
Semiconductor
MSM7584C
1/57
p
/4 Shift QPSK MODEM/ADPCM CODEC
GENERAL DESCRIPTION
The MSM7584C is a CMOS IC developed for use with digital cordless telephones. The device
provides a
p
/4 shift QPSK modem function and a CODEC function which performs transcoding
between the voice band analog signal and 32 kbps ADPCM data.
The MSM7584C is ideal for use in a handset of the PHS (Personal Handyphone System).
FEATURES
(
p
/4 Shift QPSK Modem)
Built-in root Nyquist filter (
a
(rolloff rate) = 0.5) for the baseband limiter
Differential I and Q analog outputs
The DC offset and gain can be adjusted with respect to the differential I and Q analog outputs
Completely digitized
p
/4 shift QPSK demodulator system
Input IF signal frequency of 1.2 MHz or 10.8 MHz is available.
Built-in A/D converter for RSSI detection
(ADPCM CODEC)
ADPCM : ITU-T Recommendations G.721 (32 kbps)
Transmit/receive full duplex capability
PCM interface code format: selectable between
m
-law and A-law
Built-in transmit/receive mute function and transmit/receive programmable gain setting
function
Side tone path formation and level adjustment capabilities
Built-in DTMF tone and other tones
Built-in VOX function
Built-in speech recording/playing interface
Built-in 150
W
driving OP AMP
Built-in various analog switches
(Common)
Single 3V power supply (V
DD
: 2.7 V to 3.6 V)
Mode setting through serial interface
Low power consumption
When the modem unit is operating :
When the ADPCM CODEC unit is operating :
When in the power down mode :
Package:
80-pin plastic TQFP
13 mA Typ. (V
DD
= 3.0 V)
7 mA Typ. (V
DD
= 3.0 V)
0.03 mA Typ. (V
DD
= 3.0 V)
(TQFP80-P-1212-0.50-K) (Product name : MSM7584CTS-K)
E2U0046-16-X2
This version: Jan. 1998
Previous version: Nov. 1996