PIC16LF18854 Datasheet, PDF (266/668 Pages) Microchip Technology – C Compiler Optimized RISC Architecture

PIC16(L)F18856/76
16.0 FIXED VOLTAGE REFERENCE
(FVR)
The Fixed Voltage Reference, or FVR, is a stable
voltage reference, independent of VDD, with 1.024V,
2.048V or 4.096V selectable output levels. The output
of the FVR can be configured to supply a reference
voltage to the following:
• ADC input channel
• ADC positive reference
• Comparator positive input
• Digital-to-Analog Converter (DAC)
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
Note: Fixed Voltage Reference output cannot
exceed VDD.
16.1 Independent Gain Amplifiers
The output of the FVR, which is connected to the ADC,
comparators, and DAC, is routed through two
independent programmable gain amplifiers. 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.
Reference Section 23.0 “Analog-to-Digital Con-
verter With Computation (ADC2) Module” for addi-
tional 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 DAC and comparator
module. Reference Section 25.0 “5-Bit Digi-
tal-to-Analog Converter (DAC1) Module” and
Section 18.0 “Comparator Module” for additional
information.
FIGURE 16-1:
16.2 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.
VOLTAGE REFERENCE BLOCK DIAGRAM
Rev. 10-000 053C
12/9/201 3
ADFVR<1:0>
2
1x
2x
4x
CDAFVR<1:0>
2
1x
2x
4x
FVR_buffer1
(To ADC Module)
FVR_buffer2
(To Comparators
and DAC)
FVREN
Note 1
+_{_}
FVRRDY
DS40001824A-page 266
Preliminary
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