Datasheet

AD5280/AD5282
Rev. C | Page 24 of 28
02929-068
C
W
8
5
p
F
RDAC CIRCUIT SIMULATION MODEL
The internal parasitic capacitances and the external capacitive
loads dominate the ac characteristics of the RDACs. Configured
as a potentiometer divider, the −3 dB bandwidth of the AD5280
(20 kΩ resistor) measures 310 kHz at half scale. Figure 24
provides the Bode plot characteristics of the three available
resistor versions: 20 kΩ, 50 kΩ, and 200 kΩ. A parasitic
simulation model is shown in Figure 65. A macro model net list
for the 20 kΩ RDAC is provided.
C
A
2
5
p
F
C
A
2
5
p
F
RDAC
20k
A B
Figure 65. RDAC Circuit Simulation Model for RDAC = 20 kΩ
MACRO MODEL NET LIST FOR RDAC
.PARAM D=256, RDAC=20E3
*
.SUBCKT DPOT (A,W,B)
*
CA A 0 25E-12
RWA A W {(1-D/256)*RDAC+60}
CW W 0 55E-12
RWB W B {D/256*RDAC+60}
CB B 0 25E-12
*
.ENDS DPOT