Datasheet

 2004 Microchip Technology Inc. DS21908A-page 17
MCP6S91/2/3
3.0 PIN DESCRIPTIONS
Descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN FUNCTION TABLE
3.1 Analog Output
The output pin (V
OUT
) is a low-impedance voltage
source. The selected gain (G), selected input (CH0,
CH1) and voltage at V
REF
determine its value.
3.2 Analog Inputs (CH0, CH1)
The inputs CH0 and CH1 connect to the signal
sources. They are high-impedance CMOS inputs with
low bias currents. The internal MUX selects which one
is amplified to the output.
3.3 External Reference Voltage (V
REF
)
The V
REF
pin, which is an analog input, should be at a
voltage between V
SS
and V
DD
(the MCP6S92 has
V
REF
tied internally to V
SS
). The voltage at this pin
shifts the output voltage.
3.4 Power Supply (V
SS
and V
DD
)
The Positive Power Supply Pin (V
DD
) is 2.5V to 5.5V
higher than the Negative Power Supply Pin (V
SS
). For
normal operation, the other pins are at voltages
between V
SS
and V
DD
.
Typically, these parts are used in a single (positive)
supply configuration. In this case, V
SS
is connected to
ground and V
DD
is connected to the supply. V
DD
will
need a local bypass capacitor (typically 0.01 µF to
0.1 µF) within 2 mm of the V
DD
pin. These parts can
share a bulk capacitor with analog parts (typically
2.2 µF to 10 µF) within 100 mm of the V
DD
pin.
3.5 Digital Inputs
The SPI interface inputs are: Chip Select (CS), Serial
Input (SI) and Serial Clock (SCK). These are Schmitt-
triggered, CMOS logic inputs.
3.6 Digital Output
The MCP6S93 device has a SPI interface Serial Output
(SO) pin. This is a CMOS push-pull output and does
not ever go High-Z. Once the device is deselected (CS
goes high), SO is forced low. This feature supports
daisy-chaining, as explained in Section 5.3 “Daisy-
Chain Configuration”.
MCP6S91 MCP6S92 MCP6S93 Symbol Description
111V
OUT
Analog Output
2 2 2 CH0 Analog Input
— 3 3 CH1 Analog Input
3—4V
REF
External Reference Pin
445V
SS
Negative Power Supply
556
CS
SPI™ Chip Select
6 6 7 SI SPI Serial Data Input
— — 8 SO SPI Serial Data Output
7 7 9 SCK SPI Clock Input
8810V
DD
Positive Power Supply