GENERAL DESCRIPTION
The TEA1099H is an analog bipolar circuit dedicated for telephone applications. It includes a line interface, handset (HS) microphone and earpiece amplifiers, handsfree (HF) microphone and loudspeaker amplifiers, some specific auxiliary Inputs/Outputs (I/Os) and an analog multiplexer to enable the right transmit and/or receive channels.

FEATURES
Line interface
• Low DC line voltage
• Voltage regulator with adjustable DC voltage
• Symmetrical high impedance inputs (70 kΩ) for dynamic, magnetic or electret microphones
• Dual Tone Multi-Frequency (DTMF) input with confidence tone on earphone and/or loudspeaker
• Receive amplifier for dynamic, magnetic or piezo-electric earpieces (with externally adjustable gain)
• AGC: Automatic Gain Control for true line loss compensation.

Supplies
• Provides a strong 3.35 V regulated supply for
microcontroller or dialler
• Provides filtered power supply, optimized according to
line current and compatible with external voltage or
current sources
• Filtered 2.0 V power supply output for electret
microphone
• Compatible with a ringer mode
• Power-Down (PD) logic input for power-down.

Handsfree
• Asymmetrical high-impedance input for electret microphone
• Loudspeaker amplifier with single-ended rail-to-rail output and externally adjustable gain
• Dynamic limiter on loudspeaker amplifier to prevent distortion
• Logarithmic volume control on loudspeaker amplifier via linear potentiometer
• Duplex controller consisting of:
    – Signal and noise envelope monitors for both channels (with adjustable sensitivities and timing)
    – Decision logic (with adjustable switch-over and Idle mode timing)
    – Voice switch control (with adjustable switching range and constant sum of gain during switching).

Auxiliary interfaces
• General auxiliary output for transmit and receive purposes
• Auxiliary transmit input with high signal level capability dedicated to line transmission
• Auxiliary receive input with high signal level capability
• Integrated multiplexer for channels selection.

APPLICATIONS
• Line powered telephone sets
• Cordless telephones
• Fax machines
• Answering machines.