CD4440CS datasheet(3/20 Pages) PHILIPS

3 / 20 page

1996 Dec 20

Philips Semiconductors

Product speciﬁcation

Analog voice scrambler/descrambler

PCD4440T

FEATURES

• Scrambler or descrambler function

• Scrambling in frequency domain

• Selectable split frequency (up to 10 selections per

second)

• Telephony-band filtering included

• No increase in bandwidth

• No external components required

• Small signal delay

• Insensitive to distortion and group delay of transmission

channel

• Control via serial I2C-bus

• Low transfer loss of speech

• Mute option

• Transparent mode

• High signal input impedance

• Low signal output impedance

• Low power consumption.

APPLICATIONS

• Cordless telephones

• Security telephones

• Portable phones

• Private Mobile Radio (PMR).

GENERAL DESCRIPTION

The PCD4440T is a silicon gate CMOS integrated circuit

intended to be used in cordless telephony, radio, and line

telecommunications products utilizing a microcontroller for

the control functions. The purpose of the device is to

prevent unauthorized ‘listening-in’ on conversations.

A major application is protection of the vulnerable radio link

between a CT0 type cordless handset and its base unit.

Analog scrambling/descrambling is based on the split

frequency method realized in a sophisticated

switched-capacitor technology. The PCD4440T is

compatible with most microcontrollers and communicates

via a two line bidirectional I2C-bus.

ORDERING INFORMATION

TYPE

NUMBER

PACKAGE

NAME

DESCRIPTION

VERSION

PCD4440T

SO8

plastic small outline package; 8 leads; body width 7.5 mm

SOT176-1

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