TC9400_06 Datasheet, PDF (8/24 Pages) Microchip Technology – Voltage-to-Frequency/Frequency-to-Voltage Converters

TC9400/9401/9402
3.2 Voltage-to-Time Measurements
The TC9400 output can be measured in the time
domain as well as the frequency domain. Some micro-
computers, for example, have extensive timing capabil-
ity, but limited counter capability. Also, the response
time of a time domain measurement is only the period
between two output pulses, while the frequency mea-
surement must accumulate pulses during the entire
counter time-base period.
Time measurements can be made from either the
TC9400’s PULSE FREQ OUT output, or from the
FREQ/2 OUT output. The FREQ/2 OUT output
changes state on the rising edge of PULSE FREQ
OUT, so FREQ/2 OUT is a symmetrical square wave at
one-half the pulse output frequency. Timing measure-
ments can, therefore, be made between successive
PULSE FREQ OUT pulses, or while FREQ/2 OUT is
high (or low).
DS21483C-page 8
© 2006 Microchip Technology Inc.