L3281

L3281 LOW VOLTAGE TELEPHONE SPEECH CIRCUITS PRELIMINARY DATA OPERATION DOWN TO 1.6V / 6.5mA DTMF & BEEP TONE INPUTS EXTERNAL MUTING FOR EARPHONE AND MICROPHONE SUITABLE FOR DYNAMIC EARPHONE AND DYNAMIC OR ELECTRET MICROPHONE AGC CONTROL ON BOTH SENDING AND RECEIVING DIP14 SO14 DESCRIPTION The L3281 is an electronic speech circuit developed to replace hybrid circuits in telephone sets that can be operated in parallel with other phones. BLOCK DIAGRAM ORDERING NUMBERS: L3281AB L3281AD1 June 1993 1/10 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. L3281 PIN CONNECTION (top view) ABSOLUTE MAXIMUM RATINGS Symbol VL IL Ptot Top Tj Parameter Line Voltage (3 ms pulse) Line Current Total Power Dissipation, Tamb = 55°C Operating Temperature Junction Temperature 1.0 – 20 to 55 – 65 to 150 Value DIP-14 15 150 0.6 SO-14 Unit V mA W °C °C THERMAL DATA Symbol Rth j-amb Parameter Thermal Resistance Junction Ambient Max Value DIP-14 90 SO-14 130 Unit °C/W 2/10 L3281 TEST CIRCUITS Figure 1. Figure 2. Figure 3. 3/10 L3281 ELECTRICAL CHARACTERISTICS IL = 20 to 100mA; R4 =( 51Ω // diode) + 33Ω; T = 25°C; f = 1kHz; Unless Otherwise Specified Symbol Vl Parameter Line Voltage IL IL IL IL Test Condition = 6.5mA = 20mA = 50mA = 80mA 50 Vmi = 10mV; IL = 20mA Vmi = 10mV; IL = 70mA Vso = 700mV; IL = 20mA Vmi = 0V; IL = 50mA Vmi = 10mV IL = 20mA; Vri = 0.2V IL = 70mA; Vri = 0.2V Vro = 350mV; Load = 35...