AD5174

Rev. 0 | Page 17 of 20

EXT_CAP CAPACITOR

pin, as shown in Figure 28, on power-up and throughout the

operation of the AD5174.

AD5174

50-TP

MEMORY

BLOCK

EXT_CAP

C1

1µF

Figure 28. EXT_CAP Hardware Setup

TERMINAL VOLTAGE OPERATING RANGE

define the boundary conditions for proper 2-terminal digital

resistor operation. Supply signals present on Terminal A and

forward-biased diodes (see Figure 29).

A

W

The ground pin of the AD5174 is primarily used as a digital

ground reference. To minimize the digital ground bounce, join the

AD5174 ground terminal remotely to the common ground. The

digital input control signals to the AD5174 must be referenced

to the device ground pin (GND) and must satisfy the logic level

defined in the Specifications section. An internal level shift

circuit ensures that the common-mode voltage range of the

digital input level.

POWER-UP SEQUENCE

Because there are diodes to limit the voltage compliance at

Terminal A and Terminal W (see Figure 29), it is important to

and Terminal W; otherwise, the diode is forward-biased such

which first sets the RDAC to midscale and then restores the

last programmed 50-TP value to the RDAC register.