tc9400 Microchip Technology Inc., tc9400 Datasheet - Page 9

• Manufacturer Part Number: tc9400
• Description: Voltage-to-frequency / Frequency-to-voltage Converters
• Manufacturer: Microchip Technology Inc.

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
measurement 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).
© 2007 Microchip Technology Inc.
DS21483D-page 9