MCP3302-XI/SL Microchip Technology, MCP3302-XI/SL Datasheet - Page 15

• Manufacturer Part Number: MCP3302-XI/SL
• Description: 13-Bit Differential Input, Low Power A/D Converter with SPI Serial Interface, -40C to +85C, 14-SOIC 150mil, TUBE
• Manufacturer: Microchip Technology

4.0
The descriptions of the pins are listed in
TABLE 4-1:
4.1
Analog input channels. These pins have an absolute
voltage range of V
differential input range is defined as the absolute value
of (IN+) - (IN-). This difference can not exceed the
value of V
occur.
4.2
Ground connection to internal digital circuitry. To
ensure accuracy this pin must be connected to the
same ground as AGND. If an analog ground plane is
available, it is recommended that this device be tied to
the analog ground plane in the circuit. See Section 6.6
“Layout Considerations” for more information
regarding circuit layout.
4.3
The CS/SHDN pin is used to initiate communication
with the device when pulled low. This pin will end a
conversion and put the device in low power standby
when pulled high. The CS/SHDN pin must be pulled
high between conversions and cannot be tied low for
multiple conversions. See
communication protocol.
4.4
The SPI port serial data input pin is used to clock in
input channel configuration data. Data is latched on the
rising edge of the clock. See
communication protocol.
© 2007 Microchip Technology Inc.
CH0-CH7
DGND
CS/SHDN
D
D
CLK
AGND
V
V
REF
DD
IN
OUT
Name
PIN DESCRIPTIONS
CH0-CH7
DGND
Chip Select/Shutdown (CS/SHDN)
Serial Data Input (D
REF
Analog Inputs
Digital Ground
Chip Select / Shutdown Input
Serial Data In
Serial Data Out
Serial Clock
Analog Ground
Reference Voltage Input
+2.7V to 5.5V Power Supply
- 1 LSB or digital code saturation will
SS
PIN FUNCTION TABLE
- 0.3V to V
Function
DD
Figure 7-2
Figure 7-2
+ 0.3V. The full scale
IN
)
Table
for serial
for serial
4-1.
4.5
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
protocol.
4.6
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 “Driving the Analog Input” for
constraints on clock speed. See
communication protocol.
4.7
Ground connection to internal analog circuitry. To
ensure accuracy, this pin must be connected to the
same ground as DGND. If an analog ground plane is
available, it is recommended that this device be tied to
the analog ground plane in the circuit. See Section 6.6
“Layout Considerations” for more information
regarding circuit layout.
4.8
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.
EQUATION 4-1:
When using an external voltage reference device, the
system designer should always refer to the manufac-
turer’s recommendations for circuit layout. Any
instability in the operation of the reference device will
have a direct effect on the accuracy of the ADC
conversion results.
4.9
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 “Layout Considerations” for more
information regarding circuit layout.
Serial Data Output (D
Serial Clock (CLK)
AGND
Voltage Reference (V
V
DD
LSB Size =
Figure 7-2
MCP3302/04
2 x V
for serial communication
8192
Figure 7-2
REF
REF
DS21697D-page 15
OUT
)
)
for serial