PCA2001U/AC/1,026

Overview

The PCA2001U/AC/1 is a CMOS integrated circuit designed for battery-operated wrist watches, utilizing a 32 kHz quartz crystal as the timing element and driving a bipolar 1 Hz stepping motor. It features an amplitude-regulated oscillator optimized for minimum power consumption, achieving typical supply currents of 90 nA at VDD = 3.3 V. The device includes programmable digital frequency adjustment with 1 ppm resolution stored in One Time Programmable (OTP) memory. Unlike the PCA2000 variant, the PCA2001 does not include an End Of Life (EOL) warning function. It provides automatic motor pulse adaptation to ensure correct motor steps while minimizing drive current.

Feature Summary

• Amplitude-regulated 32 kHz quartz crystal oscillator with excellent frequency stability
• Electrically programmable time calibration with 1 ppm resolution stored in OTP memory
• Very low power consumption, typically 90 nA
• Automatic motor pulse adaptation based on safe dynamic detection of successful motor steps

Applications

• Driver circuits for bipolar stepping motors
• High immunity motor drive circuits
• Battery operated wrist watches

Procurement Notes

Verify that the specific application requires the PCA2001 variant without the EOL function, as the PCA2000 includes this feature. Confirm compatibility with the bipolar stepping motor torque requirements and the available programming infrastructure for OTP writing via supply voltage modulation. Ensure the wire bond die package format aligns with the manufacturing assembly process.

Selection Notes

Select the PCA2001 when the End Of Life indication is not required for the watch design. The device supports programmable motor pulse width (0.98 ms to 7.8 ms), duty cycle, and number of driving levels (3 to 6). Time calibration can be performed after assembly by measuring the oscillator frequency at pad RESET and storing the correction pulses in OTP memory.

Part Context

The PCA2001 is part of the PCA2000/PCA2001 family of 32 kHz watch circuits. It shares the same core architecture and pinout as the PCA2000 but omits the battery EOL warning circuitry. Both devices are available in wire bond die and WLCSP packages, offering flexibility for different manufacturing needs.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.