PRODUCT SUMMARY
SKY74693: Receiver for CDMA, AMPS, PCS, and GPS Mobile
Handset Applications
Applications
•
Tri-band, tri-mode handsets
•
PCS and GPS phones
•
CDMA and GPS phones
Except for the Surface Acoustic Wave (SAW) filters, a UHF Voltage
Controlled Oscillator (VCO), and matching components, the device
incorporates everything required to implement the receiver chain,
from the Low-Noise Amplifier (LNA) to the In-Phase and
Quadrature (I/Q) demodulator stages. Three LNAs are in the front-
end receiver: a three-step gain stage cellular LNA (high, mid, and
bypass), a two-step gain stage PCS LNA (high, bypass), and a
high gain stage GPS LNA.
After RF LNA signal amplification and filtering from the antenna,
the received signal is mixed down from RF to the IF. There are
separate mixers for AMPS, CDMA-cellular, CDMA-PCS, and GPS
modes. To use a single IF frequency plan, the CDMA and PCS
mixer outputs have been combined. Therefore, both CDMA and
PCS bands use the same IF SAW filter. The AMPS differential
output can be combined externally to mate to a single-ended SAW
filter. The GPS mixer is an image-reject mixer, which eliminates
the need for an external RF SAW filter between the LNA and
mixer. The GPS image-reject mixer has a differential output for an
external L-C bandpass filter. After IF filtering, the IF signal is
amplified by a Variable Gain Amplifier (VGA) and fed to an I/Q
demodulator, resulting in baseband I/Q signals at the output.
The SKY74693 is also designed with a single Local Oscillator (LO)
input port for the AMPS/CDMA/PCS/GPS mixer. These mixers
operate at different RF frequency inputs, but have the same IF
frequency output. This usually refers to a single IF plan at
183.6 MHz. The LO_IN signal (pin 39) provides an LO port for the
CDMA/PCS/GPS mixers. In the cellular band, an internal divider
divides the frequency by two, which provides the LO input to the
cellular mixer. In the GPS band, the UHF LO frequency is 2/3 that
of the UHF VCO frequency. This allows only a single external VCO.
The UHF VCO is also buffered and amplified internally, which
provides the LO to drive the transmtiter upconverter LO port.
The VGA has a minimum dynamic range of 90 dB with a control
voltage range of 0.5 to 2.5 V, which is common to all modes. A
VHF oscillator operates with external tank circuits to provide LO
frequencies for the I/Q demodulator in the cellular, PCS, and GPS
modes. The noise figure, gain, and third order Input Intercept
Point (IIP3) of each stage in the receiver are optimized to meet the
system requirements for AMPS and CDMA modes according to
TIA/EIA-98-C. The design employs SiGe BiCMOS technology for
low cost, high performance, and a high level of integration.
A block diagram of the SKY74693 is shown in Figure 1.
Features
•
Two-step gain control, PCS LNA
•
Three-step gain control, cellular LNA
•
GPS LNA
•
External resistor to adjust LNA bias current
•
Independent AMPS, CDMA, PCS, and GPS mixers
•
Single LO input for CDMA, PCS, and GPS mixer
•
Buffered LO signal for transmit upconverter
•
Single external UHF VCO for PLL circuitry
•
VGA with 90 dB dynamic range
•
Integrated VHF oscillator and tank circuit
•
VCO_ON control for current optimization
•
Battery cell operation (2.7 V < VCC < 3.3 V)
•
RFLGA™ package (48-pins, 7 x 7 x 1 mm) Pb-free (MSL3,
260
°C
per JEDEC J-STD-020) package with downset paddle
Skyworks offers lead (Pb)-free “environmentally
friendly” packaging that is RoHS compliant
(European Parliament for the Restriction of
Hazardous Substances).
Description
The SKY74693 is a highly integrated, single Intermediate
Frequency (IF) receiver intended for use in Code Division Multiple
Access (CDMA) phones operating in Personal Communications
System (PCS), cellular CDMA, Advanced Mobile Phone System
(AMPS), and Global Positioning System (GPS) modes. Skyworks
provides the following three product options:
•
SKY74693-12. Single-band, single-mode (CDMA).
•
SKY74693-13. Dual-band, single-mode (cellular CDMA and
PCS).
•
SKY74693-14. Tri-band, tri-mode (CDMA, AMPS, PCS, GPS).
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
200154A • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • February 16, 2005
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SKYWORKS [ SKYWORKS SOLUTIONS INC. ]
