIN SCLK D.N.C Exposed Pad
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9
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Functional Diagrams
H1
VDD GND VSS POR SPI INTERFACE 2 x 10 BIT NVM
10-BIT LATCH
10 DECODER
1024 TAPS
W1
CS SCLK DIN
10-BIT LATCH
10
L1 H2
MAX5494 MAX5495
DECODER
1024 TAPS
W2
L2
NOTE: THE PROGRAMMABLE VOLTAGE-DIVIDER IS NOT INTENDED FOR CURRENT TO FLOW THROUGH THE WIPER. NOTE: SEE THE MAX5494/MAX5495/MAX5498/MAX5499 PROGRAMMABLE VOLTAGE-DIVIDERS SECTION.
Figure 1. MAX5494/MAX5495 Functional Diagram
10
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
Functional Diagrams (continued)
MAX5494-MAX5499
VDD GND VSS POR SPI INTERFACE 2 x 10 BIT NVM
10-BIT LATCH
10 DECODER
1024 TAPS
W1
L1
CS SCLK DIN
10-BIT LATCH
10 DECODER
1024 TAPS
W2
MAX5496 MAX5497
L2
Figure 2. MAX5496/MAX5497 Functional Diagram
H1
VDD GND VSS POR SPI INTERFACE 2 x 10 BIT NVM
10-BIT LATCH
10 DECODER
1024 TAPS
W1
CS SCLK DIN
10-BIT LATCH
10
L1
MAX5498 MAX5499
DECODER
1024 TAPS
W2
L2
NOTE: THE PROGRAMMABLE VOLTAGE-DIVIDER IS NOT INTENDED FOR CURRENT TO FLOW THROUGH THE WIPER. NOTE: SEE THE MAX5494/MAX5495/MAX5498/MAX5499 PROGRAMMABLE VOLTAGE-DIVIDERS SECTION.
Figure 3. MAX5498/MAX5499 Functional Diagram
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11
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Detailed Description
The MAX5494-MAX5499 dual, nonvolatile, linear-taper, programmable voltage-dividers and variable resistors feature 1024 tap points (10-bit resolution) (see the Functional Diagrams). These devices consist of multiple strings of equal resistor segments with a wiper contact that moves among the 1024 effective tap points by a 3-wire SPI-compatible serial interface. The MAX5494/MAX5496/MAX5498 provide a total 10k end-to-end resistance, and the MAX5495/MAX5497/ MAX5499 feature a 50k end-to-end resistance. The MAX5494/MAX5495/MAX5498/MAX5499 allow access to the high, low, and wiper terminals for a standard voltage-divider configuration. Ensure that the terminal voltages fall between VSS and VDD. VHL - (| VFSE | + | VZSE |) D + VL + | VZSE | 1023 where D is the decimal equivalent of the 10 data bits written (0 to 1023), VHL is the voltage difference between the H_ and L_ terminals, and: V VFSE = FSE HL 1024 V VZSE = ZSE HL 1024 The MAX5494/MAX5498 provide a 10k end-to-end resistance value, while the MAX5495/MAX5499 feature a 50k end-to-end resistance value. Note that the programmable voltage-divider is not intended to be used as a variable resistor. Wiper current creates a nonlinear voltage drop in series with the wiper. To ensure temperature drift remains within specifications, do not pull current through the voltage-divider wiper. Connect the wiper to a high-impedance node. Figures 4 and 5 show the behavior of the programmable voltage-divider resistance from W_ to H_ and W_ to L_, respectively. This does not apply to the variable-resistor devices.
MAX5494/MAX5495/MAX5498/MAX5499 Programmable Voltage-Dividers
The MAX5494/MAX5495/MAX5498/MAX5499 programmable voltage-dividers provide a weighted average of the voltage between the H_ and L_ inputs at the W_ output. The MAX5494/MAX5495/MAX5498/MAX5499 programmable voltage-divider network provides up to 1024 division ratios between the H_ and L_ voltage. Ideally, the VL voltage occurs at the wiper terminal when all data bits are zeros and the VH voltage occurs at the wiper terminal when all data bits are one (see the wiper voltage equation). The step-size voltage (1 LSB) is equal to the voltage applied across terminals H and L divided by 210. Calculate the wiper voltage VW as follows:
MAX5496-MAX5499 Variable Resistors
The MAX5496-MAX5499 provide a programmable resistance from W_ to L_. The MAX5496/MAX5498 provide a 10k end-to-end resistance value, while the MAX5497/MAX5499 feature a 50k end-to-end resistance value. The programmable resolution of this
18 16 14 12 RW_H_ (k) 10 8 6 4 2 0 0 128 256 384 512 640 768 896 1024 CODE (DECIMAL) 50k SCALES BY A FACTOR OF FIVE RW_L_ (k)
18 16 14 12 10 8 6 4 2 0 0 128 256 384 512 640 768 896 1024 CODE (DECIMAL) 50k SCALES BY A FACTOR OF FIVE
Figure 4. Resistance from W_ to H_ vs. Code (10k VoltageDivider) 12
Figure 5. Resistance from W_ to L_ vs. Code (10k VoltageDivider)
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10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
resistance is equal to the nominal end-to-end resistance divided by 1024 (10-bit resolution). For example, the programmable resolution is 9.8 and 48.8 for the MAX5496/MAX5498 and the MAX5497/MAX5499, respectively. The 10-bit data in the 10-bit latch register selects the wiper position from the 1024 possible positions, resulting in 1024 values for the resistance from W_ to L_. Calculate the resistance from W_ to L_ (RWL) from the formula below: D RWL (D) = x RW-L + RZ 1023 where D is decimal equivalent of the 10 data bits written, RW-L is the nominal end-to-end resistance, and RZ is the zero-scale error. Table 1 shows RWL at selected codes. either eight clock cycles to transfer the command bits (Figure 7b) or 24 clock cycles with 16 bits disregarded by the device (Figure 7a). After the loading of data into the shift register, drive CS high to latch the data into the appropriate control register (specified by RA1 and RA0) and disable the serial interface. Keep CS low during the entire serial data stream to avoid corruption of the data. Table 2 shows the register map. Write Wiper Register The "write wiper register" command (C1, C0 = 00) controls the wiper positions. The 10 data bits (D9-D0) indicate the position of the wiper. For example, if DIN = 000000 0000, the wiper moves to the position closest to L_. If DIN = 11 1111 1111, the wiper moves closest to H_.
MAX5494-MAX5499
Table 1. RWL at Selected Codes
END-TO-END RESISTANCE VALUE CODE (DECIMAL) 0 1 512 1023 10k RWL () 70 80 5,070 10,070 50k RWL () 110 160 25,110 50,110
SPI-Compatible Serial Interface
The MAX5494-MAX5499 use a 3-wire, SPI-compatible, serial data interface (Figure 6). This write-only interface contains three inputs: chip-select (CS), data input (DIN), and data clock (SCLK). Drive CS low to enable the serial interface and clock data synchronously into the shift register on each SCLK rising edge. The WRITE commands (C1, C0 = 00 or 01) require 24 clock cycles to transfer the command and data (Figure 7a). The COPY commands (C1, C0 = 10 or 11) use
CS tCSS tCSO SCLK tCL tCH tCP tCSH
tCSW tCS1
tDS DIN
tDH
Figure 6. SPI-Interface Timing Diagram
______________________________________________________________________________________
13
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
a) 24-BIT COMMAND/DATA WORD CS
SCLK 1 DIN 2 3 4 5 6 7 8 9 10 D8 11 D7 12 D6 13 D5 14 D4 15 D3 16 D2 17 D1 18 D0 19 20 21 22 23 24
C1 C0
RA1 RA0 D9
b) 8-BIT COMMAND WORD CS
SCLK 1 DIN 2 3 4 5 6 7 8
C1 C0
RA1 RA0
Figure 7. SPI-Compatible Serial-Interface Format
Table 2. Register Map*
CLOCK EDGE Bit Name Write Wiper Register 1 Write Wiper Register 2 Write NV Register 1 Write NV Register 2 Copy Wiper Register 1 to NV Register 1 Copy Wiper Register 2 to NV Register 2 Copy Wiper Register 1 to NV Register 1 and Copy Wiper Register 2 to NV Register 2 Simultaneously Copy NV Register 1 to Wiper Register 1 Copy NV Register 2 to Wiper Register 2 Copy NV Register 1 to Wiper Register 1 and Copy NV Register 2 to Wiper Register 2 Simultaneously 1 -- 0 0 0 0 0 0 2 -- 0 0 0 0 0 0 3 C1 0 0 0 0 1 1 4 C0 0 0 1 1 0 0 5 -- 0 0 0 0 0 0 6 -- 0 0 0 0 0 0 7 0 1 0 1 0 1 8 1 0 1 0 1 0 9 D9 D9 D9 D9 D9 -- -- 10 D8 D8 D8 D8 D8 -- -- 11 D7 D7 D7 D7 D7 -- -- 12 D6 D6 D6 D6 D6 -- -- 13 D5 D5 D5 D5 D5 -- -- 14 D4 D4 D4 D4 D4 -- -- 15 D3 D3 D3 D3 D3 -- -- 16 D2 D2 D2 D2 D2 -- -- 17 D1 D1 D1 D1 D1 -- -- 18 D0 D0 D0 D0 D0 -- -- ... -- -- -- -- -- -- -- 24 -- -- -- -- -- -- -- RA1 RA0
0
0
1
0
0
0
1
1
--
--
--
--
--
--
--
--
--
--
--
--
0 0
0 0
1 1
1 1
0 0
0 0
0 1
1 0
-- --
-- --
-- --
-- --
-- --
-- --
-- --
-- --
-- --
-- --
-- --
-- --
0
0
1
1
0
0
1
1
--
--
--
--
--
--
--
--
--
--
--
--
*D9 is the MSB and D0 is the LSB of the data bits.
14
______________________________________________________________________________________
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
The "write wiper register" command writes data to the volatile random access memory (RAM), leaving the NV registers unchanged. When the device powers up, the data stored in the NV registers transfers to the wiper register, moving the wiper to the stored position. Figure 8 shows how to write data to wiper register 1. Write NV Register The "write NV register" command (C1, C0 = 01) stores the position of the wiper to the NV registers for use at power-up. Alternatively, the "copy wiper register to NV register" command writes to the NV register. Writing to the NV register does not affect the position of the wipers. The operation takes up to 12ms (max) after CS goes high to complete and no other operation should be performed until completion. Figure 9 shows how to write data to the NV register 1. Copy Wiper Register to NV Register The "copy wiper register to NV register" command (C1, C0 = 10) stores the current position of the wiper to the NV register for use at power-up. Figure 10 shows how to copy data from wiper register 1 to NV register 1.
MAX5494-MAX5499
CS
1 SCLK
2
3
4
5
6
7
8
9
10
11 12 13 14
15
16
17
18
19 20 21 22
23
24
C1 C0 DIN 0 0 0 0 0 0
RA1 RA0 0 1 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X
ACTION
WIPER REGISTER 1 UPDATED
Figure 8. Write Wiper Register 1
CS
1 SCLK
2
3
4
5
6
7
8
9
10
11 12 13 14
15
16
17
18
19 20 21 22
23
24
C1 C0 DIN 0 0 0 1 0 0
RA1 RA0 0 1 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X
tBUSY WRITE NV REGISTER 1 (DEVICE IS BUSY)
ACTION
Figure 9. Write NV Register 1 ______________________________________________________________________________________ 15
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Copy NV Register to Wiper Register The "copy NV register to wiper register" (C1, C0 = 11) restores the wiper position to the current value stored in the NV register. Figure 11 shows how to copy data from NV register 1 to wiper register 1. the factory. The nonvolatile memory is guaranteed for 50 years for wiper data retention and up to 200,000 wiper write cycles.
Power-Up
Upon power-up, the MAX5494-MAX5499 load the data stored in the nonvolatile wiper register into the wiper register, updating the wiper position with the data stored in the nonvolatile wiper register.
Standby Mode
The MAX5494-MAX5499 feature a low-power standby mode. When the device is not being programmed, it enters into standby mode and supply current drops to 0.6A (typ).
Applications Information
The MAX5494-MAX5499 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.
Nonvolatile Memory
The internal EEPROM consists of a nonvolatile register that retains the last value stored prior to power-down. The nonvolatile register is programmed to midscale at
CS
CS
1 SCLK
2
3
4
5
6
7
8
SCLK
1
2
3
4
5
6
7
8
C1 DIN 0 0 1
C0 0 0 0
RA1 0
RA0 1
DIN 0 0
C1 1
C0 1 0 0
RA1 0
RA0 1
tBUSY WRITE NV REGISTER 1 (DEVICE IS BUSY)
WIPER REGISTER 1 UPDATED
ACTION
ACTION
Figure 10. Copy Wiper Register 1 to NV Register 1
Figure 11. Copy NV Register 1 to Wiper Register 1
16
______________________________________________________________________________________
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
Positive LCD Bias Control
Figures 12 and 13 show an application where the voltage-divider 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.
MAX5494-MAX5499
R1 R2 1 fC = 2 x R3 x C G = 1+
Programmable Filter
Figure 14 shows the configuration for 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).
Gain and Offset Voltage Adjustment
Figure 15 shows an application using the MAX5498/ MAX5499 to adjust the gain and nullify the offset voltage.
5V H_ 30V 1/2 MAX5494/MAX5495 1/2 MAX5498/MAX5499 L_ 1/2 MAX5496-MAX5499 W_ MAX480
5V
30V
VOUT
MAX480
VOUT
W_ L_
Figure 12. Positive LCD Bias Control Using a Voltage-Divider
Figure 13. Positive LCD Bias Control Using a Variable Resistor
C VIN VOUT 1/2 MAX5498/MAX5499 1/2 MAX5496-MAX5499 R3 W_ L_ R1
VREF H_
W_ L_
VOUT
1/2 MAX5496-MAX5499
R2 W_ L_
1/2 MAX5498/MAX5499 W_ VIN L_
Figure 14. Programmable Filter
Figure 15. Gain- and Offset-Voltage Adjustment Circuit
______________________________________________________________________________________
17
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
Selector Guide
PART CONFIGURATION Two programmable voltagedividers Two programmable voltagedividers Two variable resistors Two variable resistors One programmable voltagedivider and one variable resistor One programmable voltagedivider and one variable resistor END-TO-END RESISTANCE (k) 10 50 10 50 10 50
Ordering Information (continued)
PART MAX5496ETE MAX5497ETE MAX5498ETE MAX5499ETE TEMP RANGE PINPACKAGE PKG CODE T1655-2 T1655-2 T1655-2 T1655-2
-40C to +85C 16 TQFN-EP* -40C to +85C 16 TQFN-EP* -40C to +85C 16 TQFN-EP* -40C to +85C 16 TQFN-EP*
MAX5494ETE MAX5495ETE MAX5496ETE MAX5497ETE MAX5498ETE MAX5499ETE
*EP = Exposed pad.
Chip Information
TRANSISTOR COUNT: 32,262 PROCESS: BiCMOS
Pin Configurations (continued)
TOP VIEW
GND W1 H1 9 8 INTERFACE 7 VSS N.C. N.C. VDD L1 10
12 DIN 13 N.C. 14 N.C. 15 SCLK 16 1 CS
11
MAX5498 MAX5499
6 5
2 W2
3 L2
4 D.N.C.
5mm x 5mm x 0.8mm TQFN
18
______________________________________________________________________________________
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers
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.)
QFN THIN.EPS
MAX5494-MAX5499
D2 D D/2 MARKING k L E/2 E2/2 E (NE-1) X e
C L C L
b D2/2
0.10 M C A B
XXXXX
E2
PIN # 1 I.D.
DETAIL A
e (ND-1) X e
e/2
PIN # 1 I.D. 0.35x45 DETAIL B
e
L1
L
C L
C L
L
L
e 0.10 C A 0.08 C
e
C
A1 A3 PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm
-DRAWING NOT TO SCALE-
21-0140
H
1
2
______________________________________________________________________________________
19
10-Bit, Dual, Nonvolatile, Linear-Taper Digital Potentiometers MAX5494-MAX5499
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.)
COMMON DIMENSIONS
PKG. 16L 5x5 20L 5x5 28L 5x5 32L 5x5 40L 5x5 SYMBOL MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX.
EXPOSED PAD VARIATIONS PKG. CODES T1655-1 T1655-2 T1655N-1 T2055-2 T2055-3 T2055-4 T2055-5 T2855-1 T2855-2 T2855-3 T2855-4 T2855-5 T2855-6 T2855-7 T2855-8 T2855N-1 T3255-2 T3255-3 T3255-4 T3255N-1 T4055-1
D2
MIN. NOM. MAX. MIN.
E2
NOM. MAX.
L
0.15
A A1 A3 b D E e k L L1 N ND NE JEDEC
NOTES:
DOWN BONDS ALLOWED
0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 0 0.02 0.05 0 0.02 0.05 0 0.02 0.05 0.20 REF. 0.20 0.25 0.30 4.90 5.00 5.10 4.90 5.00 5.10 0.50 BSC. 0.25 0 0.02 0.05 0.20 REF. 0.20 0.25 0.30 4.90 5.00 5.10 4.90 5.00 5.10 0.50 BSC. 0.25 0 0.02 0.05 0.20 REF. 0.20 REF. 0.25 0.30 0.35 0.25 0.30 0.35 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 4.90 5.00 5.10 0.80 BSC. 0.65 BSC. 0.25 - 0.25 0.20 REF. 0.15 0.20 0.25 4.90 5.00 5.10 4.90 5.00 5.10 0.40 BSC. 0.25 0.35 0.45
3.00 3.00 3.00 3.00 3.00 3.00 3.15 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.15 3.15 3.00 3.00 3.00 3.00 3.20
3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.10 3.20 3.00 3.25 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.25 3.25 3.10 3.10 3.10 3.10 3.35 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.35 3.35 3.20 3.20 3.20 3.20 3.15 3.15 2.60 3.15 2.60 2.60 3.15 2.60 3.15 3.15 3.00 3.00 3.00 3.00
3.10 3.10 3.10 3.10 3.10 3.10 3.25 3.25 2.70 3.25 2.70 2.70 3.25 2.70 3.25 3.25 3.10 3.10 3.10 3.10 3.30
3.20 3.20 3.20 3.20 3.20 3.20 3.35 3.35 2.80 3.35 2.80 2.80 3.35 2.80 3.35 3.35 3.20 3.20 3.20 3.20 3.40
** ** ** ** ** ** 0.40 ** ** ** ** ** ** ** 0.40 ** ** ** ** ** **
NO YES NO NO YES NO YES NO NO YES YES NO NO YES YES NO NO YES NO NO YES
0.30 0.40 0.50 0.45 0.55 0.65 0.45 0.55 0.65 0.30 0.40 0.50 0.40 0.50 0.60 - 0.30 0.40 0.50 16 20 28 32 40 4 5 7 8 10 4 5 7 8 10 WHHB WHHC WHHD-1 WHHD-2 -----
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994. 2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES. 3. N IS THE TOTAL NUMBER OF TERMINALS. 4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE. 5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm FROM TERMINAL TIP. 6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY. 7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION. 8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS. 9. DRAWING CONFORMS TO JEDEC MO220, EXCEPT EXPOSED PAD DIMENSION FOR T2855-1, T2855-3, AND T2855-6. 10. WARPAGE SHALL NOT EXCEED 0.10 mm. 11. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY. 12. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY. 13. LEAD CENTERLINES TO BE AT TRUE POSITION AS DEFINED BY BASIC DIMENSION "e", 0.05.
3.30 3.40 3.20
** SEE COMMON DIMENSIONS TABLE
PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm
-DRAWING NOT TO SCALE-
21-0140
H
2
2
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.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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