CS5501-BS Cirrus Logic Inc, CS5501-BS Datasheet - Page 20

• Manufacturer Part Number: CS5501-BS
• Description: A/D Converter (A-D) IC
• Manufacturer: Cirrus Logic Inc

Specifications of CS5501-BS

• Peak Reflow Compatible (260 C): No
• No. Of Bits: 16 Bit
• Leaded Process Compatible: No
• Mounting Type: Surface Mount
• Interface Type: Serial
• Package / Case: 20-SOIC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Tables 3 and 4 indicate the output code size and
output coding of the CS5501/CS5503 in its vari-
ous modes. The calibration equations which
represent the CS5501/CS5503 transfer function
are shown in Figure 10.
DOUT = Slope (AIN - Unipolar Offset) + 0.5 LSB
CS5501
DOUT = Slope (AIN - Bipolar Offset) + 2
CS5503
DOUT = Slope(AIN - Bipolar Offset) + 2
Figure 10. Calibration Equations
20
(SGAIN - SOFF)/2 - 0.5 LSB VREF/2 - 0.5 LSB
System Cal
Cal Mode
Self-Cal
>(SGAIN - 1.5 LSB)
<(SOFF + 0.5 LSB)
SGAIN - 1.5 LSB
SOFF + 0.5 LSB
System-Cal
Input Voltage, Unipolar Mode
a. Unipolar Calibration
Zero Scale
b. Bipolar Calibration
AGND
SOFF
>(VREF - 1.5 LSB)
<(AGND+0.5 LSB)
AGND + 0.5 LSB
Gain Factor
VREF - 1.5 LSB
SGAIN
VREF
Self-Cal
Table 3. Output Code Size After Calibration
19
15
+ 0.5 LSB
+ 0.5 LSB
SGAIN
CS5501
Table 4. Output Coding
Output Codes (Hex)
CS5501
65,536
65,536
VREF
FFFF
FFFF
FFFE
7FFF
8000
0001
0000
0000
SOFF
20
16
Unipolar
CS5503
FFFFE
FFFFF
FFFFF
7FFFF
80000
00001
00000
00000
Underrange And Overrange Considerations
The input signal range of the CS5501/CS5503
will be determined by the mode in which the part
is calibrated. Table 4 indicates the input signal
range in the various modes of operation. If the
input signal exceeds the full scale point the con-
verter will output all ones. If the signal is less
than the zero scale point (in unipolar) or more
negative in magnitude than minus the full scale
point (in bipolar) it will output all zeroes.
Note that the modulator-filter combination in the
chip CS5501/CS5503 is designed to accurately
convert and filter input signals with noise excur-
sions which extend up to 100 mV below the
analog value which produces all zeros out or
above the analog value which produces all ones
out. Overrange noise excursions greater than
100 mV may increase output noise.
All pins of the CS5501/CS5503 include diodes
which clamp the input signals to within the posi-
tive and negative supplies. If a signal on any pin
(including AIN) exceeds the supply voltage (either
SGAIN
1,048,526
1,048,526
CS5503
VREF
>(VREF - 1.5 LSB)
<(-VREF+0.5 LSB)
AGND - 0.5 LSB
-VREF+ 0.5 LSB
VREF - 1.5 LSB
SOFF
Input Voltage, Bipolar Mode
Self-Cal
1LSB
2 SGAIN
CS5501
2VREF
65,536
65,536
-SGAIN + 2SOFF + 0.5 LSB
<(-SGAIN+2SOFF+0.5 LSB)
CS5501/CS5503
SOFF
>(SGAIN - 1.5 LSB)
SGAIN - 1.5 LSB
Bipolar
SOFF -0.5 LSB
System Cal
2 SGAIN
1,048,526
1,048,526
CS5503
2VREF
DS31F2
SOFF