PIC16LF1526 Datasheet, PDF (145/354 Pages) Microchip Technology – 64-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC16(L)F1526/27
14.0 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
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
14.1 Independent Gain Amplifiers
The output of the FVR supplied to the ADC module is
routed through two independent programmable gain
amplifiers. Each amplifier can be configured to amplify
the reference voltage by 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 16.0 “Analog-to-Digital Converter
(ADC) Module” for additional information.
14.2 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
Section 25.0 “Electrical Specifications” for the
minimum delay requirement.
FIGURE 14-1:
VOLTAGE REFERENCE BLOCK DIAGRAM
ADFVR<1:0>
2
x1
x2
x4
FVREN
Any peripheral requiring
the Fixed Reference
(See Table 14-1)
1.024V Fixed
Reference
+
FVRRDY
-
FVR BUFFER1
(To ADC Module)
TABLE 14-1: PERIPHERALS REQUIRING THE FIXED VOLTAGE REFERENCE (FVR)
Peripheral
Conditions
Description
HFINTOSC
BOR
LDO
FOSC<2:0> = 100 and
IRCF<3:0> = 000x
BOREN<1:0> = 11
BOREN<1:0> = 10 and BORFS = 1
BOREN<1:0> = 01 and BORFS = 1
All PIC16F1526/27 devices, when
VREGPM = 1 and not in Sleep
INTOSC is active and device is not in Sleep.
BOR always enabled.
BOR disabled in Sleep mode, BOR Fast Start enabled.
BOR under software control, BOR Fast Start enabled.
The device runs off of the low-power regulator when in Sleep
mode.
 2011 Microchip Technology Inc.
Preliminary
DS41458A-page 145