U4089B-P

• DC Characteristic Adjustable
• Transmit and Receive Gain Adjustable
• Symmetrical Input of Microphone Amplifier
• Anti-clipping in Transmit Direction
• Automatic Line-loss Compensation
• Built-in Ear Protection
• DTMF and MUTE Input
• Adjustable Sidetone Suppression Independent of Sending and Receiving Amplification
• Integrated Amplifier for Loudhearing Operation
• Anti-clipping for Loudspeaker Amplifier
• Improved Acoustical Feedback Suppression
• Selectable Line Impedance
• Voice Switch
• Supply Voltages for All Functional Blocks of a Subscriber Set
• Operation Possible from 10-mA Line Current
• Filters Against EMI on Critical I/O

The telephone circuit U4089B-P is a linear integrated circuit for use in feature phones, answering machines and fax machines. It contains the speech circuit, sidetone equivalent and ear protection rectifiers. The U4089B-P is line-powered and contains all components necessary for the amplification of signals and adaptation to the line.

An integrated voice switch with loudspeaker amplifier enables loudhearing or handsfreeoperation. With an anti-feedback function, acoustical feedback during loudhearing can be reduced significantly. The generated supply voltage of U4089B-P is suitable for awide range of peripheral circuits.