Maxim MAX5393LAUD+ Dual 256-tap, volatile, low-voltage linear taper digital potentiometer Datasheet

19-5035; Rev 0; 10/09
TION KIT
EVALUA BLE
IL
AVA A
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
Features
The MAX5391/MAX5393 dual 256-tap, volatile, lowvoltage linear taper digital potentiometers offer three
end-to-end resistance values of 10kI, 50kI, and 100kI.
Operating from a single +1.7V to +5.5V power supply, these devices provide a low 35ppm/NC end-to-end
temperature coefficient. The devices feature an SPIK
interface.
S Dual 256-Tap Linear Taper Positions
The small package size, low supply voltage, low supply current, and automotive temperature range of the
MAX5391/MAX5393 make the devices uniquely suitable
for the portable consumer market, battery backup industrial applications, and the automotive market.
S Wiper Set to Midscale on Power-Up
The MAX5391/MAX5393 include two digital potentiometers in a voltage-divider configuration. The MAX5391/
MAX5393 are specified over the -40NC to +125NC automotive temperature range and are available in a 16-pin,
3mm x 3mm TQFN and a 14-pin TSSOP package,
respectively.
Applications
Low-Voltage Battery Applications
Portable Electronics
Mechanical Potentiometer Replacement
Offset and Gain Control
S Single +1.7V to +5.5V Supply Operation
S Low 12µA Quiescent Supply Current
S 10kI, 50kI, and 100kI End-to-End Resistance
Values
S SPI-Compatible Interface
S -40NC to +125NC Operating Temperature Range
Ordering Information
PART
PIN-PACKAGE
END-TO-END
RESISTANCE (kI)
MAX5391LATE+
16 TQFN-EP*
10
MAX5391MATE+
16 TQFN-EP*
50
MAX5391NATE+
16 TQFN-EP*
100
MAX5393LAUD+
14 TSSOP
10
MAX5393MAUD+
14 TSSOP
50
MAX5393NAUD+
14 TSSOP
100
Note: All devices are specified in the -40NC to +125NC temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package
*EP = Exposed pad.
Adjustable Voltage References/Linear Regulators
Automotive Electronics
Functional Diagram
VDD
WA
HA
BYP
LA
CHARGE
PUMP
CS
SCLK
DIN
LATCH
256 DECODER
POR
MAX5391
MAX5393
LATCH
256 DECODER
HB
SPI
WB
LB
GND
SPI is a trademark of Motorola, Inc.
________________________________________________________________ Maxim Integrated Products 1
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.
MAX5391/MAX5393
General Description
MAX5391/MAX5393
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
ABSOLUTE MAXIMUM RATINGS
VDD to GND ............................................................-0.3V to +6V
H_, W_, L_ to GND.......................................-0.3V to the lower of
(VDD + 0.3V) or +6V
All Other Pins to GND..............................................-0.3V to +6V
Continuous Current into H_, W_, and L_
MAX5391L/MAX5393L.................................................... Q5mA
MAX5391M/MAX5393M.................................................. Q2mA
MAX5391N/MAX5393N.................................................. Q1mA
Continuous Power Dissipation (TA = +70NC)
14-Pin TSSOP (derate 10mW/NC above +70NC).......796.8mW
16-Pin TQFN (derate 14.7mW/NC above +70NC)....1176.5mW
Operating Temperature Range . ...................... -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Lead Temperature (soldering, 10s).................................+300NC
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 = +1.7V to +5.5V, VH_ = VDD, VL_ = GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +1.8V,
TA = +25NC.) (Note 1)
PARAMETER
Resolution
SYMBOL
CONDITIONS
N
MIN
TYP
MAX
256
UNITS
Tap
DC PERFORMANCE (Voltage-Divider Mode)
Integral Nonlinearity
INL
(Note 2)
-0.5
+0.5
LSB
Differential Nonlinearity
DNL
(Note 2)
-0.5
+0.5
LSB
Dual-Code Matching
Register A = Register B
-0.5
+0.5
Ratiometric Resistor Tempco
(DVW/VW)/DT, no load
Full-Scale Error
Code = FFh
Zero-Scale Error
Code = 00h
5
MAX5391L/MAX5393L
-3
-2.2
MAX5391M/MAX5393M
-1
-0.6
MAX5391N/MAX5393N
-0.5
-0.3
LSB
ppm/NC
LSB
MAX5391L/MAX5393L
2.2
3
MAX5391M/MAX5393M
0.6
1
MAX5391N/MAX5393N
0.3
0.5
LSB
DC PERFORMANCE (Variable Resistor Mode)
Integral Nonlinearity
R-INL
(Note 3)
-1.0
+1.5
LSB
Differential Nonlinearity
R-DNL
(Note 3)
-0.5
+0.5
LSB
DC PERFORMANCE (Resistor Characteristics)
Wiper Resistance
Terminal Capacitance
RWL
(Note 4)
200
I
CH_, CL_
Measured to GND
10
Wiper Capacitance
CW_
Measured to GND
50
pF
End-to-End Resistor Tempco
TCR
No load
35
ppm/NC
End-to-End Resistor Tolerance
DRHL
Wiper not connected
-25
pF
+25
%
AC PERFORMANCE
Crosstalk
(Note 5)
-3dB Bandwidth
Code = 08H,
10pF load,
VDD = 1.8V
Total Harmonic Distortion Plus
Noise
Wiper Settling Time (Note 6)
BW
THD+N
tS
-90
MAX5391L/MAX5393L
600
MAX5391M/MAX5393M
100
MAX5391N/MAX5393N
50
Measured at W, VH_ = 1VRMS at 1kHz
0.02
MAX5391L/MAX5393L
400
MAX5391M/MAX5393M
1200
MAX5391N/MAX5393N
2200
2 _______________________________________________________________________________________
dB
kHz
%
ns
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
(VDD = +1.7V to +5.5V, VH_ = VDD, VL_ = GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +1.8V,
TA = +25NC.) (Note 1)
PARAMETER
SYMBOL
Charge-Pump Feedthrough at W_
VRW
CONDITIONS
MIN
fCLK = 600kHz, COUT = 0nF
TYP
MAX
200
UNITS
nVP-P
POWER SUPPLIES
Supply Voltage Range
VDD
Standby Current
1.7
VDD = 5.5V
27
VDD = 1.7V
12
VDD = 2.6V to 5.5V
70
VDD = 1.7V to 2.6V
75
5.5
V
FA
DIGITAL INPUTS
Minimum Input High Voltage
VIH
Maximum Input Low Voltage
VIL
Input Leakage Current
% x VDD
VDD = 2.6V to 5.5V
30
VDD = 1.7V to 2.6V
25
-1
Input Capacitance
+1
5
% x VDD
FA
pF
TIMING CHARACTERISTICS—SPI (Note 7)
SCLK Frequency
fMAX
10
MHz
SCLK Clock Period
tCP
100
ns
SCLK Pulse-Width High
tCH
40
ns
SCLK Pulse-Width Low
tCL
40
ns
CS Fall to SCK Rise Setup Time
tCSS
40
ns
SCLK Rise to CS Rise Hold Time
tCSH
0
ns
DIN Setup Time
tDS
40
ns
DIN Hold Time
tDH
0
ns
SCLK Rise to CS Fall Delay
tCS0
10
ns
SCLK Rise to SCLK Rise Hold
Time
tCS1
40
ns
CS Pulse-Width High
tCSW
100
ns
Note 1: All devices are 100% production tested at TA = +25NC. Specifications over temperature limits are guaranteed by design
and characterization.
Note 2: DNL and INL are measured with the potentiometer configured as a voltage-divider (Figure 1) with H_ = VDD and L_ =
GND. The wiper terminal is unloaded and measured with a high-input-impedance voltmeter.
Note 3: R-DNL and R-INL are measured with the potentiometer configured as a variable resistor (Figure 1). DNL and INL are
measured with the potentiometer configured as a variable resistor. H_ is unconnected and L_ = GND. For VDD = +5V, the
wiper terminal is driven with a source current of 400FA for the 10kI configuration, 80FA for the 50kI configuration, and
40FA for the 100kI configuration. For VDD = +1.7V, the wiper terminal is driven with a source current of 150FA for the
10kI configuration, 30FA for the 50kI configuration, and 15FA for the 100kI configuration.
Note 4: The wiper resistance is the value measured by injecting the currents given in Note 3 into W_ with L_ = GND.
RW_ = (VW_ - VH_)/IW_.
Note 5: Drive HA with a 1kHz GND to VDD amplitude tone. LA = LB = GND. No load. WB is at midscale with a 10pF load.
Measure WB.
Note 6: The 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 loaded with 10pF capacitance to ground.
Note 7: Digital timing is guaranteed by design and characterization, not production tested.
_______________________________________________________________________________________ 3
MAX5391/MAX5393
ELECTRICAL CHARACTERISTICS (continued)
H
N.C.
W
W
L
L
Figure 1. Voltage-Divider and Variable Resistor Configurations
Typical Operating Characteristics
(VDD = 1.8V, TA = +25NC, unless otherwise noted.)
SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
20
VDD = 2.6V
15
10
VDD = 1.8V
MAX5391 toc03
VDD = 5V
SUPPLY CURRENT (µA)
30
1000
25
VDD = 2.6V
100
10
20
15
5
VDD = 1.8V
1
0
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
10
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
1.7
2.7
3.2
3.7
4.2
4.7
DIGITAL INPUT VOLTAGE (V)
VDD (V)
RESISTANCE (W_-TO-L_)
vs. TAP POSITION (10kI)
RESISTANCE (W_-TO-L_)
vs. TAP POSITION (50kI)
RESISTANCE (W_-TO-L_)
vs. TAP POSITION (100kI)
W-TO-L RESISTANCE (kI)
8
45
7
6
5
4
3
100
40
90
W-TO-L RESISTANCE (kI)
9
MAX5391 toc05
50
MAX5391 toc04
10
35
30
25
20
15
80
60
50
40
30
10
20
1
5
10
0
0
51
102
153
TAP POSITION
204
255
5.2
70
2
0
2.2
TEMPERATURE (°C)
MAX5391 toc06
SUPPLY CURRENT (µA)
25
10,000
IDD (µA)
VDD = 5V
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX5391 toc02
30
MAX5391 toc01
SUPPLY CURRENT
vs. TEMPERATURE
W-TO-L RESISTANCE (kI)
MAX5391/MAX5393
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
0
0
51
102
153
TAP POSITION
204
255
0
51
102
153
TAP POSITION
4 _______________________________________________________________________________________
204
255
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
WIPER RESISTANCE
vs. WIPER VOLTAGE
VDD = 5V
80
VDD = 1.8V
VDD = 2.6V
60
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0.04
0.02
0.01
50kI
0
10kI
0.02
0
-0.02
-0.04
-0.01
-0.06
-0.02
-0.08
-0.03
-0.10
-40 -25 -10 5 20 35 50 65 80 95 110 125
0
51
102
153
204
VARIABLE RESISTOR DNL
vs. TAP POSITION (50kI)
VARIABLE RESISTOR DNL
vs. TAP POSITION (100kI)
VARIABLE RESISTOR INL
vs. TAP POSITION (10kI)
0.08
0.06
0.8
0.6
0.02
0.2
0
-0.02
INL (LSB)
0.4
0.02
DNL (LSB)
0.04
0
-0.02
0
-0.2
-0.04
-0.04
-0.4
-0.06
-0.06
-0.6
-0.08
-0.08
IWIPER = 30µA
-0.8
IWIPER = 15µA
-0.10
-0.10
51
102
153
204
IWIPER = 150µA
-1.0
0
255
51
102
153
204
255
0
51
102
153
204
TAP POSITION
TAP POSITION
TAP POSITION
VARIABLE RESISTOR INL
vs. TAP POSITION (50kI)
VARIABLE RESISTOR INL
vs. TAP POSITION (100kI)
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (10kI)
0.3
0.4
0.10
0.3
0.08
0.06
0.04
0.1
0.1
0.02
0
-0.1
DNL (LSB)
0.2
INL (LSB)
0.2
0
-0.1
0
-0.02
-0.2
-0.2
-0.04
-0.3
-0.3
-0.06
-0.4
-0.4
IWIPER = 30µA
-0.5
-0.08
IWIPER = 15µA
-0.5
51
102
153
TAP POSITION
204
255
255
MAX5391 toc15
0.4
MAX5391 toc14
0.5
MAX5391 toc13
0.5
255
MAX5391 toc12
1.0
MAX5391 toc11
MAX5391 toc10
0.10
0.04
0
IWIPER = 150µA
TAP POSITION
0.06
0
MAX5391 toc09
0.06
TEMPERATURE (°C)
0.08
DNL (LSB)
0.08
WIPER VOLTAGE (V)
0.10
INL (LSB)
100kI
DNL (LSB)
100
0.04
0.03
0.10
MAX5391 toc08
MAX5391 toc07
120
0.05
END-TO-END RESISTANCE % CHANGE
WIPER RESISTANCE (I)
140
0
VARIABLE RESISTOR DNL
vs. TAP POSITION (10kI)
END-TO-END RESISTANCE PERCENTAGE
CHANGE vs. TEMPERATURE
-0.10
0
51
102
153
TAP POSITION
204
255
0
51
102
153
204
255
TAP POSITION
_______________________________________________________________________________________ 5
MAX5391/MAX5393
Typical Operating Characteristics (continued)
(VDD = 1.8V, TA = +25NC, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VDD = 1.8V, TA = +25NC, unless otherwise noted.)
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (100kI)
0.06
0.5
MAX5391 toc17
0.08
0.08
0.06
0.4
0.3
0.04
0.2
0.02
0.02
0.1
0
-0.02
INL (LSB)
0.04
DNL (LSB)
0
-0.02
0
-0.1
-0.04
-0.04
-0.2
-0.06
-0.06
-0.3
-0.08
-0.08
-0.4
-0.10
-0.10
0
51
102
153
204
255
51
102
153
204
255
0
51
102
153
204
255
TAP POSITION
TAP POSITION
TAP POSITION
VOLTAGE-DIVIDER INL
vs. TAP POSITION (50kI)
VOLTAGE-DIVIDER INL
vs. TAP POSITION (100kI)
TAP-TO-TAP SWITCHING TRANSIENT
(CODE 127 TO CODE 128) (10kI)
0.5
MAX5391 toc19
0.5
0.4
0.3
0.4
0.3
0.2
0.1
0.1
INL (LSB)
0.2
0
-0.1
-0.2
-0.3
-0.4
-0.4
-0.5
-0.5
102
153
204
VW_-L_
20mV/div
0
-0.3
51
CS
5V/div
0
255
51
102
153
204
255
TAP POSITION
TAP POSITION
TAP-TO-TAP SWITCHING TRANSIENT
(CODE 127 TO CODE 128) (50kI)
TAP-TO-TAP SWITCHING TRANSIENT
(CODE 127 TO CODE 128) (100kI)
400ns/div
MAX5391M P0WER-ON TRANSIENT
MAX5391 toc24
MAX5391 toc23
MAX5391 toc22
VW_-L_
20mV/div
VW_-L_
20mV/div
CS
5V/div
1µs/div
MAX5391 toc21
-0.1
-0.2
0
-0.5
0
MAX5391 toc20
DNL (LSB)
0.10
MAX5391 toc16
0.10
VOLTAGE-DIVIDER INL
vs. TAP POSITION (10kI)
MAX5391 toc18
VOLTAGE-DIVIDER DNL
vs. TAP POSITION (50kI)
INL (LSB)
MAX5391/MAX5393
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
VW_-L_
1V/div
CS
5V/div
1µs/div
VDD
5V/div
2µs/div
6 _______________________________________________________________________________________
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
MIDSCALE FREQUENCY
RESPONSE (50kI)
GAIN (dB)
-10
VDD = 1.8V
-10
VDD = 5V
0
-10
VDD = 1.8V
VDD = 1.8V
-20
-20
-20
VIN = 1VP-P
VIN = 1VP-P
-30
VIN = 1VP-P
-30
1
10k
100
-30
0.01
FREQUENCY (kHz)
1
10k
100
-20
0.20
0.18
0.16
100kI
10k
10kI
0.14
THD+N (%)
-40
100
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX5391 toc28
0
CROSSTALK (dB)
1
FREQUENCY (kHz)
CROSSTALK vs. FREQUENCY
-60
0.01
FREQUENCY (kHz)
MAX5391 toc29
0.01
50kI
-80
100kI
0.12
0.10
0.08
0.06
-100
0.04
-120
0
-140
0.1
1
10
100
0.01
1000
0.1
1
10
FREQUENCY (kHz)
FREQUENCY (kHz)
BYP RAMP vs. CBYP
CHARGE-PUMP FEEDTHROUGH
AT W_ vs. CBYP
700
MAX5391 toc30
120
600
VOLTAGE (nVRMS)
100
80
60
40
100
MAX5391 toc31
0.01
50kI
0.02
10kI
RAMP TIME (ms)
GAIN (dB)
VDD = 5V
0
GAIN (dB)
VDD = 5V
0
10
MAX5391 toc26
10
MAX5391 toc25
10
MIDSCALE FREQUENCY
RESPONSE (100kI)
MAX5391 toc27
MIDSCALE FREQUENCY
RESPONSE (10kI)
500
400
300
200
20
100
0
0
0
0.02
0.04
0.05
CAPACITANCE (µF)
0.08
0.10
0
200
400
600
800
CAPACITANCE (pF)
_______________________________________________________________________________________ 7
MAX5391/MAX5393
Typical Operating Characteristics (continued)
(VDD = 1.8V, TA = +25NC, unless otherwise noted.)
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
MAX5391/MAX5393
Pin Configurations
VDD
N.C.
SCLK
DIN
TOP VIEW
12
11
10
9
8
N.C. 13
HA 14
MAX5391
WA 15
*EP
LA 16
GND 1
CS
7
BYP
6
N.C.
5
GND
+
2
3
4
WB
LB
I.C.
14 LA
LB 2
13 HA
HB 3
12 WA
WB 4
MAX5393
11 VDD
I.C. 5
10 N.C.
BYP 6
9 SCLK
CS 7
1
HB
+
TOP VIEW
8 DIN
*EP = EXPOSED PAD
Pin Description
PIN
MAX5391
(TQFN-EP)
MAX5393
(TSSOP)
NAME
FUNCTION
1
3
HB
Resistor B High Terminal. The voltage at HB can be higher or lower than the voltage at
LB. Current can flow into or out of HB.
2
4
WB
Resistor B Wiper Terminal
3
2
LB
Resistor B Low Terminal. The voltage at LB can be higher or lower than the voltage at HB.
Current can flow into or out of LB.
4
5
I.C.
Internally Connected. Connect to GND.
5
1
GND
Ground
6, 11, 13
10
N.C.
No Connection. Not internally connected.
7
6
BYP
Internal Power-Supply Bypass. For additional charge-pump filtering, bypass to GND with
a capacitor close to the device.
8
7
9
8
CS
DIN
10
9
SCLK
12
11
VDD
Power-Supply Input. Bypass VDD to GND with a 0.1FF capacitor close to the device.
Active-Low Chip-Select Input
Serial-Interface Data Input
Serial-Interface Clock Input
14
13
HA
Resistor A High Terminal. The voltage at HA can be higher or lower than the voltage at
LA. Current can flow into or out of HA.
15
12
WA
Resistor A Wiper Terminal
16
14
LA
Resistor A Low Terminal. The voltage at LA can be higher or lower than the voltage at HA.
Current can flow into or out of LA.
—
—
EP
Exposed Pad (MAX5391 Only). Connect to GND.
8 _______________________________________________________________________________________
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
CBYP does affect the startup time of the charge pump;
however, CBYP does not impact the ability to communicate with the device, nor is there a minimum CBYP
requirement. The maximum wiper impedance specification is not guaranteed until the charge pump is fully
settled. See the BYP Ramp vs. CBYP graph in the Typical
Operating Characteristics for CBYP impact on chargepump settling time.
The MAX5391/MAX5393 dual 256-tap, volatile, low-voltage linear taper digital potentiometers offer three end-toend resistance values of 10kI, 50kI, and 100kI. Each
potentiometer consists of 255 fixed resistors in series
between terminals H_ and L_. The potentiometer wiper,
W_, is programmable to access any one of the 256 tap
points on the resistor string.
SPI Digital Interface
The potentiometers in each device are programmable
independently of each other. The MAX5391/MAX5393
feature an SPI interface.
The MAX5391/MAX5393 include a SPI interface that provides a 3-wire write-only serial-data interface to control
the wiper tap position through inputs chip select (CS),
data in (DIN), and data clock (SCLK). Drive CS low to
load data from DIN synchronously into the serial shift
register on the rising edge of each SCLK pulse. The
MAX5391/MAX5393 load the last 10 bits of clocked data
into the appropriate potentiometer control register once
CS transitions high. See Figures 2 and 3. Data written
to a memory register immediately updates the wiper
position. Keep CS low during the entire data stream to
prevent the data from being terminated.
Charge Pump
The MAX5391/MAX5393 contain an internal charge
pump that guarantees the maximum wiper resistance,
RWL, to be less then 200I for supply voltages down to
1.7V. Pins H_, W_, and L_ are still required to be less
than VDD + 0.3V. A bypass input, BYP, is provided to
allow additional filtering of the charge-pump output, further reducing clock feed through that may occur on H_,
W_, or L_. The nominal clock rate of the charge pump
is 600kHz. BYP should remain resistively unloaded as
any additional load would produce a ripple of approximately IBYP/(600kHz x CBYP) volts. See the ChargePump Feedthrough at W_ vs. CBYP graph in the Typical
Operating Characteristics for CBYP sizing guidelines with
respect to clock feedthrough to the wiper. The value of
The first two bits A1:A0 (address bits) address one of
the two potentiometers. See Table 1. The power-on reset
(POR) circuitry sets the wiper to midscale.
Table 1. SPI Register Map
Bit Number
1
2
3
4
5
6
7
8
9
10
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
Write Wiper Register A
0
0
D7
D6
D5
D4
D3
D2
D1
D0
Write Wiper Register B
0
1
D7
D6
D5
D4
D3
D2
D1
D0
Write to Both A and B
1
1
D7
D6
D5
D4
D3
D2
D1
D0
Bit Name
COMMAND
STARTED 10-BIT
WIPER REGISTER
LOADED
CS
SCLK
DIN
A0
A1
D7
D6
D5
D4
D3
D2
D1
D0
Figure 2. SPI Digital Interface Format
_______________________________________________________________________________________ 9
MAX5391/MAX5393
Detailed Description
MAX5391/MAX5393
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
tCSW
CS
tCS1
tCSO
tCH
tCSS
tCL
tCP
tCSH
tDH
SCLK
tDS
DIN
Figure 3. SPI Timing Diagram
REG A: The data byte writes to register A, and the wiper
of potentiometer A moves to the appropriate position at
the rising edge of CS. D[7:0] indicates the position of the
wiper. D[7:0] = 00h moves the wiper to the position closest to LA. D[7:0] = FFh moves the wiper closest to HA.
D[7:0] is 80h following power-on.
REG B: The data byte writes to register B, and the wiper
of potentiometer B moves to the appropriate position at
the rising edge of CS. D[7:0] indicates the position of the
wiper. D[7:0] = 00h moves the wiper to the position closest to LB. D[7:0] = FFh moves the wiper to the position
closest to HB. D[7:0] is 80h following power-on.
REG A and B: The data byte writes to registers A and
B, and the wipers of potentiometers A and B move to the
appropriate position. D[7:0] indicates the position of the
wiper. D[7:0] = 00h moves the wiper to the position closest to L_. D[7:0] = FFh moves the wiper to the position
closest to H_. D[7:0] is 80h following power-on.
Applications Information
Variable Gain Amplifier
Figure 4 shows a potentiometer adjusting the gain of a
noninverting amplifier. Figure 5 shows a potentiometer
adjusting the gain of an inverting amplifier.
Adjustable Dual Regulator
Figure 6 shows an adjustable dual linear regulator using
a dual potentiometer as two variable resistors.
Adjustable Voltage Reference
Figure 7 shows an adjustable voltage reference circuit
using a potentiometer as a voltage divider.
10 �������������������������������������������������������������������������������������
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
L_
VOUT
W_
VIN
VOUT
W_
H_
L_
Figure 4. Variable-Gain Noninverting Amplifier
VOUT1
OUT1
VOUT2
OUT2
H_
IN
W_
L_
VREF
OUT
H_
W_
SET1
+2.5V
IN
MAX8866
V+
Figure 5. Variable-Gain Inverting Amplifier
MAX6037
H_
W_
L_
GND
L_
SET2
Figure 6. Adjustable Dual Linear Regulator
Figure 7. Adjustable Voltage Reference
______________________________________________________________________________________ 11
MAX5391/MAX5393
H_
VIN
MAX5391/MAX5393
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
Variable-Gain Current-to-Voltage Converter
Figure 8 shows a variable-gain current-to-voltage converter using a potentiometer as a variable resistor.
Offset Voltage Adjustment Circuit
Figure 11 shows an offset voltage adjustment circuit
using a dual potentiometer.
LCD Bias Control
Figure 9 shows a positive LCD bias control circuit using
a potentiometer as a voltage-divider.
Process Information
PROCESS: BiCMOS
Programmable Filter
Figure 10 shows a programmable filter using a dual
potentiometer.
R3
+1.8V
H_
W_
H_
R1
W_
R2
VOUT
IS
L_
L_
VOUT
VOUT = IS x ((R3 x (1 + R2/R1)) + R2)
Figure 8. Variable Gain I-to-V Converter
Figure 9. Positive LCD Bias Control Using a Voltage-Divider
+1.8V
WA
WB
VIN
LA
HA
LB
HB
VOUT
R3
VIN
VOUT
R1
HA
HB
R2
WA
LA
WB
LB
Figure 10. Programmable Filter
Figure 11. Offset Voltage Adjustment Circuit
12 �������������������������������������������������������������������������������������
Dual 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometers
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 drawings may show a different suffix character,
but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
14 TSSOP
U14+1
21-0066
16 TQFN-EP
T1633+5
21-0136
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
©
2009 Maxim Integrated Products
13
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX5391/MAX5393
Package Information
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