Datasheet

PIC16F631/677/685/687/689/690
DS40001262F-page 254  2005-2015 Microchip Technology Inc.
TABLE 17-18: ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES (VDD > 3.0V,
V
REF > 2.5V)
ADC Clock Period (TAD) Device Frequency (FOSC)
ADC Clock Source ADCS<2:0> 20 MHz 8 MHz 4 MHz 1 MHz
Fosc/2 000
100 ns 250 ns 500 ns 2.0 s
Fosc/4 100 200 ns 500 ns 1.0 s4.0 s
Fosc/8 001
400 ns 1.0 s2.0 s 8.0 s
Fosc/16 101 800 ns 2.0 s4.0 s 16.0 s
Fosc/32 010 1.6 s4.0 s 8.0 s 32.0 s
Fosc/64 110 3.2 s
8.0 s 16.0 s 64.0 s
Frc x11 2-6 s2-6 s2-6 s2-6 s
Legend: Shaded cells should not be used for conversions at temperatures above +125°C.
Note 1: TAD must be between 1.6 s and 4.0 s.