66MHz Oscillator values?

Ed.D

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Hi guys,

Anyone know the difference between the IQX0-350c and the IQX0-149CF oscillators ?

Thanks,
Ed.

- - - Updated - - -

Ah, I think I just found the answer, (Frequency Stability) but is there any reason why the 149CF could cause lock ups in a A3640 33MHZ upgrade? I upgraded my A3640 today adding a socket and rerouting R101 and it runs ok for about 5 minutes then freezes.



IQX0-350c
Frequency: 66.000000MHz
Supply Voltage: 5.0V ±0.25V
Ageing: ±5ppm max per year
Output Compatibility: HCMOS/TTL
Drive Capability: 50pF max or 10TTL loads
Frequency Stability: ±25ppm to ±100ppm(inclusive of supply voltage and output load variations over the operating temperature range)
Operating Temperature: 0 to 70°C
Storage Temperature: -55 to 125°C


IQX0-149CF
Frequency: 66.000000MHz
Supply Voltage: 5.0V ±0.25V
Ageing: ±5ppm max per year
Output Compatibility: HCMOS/TTL
Drive Capability: 50pF max or 10TTL loads
Frequency Stability: ±100ppm (inclusive of supply voltage and output load variations over the operating temperature range)
Operating Temperature: 0 to 70°C
Storage Temperature: -55 to 125°C
 
Last edited:
Hi,

The MC68040 requires PCLK/BCLK with a maximum rise/fall time of 3ns, the IQD oscillators you link to have maximum rise times of 4ns. IT might start ok but as things heat up, it could drift out. Motorola/Freescale microprocessors are fussy on oscillator rise fall/times.

Datasheets here:

http://www.iqdfrequencyproducts.com/

The MC68040 can tolerate 1000ppm accuracy, not surprising for an old microprocessor.

Try locating an oscillator with better rise/fall times.

Ian
 
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