D

Description

_________________

The MSCBT IC is a CMOS chip that has the ana-

log signal processing functions required by cellular

phones and radio and other full duplex and half

duplex devices.

The MSCBT integrated circuit allows bi-directional

transmit and receive gain volume and filtering for

the voice band. In addition, the MSCBT provides

the

filter needed for Continuous Tone Control

Squelch System (CTCSS) and Continuous Digital

Control Squelch

System (CDCSS)

generation

and

detection.

A comparator in the MSCBT allows for

the recovered squelch or DTMF tones

to be

applied to a microcontroller for decoding.

An internal highpass filter attenuates the tones from

the voice band, by 50 dB, preventing voice

from

effecting tone transmission.

A limiter increases the

voice signals to be transmitted to 2Vpp for more

effective modulation.

The transmit output is fil-

tered to a selectable 2.55 or 3kHz bandwidth

before gain adjusts.

A differential output is pro-

vided for interface with a variety of FM transmitter

choices.

The MSCBT will operate from 3.3 V to 5.5 VDC.

The MSCBT is available in a 32 pin 7x7mm LQFP.

FFeatures ___________________________

Function down to 3.3 VDC

Low Power Consumption

50 CTCSS Squelch Tones filtered

CDCSS Code filter

Programmable filter for pre-detection filtering

Comparator for direct uP interface of detected signals

Family Radio Service (FRS) 2-way Radio

Land Mobile Radio (LMR) 2 way Radios

General Mobile Radio Service (GMRS) 2 way Radios

Low Power Radio Service (LPRS) 2 way Cellular

Non-standard Voice-band communications

Wired and Wireless Intercom

Half-Duplex Speakerphone Analog Signal Processing

Full-Duplex Speakerphone Analog Signal Processing

Absolute M

Maximum R

Ratings______

Power Supply Voltage

+6v

Storage Temperature

-60 to +150

°C

Operating Temperature

-20 to +85

°C

10/2014

Communications Baseband Transceiver

Data Sheet

www.mix-sig.com

©

2014 Mixed Signal Integration

1

RXIN

67 Hz to 500 Hz

CxCSS Tone

TXTone

CTCSS/CDCSS TONE

FILTER

GAIN

RXTIN+

COUT

RXTIN-

TONEIN

OUT-

MICIN

OUT+

RXIN

VOUT

DA2O

ADIN

DA1O

VDDD

VDDA

AGND

BYPASS

DGND

VSS

X1

X2

RECEIVED SIGNAL SIGNAL

PROCESSING

SERIAL

CONTROL INTERFACE

TRANSMIT SIGNAL PROCESSING

8-BIT A-to-D

CONVERTER

8-BIT D-to-A

CONVERTER

8-BIT D-to-A

CONVERTER

Figure 1: MSCBT Block Diagram