PIC12F635-E/MD MICROCHIP [Microchip Technology], PIC12F635-E/MD Datasheet - Page 75

• Manufacturer Part Number: PIC12F635-E/MD
• Description: 8/14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

7.2
A simplified circuit for an analog input is shown in
Figure 7-5. Since the analog input pins share their con-
nection with a digital input, they have reverse biased
ESD protection diodes to V
input, therefore, must be between V
input voltage deviates from this range by more than
0.6V in either direction, one of the diodes is forward
biased and a latch-up may occur.
A maximum source impedance of 10 k is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
FIGURE 7-5:
© 2007 Microchip Technology Inc.
Analog Input Connection
Considerations
Legend: C
V
A
Rs < 10K
ANALOG INPUT MODEL
I
R
R
V
V
LEAKAGE
A
T
PIN
IC
S
DD
A
IN
and V
= Input Capacitance
= Leakage Current at the pin due to various junctions
= Interconnect Resistance
= Source Impedance
= Analog Voltage
= Threshold Voltage
C
5 pF
SS
PIN
SS
and V
. The analog
DD
V
. If the
DD
PIC12F635/PIC16F636/639
V
V
T
T
0.6V
0.6V
Note 1: When reading a PORT register, all pins
I
±500 nA
Vss
LEAKAGE
2: Analog levels on any pin defined as a
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.
digital input, may cause the input buffer to
consume more current than is specified.
R
IC
To Comparator
DS41232D-page 73