Dual CVSD/PLL Cordless Phone System

The MC33410 Dual CVSD/Cordless Phone system is designed to fit the requirements of a 900 MHz digital cordless telephone system. The device contains a CVSD (Continuously Variable Slope Delta Modulator/Demodulator) Encoder to digitize the speech for the RF transmission, and a CVSD Decoder to reconstruct the received digital speech from the RF receiver. Provisions are made to transmit and receive data as well. Included are three PLLs (Phase–Locked Loops). Two are intended for use with external VCOs and 64/65 or 128/129 dual modulus prescalers, and can control the transmit and receive (LO1) frequencies for the 900 MHz communication. The third PLL is configured as the 2nd local oscillator (LO2), and is functional to 80 MHz. Also included are muting, audio gain adjust (internal and external), low battery/carrier detect, and a wide range for the PLL reference frequency. The power supply range is 2.7 to 5.5 V. A data only (non–voice) mode is also included.

• Two Complete CVSD Sections for Full Duplex Operation

• Two PLLs and an LO Suitable for a 900 MHz System

• Adjustable Detection for Low Battery or Carrier Signal (RSSI)

• Minimal External Components

• Encode Path Includes Adjustable Gain Amplifiers, Filters, Mute, CVSD

Encoder, Data Insert, and Scrambler

• Decoder Path Contains Data Slicer, Clock Recovery, Descrambler, Data

Detect, CVSD Decoder, Filters, Mute and Power Amplifier

• Data can be Transmitted During Voice Conversation with Minimal or No

Noticeable Audio Disruption

• Idle Channel Noise Control

• Independent Power Amplifier with Differential Outputs, Mute

• Selectable Frequency for Switched Capacitor Filters, CVSD Function,

PLLs, and the LO

• Reference Frequency Source can be a Crystal or System Clock

• Serial µP Port to Control Gain, Mute, Frequency Selection, Phase

Detector Gain, Power Down Modes, Idle Channel Control, Scrambler

Operation, Low Battery Detect, and Others

• Mode Available for Data Only Transmission (non–voice)

• Ambient Temperature Range: –20 to 70°C

• Power Supply Range: 2.7 to 5.5 V

• Power Down Modes for Power Conservation

• 48 Pin LQFP with 0.5 mm Lead Pitch