General Description
The MAX5487/MAX5488/MAX5489 dual, linear-taper,
digital potentiometers function as mechanical poten-
tiometers with a simple 3-wire SPI™-compatible digital
interface that programs the wipers to any one of 256
tap positions. These digital potentiometers feature a
nonvolatile memory (EEPROM) to return the wipers to
their previously stored positions upon power-up.
The MAX5487 has an end-to-end resistance of 10kΩ,
while the MAX5488 and MAX5489 have resistances of
50kΩand 100kΩ, respectively. These devices have a
low 35ppm/°C end-to-end temperature coefficient, and
operate from a single +2.7V to +5.25V supply.
The MAX5487/MAX5488/MAX5489 are available in
16-pin 3mm x 3mm x 0.8mm TQFN or 14-pin TSSOP
packages. Each device is guaranteed over the extended
-40°C to +85°C temperature range.
Applications
LCD Screen Adjustment
Audio Volume Control
Mechanical Potentiometer Replacement
Low-Drift Programmable Filters
Low-Drift Programmable-Gain Amplifiers
Features
oWiper Position Stored in Nonvolatile Memory
(EEPROM) and Recalled Upon Power-Up or
Recalled by an Interface Command
o3mm x 3mm x 0.8mm, 16-Pin TQFN or 14-Pin
TSSOP Packages
o±1 LSB INL, ±0.5 LSB DNL (Voltage-Divider Mode)
o256 Tap Positions
o35ppm/°C End-to-End Resistance Temperature
Coefficient
o5ppm/°C Ratiometric Temperature Coefficient
o10kΩ, 50kΩ, and 100kΩ End-to-End Resistance
Values
oSPI-Compatible Serial Interface
oReliability
200,000 Wiper Store Cycles
50-Year Wiper Data Retention
o+2.7V to +5.25V Single-Supply Operation
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
________________________________________________________________
Maxim Integrated Products
1
19-3478; Rev 4; 4/10
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
SPI is a trademark of Motorola, Inc.
Ordering Information
PART TEMP RANGE PIN-PACKAGE END-TO-END
RESISTANCE (kΩ)TOP MARK
MAX5487ETE+ -40°C to +85°C 16 TQFN-EP* 10 ABR
MAX5487EUD+ -40°C to +85°C 14 TSSOP 10 —
*
EP = Exposed pad.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
MAX5487
MAX5488
MAX5489
POR
8-BIT
LATCH
16-BIT
NV RAM
SCLK
DIN
CS
DECODER
8
8
256
DECODER
256
HA
WA
LA
HB
WB
LB
VDD
GND
SPI
INTERFACE
8-BIT
LATCH
Functional Diagram
15
16
14
13
5
*EP
*EXPOSED PAD.
6
7
DIN
CS
8
VDD
LB
N.C.
HB
1
+
3
WA
4
12 10 9
HA
I.C.
I.C.
GND
N.C.
N.C.
MAX5487
MAX5488
MAX5489
SCLK WB
2
11
LA
TQFN
3mm x 3mm
TOP VIEW
Pin Configurations
Pin Configurations continued at end of data sheet.
Ordering Information continued at end of data sheet.
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
VDD to GND...........................................................-0.3V to +6.0V
All Other Pins
to GND......................-0.3V to the lower of (VDD + 0.3V) and +6.0V
Maximum Continuous Current into H_, W_, and L_
MAX5487......................................................................±5.0mA
MAX5488......................................................................±1.3mA
MAX5489......................................................................±0.6mA
Continuous Power Dissipation (TA= +70°C)
16-Pin TQFN (derate 17.5mW/°C above +70°C) ..........1398mW
14-Pin TSSOP (derate 9.1mW/°C above +70°C).............727mW
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
Soldering Temperature (reflow) .......................................+260°C
DC ELECTRICAL CHARACTERISTICS
(VDD = +2.7V to +5.25V, VH= VDD, VL= GND, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC PERFORMANCE (Voltage-Divider Mode, Figure 1)
Resolution N 256 Taps
Integral Nonlinearity INL (Note 2) ±1 LSB
Differential Nonlinearity DNL (Note 2) ±0.5 LSB
Dual-Code Matching Register A = register B 2 LSB
End-to-End Resistor Tempco TCR35 ppm/°C
Ratiometric Resistor Tempco 5 ppm/°C
MAX5487 3.5 6
MAX5488 -0.6 +1.2Full-Scale Error
MAX5489 -0.3 +1.2
LSB
MAX5487 3.5 6
MAX5488 -0.6 1.5Zero-Scale Error
MAX5489 0.3 1
LSB
DC PERFORMANCE (Variable-Resistor Mode, Figure 1)
Resolution 256 Taps
VDD = 5.0V ±1.5
Integral Nonlinearity (Note 3) VDD = 3.0V ±3 LSB
VDD = 5.0V ±1
Differential Nonlinearity (Note 3) VDD = 3.0V ±1 LSB
DC PERFORMANCE (Resistor Characteristics)
VDD = 5.0V 200 350
Wiper Resistance (Note 4) RWVDD = 3.0V 325 675
Ω
Wiper Capacitance CW50 pF
MAX5487 7.5 10 12.5
MAX5488 37.5 50 62.5End-to-End Resistance RHL
MAX5489 75 100 125
kΩ
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
_______________________________________________________________________________________ 3
DC ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.25V, VH= VDD, VL= GND, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DIGITAL INPUTS
VDD = 3.6V to 5.25V 2.4
Input High Voltage (Note 5) VIH VDD = 2.7V to 3.6V 0.7 x
VDD
V
Input Low Voltage VIL VDD = 2.7V to 5.25V (Note 5) 0.8 V
Input Leakage Current IIN ±1.0 µA
Input Capacitance CIN 5.0 pF
AC PERFORMANCE
Crosstalk fH_ = 1kHz, L_ = GND, measurement at W_
(Note 6) -90 dB
MAX5487 350
MAX5488 90-3dB Bandwidth BW Wiper at midscale
CW_ = 10pF
MAX5489 45
kHz
Total Harmonic Distortion THD VH_ = 1VRMS at 1kHz, L_ = GND,
measurement at W_ 0.02 %
TIMING CHARACTERISTICS (Analog)
MAX5487 0.5
MAX5488 0.75Wiper-Settling Time tSCode 0 to 127
(Note 7)
MAX5489 1.5
µs
TIMING CHARACTERISTICS (Digital, Figure 2, Note 8)
SCLK Frequency 5 MHz
SCLK Clock Period tCP 200 ns
SCLK Pulse-Width High tCH 80 ns
SCLK Pulse-Width Low tCL 80 ns
CS Fall to SCLK Rise Setup tCSS 80 ns
SCLK Rise to CS Rise Hold tCSH 0ns
DIN to SCLK Setup tDS 50 ns
DIN Hold after SCLK tDH 0ns
SCLK Rise to CS Fall Delay tCS0 20 ns
CS Rise to SCLK Rise Hold tCS1 80 ns
CS Pulse-Width High tCSW 200 ns
Write NV Register Busy Time tBUSY 12 ms
Read NV Register Access Time tACC 1µs
W r i te W i p er Reg i ster to O utp ut D el ay tWO 1µs
NONVOLATILE MEMORY RELIABILITY
Data Retention TA = +85°C 50 Years
TA = +25°C 200,000
Endurance TA = +85°C 50,000 Stores
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
4 _______________________________________________________________________________________
Note 1: All devices are production tested at TA= +85°C and are guaranteed by design and characterization for -40°C < TA< +85°C.
Note 2: DNL and INL are measured with the potentiometer configured as a voltage-divider with H_ = VDD and L_ = 0. The wiper terminal
is unloaded and measured with an ideal voltmeter.
Note 3: DNL and INL are measured with the potentiometer configured as a variable resistor. H_ is unconnected and L_ = 0. For VDD =
+5V, the wiper terminal is driven with a source current of 400µA for the 10kΩconfiguration, 80µA for the 50kΩconfiguration,
and 40µA for the 100kΩconfiguration. For VDD = +3V, the wiper terminal is driven with a source current of 200µA for the 10kΩ
configuration, 40µA for the 50kΩconfiguration, and 20µA for the 100kΩconfiguration.
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: The device draws higher supply current when the digital inputs are driven with voltages between (VDD - 0.5V) and (GND +
0.5V). See Supply Current vs. Digital Input Voltage in the
Typical Operating Characteristics
section.
Note 6: Wiper at midscale with a 10pF load.
Note 7: Wiper-settling time is the worst-case 0-to-50% rise time, measured between tap 0 and tap 127. 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
section).
Note 8: Digital timing is guaranteed by design and characterization, and is not production tested.
DC ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.25V, VH= VDD, VL= GND, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +5.0V,
TA= +25°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLIES
Power-Supply Voltage VDD 2.70 5.25 V
Supply Current IDD During write cycle only, digital inputs =
VDD or GND 400 µA
Standby Current Digital inputs = VDD or GND, TA = +25°C 0.5 1 µA
H
L
W
VOLTAGE-DIVIDER
CONFIGURATION
VARIABLE-RESISTOR
CONFIGURATION
H
L
Figure 1. Voltage-Divider/Variable-Resistor Configurations
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
_______________________________________________________________________________________
5
0.1
0
-40-20 0204060 80
0.5
0.4
0.3
0.2
0.6
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
SUPPLY CURRENT
vs. TEMPERATURE
MAX5487-89 toc01
VDD = 3V
VDD = 5V
SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
MAX5487-89 toc02
DIGITAL INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
4321
1
10
100
1000
10,000
0
05
VCC = 5V
VCC = 3V
0
50
150
100
200
250
0649632 128 160 192 224 256
WIPER RESISTANCE
vs. TAP POSITION
MAX5487-89 toc03
TAP POSITION
WIPER RESISTANCE (Ω)
1µs/div
TAP-TO-TAP SWITCHING TRANSIENT
(MAX5487)
CS
2.0V/div
WIPER
20mV/div
MAX5487-89 toc04
VH_ = 5.0V
TAP-TO-TAP SWITCHING TRANSIENT
(MAX5488)
MAX5487-89 toc05
1.0µs/div
WIPER
20mV/div
VH_ = 5.0V
CS
2.0V/div
WIPER TRANSIENT AT POWER-ON
MAX5487-89 toc07
2.0µs/div
WIPER
2.0V/div
VH_ = VDD
VDD
2.0V/div
FREQUENCY (kHz)
GAIN (dB)
MIDSCALE FREQUENCY RESPONSE
(MAX5487)
0
-2
-4
-6
-8
-10
-12
-14
-16
-18
-20
0.1 1 10 100 1000
MAX5487-89 toc08
CW = 10pF
CW_ = 50pF
TAP-TO-TAP SWITCHING TRANSIENT
(MAX5489)
MAX5487-89 toc06
1.0µs/div
WIPER
20mV/div
VH_ = 5.0V
CS
2.0V/div
Typical Operating Characteristics
(VDD = +5.0V, TA= +25°C, unless otherwise noted.)
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
6 _______________________________________________________________________________________
VARIABLE-RESISTOR INL
vs. TAP POSITION (MAX5488)
MAx5487-89 toc12
TAP POSITION
INL (LSB)
22419232 64 96 128 160
-0.6
-0.8
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
0256
-0.20
-0.10
-0.15
0
-0.05
0.05
0.10
0.15
0.20
0649632 128 160 192 224 256
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (MAX5487)
MAX5487-89 toc13
TAP POSITION
DNL (LSB)
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (MAX5488)
MAx5487-89 toc15
TAP POSITION
DNL (LSB)
22419232 64 96 128 160
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
-0.20
0256
VOLTAGE-DIVIDER INL
vs. TAP POSITION (MAX5488)
MAx5487-89 toc16
TAP POSITION
INL (LSB)
22419232 64 96 128 160
-0.6
-0.8
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
0 256
0.6
0.2
0.4
0.2
0
0.6
0.4
0.8
1.2
1.0
1.4
0649632 128 160 192 224 256
VOLTAGE-DIVIDER INL
vs. TAP POSITION (MAX5487)
MAX5487-89 toc14
TAP POSITION
INL (LSB)
Typical Operating Characteristics (continued)
(VDD = +5.0V, TA= +25°C, unless otherwise noted.)
MIDSCALE FREQUENCY RESPONSE
(MAX5488)
MAX5487-89 toc09
FREQUENCY (kHz)
GAIN (dB)
100101
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
-50
0.1 1000
CW_ = 10pF
CW_ = 50pF
MIDSCALE FREQUENCY RESPONSE
(MAX5489)
MAX5487-89 toc10
FREQUENCY (kHz)
GAIN (dB)
100101
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
-50
0.1 1000
CW_ = 10pF
CW_ = 50pF
VARIABLE-RESISTOR DNL
vs. TAP POSITION (MAX5488)
MAx5487-89 toc11
TAP POSITION
DNL (LSB)
22419232 64 96 128 160
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
-0.20
0256
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
_______________________________________________________________________________________ 7
VARIABLE-RESISTOR DNL
vs. TAP POSITION (MAX5489)
MAx5487-89 toc17
TAP POSITION
DNL (LSB)
22419232 64 96 128 160
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
-0.20
0256
VOLTAGE-DIVIDER INL
vs. TAP POSITION (MAX5489)
MAx5487-89 toc20
TAP POSITION
INL (LSB)
22419232 64 96 128 160
-0.6
-0.8
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
0256
VARIABLE-RESISTOR INL
vs. TAP POSITION (MAX5489)
MAx5487-89 toc18
TAP POSITION
INL (LSB)
22419232 64 96 128 160
-0.6
-0.8
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
0 256
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (MAX5489)
MAx5487-89 toc19
TAP POSITION
DNL (LSB)
22419232 64 96 128 160
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
-0.20
0256
-0.010
-0.004
-0.006
-0.008
-0.002
0
0.002
0.004
0.006
0.008
0.010
-40 10-15 356085
END-TO-END RESISTANCE CHANGE
vs. TEMPERATURE (MAX5487)
MAX5487-89 toc22
TEMPERATURE (°C)
RESISTANCE CHANGE (%)
-100
-80
-90
-60
-70
-40
-50
-30
CROSSTALK
vs. FREQUENCY
MAX5487-89 toc21
FREQUENCY (kHz)
CROSSTALK (dB)
0.1 1 10 100 1000
MAX5487
MAX5488
MAX5489
CW_ = 10pF
-0.010
-0.004
-0.006
-0.008
-0.002
0
0.002
0.004
0.006
0.008
0.010
-40 10-15 35 60 85
END-TO-END RESISTANCE CHANGE
vs. TEMPERATURE (MAX5488)
MAX5487-89 toc23
TEMPERATURE (°C)
RESISTANCE CHANGE (%)
-0.010
-0.004
-0.006
-0.008
-0.002
0
0.002
0.004
0.006
0.008
0.010
-40 10-15 35 60 85
END-TO-END RESISTANCE CHANGE
vs. TEMPERATURE (MAX5489)
MAX5487-89 toc24
TEMPERATURE (°C)
RESISTANCE CHANGE (%)
Typical Operating Characteristics (continued)
(VDD = +5.0V, TA= +25°C, unless otherwise noted.)
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
8 _______________________________________________________________________________________
Detailed Description
The MAX5487/MAX5488/MAX5489 contain two resistor
arrays, with 255 resistive elements each. The MAX5487
has an end-to-end resistance of 10kΩ, while the
MAX5488 and MAX5489 have resistances of 50kΩand
100kΩ, respectively. The MAX5487/MAX5488/MAX5489
allow access to the high, low, and wiper terminals on
both potentiometers for a standard voltage-divider con-
figuration. Connect the wiper to the high terminal, and
connect the low terminal to ground, to make the device
a variable resistor (see Figure 1).
A simple 3-wire serial interface programs either wiper
directly to any of the 256 tap points. The nonvolatile
memory stores the wiper position prior to power-down
and recalls the wiper to the same point upon power-up
or by using an interface command (see Table 1). The
nonvolatile memory is guaranteed for 200,000 wiper
store cycles and 50 years for wiper data retention.
SPI Digital Interface
The MAX5487/MAX5488/MAX5489 use a 3-wire SPI-
compatible serial data interface (Figures 2 and 3). This
write-only interface contains three inputs: chip-select
(CS), data clock (SCLK), and data in (DIN). Drive CS low
to enable the serial interface and clock data synchro-
nously into the shift register on each SCLK rising edge.
The WRITE commands (C1, C0 = 00 or 01) require 16
clock cycles to clock in the command, address, and data
(Figure 3a). The COPY commands (C1, C0 = 10, 11) can
use either eight clock cycles to transfer only command
and address bits (Figure 3b) or 16 clock cycles, with the
device disregarding 8 data bits (Figure 3a).
After loading data into the shift register, drive CS high
to latch the data into the appropriate potentiometer
control register and disable the serial interface. Keep
CS low during the entire serial data stream to avoid cor-
ruption of the data.
Digital-Interface Format
The data format consists of three elements: command
bits, address bits, and data bits (see Table 1 and
Figure 3). The command bits (C1 and C0) indicate the
action to be taken such as changing or storing the
wiper position. The address bits (A1 and A0) specify
which potentiometer the command affects and the 8
data bits (D7 to D0) specify the wiper position.
PIN
TQFN TSSOP NAME FUNCTION
114V
DD Power Supply. Bypass VDD to GND with a 0.1µF capacitor as close to the device as possible.
2 13 SCLK Serial-Interface Clock Input
3 12 DIN Serial-Interface Data Input
411CS Active-Low Chip-Select Digital Input
5, 6, 9 7, 9, 10 N.C. No Connection. Not internally connected.
7 8 GND Ground
8, 16 — I.C. Internally connected to EP. Leave unconnected.
10 6 LB Low Terminal of Resistor B. The voltage at L can be greater than or less than the voltage at H.
Current can flow into or out of L.
11 5 WB Wiper Terminal of Resistor B
12 4 HB High Terminal of Resistor B. The voltage at H can be greater than or less than the voltage at L.
Current can flow into or out of H.
13 3 LA Low Terminal of Resistor A. The voltage at L can be greater than or less than the voltage at H.
Current can flow into or out of L.
14 2 WA Wiper Terminal of Resistor A
15 1 HA High Terminal of Resistor A. The voltage at H can be greater than or less than the voltage at L.
Current can flow into or out of H.
— — EP Exposed Pad (TQFN only). Internally connected to pins 8 and 16. Leave unconnected.
Pin Description
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
_______________________________________________________________________________________ 9
Write-Wiper Register (Command 00)
Data written to the write-wiper registers (C1, C0 = 00)
controls the wiper positions. The 8 data bits (D7 to D0)
indicate the position of the wiper. For example, if DIN =
0000 0000, the wiper moves to the position closest to
L_. If DIN = 1111 1111, the wiper moves closest to H_.
This command writes data to the volatile RAM, leaving the
NV registers unchanged. When the device powers up,
the data stored in the NV registers transfers to the volatile
wiper register, moving the wiper to the stored position.
Write-NV Register (Command 01)
This command (C1, C0 = 01) stores the position of the
wipers to the NV registers for use at power-up.
Alternatively, the “copy wiper register to NV register”
command can be used to store the position of the
wipers to the NV registers. Writing to the NV registers
does not affect the position of the wipers.
Copy Wiper Register to NV Register (Command 10)
This command (C1, C0 = 10) stores the current position
of the wiper to the NV register, for use at power-up.
This command may affect one potentiometer at a time,
Table 1. Register Map
12345678910111213141516
CLOCK EDGE — — C1 C0 — — A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
Write Wiper Register A 00000001D7D6D5D4D3D2D1D0
Write Wiper Register B 00000010D7D6D5D4D3D2D1D0
Write NV Register A 00010001D7D6D5D4D3D2D1D0
Write NV Register B 00010010D7D6D5D4D3D2D1D0
Copy Wiper Register A to NV
Register A 00100001————————
Copy Wiper Register B to NV
Register B 00100010————————
Copy Both Wiper Registers to
NV Registers 00100011————————
Copy NV Register A to Wiper
Register A 00110001————————
Copy NV Register B to Wiper
Register B 00110010————————
Copy Both NV Registers to
Wiper Registers 00110011————————
Figure 2. Timing Diagram
CS
tCSO
tCSS tCL tCH
tDH
tDS
tCP tCSH
tCSW
tCS1
SCLK
DIN
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
10 ______________________________________________________________________________________
or both simultaneously, depending on the state of A1
and A0. Alternatively, the “write NV register” command
can be used to store the current position of the wiper to
the NV register.
Copy NV Register to Wiper Register (Command 11)
This command (C1, C0 = 11) restores the wiper position
to the previously stored position in the NV register. This
command may affect one potentiometer at a time, or both
simultaneously, depending on the state of A1 and A0.
Nonvolatile Memory
The internal EEPROM consists of a nonvolatile register
that retains the last stored value prior to power-down.
The nonvolatile register is programmed to midscale at
the factory. The nonvolatile memory is guaranteed for
200,000 wiper write cycles and 50 years for wiper data
retention.
Power-Up
Upon power-up, the MAX5487/MAX5488/MAX5489
load the data stored in the nonvolatile wiper register
into the volatile memory register, updating the wiper
position with the data stored in the nonvolatile wiper
register. This initialization period takes 5µs.
Standby
The MAX5487/MAX5488/MAX5489 feature a low-power
standby mode. When the device is not being pro-
grammed, it enters into standby mode and supply cur-
rent drops to 0.5µA (typ).
Applications Information
The MAX5487/MAX5488/MAX5489 are ideal for circuits
requiring digitally controlled adjustable resistance,
such as LCD contrast control (where voltage biasing
adjusts the display contrast), or for programmable fil-
ters with adjustable gain and/or cutoff frequency.
Positive LCD Bias Control
Figures 4 and 5 show an application where the
MAX5487/MAX5488/MAX5489 provide an adjustable,
positive LCD-bias voltage. The op amp provides buffer-
ing and gain to the resistor-divider network made by
the potentiometer (Figure 4) or by a fixed resistor and a
variable resistor (Figure 5).
Programmable Filter
Figure 6 shows the MAX5487/MAX5488/MAX5489 in a
1st-order programmable-filter application. Adjust the gain
of the filter with R2, and set the cutoff frequency with R3.
Figure 3. Digital-Interface Format
16151413121110987654321
SCLK
C1 C0 D7 D6 D5 D4 D3 D2 D1 D0A1 A0
87654321
C1 C0 A1 A0
DIN
SCLK
CS
B) 8-BIT COMMAND WORD
A) 16-BIT COMMAND/DATA WORD
CS
DIN
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
______________________________________________________________________________________ 11
Use the following equations to calculate the gain (A)
and the -3dB cutoff frequency (fC):
Adjustable Voltage Reference
Figure 7 shows the MAX5487/MAX5488/MAX5489 used
as the feedback resistors in multiple adjustable volt-
age-reference applications. Independently adjust the
output voltages of the MAX6160s from 1.23V to VIN -
0.2V by changing the wiper positions of the MAX5487/
MAX5488/MAX5489.
Offset Voltage and Gain Adjustment
Connect the high and low terminals of one potentiome-
ter of a MAX5487/MAX5488/MAX5489 to the NULL
inputs of a MAX410, and connect the wiper to the op
amp’s positive supply to nullify the offset voltage over
the operating temperature range. Install the other
potentiometer in the feedback path to adjust the gain of
the MAX410 (see Figure 8).
Chip Information
PROCESS: BiCMOS
fRC
C=××
1
23
π
AR
R
=+
11
2
Figure 4. Positive LCD-Bias Control Using a Voltage-Divider
VOUT
30V
5V
W_
H_
L_
MAX5487
MAX5488
MAX5489 MAX480
Figure 5. Positive LCD-Bias Control Using a Variable Resistor
VOUT
30V
5V
W_
H_
L_
MAX5487
MAX5488
MAX5489
MAX480
14
13
12
11
10
9
8
1
2
3
4
5
6
7
VDD
SCLK
DIN
CS
HB
LA
WA
HA
TOP VIEW
MAX5487
MAX5488
MAX5489
N.C.
N.C.
GNDN.C.
LB
WB
TSSOP
+
Figure 6. Programmable Filter
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
VIN
R2
HB
WB
LB
R1
VOUT
R3
HA
WA
LA
CMAX410
V+
V-
R2, R3 = RHL x D / 256
WHERE RHL = END-TO-END RESISTANCE
AND D = DECIMAL VALUE OF WIPER CODE
Pin Configurations (continued)
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
12 ______________________________________________________________________________________
Figure 7. Adjustable Voltage Reference
MAX6160
IN
5V
OUT
ADJ
GND
HA
LA
WA
VOUT1 IN OUT
ADJ
GND
HB
LB
WB
VOUT2
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
MAX6160
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
FOR THE MAX5487
VOUT_ = 1.23V x 10kΩ
R
FOR THE MAX5488
VOUT_ = 1.23V x 50kΩ
R
FOR THE MAX5489
VOUT_ = 1.23V x 100kΩ
R
R2 = RHL x D / 256
WHERE RHL = END-TO-END RESISTANCE
AND D = DECIMAL VALUE OF WIPER CODE
RR
Figure 8. Offset Voltage and Gain Adjustment
3
2
5V
7
4
1
6
8
MAX410
HA LA
WA
R2
R1
HB
LB
WB
1/2 MAX5487/MAX5488/MAX5489
1/2 MAX5487/MAX5488/MAX5489
R2 = RHL x D / 256
WHERE RHL = END-TO-END RESISTANCE
AND = D DECIMAL VALUE OF WIPER CODE
Ordering Information (continued)
PART TEMP RANGE PIN-PACKAGE END-TO-END
RESISTANCE (kΩ)TOP MARK
MAX5488ETE+ -40°C to +85°C 16 TQFN-EP* 50 ABS
MAX5488EUD+ -40°C to +85°C 14 TSSOP 50 —
MAX5489ETE+ -40°C to +85°C 16 TQFN-EP* 100 ABT
MAX5489EUD+ -40°C to +85°C 14 TSSOP 100 —
MAX5489ETE/V+ -40°C to +85°C 16 TQFN-EP* 100 AIE
*
EP = Exposed pad.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package draw-
ings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
16 TQFN-EP T1633F+3 21-0136 90-0033
14 TSSOP U14+1 21-0066 90-0113
MAX5487/MAX5488/MAX5489
Dual, 256-Tap, Nonvolatile, SPI-Interface,
Linear-Taper Digital Potentiometers
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
13
© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
3 1/07 — 1, 8, 12, 15
4 4/10
Updated Ordering Information (added lead-free packaging and automotive
qualified part, released TSSOP package), and updated Absolute Maximum
Ratings
1, 2, 12
