MCP6S21 N/A, MCP6S21 Datasheet - Page 26

• Manufacturer Part Number: MCP6S21
• Description: Single-Ended, Rail-to-Rail I-O, Low Gain PGA
• Manufacturer: N/A

MCP6S21/2/6/8
6.4
6.4.1
Figure 6-3 shows a circuit that measures the current I
It benefits from changing the gain on the PGA. Just as
a hand-held multimeter uses different measurement
ranges to obtain the best results, this circuit makes it
easy to set a high gain for small signals and a low gain
for large signals. As a result, the required dynamic
range at the PGA’s output is less than at its input (by up
to 30 dB).
FIGURE 6-3:
Current Measurement Circuit.
6.4.2
Figure 6-4 shows a circuit using an MCP6021 at a gain
of +10 in front of an MCP6S21. This changes the over-
all gain range to +10 V/V to +320 V/V (from +1 V/V to
+32 V/V).
FIGURE 6-4:
Range.
It is also easy to shift the gain range to lower gains (see
Figure 6-6). The MCP6021 acts as a unity gain buffer,
and the resistive voltage divider shifts the gain range
down to +0.1 V/V to +3.2 V/V (from +1 V/V to +32 V/V).
DS21117A-page 26
V
IN
I
X
1.11 k
Typical Applications
MCP6021
GAIN RANGING
SHIFTED GAIN RANGE PGA
10.0 k
R
S
Wide Dynamic Range
PGA with Modified Gain
MCP6S2X
MCP6S21
V
OUT
V
OUT
X
.
FIGURE 6-5:
6.4.3
Figure 6-6 gives a +1 V/V to +1024 V/V gain range,
which is much greater than the range for a single PGA
(+1 V/V to +32 V/V). The first PGA provides input mul-
tiplexing capability, while the second PGA only needs
one input. These devices can be daisy chained
(Section 5.3, “Daisy Chain Configuration”).
FIGURE 6-6:
Range.
6.4.4
The multiple channel PGAs (except the MCP6S21)
allow the user to select which sensor appears on the
output (see Figure 6-7). These devices can also
change the gain to optimize performance for each
sensor.
FIGURE 6-7:
Inputs.
V
V
IN
IN
Sensor # 0
Sensor # 1
Sensor # 5
MCP6021
EXTENDED GAIN RANGE PGA
MCP6S28
MULTIPLE SENSOR AMPLIFIER
1.11 k
PGA with lower gain range.
PGA with Extended Gain
PGA with Multiple Sensor
MCP6S26
2003 Microchip Technology Inc.
MCP6S21
10.0 k
MCP6S21
V
OUT
V
V
OUT
OUT