CS5522-ASZR Cirrus Logic Inc, CS5522-ASZR Datasheet - Page 32

• Manufacturer Part Number: CS5522-ASZR
• Description: IC ADC 24BIT 2CH 20-SSOP
• Manufacturer: Cirrus Logic Inc

Specifications of CS5522-ASZR

• Number Of Bits: 24
• Data Interface: Serial
• Number Of Converters: 1
• Power Dissipation (max): 14.8mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

offset to occur in the 25 mV, 55 mV, and 100 mV
ranges, the AIN- pin must be at the proper com-
mon-mode voltage as specified in ‘Common Mode
+Signal AIN+/-’ specification in the Analog Input
section (if AIN- = 0 V, NBV must be between -
1.8 V to -2.5 V). For self calibration of offset in the
1.0 V, 2.5 V, and 5 V ranges, the inputs of the mod-
ulator are connected together and then routed to the
VREF- pin as shown in Figure 12.
For self calibration of gain, the differential inputs
of the modulator are connected to VREF+ and
VREF- as shown in Figure 13. For any input range
other than the 2.5 V range, the converter’s gain er-
ror can not be completely calibrated out when using
self calibration. This is due to the lack of an accu-
rate full-scale voltage internal to the chips. The
2.5 V range is an exception because the external
reference voltage is 2.5 V nominal and is used as
32
Reference
Figure 11. Self Calibration of Offset (Low Ranges)
Figure 13. Self Calibration of Gain (All Ranges)
AIN+
AIN-
+
-
CLOSED
OPEN
VREF+
VREF-
S1
AIN+
AIN-
S2
+
-
X20
+
-
X20
CLOSED
CLOSED
OPEN
OPEN
+
-
+
-
the full-scale voltage. In addition, when self cali-
bration of gain is performed in the 25 mV, 55 mV,
and 100 mV input ranges, the instrumentation am-
plifier’s gain is not calibrated. These two factors
can leave the converters with a gain error of up to
±20% after self calibration of gain. Therefore, a
system gain calibration is required to get better ac-
curacy, except for the 2.5 V range.
1.3.2 System Calibration
For the system calibration functions, the user must
supply the calibration signals to the converter which
represent ground and full scale. When a system offset
calibration is performed, a ground-referenced signal
must
Figures 14 and 15.
As shown in Figures 16 and 17, the user must input
a signal representing the positive full-scale point to
Figure 14. System Calibration of Offset (Low Ranges)
CM + -
0V + -
Figure 12. Self Calibration of Offset (High Ranges)
External
Connections
VREF-
AIN+
AIN-
be
AIN+
AIN-
applied
CS5521/22/23/24/28
+
-
to
+
-
X20
X20
the
CLOSED
S4
OPEN
OPEN
S2
S1
converters.
+
-
DS317F8
+
-
See