Datasheet

AD5231 Data Sheet
Rev. D | Page 26 of 28
RDAC CIRCUIT SIMULATION MODEL
The internal parasitic capacitances and the external load
dominates the ac characteristics of the RDACs. The −3 dB
bandwidth of the AD5231BRU10 (10 kΩ resistor) measures
370 kHz at half scale when configured as a potentiometer
divider. Figure 15 provides the large signal BODE plot charac-
teristics. A parasitic simulation mode is shown in Figure 57.
A
RDAC
10kΩ
W
B
C
A
50pF
C
B
50pF
C
W
50pF
02739-056
Figure 57. RDAC Circuit Simulation Model for RDAC = 10 kΩ
The following code provides a macro model net list for the
10 kΩ RDAC:
.PARAM D = 1024, RDAC = 10E3
*
.SUBCKT DPOT (A, W, B)
*
CA A 0 50E-12
RWA A W {(1-D/1024)* RDAC + 15}
CW W 0 50E-12
RWB W B {D/1024 * RDAC + 15}
CB B 0 50E-12
*
.ENDS DPOT