MCP6S92 Microchip Technology Inc., MCP6S92 Datasheet - Page 30

• Manufacturer Part Number: MCP6S92
• Description: Single-ended, Rail-to-rail I/o, Low-gain Pga
• Manufacturer: Microchip Technology Inc.

6.4.5
Figure 6-10
MCP6S92s PGAs that provide up to 9 input channels.
Obviously, Sensors #1-8 have a high total gain range
available, as explained in Section 6.4.3 “Extended
Gain Range PGA”. These devices can be daisy-
chained (Section 5.3 “Daisy-Chain Configuration”).
FIGURE 6-10:
6.4.6
Figure 6-11 shows a MCP6S93 driving an analog input
to a PICmicro microcontroller. This greatly expands the
input capacity of the microcontroller, while adding the
ability to select the appropriate gain for each source.
FIGURE 6-11:
PICmicro
 2004 Microchip Technology Inc.
Sensors
Sensor
# 1-8
# 0
V
IN
®
EXPANDED INPUT PGA
PICmicro
INPUT CAPABILITY
Microcontroller.
shows
MCP6S93
MCP6S28
®
PGA with Expanded Inputs.
Expanded Input for a
cascaded
MCU WITH EXPANDED
SPI
MCP6S92
™
Microcontroller
PICmicro
MCP6S28
®
V
OUT
and
6.4.7
This family of PGAs is well suited for driving Analog-to-
Digital Converters (ADCs). The binary gains (1, 2, 4, 8,
16 and 32) effectively add five more bits to the input
range (see Figure 6-12). This works well for applica-
tions needing relative accuracy more than absolute
accuracy (e.g., power monitoring).
FIGURE 6-12:
At low gains, the ADC’s Signal-to-Noise Ratio (SNR)
will dominate since the PGA’s input noise voltage
density is so low (10 nV/ Hz @ 10 kHz, typ.). At high
gains, the PGA’s noise will dominate the SNR, but it is
low enough to support most applications. These PGAs
add the flexibility of selecting the best gain for an
application.
The low-pass filter in the block diagram reduces the
integrated noise at the MCP6S92’s output and serves
as an anti-aliasing filter. This filter may be designed
using Microchip’s FilterLab
www.microchip.com.
V
IN
MCP6S92
ADC DRIVER
MCP6S91/2/3
Low-pass
PGA as an ADC driver.
Filter
®
software, available at
MCP3201
12-bit
ADC
DS21908A-page 30
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OUT