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The demise of 5V crystal oscillators and the effects


Euroquartz explores how the demand for lower power signals the end of an era for 5V crystal oscillators


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n recent years the use of 5V logic has declined, principally due to the increase in low power battery operated systems that require reduced current consumption implying lower voltage inputs.


If we take time to look at all the number of battery-operated handheld devices that are in use today and new developments such as remote battery-operated site applications one can clearly see an irreversible trend in electronic design.


Systems based on 5V TTL drain significant amps from the power source, so battery operation is not an especially practical option.


28 MARCH 2022 | ELECTRONICS TODAY


Even if 5V batteries were available, the voltage range would not be suited to TTL requirements. It is understood that TTL logic normally operates in the range of 4.75 to 5.25 V (± 5% tolerance) so, considering a four NiCad cells battery, the voltage range delivered is 4.4V (completely drained) to 5.6V (fully charged). This would require an IC with at least ±13% supply voltage tolerance.


During the two-year Covid pandemic, many of the leading semiconductor manufacturers started to reassess the product ranges on offer as supply and demand pressures first contracted and then rebounded. The


production of any particular semiconductor variant is largely dependent on the volumes used by customers across the board. Most of the semiconductors now used in oscillator production are 3.3V or lower which has resulted in the decision to cease production of 5V logic devices.


When considering 5V logic, it is usually assumed that we are talking about TTL logic, but what is this logic? TTL or Transistor- Transistor Logic, as opposed to CMOS (Complementary Metal Oxide Semiconductor) logic, was invented in 1961 at a time when semiconductor technology was in its infancy.


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