DATA SHEET
SKY77518-21 TX–RX iPAC™ FEM for Dual-Band GSM/GPRS
Applications
• Dual-band cellular handsets encompassing - Class 4 GSM900 - DCS1800 - Class 12 GPRS multi-slot operation
Description
The SKY77518-21 is a transmit and receive front-end module (FEM) with Integrated Power Amplifier Control (iPAC™) for dual-band cellular handsets comprising GSM900 and DCS1800 operation. Designed in a low profile, compact form factor, the SKY77518-21 offers a complete Transmit VCO-to-Antenna and Antenna-to-Receive SAW filter solution. The FEM also supports Class 12 General Packet Radio Service (GPRS) multi-slot operation. The module consists of a GSM900 PA block and a DCS1800 PA block, impedance-matching circuitry for 50 Ω input and output impedances, TX harmonics filtering, high linearity and low insertion loss PHEMT RF switches, diplexer and a Power Amplifier Control (PAC) block with internal current sense resistor. A custom BiCMOS integrated circuit provides the internal PAC function and decoder circuitry to control the RF switches. The two Heterojunction Bipolar Transistor (HBT) PA blocks are fabricated onto a single Gallium Arsenide (GaAs) die. One PA block supports the GSM900 band and the other PA block supports the DCS1800 band. Both PA blocks share common power supply pads to distribute current. The output of each PA block and the outputs to the two receive pads are connected to the antenna pad through PHEMT RF switches and a diplexer. The GaAs die, PHEMT die, Silicon (Si) die and passive components are mounted on a multi-layer laminate substrate. The assembly is encapsulated with plastic overmold. Band selection and control of transmit and receive modes are performed using two external control pads. Refer to the functional block diagram in Figure 1 below. The band select pad (BS) selects between GSM and DCS modes of operation. The transmit enable (TX_EN) pad controls receive or transmit mode of the respective RF switch (TX = logic 1). Proper timing between transmit enable (TX_EN) and Analog Power Control (VRAMP) allows for high isolation between the antenna and TX-VCO while the VCO is being tuned prior to the transmit burst. The SKY77518-21 is compatible with logic levels from 1.2 V to VCC for BS and TX_EN pads, depending on the level applied to the VLOGIC pad. This feature provides additional flexibility for the designer in the selection of FEM interface control logic.
Features
• High efficiency - GSM900 48% - DCS 41% • Low transmit supply current - GSM900 1.26 A - DCS1800 0.9 A • Internal ICC sense resistor for iPAC • Closed loop iPAC • 50 Ω matched Input/Output • TX–VCO-to-antenna and antennato-RX-SAW filter RF interface • TX harmonics below –33 dBm • PHEMT RF switches afford high linearity, low insertion loss, and less than 20 μA supply current in receive modes • Small outline: 6 mm x 8 mm • Low profile: 1.2 mm • Compatible with multiple logic families • Low APC current: 25 μA
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Figure 1. Functional Block Diagram
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 •
[email protected] • www.skyworksinc.com
200786A • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice. • November 6, 2007
1
DATA SHEET
SKY77518-21 TX–RX iPAC™ FEM FOR DUAL-BAND GSM/GPRS
Electrical Specifications
The following tables list the electrical characteristics of the SKY77518-21 Front-End Module. The absolute maximum ratings and recommended operating conditions for the SKY77518-21 are listed in Table 1 and Table 2, respectively. Table 3 specifies the mode control logic and Table 4 contains the electrical characteristics of the SKY77518-21 for modes GSM900 and DCS1800. Figure 2 presents an application schematic for the SKY77518-21. The SKY77518-21 is a static-sensitive electronic device and should not be stored or operated near strong electrostatic fields. Detailed information on device dimensions, pad descriptions, packaging and handling can be found in later sections of this data sheet.
Table 1. Absolute Maximum Ratings
Parameter Input Power (PIN) Supply Voltage (VCC), Standby VRAMP ≤ 0.3 V VLOGIC ≤ 0.5 V Control Voltage (VRAMP) Storage Temperature Minimum ⎯ ⎯ Maximum 15 7 VCC_MAX – 0.2 V (See Table 4) 150 Unit dBm V
–0.5 –55
V °C
Table 2. Recommended Operating Conditions
Parameter Supply Voltage (VCC) Supply Current (ICC) Operating Case Temperature (TCASE) 1
1
Minimum 2.7 0 1-Slot (12.5% duty cycle) 2-Slot (25% duty cycle) –20 –20
Typical 3.3
Maximum 4.8 1.8 85 85
Unit V A
Case Operating Temperature refers to the temperature of the GROUND PAD on the underside of the package.
Table 3. SKY77518-21 Mode Control Logic
Mode STANDBY GSM_RX DCS_RX GSM_TX DCS_TX
1
VLOGIC TX_En 0 1 1 1 1 X1 0 0 1 1
Input Control Bits BS X1 0 1 0 1
X = don’t care
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 •
[email protected] • www.skyworksinc.com 2
November 6, 2007 • Skyworks Pro.