32kHz Design for Lower Power Applications

Reducing Power Consumption for 32kHz Quartz Crystal Oscillator Circuit




The intent of this investigation is to show the advantages of 32kHz crystals with reduced CL and lower ESR over conventional 32kHz crystals with regard to power consumption, oscillation allowance, starting time and drive level.
The following draft confirms the advantage of the use of Geyer Electronic KX-327NHT with Load Capacitance of 7pF instead of 12,5pF.

Part number 12.87153           7pF +/-20ppm           ≤ 80k Ohm, 50k Ohm typ.
Part number 12.87148           7pF +/-20ppm           ≤ 50k Ohm, 35k Ohm typ.
– Considerably reduced Power Consumption
– Improved Start up Performance
– Faster Start up time
– Stable operation for lower drive level
1. Reducing Power Consumption in CMOS Oscillator Circuit
2. Relationship for CL and Power Consumption in the Oscillator Circuit
3. Relationship of Negative Resistance (Oscillation Allowance) and CL
4. Relationship for Oscillator circuit current and R1
5. Another Advantage of Low-CL (Oscillation Rising Time)
6. Another Advantage of Low-CL (Drive Level)
7. Precision vs. Power Consumption

Annex: Circuit Matching Investigation

Annex: Data Sheets – Part number 12.87153, 12.87148 and 12.87150

1. Reducing Power Consumption in CMOS Oscillator Circuit
Current consumption of the crystal oscillator circuit depend on power supply voltage (Vdd), frequency, load capacitance, and R1 of the quartz crystal.  CONTINUED …..