PCA2000 and PCA2001 are integrated circuits for 32 kHz watch circuits with programmable adaptive motor pulse. They feature oscillator, programmable time calibration, low power consumption, and stepping motor drive.
The Philips PCA2000 and PCA2001 are CMOS integrated circuits designed for battery-operated wrist watches. They utilize a 32 kHz quartz crystal as the timing element and drive a bipolar 1 Hz stepping motor with an amplitude-regulated oscillator to ensure excellent frequency stability and high immunity to leakage currents.
A key feature is the automatic motor pulse adaptation function, which supplies only the minimum necessary drive current by chopping the motor pulse with a variable duty cycle. This self-adaptation optimizes power consumption based on the required torque. The circuits include an electrically programmable time calibration with 1 ppm resolution stored in One Time Programmable (OTP) memory.
| Oscillator Frequency | 32 kHz |
|---|---|
| Power Consumption (Typical) | 90 nA |
| Time Calibration Resolution | 1 ppm |
| Motor Output Frequency | 1 Hz |
| Pulse Width Range | 0.98 to 7.8 ms |
| Number of Driving Levels | 3 to 6 |
The PCA2000 includes an End Of Life (EOL) indication for silver oxide or lithium batteries, while the PCA2001 does not have this function.
The driving level is regulated by chopping the driving pulse with a variable duty cycle, starting from a programmed minimum value.
For PCA2000, the motor steps change from one pulse per second to a burst of four pulses every 4 seconds.