Datasheet

PIC16(L)F1507
DS41586A-page 117 Preliminary  2011 Microchip Technology Inc.
13.0 FIXED VOLTAGE REFERENCE
(FVR)
The Fixed Voltage Reference, or FVR, is a stable
voltage reference, independent of V
DD, 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
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 ADC is routed
through a programmable gain amplifier. The 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.
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
Section 25.0 “Electrical Specifications” for the
minimum delay requirement.
FIGURE 13-1: VOLTAGE REFERENCE BLOCK DIAGRAM
FVR BUFFER1
(To ADC Module)
x1
x2
x4
+
-
1.024V Fixed
Reference
FVREN
FVRRDY
2
ADFVR<1:0>
Any peripheral requiring
the Fixed Reference
(See Table 13-1)
TABLE 13-1: PERIPHERALS REQUIRING THE FIXED VOLTAGE REFERENCE (FVR)
Peripheral Conditions Description
HFINTOSC FOSC<1:0> = 00 and
IRCF<3:0> = 000x
INTOSC is active and device is not in Sleep.
BOR
BOREN<1:0> = 11 BOR always enabled.
BOREN<1:0> = 10 and BORFS = 1 BOR disabled in Sleep mode, BOR Fast Start enabled.
BOREN<1:0> = 01 and BORFS = 1 BOR under software control, BOR Fast Start enabled.
LDO All PIC16F1507 devices, when
VREGPM = 1 and not in Sleep
The device runs off of the Low-Power Regulator when in
Sleep mode.