UTC1240A
DESCRIPTION
LINEAR INTEGRATED CIRCUIT
ELECTRONIC DUAL-TONE RINGER
The UTC1240A are monolithic integrated circuits designed
to replace the mechanical bell in telephone sets in connection
with an electro-acoustical converter.Both devices can drive
directly a piezoceramic converter (buzzer).
The output of UTC1240A needs a decoupling capacitor.
No current limitation is provided on the output stage of
UTC1240A,so a minimum load DC of 50 ohms is adviced.
The two tone frequencies generated are switched by an
internal oscillator in a fast sequence and made audible across
an output amplifier in the loudspeaker,both tone frequencies
and the switching frequency can be externally adjusted.The
signal and the circuit is designed so that noise on the lin or
variations of the ringing signal cannot affect correct operation
of the device.
DIP-8
SOP-8
FEATURES
* Low current consumption,in order to allow the parallel
operation of 4 devices.
* Integrated rectifier bridge with zener diodes to protect
against overvoltage.
* Little external circuitry.
* Tone and switching frequencies adjustable
by external components.
* Intergrated voltage and current hysteresis
TEST CIRCUIT
VAB
7
YOUWANG ELECTRONICS CO.LTD
1
)Ω
f1=
27200
R1(k
f2=0.725f1
750
f (
SWEEP
)= C1(nF)
Ω
μ
10
F
1
Ω
8
5
μ
1
F
2.2k
UTC1240A
RL
Vout
2
3
4
C1
100nF
R1
14k
2005.08.25 V1.1
UTC-IC [ UNISONIC TECHNOLOGIES ]
