LS1240AD1 [Wing Shing]
Electronic Two-Tone Ringer; 电子双音振铃
| 型号： | LS1240AD1 |
| 厂家： | 
WING SHING COMPUTER COMPONENTS |
| 描述： | Electronic Two-Tone Ringer |
| 文件： | 总4页 (文件大小：294K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LS1240A
Electronic Two-Tone Ringer
.
LOW CURRENT CONSUMPTION, IN ORDER
TO ALLOW THE PARALLEL OPERATION OF 4
DEVICES
INTEGRATED RECTIFIER BRIDGE WITH
ZENER DIODES TO PROTECT AGAINST
OVERVOLTAGES
.
.
.
LITTLE EXTERNAL CIRCUITRY
TONE AND SWITCHING FREQUENCIES AD-
JUSTABLE BY EXTERNAL COMPONENTS
INTEGRATED VOLTAGE AND CURRENT
HYSTERESIS
Minidip
.
DESCRIPTION
LS1240A is a monolithic integrated circuit designed
to replace the mechanical bell in telephone sets in
connection with an electro-acoustical converter. It
can drive directly a piezoceramic converter (buzz-
er)or a dynamic loudspeaker.
SO8
The output current capability of LS1240A is higher
than standard ringer. For driving a dynamic loud-
speaker LS1240A can simply use a decoupling ca-
pacitor, thus eliminating the usual transformer.
ORDERING NUMBERS
No current limitation is provided on the output stage
of LS1240A, so a minimum load DC of 50 Ω is ad-
viced, in series with a proper capacitor.
Minidip
SO8
LS1240A
LS1240AD1
The two tone frequencies generated are switched
by an internal oscillator in a fastsequence and made
audible across an output amplifier in the loud-
speaker, both tone frequencies and the switching
frequency can be externally adjusted.
The supply voltage is obtained from the AC ring sig-
nal and the circuit is designed so that noise on the
line or variations of the ringing signal cannot affect
correct operation of the device.
PIN CONNECTION (top view)
Wing Shing Computer Components Co., (H.K.)Ltd.
Homepage: http://www.wingshing.com
Tel:(852)2341 9276 Fax:(852)2797 8153
E-mail: wsccltd@hkstar.com
LS1240A
WS
BLOCK DIAGRAM
Figure 1 : Test Circuit.
2.72 104
R1 =
f1
1943
750
C1 (nF)
1 − 0.04 ln
f2 = 0.725 f1
fSWEEP =
(
)
f1 (Hz)
WS
LS1240A
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
120
200
30
Unit
Vrms
Vrms
mA
°C
VAB
VAB
DC
Top
Tstg
Calling Voltage (f = 50 Hz) Continuous
Calling Voltage (f = 50 Hz) 5s ON/10s OFF
Supply Current
Operating Temperature
– 0 to + 70
2
Storage and Junction Temperature
– 65 to + 150
°C
THERMAL DATA
Symbol
Parameter
Value
Unit
Rth j-amb
Thermal Resistance Junction-ambient
Max
00
2
°C/W
ELECTRICAL CHARACTERISTICS
(Tamb = 25 °C; Vs = applied between pins 7-2 unless otherwise specified)
Symbol
Vs
Parameter
Test Conditions
Min. Typ. Max. Unit
Supply Voltage
26
1.8
V
IB
Current Consumption without Load (pins 8-1)
Activation Voltage
V8-1 = 9.3 to 25 V
1.5
mA
VON
VOFF
RD
13.5
9.3
12
V
V
Sustaining Voltage
7.8
Differential Resistance in OFF Condition (pins 8-1)
Output Voltage Swing
6.4
kΩ
V
VOUT
IOUT
Vs – 5
70
Short Circuit Current (pins 5-2)
mA
Vs = 20V RL = 250Ω
AC OPERATION
Output Frequencies
kHz
Vs = 26V, R1 = 14kΩ
Vs = 0 V
Vs = 6V
1.55
1.08
f1
f2
fout1
2.53
1.9
fout2
fOUT1
fOUT2
1.33
1.43
Programming Resistor Range
Sweep Frequency
8
56
kΩ
fSWEEP
5.25
7.5
9.75
Hz
R1 = 14kΩ, C1 = 100nF
WS
LS1240A
Figure 2 : Typical Application with BUZZER
Figure 3 : Typical Application with Loudspeaker (no transformer needed)
C1 such that ZLOAD > 1 ΚΩ
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