ADS930MC Murata Power Solutions Inc, ADS930MC Datasheet - Page 5

• Manufacturer Part Number: ADS930MC
• Description: Analog To Digital Converter
• Manufacturer: Murata Power Solutions Inc

CALIBRATION PROCEDURE (Refer to Figure 2 and Tables 3a and 3b)
DATEL
Straight Binary
Complementary Binary
Complementary Offset Binary
Offset Binary
Complementary Two’s Complement (Using MSB, pin 40)
Two’s Complement (Using MSB, pin 40)
–1/2FS –1/2LSB
–FS +1 1/2 LSB
Connect the converter per Table 2 for the appropriate input voltage range.
A/D converters are calibrated by positioning their digital outputs exactly
For the ADS-930, offset adjusting is normally accomplished when the ana-
Gain adjusting is accomplished when the analog input is at nominal full
Note: Connect pin 5 to ANALOG GROUND (pin 4) for operation without
Any offset/gain calibration procedures should not be implemented until
the device is fully warmed up. To avoid interaction, adjust offset before
gain. The ranges of adjustment for the circuits in Figure 2 are guaranteed
to compensate for the ADS-930's initial accuracy errors and may not be
able to compensate for additional system errors.
on the transition point between two adjacent digital output codes. This is
accomplished by connecting LED's to the digital outputs and performing
adjustments until certain LED's "fl icker" equally between on and off. Other
approaches employ digital comparators or microcontrollers to detect when
the outputs change from one code to the next.
log input is 0 minus ½ LSB (–76μV). See Table 3b for the proper bipolar
and unipolar output coding.
scale minus 1½ LSB's (–9.999771V for unipolar and +4.999771V for
bipolar).
zero/offset adjustment. Connect pin 6 to pin 4 for operation without gain
adjustment.
–FS +1 LSB
UNIPOLAR
–1/2LSB
–7/8 FS
–3/4 FS
–1/2FS
–1/4FS
–1/8FS
–1 LSB
®
SCALE
0
INPUT RANGE
Table 3a. Setting Output Coding Selection (Pin 8)
0 to –10V
±5V
OUTPUT FORMAT
INPUT RANGE 0 to
–9.999847
–9.999771
–8.750000
–7.500000
–5.000000
–4.999924
–2.500000
–1.250000
–0.000153
–0.000076
Table 2. Input Connections
0.000000
–10V
INPUT PIN
Pin 3
Pin 3
MSB
1111 1111 1111 1111
1110 0000 0000 0000
1100 0000 0000 0000
1000 0000 0000 0000
0111 1111 1111 1111
0100 0000 0000 0000
0010 0000 0000 0000
0000 0000 0000 0001
0000 0000 0000 0000
COMP. OFF. BIN.
STRAIGHT BIN.
LSB "1" to "0"
LSB "0" to "1"
TIE TOGETHER
Pins 2 and 4
Pins 1 and 2
®
• 11 Cabot Boulevard, Mansfi eld, MA 02048-1151 USA • Tel: [phone] • www.datel.com • e-mail: [e-mail]
PIN 8 LOGIC LEVEL
LSB
1
0
0
1
0
1
MSB
0000 0000 0000 0000
0001 1111 1111 1111
0011 1111 1111 1111
0111 1111 1111 1111
1000 0000 0000 0000
1011 1111 1111 1111
1101 1111 1111 1111
1111 1111 1111 1110
1111 1111 1111 1111
OFFSET BINARY
COMP. BINARY
LSB "0" to "1"
LSB "1" to "0"
Table 3b. Output Coding
OUTPUT CODING
LSB
MSB
0111 1111 1111 1111
0110 0000 0000 0000
0100 0000 0000 0000
0000 0000 0000 0000
1111 1111 1111 1111
1100 0000 0000 0000
1010 0000 0000 0000
1000 0000 0000 0001
1000 0000 0000 0000
–15V
COMP. TWO'S COMP.
+15V
Zero/Offset Adjust Procedure
1. Apply a train of pulses to the START CONVERT input (pin 17) so that the
2. For unipolar or bipolar zero/offset adjust, apply –76.3μV to the ANALOG
3. For a bipolar input - adjust the offset potentiometer until the code fl ickers
4. Two's complement coding requires using BIT 1 (MSB) (pin 40). With pin 8
+5V
LSB "1" to "0"
LSB "0" to "1"
converter is continuously converting.
INPUT (pin 3).
between 1000 0000 0000 0000 and 0111 1111 1111 1111 with pin 8
tied high (offset binary) or between 0111 1111 1111 1111 and 1000 0000
0000 0000 with pin 8 tied low (complementary offset binary).
For a unipolar input - adjust the offset potentiometer until all output bits
are 0's and the LSB fl ickers between 0 and 1 with pin 8 tied high (straight
binary) or until all output bits are 1's and the LSB fl ickers between 0 and 1
with pin 8 tied low (complementary binary).
tied high, adjust the trimpot until the output code fl ickers between all 0's
and all 1's.
0.1—F
4.7—F
4.7—F
4.7—F
4.7—F
0.1—F
0.1—F
0.1—F
LSB
16-Bit, 500kHz Sampling A/D Converters
Figure 2. Bipolar Connection Diagram
MSB
1000 0000 0000 0000
1001 1111 1111 1111
1011 1111 1111 1111
1111 1111 1111 1111
0000 0000 0000 0000
0011 1111 1111 1111
0101 1111 1111 1111
0111 1111 1111 1110
12
01111111 1111 1111
23 FIFO/DIR
19 FSTAT1
20 FSTAT2
16
18, 24
7
13, 30
2 BIPOLAR
1
4, 11
9 ENABLE
+15V
–15V
+10V REF. OUT
+5V
DIGITAL
+15V
LSB "0" to "1"
LSB "1" to "0"
TWO'S COMP.
ANALOG
GROUND
DIGITAL
GROUND
ADJUST
GAIN
20k
6
–15V
01 Apr 2011 MDA_ADS-930.B02 Page 5 of 8
ADS-930
LSB
+15V
START CONVERT
ANALOG INPUT
INPUT RANGE
OFFSET
ADJUST
+4.999847
+4.999771
+3.750000
+2.500000
–0.000076
–2.500000
–3.750000
–4.999847
–4.999924
–5.000000
COMP. BITS
20k
0.000000
FIFO READ
5
±5V
–15V
ADS-930
10
17
8
3
+FS –1 1/2 LSB
–FS + 1/2 LSB
15
14
40
39
38
37
36
35
34
33
32
31
29
28
27
26
25
22
21
+FS –1 LSB
–FS +1 LSB
+5V
–1/2 LSB
BIPOLAR
+3/4 FS
+1/2 FS
–1/2 FS
–3/4 FS
EOC
OVERFLOW
BIT 1 (MSB)
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14
BIT 15
BIT 16 (LSB)
SCALE
–FS
0