PRODUCT SUMMARY
SKY74691: Receiver for CDMA Mobile Handset Applications
Applications
•
Single mode CDMA handsets
After RF LNA signal amplification and filtering from the antenna,
the received signal is downconverted from RF to the Intermediate
Frequency (IF).
The LO_IN signal (pin 39) provides a Local Oscillator (LO) port for
the RF mixer. The UHF Voltage Controlled Oscillator (VCO) is
buffered and amplified internally, and provides the LO to drive the
LO port of a transmitter upconverter (such as Skyworks
CX74002).
The Variable Gain Amplifier (VGA) has a minimum dynamic range
of 90 dB with a control voltage range of 0.2 to 2.7 V. A VHF
oscillator operates with an internal tank circuit to provide LO
frequencies for the I/Q demodulator.
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 CDMA according to TIA/EIA-98-B/C. The design
employs SiGe BiCMOS technology for low cost, high performance,
and a high level of integration.
The device package and pinout for the 48-pin RF Land Grid Array
(RFLGA) are shown in Figure 1 and a block diagram of the
SKY74691 is shown in Figure 2.
Skyworks offers lead (Pb)-free “environmentally
friendly” packaging that is RoHS compliant
(European Parliament for the Restriction of
Hazardous Substances).
Features
•
Three-step gain control, cellular LNA
•
External resistor to adjust LNA bias current
•
Buffered LO signal for transmit upconverter
•
VGA with 90 dB dynamic range
•
Integrated IF VCO and tank circuit
•
VCO_ON auto-tuning control
•
Battery cell operation (2.7 V < VCC < 3.3 V)
•
RFLGA™ (48-pin, 7 x 7 mm) Pb-free package (MSL3, 260
°C
per JEDEC-J-STD-020) with downset paddle
Description
The SKY74691 is a highly integrated, super-heterodyne receiver.
This single band receiver is intended for use in Code Division
Multiple Access (CDMA) phones in cellular CDMA mode.
Except for the Surface Acoustic Wave (SAW) filters and matching
components, the device incorporates all the components required
to implement the receiver chain, from the Low-Noise Amplifier
(LNA) to the In-Phase and Quadrature (I/Q) demodulator stages.
CELL_LNA_OUT
RF_BIAS_RES
CELL_MIX_IN
MIX_VCC
GND
CELL_LNA_IN
GND
N/C
GND
N/C
VCC_RF_BIAS
LNA_BIAS_RES
LNA_0
LNA_1
VCO_ON
VCO_DEC_CAP
VCO_TUNE
1
2
3
4
5
6
7
8
9
10
11
12
13
48 47 46 45 44 43 42 41
40 39 38
MODE_0
LO_IN
GND
N/C
GND
N/C
N/C
37
36
35
34
33
32
31
30
29
28
27
26
25
MODE_1
LO_OUT
LO_BUFF_VCC
N/C
N/C
CELL_IF+
CELL_IF–
N/C
N/C
VGA_VCC
N/C
CDMA_VGA_IN+
CDMA_VGA_IN–
14 15 16 17 18 19 20 21
22 23 24
VGACTRL
BUFF_EN
XTAL
PLL
VCC_VCO
SLEEP
N/C
I+
I–
Q+
Q–
S307
Figure 1. SKY74691 Pinout – 48-Pin RFLGA
(Top View)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
200029B • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice • January 14, 2005
1
SKYWORKS [ SKYWORKS SOLUTIONS INC. ]
