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Telephone Tone Ringer with
Bridge Diode
The IN2418 is a monolithic integrated circuit telephone tone ringer
with bridge diode, when coupled with an appropriate transducer, it
replaces the electro-mechanical bell. The device is designed for use
with either a piezo transducer or an inexpensive transformer coupled
speaker to produce a pleasing tone composed of a high frequency (f
alternating with a low frequency (f
The supply volt age is o bta ined from the AC r ing signa l a nd t he c ircui t
is designed so tha t noise on the line o r variation of the ringing signal
can not affect correct operation of the device.
•
On chip high voltage full wave diode bridge rectifier
•
Low current consumption, in order to allow the parallel operation
of the 4 devices
•
Low external component count
•
Tone and switching frequencies adjustable by external
components
•
High noise immunity due to built-in voltage-current hysteresis
•
Activation voltage adjustable
•
Internal zener diodes to protect against over voltages
•
Ringer impedance adjustable with external components
) resulting in a warble frequency.
L
TECHNICAL DATA
IN2418
)
R
ORDERING INFORMATION
IN2418N Plastic
TA = -20° to 70° C
for package
PIN ASSIGNMENT
BLOCK DIAGRAM
1
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IN2418
MAXIMUM RATINGS*
(TA = 25°C)
Symbol Parameter Value Unit
V
TP
V
TP
I
CC
Tstg Storage and Junction Temperature -65 to +150
*
Maximum Ratings are those values beyond which damage to the device may occur.
Calling Voltage (f = 50 Hz) Conti nuous 120 Vrms
Calling Voltage (f = 50 Hz) 5 Sec ON/10 Sec OFF 200 Vrms
Supply Current 22 mA
°
C
Functional operation should be restricted to the Recommended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Max Unit
V
CC
T
A
This device c ontains p rote ction ci rcuitr y to guard a gainst damage d ue to high st atic voltages or electr ic
fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated
voltages to this high-impedance circuit. For proper operation, V
GND≤(V
Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or V
Unused outputs must be left open.
Supply Voltage 26 V
Operating Temperature -20 +70
IN
or V
OUT
)≤VCC.
and V
IN
should be constrained to the range
OUT
°
C
CC
).
ELECTRICAL CHARACTERISTICS
(TA = 25°C)
Symbol Parameter Test Conditions
I
CC
Current Consumption without
VS=8.8 to 26 V 1.8 mA
Load
V
ON
V
ONR
V
SUS
R
Activiation Voltage 12.2 13 V
Activiation Voltage Range
R
= 1 K
A
Ω
Sustaining Voltage 8 8.8 V
Differential Resistance in Off
D
Condition
V
OUT
I
OUT
Output Voltage Swing VCC-3 V
Short Circuit Current VS = 26 V 35 mA
Guaranteed Limits
Unit
Min Typ Max
810V
6.4
Ω
K
2
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AC CHARACTERISTICS
Symbol Parameter Test Conditions
Output Frequenci es
f
H1
f
H2
f
H1
f
H2
fH1 Range
f
L
Sweep Frequency
V
= 26 V, R1 = 14 K
CC
V
= 0 V
CC
V
= 6 V
CC
R1 = 27 KΩ to 1.7 K
R
= 14 KΩ, C1 = 100 nF
1
TEST AND APPLICATION CIRCUIT
IN2418
Guaranteed Limits
Unit
Min Typ Max
Ω
2300
1700
Ω
0.1 15 KHz
10 Hz
Hz
Hz
f1 = 3.22 •104 / R1 (KΩ); f2 = 5/7 f1; f
= 1000 / C1(nF)
sweep
DESCRIPTION
The IN2418 tone ringer derives its power supply by rectifying the AC ringing signal. It uses this power to
activate two tone generators. The two tone frequencies generated are switched by 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 device can drive either directly a piezo ceramic converter (buzzer) or small loudspeaker. In case of
using a loud-speaker, a transformer is needed.
An internal shunt voltage regulator p rovides DC voltage to the outp ut stage, low frequency oscillator , and
high frequency oscillator. To protect the IC from telephone line transients, a zener Diode is included.
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