LMV393G-S08-R datasheet(7/11 Pages) UTC

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LMV393

Preliminary

LINEAR INTEGRATED CIRCUIT

UNISONIC TECHNOLOGIES CO., LTD

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QW-R104-004.c

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APPLI CAT I ON CI RCU I T S(Cont .)

Free Running Multivibrator

This oscillator circuit can generate a train of stable clock for precise timekeeping applications. We can obtain it by

using a resonator as the feedback component. A quartz crystal in its series-resonant mode can make the circuit

oscillating well. For the comparator be switching symmetrically about +VCC/2, the value of R1 and R2 must choose

equal. The RC time constant of R3 and C1 is set to be several times greater than the period of the oscillating

frequency. When choose crystal, be sure to order series resonant with desired temperature coefficient.

Pulse generator with variable duty cycle:

A pulse generator with variable duty cycle can be obtained by creating two separated paths for C1 charge and

discharge into the basic square wave generator. One path, through R2 and D2 will charge the capacitor and set the

pulse width (t1). The other path, R1 and D1 will discharge the capacitor and set the time between pulses (t2).

Varying resistor R1, R2 can alter the time between pulses and the pulse width. Both controls also change the

frequency of the generator.

The pulse width and time between pulses can be found from:

)

-t

max

Rise time

)

-t

max

Fall time

Where

max

And

max

then

t2 is then given by:

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