Cirrus Logic CDB5378 - Manual (Page 21)

CDB5378
DS639DB4 21
2.2.4 Delta-Sigma Test DAC
The CS5373A
∆Σ DAC creates differential analog signals for system tests. Multiple test modes are avail-
able and their use is described in the CS5373A data sheet.
2.2.4.1 Precision Output - DAC_OUT
The CS5373A test DAC has a precision output (DAC_OUT) that is routed to the input selection jumper.
This output is sensitive to loading, and on CDB5378 should only be jumpered into the INB input which
does not have passive RC filter components installed. The input impedance of the CS3301A/02A ampli-
fiers are high enough that the DAC precision output can be connected to the INB input directly.
2.2.4.2 Buffered Output - DAC_BUF
The CS5373A test DAC has a buffered output (DAC_BUF) that is also routed to the input selection jump-
er. This output is less sensitive to loading than the precision output, and can be jumpered into either the
INA or INB input without affecting performance. The buffered output can also drive a sensor attached to
the input screw terminals, provided the sensor meets the impedance requirements specified in the
CS5373A data sheet.
Analog Signals Description
OUT Precision differential analog output
BUF Buffered differential analog output
CAP Capacitor connection for internal anti-alias filter
VREF Voltage reference analog inputs
Digital Signals
Description
TDATA Delta-sigma test data input
MCLK Clock input
MSYNC Synchronization input
MODE[0..2] Test mode selection
ATT[0..2] Attenuation range selection