MCP1525/41
DS21653C-page 10 2001-2012 Microchip Technology Inc.
4.2 Typical Application Circuits
4.2.1 NEGATIVE VOLTAGE REFERENCE
A negative precision voltage reference can be
generated by using the MCP1525 or MCP1541 in the
configuration shown in Figure 4-3.
FIGURE 4-3: Negative Voltage
Reference.
In this circuit, the voltage inversion is implemented
using the MCP606 and two equal resistors. The voltage
at the output of the MCP1525 or MCP1541 voltage
reference drives R
1
, which is connected to the inverting
input of the MCP606 amplifier. Since the non-inverting
input of the amplifier is biased to ground, the inverting
input will also be close to ground potential. The second
10 k resistor is placed around the feedback loop of
the amplifier. Since the inverting input of the amplifier is
high-impedance, the current generated through R
1
will
also flow through R
2
. As a consequence, the output
voltage of the amplifier is equal to -2.5V for the
MCP1525 and -4.1V for the MCP1541.
4.2.2 A/D CONVERTER REFERENCE
The MCP1525 and MCP1541 were carefully designed
to provide a voltage reference for Microchip’s 10-bit
and 12-bit families of ADCs. The circuit shown in
Figure 4-4 shows a MCP1541 configured to provide the
reference to the MCP3201, a 12-bit ADC.
FIGURE 4-4: ADC Reference Circuit.
V
SS
V
OUT
V
IN
C
L
R
1
MCP1525
MCP1541
10 µF
10 k
V
DD
=5.0V
V
REF
MCP606
V
SS
=- 5.0V
0.1%
R
2
10 k
0.1%
V
REF
=-2.5V, MCP1525
V
REF
= -4.096V, MCP1541
V
SS
V
OUT
V
IN
MCP1541
V
DD
=5.0V
C
IN
0.1 µF
MCP3201
C
L
10 µF
V
REF
IN+
IN–
V
IN
10 µF
0.1 µF
to PIC
®
Microcontroller
3
21653C.book Page 10 Thursday, January 10, 2013 12:55 PM
