Philips Semiconductors
Speech and handsfree IC
Product specification
TEA1098A
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
• DTMF input with confidence tone on earphone and/or
loudspeaker
• Earphone amplifier for dynamic, magnetic or
piezo-electric earpieces (with externally adjustable gain)
• Digital volume control on earphone amplifier (4 steps)
• Automatic Gain Control (AGC) for true line loss
compensation
• Microphone mute
• Key tone mode.
Supplies
• Provides a strong 3.35 V regulated supply for
microcontroller or dialler
• Provides filtered power supply, optimized according to
line current
• Filtered 2.0 V power supply output for electret
microphone
• PD logic input for power-down.
• Dynamic limiter on loudspeaker amplifier to prevent
distortion
• Digital volume control on loudspeaker amplifier (8 steps)
• 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).
APPLICATIONS
• Line powered telephone sets.
GENERAL DESCRIPTION
The TEA1098A is an analog bipolar circuit dedicated for
telephony applications. It includes a line interface, handset
(HS) microphone and earpiece amplifiers, handsfree (HF)
microphone and loudspeaker amplifiers and a duplex
controller with signal and noise monitors on both channels.
Digital volume control is available both on earphone and
loudspeaker amplifiers.
This IC provides a 3.35 V strong supply for a
microcontroller and a 2.0 V filtered voltage supply for an
electret microphone.
Handsfree
• Asymmetrical high input impedance for electret
microphone
• Loudspeaker amplifier with single-ended rail-to-rail
output and externally adjustable gain
ORDERING INFORMATION
TYPE NUMBER
TEA1098ATV
TEA1098AUH
NAME
VSO40
−
PACKAGE
DESCRIPTION
plastic very small outline package; 40 leads
bare die; on foil
VERSION
SOT158-1
−
2000 Aug 18
2