MCP3301 datasheet(14/32 Pages) MICROCHIP

14 / 32 page

MCP3301

DS21700B-page 14

 2002 Microchip Technology Inc.

4.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 4-1.

TABLE 4-1:

PIN FUNCTION TABLE.

4.1

Voltage Reference (V

REF)

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 by the equation shown

below. As the reference input is reduced, the LSB size

is reduced accordingly.

EQUATION

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

IN(+)

Positive analog input. This pin has an absolute voltage

range of VSS-0.3V to VDD+0.3V. The full scale input

range is defined as the absolute value of (IN+) - (IN-).

4.3

IN(-)

Negative analog input. This pin has an absolute voltage

range of VSS-0.3V to VDD+0.3V. The full scale input

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.

See Section 6.6, “Layout Considerations”, for more

information regarding circuit layout.

4.5

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 con-

version 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 multi-

ple conversions. See Figure 7-2 for serial communica-

tion protocol.

4.6

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 7-2 for serial communication

protocol.

4.7

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 6.2 for constraints on clock speed

and 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

layout.

Name

Function

REF

Reference Voltage Input

IN(+)

Positive Analog Input

IN(-)

Negative Analog Input

Ground

CS/SHDN

Chip Select / Shutdown Input

OUT

Serial Data Out

CLK

Serial Clock

+2.7V to 5.5V Power Supply

LSB Size =

2 x VREF

8192

MCP3301 датащи(PDF) 14 Page - Microchip Technology

MCP3301 датащи(HTML) 14 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

датащи скачать

ссылки URL