DAC

AS5181

AS5181

Rev. 0.4 01/10

Micross Components reserves the right to change products or specifications without notice.

9

External Reference

To disable the AS5181 internal reference, connect REN\

to DV

be applied to drive the REFO pin to set the full-scale output

(Figure 3). Choose a reference capable of supplying at least

150μA to drive the bias circuit that generates the cascode

current for the current array. For improved accuracy and drift

performance, choose a fixed output voltage reference.

Standby Mode

To enter the lower-power standby mode, connect digital

inputs PD and DACEN to DGND. In standby, both the refer-

ence and the control amplifier are active with the current array

inactive. To exit this condition, DACEN must be pulled high

with PD held at DGND. The AS5181 typically require 50μs

to wake up and let both outputs and the reference settle.

Shutdown Mode

For lowest power consumption, the AS5181 provide a

power-down mode in which the reference, control amplifier,

and current array are inactive and the DAC supply current is

reduced to 1μA. To enter this mode, connect PD to DV

return to active mode, connect PD to DGND and DACEN to

DV

mode and settle to their outputs’ values prior to shutdown. The

“Power-Down Mode Selection” table lists the power-down

mode selection.

Timing Information

Figure 4 shows a detailed timing diagram for the AS5181.

With each high transition of the clock, the input latch is loaded

with the digital value set by bits D9 through D0. The content

of the input latch is then shifted to the DAC register, and the

output updates at the rising edge of the next clock.

Outputs

TheAS5181 output is designed to supply full-scale output

currents of 1mA into 400

Ω loads in parallel with a capacitive load

of 5pF.

FIGURE 2: Setting I

the Control Amplifier