Intersil Corporation HC-55536 Datasheet

March 1993

Low Bit Rate Voiceband Encoders/Decoders

Semiconductor

HC-55536

Continuously Variable Slope

Delta-Demodulator (CVSD)

Features

• All Digital

• Requires Few External Parts

• Low Power Drain: 1.5mW from Single 3V to 6V Supply

• Time Constants Determined by Clock Frequency; No
Calibration or Drift Problems; Automatic Offset
Adjustment

• Filter Reset by Digital Control

• Automatic Overload Recovery

• Automatic “Quiet” Pattern Generation

Applications

• Voice Decoder for Digital Systems and Speech
Syntheses

• Voicemail

• Audio Manipulations; Delay Lines, Echo Generation/
Suppression, Special Effects, etc.

• Pagers/Satellites

NO

FOR NEW DESIGNS

T RECOMMENDED

Description

The HC-55536 is a CMOS integrated circuit used to convert
serial NRZ digital data to an analog (voice) signal. Conver­sion is by delta demodulation, using the Continuously
Variable Slope (CVSD) method of demodulation.

While signals are compatible with other CVSD circuits, the
internal design is unique. The analog loop filters have been
replaced by digital filters which use very low power and
require no external timing components. This digital approach
allows inclusion of many desirable features, which otherwise
would be difficult to implement. The device is usable from
9Kbits/s to above 64kbits/s, and may be easily configured
with the HC-55564 CVSD for a complete transmit/receive
voice channel.

Ordering Information

PART

NUMBER

HC1-55536-5 0 to 75 14 Ld CERDIP
HC1-55536-9 -40 to 85 14 Ld CERDIP
HC3-55536-5 0 to 75 14 Ld PDIP
HC3-55536-9 -40 to 85 14 Ld PDIP

TEMP.

RANGE (oC) PACKAGE PKG. NO.

Pinout

VDD

NC

AOUT

NC
NC
NC
NC

HC-55536

(PDIP, CERDIP)

TOP VIEW

1
2
3
4
5
6
7

14

NC
FZ

13
12

DIGITAL INPUT

11

NC

10

NC

9

CLOCK

8

DIGITAL GND

Functional Diagram

(13)

FORCE ZERO

(12)

DIGITAL IN

3 BIT

SHIFT

REGISTER

A

OUT

(3)

Z

O

CLOCK

(9)

SYLLABIC

166

DIGITAL

FILTER

4.0msec

V

DD

(1)

10

DIGITAL GND

10 BIT

DAC

DIGITAL

MODULATOR

+1

SIGNAL

ESTIMATE

DIGITAL FILTER

1.0msec

(8)

CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright

© Harris Corporation 1997

4-252

File Number 2888.1