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AS1543/44

Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Figure 35 shows a typical connection diagram for the AS1543/44. In this configuration, pin AGND, GND and DGND

connected to the analog ground plane of the system. In Figure 35, REFIN is connected to a decoupled 2.5V reference

source, to provide an analog input range of 0 to 2.5V (if RANGE (page 14) is 1 and bit SE/FDN (page 14) = 1) or 0 to

interface is connected to a 3V microprocessor.

result is output in a 16-bit word. This 16-bit data stream consists of four address bits indicating which channel the con-

version result corresponds to, followed by the 12 bits of conversion data.

Note: For applications where power consumption is of concern, the power-down modes should be used between

conversions or bursts of several conversions to improve power performance (see Power Modes on page 22).

Figure 35. Typical Application

Note: For the circuit shown in Figure 35, unused input channels should be connected to ground. For optimum perfor-

mance decouple all analog input channels and the reference input voltage to the ground of AGND.

Initialisation

When power is first applied to the AS1543/44 interal power-on reset circuitry sets the device for Auto Shutdown (PM1

= 0, PM0 = X) on page 23.

Note: The device requires 10µs after the power supplies stabilize; no conversions should be initiated during this time.

The digital output at pin DOUT will be set to tri-state after internal power-on reset.

SCLK

CSN

DOUT

DIN

VDRIVE

AS1543/44

3V

DSP/µP

0.1µF

10µF

REFIN

4.7µF

2.5V

0V to

VREFIN

0.1µF

10µF

5V

GND

AGND

DGND