FEATURES

· 32 kHz oscillator, amplitude regulated with excellent

frequency stability

· High immunity of the oscillator to leakage currents

· Time calibration electrically programmable and

reprogrammable (via EEPROM)

· A quartz crystal is the only external component required

· Very low current consumption; typically 170 nA

· Output for bipolar stepping motors of different types

· Up to 50 reduction in motor current compared with

conventional circuits, by self adaption of the motor pulse

width to match the required torque of the motor

· No loss of motor steps possible because of on-chip

detection of the induced motor voltage

· Detector for lithium or silver-oxide battery voltage levels

· Indication for battery end-of-life

· Stop function for accurate timing

· Power-on reset for fast testing

· Various test modes for testing the mechanical parts of

the watch and the IC.

GENERAL DESCRIPTION

The PCA146x series devices are CMOS integrated circuits

specially suited for battery-operated,

quartz-crystal-controlled wrist-watches, with a bipolar

stepping motor.