page 3Frequency multipliers, dividers and counters

WARNINGS AND ADVICES ABOUT PRESCALER REPLACEMENTS

Very often we have request on the possibility to replace some obsolete or hard to find prescalers, this need is felt by the repairers of equipments such as instruments, measurement receivers, or other professional equipment in general, but also by those who want to make a circuit with obsolete components.

For this reason we listed the following simple advices (some simple suggestions on how to behave) because a prescaler can be used as replacements but sometimes is not known.
Who is in this need please read these advices before contact us, making sure that a prescaler is available and if it can replace the one you want.

1. Some prescalers may result exactly the same but they can differ, for example, in power supply eg. 3.5V instead of 5V, so a simple modification in power supply is enough.
2. Other types may have some missing division factors, so the replacements is possible only if the missing factors are not used.
3. Some other prescalers unlike the case above, have only one division factor, so they can be safely replaced with a type that has more than one division factor even though it will be used only one, in this case it will be only enough to set the switching pins of the division factor on the desired division value (see SP4633 and U893).
4. Others may have lower frequency, in this case only the customer can evaluate the possible replacement.
5. Some other may have the same performances and same divisions but they are not pin compatible with a differet case than the original type, in this case the changes concern the p.c. board tracks.