Overview
The LA8519M is a cordless telephone base unit IC that provides I/O switching, voice signal processing, and other functions. It integrates, on a single chip, crosspoint switch, power amplifier, electronic volume and tone control, microphone amplifier, speech network, and other functions.

Functions
• Speech network block
 — Impedance matching, 2-wire/4-wire converter, line driver, BN circuit network switching circuit, transmitter amplifier, BTL receiver amplifier, DTMF input, key tone input, receiver volume level switching, and power supply switching circuit.
• Audio signal-processing block
 — Power amplifier, electronic volume and tone control, preamplifier with ALC, voice level detection (VOX), beep tone input, ring tone (OSC) input, ring tone level switching, line volume level switching, microphone amplifier, crosspoint switch (10 × 9 point equivalent), and serial interface.

FEATUREs
• Allows switching between two anti-sidetone networks (near terminal/far terminal) depending on the line current, and thus achieves excellent sidetone characteristics over a wide range of line currents.
• Built-in transmitter/receiver amplifier driver power supply switching circuit allows communication using extension without power from the telephone network. • The receiver amplifier supports both ceramic receivers (BTL) and dynamic receiver (single).
• Built-in power amplifier (load: 8 to 32 Ω): VCC = 5 V, RL = 8 Ω, Pomax = 200 mW
• The power amplifier signal path includes an electronic volume control (7 steps of about 3.8 dB each)
• Includes a 10-input/9-output crosspoint switch that provides mixing functions for easy implementation of systems that support a diverse range of signal path switching functions.