Datasheet

 2011 Microchip Technology Inc. DS21697F-page 13
MCP3302/04
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Tabl e 3-1 .
3.1 Analog Inputs (CH0-CH7)
Analog input channels. These pins have an absolute
voltage range of V
SS
- 0.3V to V
DD
+ 0.3V. The full scale
differential input range is defined as the absolute value
of (IN+) - (IN-). This difference can not exceed the
value of V
REF
- 1 LSB or digital code saturation will
occur.
3.2 Digital Ground (DGND)
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 5.6
“Layout Considerations” for more information
regarding circuit layout.
3.3 Chip Select/Shutdown (CS/SHDN)
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 Figure 6-2 for serial
communication protocol.
3.4 Serial Data Input (D
IN
)
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 Figure 6-2 for serial
communication protocol.
3.5 Serial Data Output (D
OUT
)
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 6-2 for serial communication
protocol.
3.6 Serial Clock (CLK)
The SPI clock pin is used to initiate a conversion, as
well as to clock out each bit of the conversion as it takes
place. See Section 5.2 “Driving the Analog Input”
for constraints on clock speed, and Figure 6-2 for serial
communication protocol.
TABLE 3-1: PIN FUNCTION TABLE
MCP3302 MCP3304
Symbol Description
PDIP, SOIC, TSSOP PDIP, SOIC
1 1 CH0 Analog Input
2 2 CH1 Analog Input
3 3 CH2 Analog Input
4 4 CH3 Analog Input
— 5 CH4 Analog Input
— 6 CH5 Analog Input
— 7 CH6 Analog Input
— 8 CH7 Analog Input
7 9 DGND Digital Ground
810CS
/SHDN Chip Select / Shutdown Input
911D
IN
Serial Data In
10 12 D
OUT
Serial Data Out
11 13 CLK Serial Clock
12 14 AGND Analog Ground
13 15 V
REF
Reference Voltage Input
14 16 V
DD
+4.5V to 5.5V Power Supply
5, 6 — NC No Connection