LS1240A ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).ABSOLUTE MAXIMUM RATINGSSymbol Parameter Value UnitV Calling Voltage (f = 50 Hz) Continuous 120 VAB ..
LS1240A ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).BLOCK DIAGRAMFigure 1 : Test Circuit.42.72 ⋅ 10 f1 750R1 = ⋅ 1 - 0.04 ln f2 = 0.725 ..
LS1240A ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).ABSOLUTE MAXIMUM RATINGSSymbol Parameter Value UnitV Calling Voltage (f = 50 Hz) Continuous 120 VAB ..
LS1240A ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).BLOCK DIAGRAMFigure 1 : Test Circuit.42.72 ⋅ 10 f1 750R1 = ⋅ 1 - 0.04 ln f2 = 0.725 ..
LS1240A ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).BLOCK DIAGRAMFigure 1 : Test Circuit.42.72 ⋅ 10 f1 750R1 = ⋅ 1 - 0.04 ln f2 = 0.725 ..
LS1240A+ ,Electronic tone ringer with built-in bridge rectifier. Supply voltage Vs=26V. Current consumption without load Ib=1.5A(typ). Activation voltage Von=12V(min),13.5V(max). Sustaining voltage Voff=7.8V(min),9.3V(max).ABSOLUTE MAXIMUM RATINGSSymbol Parameter Value UnitV Calling Voltage (f = 50 Hz) Continuous 120 VAB ..
LT1620 ,Rail-to-Rail Current Sense Amplifier
LT1620CGN#PBF ,Rail-to-Rail Current Sense Amplifier
LT1620IS8 ,Rail-to-Rail Current Sense Amplifier
LT1620IS8 ,Rail-to-Rail Current Sense Amplifier
LT1620IS8#PBF ,Rail-to-Rail Current Sense Amplifier
LT1627 , Micropower Low Dropout Regulators with Shutdown
LS1240A-LS1240A+-LS1240AD1
ELECTRONIC TWO-TONE RINGER
LS1240AJuly 1998
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
DESCRIPTIONLS1240A 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.
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.
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.
The two tone frequencies generated are switched
by an internal oscillator in a fast sequence 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.
ORDERING NUMBERS
PIN CONNECTION (top view)1/7
Figure 1 : Test Circuit.
BLOCK DIAGRAM
LS1240A2/7
ABSOLUTE MAXIMUM RATINGS
THERMAL DATA
ELECTRICAL CHARACTERISTICS
(Tamb = 25 °C; Vs = applied between pins 7-2 unless otherwise specified)AC OPERATION
LS1240A3/7
Figure 2 : Typical Application with BUZZER
Figure 3 : Typical Application with Loudspeaker (no transformer needed)
LS1240A4/7
MINIDIP PACKAGE MECHANICAL DATA
LS1240A5/7
SO8 PACKAGE MECHANICAL DATA
LS1240A6/7
