PIC14000-04 Microchip Technology, PIC14000-04 Datasheet - Page 66

• Manufacturer Part Number: PIC14000-04
• Description: 28-Pin Programmable Mixed Signal Controller
• Manufacturer: Microchip Technology

PIC14000
FIGURE 9-1:
9.3
The slope reference voltage divider circuit, consisting
of a buffer amplifier and resistor divider, is connected to
the internal bandgap reference producing two other
voltage references called SREFHI and SREFLO (see
Figure 9-2). SREFHI is nominally the same as the
bandgap voltage, 1.2V, and SREFLO is nominally
0.13V. These reference voltages are available on two
of the analog multiplexer channels. The A/D module
and firmware can measure the SREFHI and SREFLO
voltages, and in conjunction with the K
ibration data correct for the A/D's offset and slope
errors. See AN624 for further details.
DS40122B-page 66
ADZERO
(ADCON<0>)
LSOFF
(SLPCON<4>)
Slope Reference Voltage Divider
Input Protection
Diodes
RA1/AN1
RD5/AN5
LEVEL-SHIFT NETWORKS
V
DD
REF
*
and K
*These switches are a matched pair
(SLPCON<4>)
LSOFF
BG
cal-
Preliminary
*
(nominal)
100 k
9.4
The internal temperature sensor is connected to the
channel 7 input of the A/D converter. The sensor volt-
age is 1.05V nominal at 25 C and its temperature coef-
ficient is approximately 3.7mV/ C. The sensor voltage
at 25 C and the temperature coefficient values are
stored in the calibration space EPROM (See
Table 4-2). To enable the temperature sensor, the
TEMPOFF bit (SLPCON<1>) must be cleared.
V
DD
Internal Temperature Sensor
5 A (nominal)
1996 Microchip Technology Inc.
To A/D mux,
programmable
reference
comparators
External
Capacitor
(Optional)
SUM
RA1/AN1 only