鈩?/div>
input and output, and bias control circuitry. Two separate Heterojunction
Bipolar Transistor (HBT) PA blocks are fabricated on a single Gallium Arsenide (GaAs) die. One PA
block operates in the EGSM900 band and the other PA block supports both the DCS1800 and the
PCS1900 bands. Optimized for lithium ion battery operation, both PA blocks share common power
supply pins to distribute current. A custom CMOS integrated circuit provides the internal interface
circuitry, including
a current amplifier that minimizes the required power control current (I
APC
) to 10
碌A(chǔ),
typical. The GaAs die, the Silicon (Si) die, and passive components are mounted on a multi-layer
laminate substrate. The assembly is encapsulated with plastic overmold.
The RF input and output ports are internally matched to 50
鈩?/div>
to reduce the number of external
components for a tri-band design. Extremely low leakage current (2
碌A(chǔ),
typical) of the dual PA module
maximizes handset standby time. The CX77304-17
also contains band-select switching circuitry to
select EGSM (logic 0) and DCS/PCS (logic 1) as determined from the Band Select (BS) signal.
In
the block diagram shown below, the BS pin selects the PA output (DCS/PCS OUT or EGSM OUT) while
the Analog Power Control (APC) controls the level of output power.
Figure 1. Functional Block Diagram
Skyworks Solutions, Inc. 鈥?Phone [781] 376-3000 鈥?Fax [781] 376-3100 鈥?sales@skyworksinc.com 鈥?www.skyworksinc.com
101943B 鈥?Skyworks Proprietary and Confidential Information 鈥?Products and Product Information are Subject to Change Without Notice. 鈥?July 29, 2004
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