PRODUCT SUMMARY SKY74702: Transmitter for CDMA Applications 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 N/C POT_CELL 37 36 35 34 33 32 31 N/C Q+ 2 30 N/C Q– 3 29 N/C VCC_IQ_MOD 4 28 N/C I+ 5 27 VCC_BIAS_DIFF_DRV I– 6 26 CDMA_DRV_OUT VCC_DIV 7 25 VCC_CDMA_DRV VCO_TANK+ 8 24 TX_PUNCTURE VCO_TANK– 9 23 DATA IREF 10 22 LATCH_ENABLE POT_IREF 11 21 CLK 12 13 14 15 16 17 18 19 20 UHF_LO 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. 38 1 SYN_LO Description 39 VCC_IF VCC_UHF • RFLGA™ (40-pin, 6 x 6 x 1 mm) package with downset paddle 40 VCC_MIXER_2 • Transmit puncture pin disables programmable portions of device VCC_MIXER_1 • Fully programmable PLL dividers and selectable charge pump currents for multi-VCO applications IF_IN– • Two separate PLL synthesizers provide dual-loop, multi-band operation and power-save mode for both standby and lower frequency of operation 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. UHF_CP • VHF VCO switching to increase the talk time of the radio LD_OUT • VHF VCO (external tank), 200 to 700 MHz IF_IN+ • Variable gain RF block for improved in-band SNR REF • Transmit power control with 90 dB dynamic range VGA_OUT– • Image reject upconverter replaces external RF SAW filter VHF_CP • Low power consumption in all operating modes 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. VGA_OUT+ • Serial bus interface control VCC_VHF Features VGA_CTRL • 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. VCC_CLK Applications S304 Figure 1. SKY74702 Pinout – 40-Pin RFLGA Package (Top View) • 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 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 200030B • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice • January 31, 2005 1 VCC_MIXER_1 UHF_LO VCC_MIXER_2 VCC VGA_CTRL VCC_CLK VCC_IF VCC Bias IREF VCC PRODUCT SUMMARY • SKY74702 VCC_ IQ_MOD I+ I– ÷2 Q+ Mux ÷4 Q– VCO_TANK+ VCO_TANK– CDMA_DRV_OUT POT_CELL CDMA Driver Bias CLK TX_PUNCTURE DATA Control Signal Enable SYN_LO UHF PLL Lock Detect VHF_CP REF VHF PLL UHF_CP ÷2 ÷1 S305 Figure 2. SKY74702 Transmitter Block Diagram Ordering Information Model Name SKY74702 CDMA Transmitter Manufacturing Part Number Product Revision SKY74702-11 Copyright © 2003, 2004, 2005 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products. These materials are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials. Skyworks may make changes to its documentation, products, specifications and product descriptions at any time, without notice. Skyworks makes no commitment to update the information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from future changes to its documentation, products, specifications and product descriptions. 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Additional information, posted at www.skyworksinc.com, is incorporated by reference. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 2 January 31, 2005 • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice • 200030B