Microchip Technology MA180025 データシート

 2010 Microchip Technology Inc.

DS39933D-page 303

A simplified circuit for an analog input is shown in
Figure 22-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to V

DD

and V

SS

. The analog input, therefore, must be between

V

SS

 and V

DD

. If the 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 condition may
occur. A maximum source impedance of 10 k

 is

recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.

INTCON

GIE/GIEH PEIE/GIEL TMR0IE

INT0IE

RBIE

TMR0IF

INT0IF

RBIF

PIR2

OSCFIF

CMIF

—

—

BCLIF

LVDIF

TMR3IF

—

PIE2

OSCFIE

CMIE

—

—

BCLIE

LVDIE

TMR3IE

—

IPR2

OSCFIP

CMIP

—

—

BCLIP

LVDIP

TMR3IP

—

CMCON

C2OUT

C1OUT

C2INV

C1INV

CIS

CM2

CM1

CM0

CVRCON

CVREN

CVROE

CVRR

CVRSS

CVR3

CVR2

CVR1

CVR0

PORTF

RF7

RF6

RF5

RF4

RF3

RF2

RF1

—

LATF

LATF7

LATF6

LATF5

LATF4

LATF3

LATF2

LATF1

—

TRISF

TRISF7

TRISF6

TRISF5

TRISF4

TRISF3

TRISF2

TRISF1

—

Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module.

VA

R

S

 < 10k

A

IN

C

PIN

5 pF

V

DD

V

T

 = 0.6V

V

T

 = 0.6V

R

IC

I

LEAKAGE

±100 nA

V

SS

C

PIN

= Input Capacitance

V

T

= Threshold 

Voltage

I

LEAKAGE

=  Leakage Current at the pin due to various junctions

R

IC

= Interconnect Resistance

R

S

= Source 

Impedance

VA

= Analog 

Voltage

Comparator
Input