SKY74702

PRODUCT SUMMARY SKY74702: Transmitter for CDMA Applications Applications • CDMA phones in the cellular band: ⎯ CDMA-US ⎯ CDMA-Japan The signal enters the chip as a baseband I/Q signal, which is upconverted by an I/Q quadrature modulator. The resulting signal is fed through a VGA to provide variable output power. After leaving the open collector output of the VGA, the signal enters a switch matrix. This switch matrix allows the signal to be routed through an external filter, or it can be filtered by the tuned collector load and passed directly to the UHF image reject mixer. The image reject mixer is internally connected to the PA driver. The mixer driver combination has a variable gain control that can be used to reduce the RF gain, which improves the in-band Signal-to-Noise Ratio (SNR) at a lower output power. The PA driver amplifies the RF signal to the appropriate level for the desired output power. This is then filtered by a bandpass filter and sent to an external PA to obtain the final rated output power at the antenna. The device package and pinout for the 40-pin RF Land Grid Array (RFLGA) are shown in Figure 1. A block diagram of the SKY74702 is shown in Figure 2. Features • Serial bus interface control • Low power consumption in all operating modes • Image reject upconverter replaces external RF SAW filter • Transmit power control with 90 dB dynamic range • Variable gain RF block for improved in-band SNR • VHF VCO (external tank), 200 to 700 MHz • VHF VCO switching to increase the talk time of the radio • Two separate PLL synthesizers provide dual-loop, multi-band operation and power-save mode for both standby and lower frequency of operation • Fully programmable PLL dividers and selectable charge pump currents for multi-VCO applications • Transmit puncture pin disables programmable portions of device • RFLGA™ (40-pin, 6 x 6 x 1 mm) package with downset paddle VCC_MIXER_1 VCC_MIXER_2 VGA_OUT+ VGA_OUT– VGA_CTRL 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 VCC_IF Q+ Q– 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 POT_CELL IF_IN+ IF_IN– N/C N/C N/C N/C N/C VCC_BIAS_DIFF_DRV CDMA_DRV_OUT VCC_CDMA_DRV TX_PUNCTURE DATA LATCH_ENABLE CLK Description The SKY74702 device is a single-supply, monolithic integrated circuit. It is designed for use in single-mode Code Division Multiple Access (CDMA) cellular voice/data applications including extensions for CDMA-Japan. The SKY74702 is a highly integrated superheterodyne transmitter that incorporates the following components: • In-Phase and Quadrature (I/Q) modulator – accepts the analog I and Q current outputs from the baseband analog processor and converts them to Intermediate Frequency (IF) signals • Voltage Controlled Oscillator (VCO) and VHF synthesizer – generates the LO signal for the quadrature modulator • UHF synthesizer – controls the UHF oscillator • Variable Gain Amplifier (VGA) – provides the variable output power for CDMA systems • Image reject upconverter and power amplifier (PA) drivers VCC_IQ_MOD I+ I– VCC_DIV VCO_TANK+ VCO_TANK– IREF POT_IREF VCC_CLK VCC_VHF VHF_CP REF UHF_CP VCC_UHF LD_OUT SYN_LO UHF_LO S304 Figure 1. SKY74702 Pinout – 40-Pin RFLGA Package (Top View) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 200030B • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice • January 31, 2005 1 PRODUCT SUMMARY • SKY74702 VCC VCC VCC_MIXER_2 VCC_ IQ_MOD I+ I– ÷4 ÷2 UHF_LO Mux Q+ Q– VCO_TANK+ VCO_TANK– VCC_MIXER_1 VCC Bias VCC_IF VGA_CTRL VCC_CLK IREF CDMA_DRV_OUT POT_CELL ÷2 ÷1 VHF PLL UHF PLL Control Signal TX_PUNCTURE Lock Detect VHF_CP UHF_CP SYN_LO DATA Enable REF CLK CDMA Driver Bias S305 Figure 2. SKY74702 Transmitter Block Diagram Ordering Information Model Name SKY74702 CDMA Transmitter Manufacturing Part Number SKY74702-11 Product Revision Copyright © 2003, 2004, 2005 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products. 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Skyworks’ customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale. The following are trademarks of Skyworks Solutions, Inc.: Skyworks®, the Skyworks logo, and Breakthrough Simplicity®. Product names or services listed in this publication are for identification purposes only, and may be trademarks of Skyworks or other third parties. Third-party brands and names are the property of their respective owners. Additional information, posted at www.skyworksinc.com, is incorporated by reference. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 2 January 31, 2005 • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice • 200030B