Datasheet

UNISONIC TECHNOLOGIES CO., LTD
LS1240A
LINEAR INTEGRATED CIRCUIT
ELECTRONIC TONE RINGER
WITH BUILT-IN BRIDGE
RECTIFIER

DESCRIPTION
The UTC LS1240A is monolithic integrated circuits and designed
to be as a telephone ringer. It can drive a piezo-ceramic
converter(buzzer) directly. The output current capacity of UTC
LS1240A is higher than standard ringer. For driving a dynamic
loudspeaker, UTC LS1240A needs only a decoupling capacitor to
replace the usual transformer in use.

FEATURES
* Low current consumption.
* Integrated rectifier bridge with zener diodes to overvoltage
Protection.
* Minimum external circuitry.
* Both frequencies of tone and switching are adjustable by external
components.
* Integrated voltage and current hysteresis.

ORDERING INFORMATION
Ordering Number
Lead Free
Halogen Free
LS1240AL-D08-T
LS1240AG-D08-T
LS1240AG-S08-R

Package
Packing
DIP-8
SOP-8
Tube
Tape Reel
MARKING
DIP-8
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Copyright © 2015 Unisonic Technologies Co., Ltd
SOP-8
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LS1240A

LINEAR INTEGRATED CIRCUIT
PIN CONFIGURATION
LINE
1
GND
2
8
LINE
7
Cr
UTC
LS1240A

CSW
3
6
NULL
Ra
4
5
OUT
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
7
8
PIN NAME
LINE
GND
Csw
Ra
OUT
NULL
Cr
LINE
DESCRIPTION
Connecting pin to B-wire
Ground
Sweep rate control capacitor
Output frequency control resistor
Buzzer
Not connected
Rectifier capacitor
Connecting pin to A-wire
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www.unisonic.com.tw
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QW-R108-002.J
LS1240A

LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
TELEPHONE
LINE
GND
SWEEP RATE
CONTROL CAPACITOR
1
IN
8
IN
7
2
3
4
OUTPUT FREQYENCY
CONTROL RESISTOR

RECTIFIER
BRIDGE
SWITCHING
FREQUENCY
GENERATOR
NONE
FREQUENCY
GENERATOR
THRESHOLD
CIRCUIT
WITH
HYSTERESIS
OUTPUT
STAGE
6
5
TELEPHONE
LINE
RECTIFIER
CAPACITOR
N.C.
BUZZER
TEST CIRCUIT
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LS1240A

LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIUM RATINGS
PARAMETER
SYMBOL
RATINGS
UNIT
Calling Voltage (f=50Hz) Continuous
VAB
120
VRMS
Calling Voltage (f=50Hz) (5s ON/10s OFF)
VAB
200
VRMS
Supply Current
IDC
30
mA
Operating Temperature
TOPR
-40 ~ +70
C
Storage Temperature
TSTG
-65 ~ +150
C
Note Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.

THERMAL DATA
PARAMETER
Junction to Ambient

SYMBOL
SOP-8
DIP-8
RATINGS
150
100
JA
UNIT
℃/W
ELECTRICAL CHARACTERISTICS (TA= 25℃, unless otherwise specified)
PARAMETER
Supply Voltage
Current Consumption without load
Activation Voltage
Sustaining Voltage
Differential Resistance in OFF Condition
Output Voltage Swing
Short Circuit Current
AC OPERATION
Output Frequencies (Vs=26V,R1=14k)
SYMBOL
VS
IB
VON
VOFF
RD
VOUT
IOUT
fOUT1
fOUT2
Fout1/Fout2
Programming Resistor Range
Sweep Frequency
UNISONIC TECHNOLOGIES CO., LTD
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TEST CONDITIONS
MIN
VS=9.3 to 25V
TYP
1.5
12
7.8
6.4
VS-5
70
VS=20V, RL=250
V3=0V
V3=6V
C1=100nF,R1=14k
1.55
1.08
1.33
8
5.25
7.5
MAX UNIT
26
V
1.8
mA
13.5
V
9.3
V
k
V
mA
2.53
1.9
1.43
56
9.75
kHz
k
Hz
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LS1240A

LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT
No current limitation is provided on the output stage of UTC LS1240A, so a minimum load DC of 50 ohms is
advised.
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 line or variations of the ringing signal cannot
affect correct operation of the device.
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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www.unisonic.com.tw
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