Datasheet

 2011-2015 Microchip Technology Inc. DS40001615C-page 105
PIC12(L)F1501
13.0 FIXED VOLTAGE REFERENCE
(FVR)
The Fixed Voltage Reference (FVR) is a stable voltage
reference, independent of V
DD, with a nominal output
level (V
FVR) of 1.024V. The output of the FVR can be
configured to supply a reference voltage to the
following:
• ADC input channel
• Comparator positive input
• Comparator negative input
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
13.1 Independent Gain Amplifier
The output of the FVR supplied to the peripherals, (listed
above), is routed through a programmable gain amplifier.
Each amplifier can be programmed for a gain of 1x, 2x or
4x, to produce the three possible voltage levels.
The ADFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the ADC module. Refer-
ence Section 15.0 “Analog-to-Digital Converter
(ADC) Module” for additional information.
The CDAFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the comparator modules.
Reference Section 17.0 “Comparator Module” for
additional information.
To minimize current consumption when the FVR is
disabled, the FVR buffers should be turned off by
clearing the Buffer Gain Selection bits.
13.2 FVR Stabilization Period
When the Fixed Voltage Reference module is enabled,
it requires time for the reference and amplifier circuits
to stabilize. Once the circuits stabilize and are ready for
use, the FVRRDY bit of the FVRCON register will be
set. See the FVR Stabilization Period characterization
graph, Figure 28-52.
FIGURE 13-1: VOLTAGE REFERENCE BLOCK DIAGRAM
1x
2x
4x
1x
2x
4x
ADFVR<1:0>
CDAFVR<1:0>
FVR_buffer1
(To ADC Module)
FVR_buffer2
(To Comparators)
+
_
FVREN
FVRRDY
Note 1
2
2
Rev. 10-000053A
8/6/2013
Note 1: Any peripheral requiring the Fixed Reference (see Table 13-1).