MCP3301-I/P Microchip Technology, MCP3301-I/P Datasheet - Page 13

• Manufacturer Part Number: MCP3301-I/P
• Description: 13-Bit Differential Input, Low Power A/D Converter with SPI Serial Interface
• Manufacturer: Microchip Technology

4.0
The descriptions of the pins are listed in Table 4-1.
TABLE 4-1:
4.1
This input pin provides the reference voltage for the
device, which determines the maximum range of the
analog input signal and the LSB size.
The LSB size is determined according to the equation
shown below. As the reference input is reduced, the
LSB size is reduced accordingly.
When using an external voltage reference device, the
system designer should always refer to the manufac-
turer’s recommendations for circuit layout. Any instabil-
ity in the operation of the reference device will have a
direct effect on the accuracy of the ADC conversion
results.
4.2
Positive analog input. This pin has an absolute voltage
range of V
range is defined as the absolute value of (IN+) - (IN-).
4.3
Negative analog input. This pin has an absolute voltage
range of V
range is defined as the absolute value of (IN+) - (IN-).
4.4
Ground connection to internal circuitry. If an analog
ground plane is available it is recommended that this
device be tied to the analog ground plane in the circuit.
Section 6.6 for more information regarding circuit lay-
out.
4.5
The CS/SHDN pin is used to initiate communication
with the device when pulled low. This pin will end a con-
version and put the device in low power standby when
V
IN(+)
IN(-)
V
CS/SHDN
D
CLK
V
2001 Microchip Technology Inc.
REF
SS
DD
OUT
Name
PIN DESCRIPTIONS
Voltage Reference (V
IN(+)
IN(-)
V
Chip Select/Shutdown (CS/SHDN)
SS
SS
SS
-0.3V to V
-0.3V to V
Reference Voltage Input
Positive Analog Input
Negative Analog Input
Ground
Chip Select / Shutdown Input
Serial Data Out
Serial Clock
+2.7V to 5.5V Power Supply
Pin Function Table.
LSB Size
DD
DD
=
+0.3V. The full scale input
+0.3V. The full scale input
2 V
---------------------
Function
8192
REF
REF
)
pulled high. The CS/SHDN pin must be pulled high
between conversions and cannot be tied low for multi-
ple conversions. See Figure 7-2 for serial communica-
tion protocol.
4.6
The SPI serial data output pin is used to shift out the
results of the A/D conversion. Data will always change
on the falling edge of each clock as the conversion
takes place. See Figure 7-2 for serial communication
protocol.
4.7
The SPI clock pin is used to initiate a conversion and to
clock out each bit of the conversion as it takes place.
See Section 6.2 for constraints on clock speed.See
Figure 7-2 for serial communication protocol.
4.8
The voltage on this pin can range from 2.7 to 5.5V. To
ensure accuracy a 0.1 µF ceramic bypass capacitor
should be placed as close as possible to the pin. See
Section 6.6 for more information regarding circuit lay-
out.
Serial Data Output (D
Serial Clock (CLK)
V
DD
MCP3301
OUT
DS21700A-page 13
)