Datasheet

DS1868B
DS1868B ABSOLUTE AND RELATIVE LINEARITY Figure 6
TYPICAL APPLICATION CONFIGURATIONS
Figures 7 and 8 show two typical application configurations for the DS1868B. By connecting the wiper
terminal of the part to a high-impedance load, the effects of the wiper resistance is minimized, since the
wiper resistance can vary from 900Ω to 2000Ω, depending on wiper voltage. Figure 7 presents the device
connected in a variable gain amplifier. The gain of the circuit on Figure 7 is given by the following
equation:
A
V
=
n-256
256 +
where n = 0 to 255
Figure 8 shows the device operating in a fixed gain attenuator where the potentiometer is used to
attenuate an incoming signal. Note the resistance R1 is chosen to be much greater than the wiper
resistance to minimize its effect on circuit gain.
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 32 64 96 128 160 192 224 256
LSB
Tap Position
Linearity vs. Tap Position
INL
DNL
DS1868B
10kΩ
Maxim Integrated ............................................................................................................................................................................................. 6