CDB5376 Datasheet, PDF (19/78 Pages) Cirrus Logic – Multichannel Seismic Evaluation System

CDB5376
2.2.3.2 Offset Enable - OFST
The CS5372 ∆Σ modulator requires differential offset to be enabled to eliminate idle tones for a terminated
input. The use of internal offset to eliminate idle tones is described in the CS5372 data sheet. OFST is
enabled by closing dip switch #4 (S5, #4 - HI).
2.2.4 Delta-Sigma Test DAC
The CS4373A DAC creates differential analog signals for system tests. Multiple test modes are available
and their use is described in the CS4373A data sheet.
Analog Signals
OUT
BUF
CAP
VREF
Description
Precision differential analog output
Buffered differential analog output
Capacitor connection for internal anti-alias filter
Voltage reference analog inputs
Digital Signals
TDATA
MCLK
SYNC
MODE[0..2]
ATT[0..2]
Description
Delta-sigma test data input
Clock input
Synchronization input
Test mode selection
Attenuation range selection
2.2.4.1 Precision Output - DAC_OUT
The CS4373A test DAC has a precision output (DAC_OUT) that is routed to the input selection jumpers
for each channel. This output is sensitive to loading, and on CDB5376 should only be jumpered into the
INB inputs which do not have passive RC filter components installed. The input impedance of the
CS3301/02 INB amplifier inputs are high enough that the precision output can be directly connected to
the INB inputs of all channels simultaneously.
2.2.4.2 Buffered Output - DAC_BUF
The CS4373A test DAC has a buffered output (DAC_BUF) that is routed to the input selection jumpers
for each channel. This output is less sensitive to loading than the precision outputs, and can be jumpered
into either the INA or INB inputs without affecting performance. The buffered output can also drive a sen-
sor attached to the input screw terminals, provided the sensor meets the impedance requirements spec-
ified in the CS4373A data sheet.
DS612DB2
19