Datasheet

MCP6G01/1R/1U/2/3/4
DS22004B-page 24 © 2006 Microchip Technology Inc.
4.8.4 SHIFTED GAIN RANGE SGA
Figure 4-12 shows a circuit using a MCP6271 at a gain
of +10 in front of a MCP6G01. This shifts the overall
gain range to +10 V/V to +500 V/V (from +1 V/V to
+50 V/V).
FIGURE 4-12: SGA with Higher Gain
Range.
It is also easy to shift the gain range to lower gains (see
Figure 4-13). The MCP6001 acts as a unity gain buffer,
and the resistive voltage divider shifts the gain range
down to +0.1 V/V to +5.0 V/V (from +1 V/V to +50 V/V).
FIGURE 4-13: SGA with Lower Gain
Range.
4.8.5 ADC DRIVER
This family of SGAs is well suited for driving Analog-to-
Digital Converters (ADC). The gains (1, 10, and 50)
effectively increase the ADC’s input resolution by a
factor of as large as 50 (i.e., by 5.6 bits). This works
well for applications needing relative accuracy more
than absolute accuracy (e.g., power monitoring); see
Figure 4-14.
FIGURE 4-14: SGA as an ADC Driver.
The low-pass filter in the block diagram reduces the
integrated noise at the MCP6G01’s output and serves
as an anti-aliasing filter. This filter may be designed
using Microchip’s FilterLab
®
software, available at
www.microchip.com.
V
IN
V
OUT
MCP6271
MCP6G01
1.11 kΩ
10.0 kΩ
V
IN
MCP6001
1.11 kΩ
10.0 kΩ
V
OUT
MCP6G01
OUT
MCP3001
10-bit
ADC
3
MCP6G01V
IN
Low-pass
Filter