LS1240A_V01 STMICROELECTRONICS | Alldatasheet

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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

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. 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. SO8 Minidip ORDERING NUMBERS Minidip SO8 LS1240A LS1240AD1 PIN CONNECTION (top view)

Figure 1 : Test Circuit. R1 = 2.72 ⋅ 104 f1 (Hz) ⋅ (1 − 0.04 ln f1 1943) f2 = 0.725 f1 fSWEEP = 750 C1 (nF) BLOCK DIAGRAM LS1240A

Symbol Parameter Value Unit VAB Calling Voltage (f = 50 Hz) Continuous 120 V rms VAB Calling Voltage (f = 50 Hz) 5s ON/10s OFF 200 V rms DC Supply Current 30 mA Top Operating Temperature – 40 to + 70 °C Tstg Storage and Junction Temperature – 65 to + 150 °C THERMAL DATA Symbol Parameter Value Unit R th j-amb Thermal Resistance Junction-ambient Max 100 °C/W

ELECTRICAL CHARACTERISTICS

(Tamb = 25 °C; Vs = applied between pins 7-2 unless otherwise specified) Symbol Parameter Test Conditions Min. Typ. Max. Unit Vs Supply Voltage 26 V IB Current Consumption without Load (pins 8-1) V8-1 = 9.3 to 25 V 1.5 1.8 mA VON Activation Voltage 12.2 13.2 V VOFF Sustaining Voltage 8 9 V R D Differential Resistance in OFF Condition (pins 8-1) 6.4 kΩ VOUT Output Voltage Swing V s – 5 V IOUT Short Circuit Current (pins 5-2) Vs = 20V R L = 250Ω 70 mA AC OPERATION Output Frequencies fout1 fout2 Vs = 26V, R1 = 14kΩ Vs = 0 V Vs = 6V 1.74 1.22 2.14 1.6 kHz fOUT1 fOUT2 1.33 1.43 Programming Resistor Range 8 56 kΩ fSWEEP Sweep Frequency R 1 = 14kΩ , C1 = 100nF 5.25 7.5 9.75 Hz LS1240A

MINIDIP PACKAGE MECHANICAL DATA DIM. mm inch A 3.32 0.131 a1 0.51 0.020 B 1.15 1.65 0.045 0.065 b 0.356 0.55 0.014 0.022 b1 0.204 0.304 0.008 0.012 D 10.92 0.430 E 7.95 9.75 0.313 0.384 e 2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 F 6.6 0.260 I 5.08 0.200 L 3.18 3.81 0.125 0.150 Z 1.52 0.060 LS1240A

SO8 PACKAGE MECHANICAL DATA DIM. mm inch A 1.75 0.069 a1 0.1 0.25 0.004 0.010 a2 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 c1 45° (typ.) D (1) 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F (1) 3.8 4.0 0.15 0.157 L 0.4 1.27 0.016 0.050 M 0.6 0.024 S 8° (max.) LS1240A

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