MAX5499 Maxim Integrated Products, MAX5499 Datasheet - Page 12

• Manufacturer Part Number: MAX5499
• Description: 10-Bit - Dual - Nonvolatile/ Linear-Taper Digital Potentiometers
• Manufacturer: Maxim Integrated Products

10-Bit, Dual, Nonvolatile, Linear-Taper
Digital Potentiometers
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 multi-
ple strings of equal resistor segments with a wiper con-
tact that moves among the 1024 effective tap points by
a 3-wire SPI-compatible serial interface. The
MAX5494/MAX5496/MAX5498 provide a total 10kΩ
end-to-end resistance, and the MAX5495/MAX5497/
MAX5499 feature a 50kΩ end-to-end resistance. The
MAX5494/MAX5495/MAX5498/MAX5499 allow access
to the high, low, and wiper terminals for a standard volt-
age-divider configuration. Ensure that the terminal volt-
ages fall between V
The MAX5494/MAX5495/MAX5498/MAX5499 program-
mable voltage-dividers provide a weighted average of
the voltage between the H_ and L_ inputs at the W_
output.
The MAX5494/MAX5495/MAX5498/MAX5499 program-
mable voltage-divider network provides up to 1024
division ratios between the H_ and L_ voltage. Ideally,
the V
data bits are zeros and the V
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 2
lows:
12
Figure 4. Resistance from W_ to H_ vs. Code (10kΩ Voltage-
Divider)
MAX5494/MAX5495/MAX5498/MAX5499
______________________________________________________________________________________
L
voltage occurs at the wiper terminal when all
18
16
14
12
10
8
6
4
2
0
10
0
50kΩ SCALES BY A FACTOR OF FIVE
Programmable Voltage-Dividers
. Calculate the wiper voltage V
128
SS
256 384
Detailed Description
and V
CODE (DECIMAL)
512 640
DD
H
.
voltage occurs at the
768
896
1024
W
as fol-
The MAX5494/MAX5498 provide a 10kΩ end-to-end
resistance value, while the MAX5495/MAX5499 feature a
50kΩ end-to-end resistance value. Note that the pro-
grammable 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 tempera-
ture 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 behav-
ior of the programmable voltage-divider resistance from
W_ to H_ and W_ to L_, respectively. This does not apply
to the variable-resistor devices.
The MAX5496–MAX5499 provide a programmable resis-
tance from W_ to L_. The MAX5496/MAX5498 provide a
10kΩ end-to-end resistance value, while the
MAX5497/MAX5499 feature a 50kΩ end-to-end resis-
tance value. The programmable resolution of this
written (0 to 1023), V
Figure 5. Resistance from W_ to L_ vs. Code (10kΩ Voltage-
Divider)
where D is the decimal equivalent of the 10 data bits
MAX5496–MAX5499 Variable Resistors
D




V
HL
18
16
14
12
10
8
6
4
2
0
the H_ and L_ terminals, and:
−
0
50kΩ SCALES BY A FACTOR OF FIVE
(
|
V
V
128
V
FSE
ZSE
1023
FSE
HL
256 384
=
=
| |
is the voltage difference between
+
FSE
ZSE
CODE (DECIMAL)
V
ZSE






512 640
1024
1024
V
V
HL
HL
|
)







+



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V
768
L
+
896
|
V
ZSE
1024
|