Philips Semiconductors
Speech and handsfree IC with auxiliary
inputs/outputs and analog multiplexer
Product specification
TEA1099H
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.
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.
The multiplexer is controlled by a logic circuit which
decodes four logic inputs provided by a microcontroller.
Thirteen different application modes have been defined
and can be accessed by selecting the right logic inputs.
An application mode is a special combination of transmit
and receive channels required by telephone applications.
This IC can be supplied by the line and/or by the mains if
available (in a cordless telephone or an answering
machine for example). It provides a 3.35 V supply for a
microcontroller or dialler and a 2.0 V filtered voltage supply
for an electret microphone. The IC is designed to facilitate
the use of the loudspeaker amplifier during ringing phase.
1999 Apr 08
2