CRD5378
18
DS639RD2
2.2.4
Delta-Sigma Test DAC
The CS5373A test 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 directly to the amplifier INB in-
puts. The input impedance of the CS3301A/02A INB amplifier inputs are high enough that the precision
output can be directly connected to the INB inputs.
2.2.4.2
Buffered Output - DAC_BUF
The CS5373A test DAC has a buffered output (DAC_BUF) that is routed to the amplifier INA inputs. This
output is less sensitive to loading than the precision outputs, and can drive a sensor attached to the am-
plifier INA inputs provided the sensor meets the impedance requirements specified in the CS5373A data
sheet.
2.2.5
Voltage Reference
A voltage reference on CRD5378 creates a precision voltage from the regulated analog supplies for the
modulator and test DAC VREF inputs. Because the voltage reference output is generated relative to the
negative analog power supply, VREF+ is near GND potential for bipolar power supplies.
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
SYNC Synchronization
input
MODE[0..2]
Test mode selection
ATT[0..2]
Attenuation range selection
Specification Value
Precision Reference - Linear Tech
LT1019AIS8-2.5
Surface Mount Package Type
SO-8
Output Voltage Tolerance
+/- 0.05%
Temperature Drift
10 ppm / degC
Quiescent Current
0.65 mA
Output Voltage Noise, 10 Hz - 1 kHz
4 ppm
RMS
Ripple Rejection, 10 Hz - 200 Hz
> 100 dB
Summary of Contents for CRD5378
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