PCA2002 Datasheet, PDF (1/25 Pages) NXP Semiconductors – 32 kHz watch circuit with programmable output period and pulse width

PCA2002
32 kHz watch circuit with programmable output period and
pulse width
Rev. 05 — 11 November 2008
Product data sheet
1. General description
The PCA2002 is a CMOS integrated circuit for battery operated wrist watches with a
32 kHz quartz crystal as the timing element and a bipolar stepping motor. The quartz
crystal oscillator and the frequency divider are optimized for minimum current
consumption. A timing accuracy of 1 ppm is achieved with a programmable, digital
frequency adjustment.
The output period and the output pulse width can be programmed. It can be selected
between a full output pulse or a chopped output pulse with a duty cycle of 75 %. In
addition, a stretching pulse can be added to the primary driving pulse.
A pad RESET is provided (used for stopping the motor) for accurate time setting and for
accelerated testing of the watch.
2. Features
I Amplitude-regulated 32 kHz quartz crystal oscillator, with excellent frequency stability
and high immunity to leakage currents
I Electrically programmable time calibration with 1 ppm resolution stored in One Time
Programmable (OTP) memory
I The quartz crystal is the only external component required
I Very low current consumption: typically 90 nA
I Output pulses for bipolar stepping motors
I Five different programmable output periods (1 s to 30 s)
I Output pulse width programmable between 1 ms and 8 ms
I Full or chopped motor pulse and pulse stretching, selectable
I Stop function for accurate time setting and current saving during shelf life
I Test mode for accelerated testing of the mechanical parts of the watch
I Test bits for type recognition
3. Applications
I Driver circuits for bipolar stepping motors
I High immunity motor drive circuits
I High production volumes