Preliminary
5
Typical Applications
• Digital and Spread-Spectrum Systems
• GMSK, QPSK, DQPSK, QAM Modulation
• Private Mobile Radio and TETRA systems
• AM, SSB, DSB Modulation
• Image-Reject Upconverters
RF2485
VHF QUADRATURE MODULATOR
Product Description
The RF2485 is a monolithic integrated universal modula-
tion system capable of generating modulated AM, PM, or
compound carriers in the VHF and UHF frequency range.
The IC contains all of the required components to imple-
ment the modulation function including differential amplifi-
ers for the baseband inputs, a 90° hybrid phase splitter,
limiting LO amplifiers, two balanced mixers, a combining
amplifier, and an output RF amplifier which will drive a
50Ω load. Component matching, which can only be
accomplished with monolithic construction, is used to full
advantage to obtain excellent amplitude balance and high
phase accuracy. The unit features low power consump-
tion, single power supply operation and adjustment free
operation with no external parts required to operate the
part as specified.
Optimum Technology Matching® Applied
Si BJT
Si Bi-CMOS
GaAs HBT
SiGe HBT
Si CMOS
0.156
0.148
.018
.014
0.010
0.004
5
MODULATORS AND
UPCONVERTERS
0.347
0.339
0.050
0.252
0.236
0.059
0.057
8° MAX
0° MIN
0.0500
0.0164
0.010
0.007
ü
GaAs MESFET
Package Style: SOIC-14
Features
• Single 5V Power Supply
• Low Power
• Excellent Amplitude and Phase Balance
• Extremely Low Broadband Noise Floor
• 200MHz to 600MHz Operation
VDD2 1
VDD1 2
NC 3
I SIG 4
I REF 5
Q REF 6
Q SIG 7
POWER
CONTROL
14 RF OUT
13 GND2
12 GND
11 GND
10 GND1
+45°
-45°
Σ
9 PHASE
8 LO IN
Ordering Information
RF2485
RF2485 PCBA
VHF Quadrature Modulator
Fully Assembled Evaluation Board
Functional Block Diagram
RF Micro Devices, Inc.
7625 Thorndike Road
Greensboro, NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Rev A3 010820
5-55
RFMD [ RF MICRO DEVICES ]
