MGCT04
Transmit Circuit for TDMA/AMPS and CDMA/AMPS
Preliminary Information
Features
•
•
•
•
•
•
Dual RF Ports for 900MHz and 1900MHz
AGC Amplifier with 90dB of Variable Gain, Fully
Compensated for Temperature
On-chip Active Filter. Removes the
Requirement for External IF SAW Filter
High Power 900MHz and 1900MHz Output
Stages
Quadrature Modulator
Small Scale MLF Package
DS5424
ISSUE 1.1
March 2001
Ordering Information
MGCT04/KG/LH1S
MGCT04/KG/LH1T
Applications
•
•
Transmit Modulator and Up-converter in TDMA/
AMPS Mobile Phones
Transmit Up-converter in CDMA/AMPS Mobile
Phones
mobile phones. It can be used for both TDMA/AMPS
or CDMA/AMPS systems. The MGCT04 is
compatible with baseband and mixed signal interface
circuits from Zarlink Semiconductor and other
manufacturers.
System costs have been kept to a minimum by
removing the requirement for an additional SAW filter
in the transmit IF path. The AGC has been split
between RF and IF sections to reduce noise and a
low pass filter has been included before the IF
variable gain amplifier to remove spurious products
produced in the modulator.
The MGCT04 circuit is designed for use in dual
band, dual mode cellular 900MHz/PCS1900MHz
CP2
8
CP1
23
CP0
5
LO 2GHz
19
UHF
OSCILLATOR
INPUT SELECT
LO 1GHz
21
CONTROL LOGIC
1900 MHz
OUTPUT DRIVER
Q IN
Q IN
13
14
27
26
POWER CONTROL
RF190
RF190
RFDEG1
RFDEG2
RF900
RF900
÷
2/4 AND
15
16
PHASE
SHIFT
IF VGA
ALL PASS
PHASE
SHIFT
NETWORK
RF VGA
28
1
3
2
SSB MIXER
900 MHz
OUTPUT DRIVER
I IN
I IN
DIV
7
OUT
VCO
BUFFER
÷
8
OSC
BUFFER
V
REF
9
BIAS
BUFFER
10
VGA CONTROL
22
VHF OSC IN
VHF OSC BIAS
AGC
Figure 1 - MGCT04 Block Diagram
1
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
