MCP3302-I/P MICROCHIP [Microchip Technology], MCP3302-I/P Datasheet - Page 22

• Manufacturer Part Number: MCP3302-I/P
• Description: 13-Bit Differential Input, Low Power A/D Converter with SPI Serial Interface
• Manufacturer: MICROCHIP [Microchip Technology]

MCP3302/04
7.0
7.1
The output code format is a binary two’s complement
scheme, with a leading sign bit that indicates the sign
of the output. If the IN+ input is higher than the IN-
input, the sign bit will be a zero. If the IN- input is higher,
the sign bit will be a ‘1’.
The diagram shown in Figure 7-1 shows the output
code transfer function. In this diagram, the horizontal
axis is the analog input voltage and the vertical axis is
the output code of the ADC. It shows that when IN+ is
equal to IN-, both the sign bit and the data word is zero.
As IN+ gets larger with respect to IN-, the sign bit is a
zero and the data word gets larger. The full scale output
code is reached at +4095 when the input [(IN+) - (IN-)]
reaches V
two’s complement output codes will be seen with the
sign bit being a one. Some examples of analog input
levels and corresponding output codes are shown in
Table 7-1.
FIGURE 7-1:
DS21697B-page 22
Scale Output = -V
Negative Full
-V
SERIAL COMMUNICATIONS
Output Code Format
REF
REF
- 1 LSB. When IN- is larger than IN+, the
REF
Output Code Transfer Function.
IN+ < IN-
0 + 1111 1111 1111 (+4095)
0 + 1111 1111 1110 (+4094)
0 + 0000 0000 0011 (+3)
0 + 0000 0000 0010 (+2)
0 + 0000 0000 0001 (+1)
0 + 0000 0000 0000 (0)
Output
Code
1 + 1111 1111 1111 (-1)
1 + 1111 1111 1110 (-2)
1 + 1111 1111 1101 (-3)
1 + 0000 0000 0001 (-4095)
1 + 0000 0000 0000 (-4096)
TABLE 7-1:
(IN+)-(IN-) = V
(IN+)-(IN-) = V
(IN+)-(IN-) = V
(IN+)-(IN-)=V
Analog Input Levels
Full Scale Negative
IN+ = (IN-) +2 LSB
IN+ = (IN-) +1 LSB
IN+ = (IN-) - 1 LSB
IN+ = (IN-) - 2 LSB
Full Scale Positive
IN+ = IN-
REF
REF
REF
REF
IN+ > IN-
-1 LSB
-2 LSB
-2 LSB
-1 LSB
BINARY TWO’S
COMPLEMENT OUTPUT
CODE EXAMPLES.
Scale Output = V
Sign
Bit
0
0
0
0
0
1
1
1
1
2002 Microchip Technology Inc.
Positive Full
1111 1111 1111
1111 1111 1110
0000 0000 0010
0000 0000 0001
0000 0000 0000
1111 1111 1111
1111 1111 1110
0000 0000 0001
0000 0000 0000
Binary Data
V
REF
REF
Analog Input
IN+ - IN-
-1 LSB
Voltage
Decimal
DATA
+4095
+4094
-4095
-4096
+2
+1
-1
-2
0