H1344 Datasheet, PDF (4/6 Pages) EM Microelectronic - MARIN SA – CMOS Circuit for Analog Quartz Clocks with Bipolar Stepping Motor Drive

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H1344
Functional Description
Oscillator and Frequency Divider
The quartz oscillator consists of an inverter, internal
feedback resistance to bias the input and integrated
capacitors. The values of the integrated capacitors are
selectable by metal mask. The oscillator is designed for
32768Hz.
Motor Drive Output
The circuit contains two push-pull output buffers for driving
bipolar stepping motors. Between two pulses, both P-
channel transistor of the other buffer are conducting. The
outputs are protected against inductive voltage spikes with
diodes to both supply pins.
Both the motor pulse period and motor pulse width are
programmable by metal mask over a wide range of values
(see page 6 for available options).
Test configuration
Alarm Output
The alarm is activated by connecting ALARM_IN to V_SS and is
deactivated by opening the connection. A metal mask
option is available to program a continuous activation of the
alarm output.
The alarm output driver contains a push-pull output buffer
to drive an external sound source by means of an external
bipolar transistor. A metal mask option is available to allow
the use of NPN or PNP-transistors.
The tone frequency, modulation frequency, modulation
frequency and cycle time (ON/OFF time) are metal mask
selectable.
Test Mode
The ALARM_IN pin fulfills three functions:
a) For normal operation, the ALARM_IN pin is left open.
The circuit provides a square wave signal of 1024Hz,
which can be used to tune the oscillator.
b) If the pin is connected to V_SS, the alarm signal is
provided at pin 6.
c) If the ALARM_IN pin is connected to V_DD, all output
frequencies are increased by a factor of 64, the alarm
modulation of f_A1 = 8Hz and f_A = 2kHz are suppressed.
1.5V +
Test
Operating range of trimmer
Capacitance: 1.5 pF ≤ C_TR ≤ 30 pF
C_TR
1
8
H1344
2 _V40 7
V41
3 _V47 6
4
5
Alarm Output
R_M
Fig. 5
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