CX74001 查看數據表（PDF） - Skyworks Solutions

零件编号

产品描述 (功能)

比赛名单

CX74001

Rx ASIC for CDMA, AMPS, and PCS Applications

Skyworks Solutions 

CX74001

RF SAW

(CELL)

LNA_CTRL1

LNA_CTRL0

CELL_LNA_IN

FM

CELL/PCS

SLEEP

PCS LNA IN

BYPASS

LNA1

LNA2

BIAS CONTROL

LOD

SIF

BIAS RESISTORS (3)

BYPASS

3

RF SAW

(PCS)

AMPS IF SAW

CDMA IF SAW

PCS IF SAW

Rx ASIC for CDMA, AMPS, and PCS Applications

PLL

I+

I-

÷2

Q+

Q-

Figure 2. CX74001 Rx ASIC Block Diagram

Technical Description

Low Noise Amplifiers (LNAs) _________________________

The cellular band LNA is designed with a low noise figure and

high linearity to achieve receiver sensitivity and single-tone

requirements. The cellular LNA is a three-step gain LNA

designed to meet the inter-modulation distortion specifications in

CDMA per TIA/EIA 98-C.

The PCS band LNA is also designed to provide a low noise

figure and high linearity to achieve receiver sensitivity and

single-tone requirements. At high signal strength, it is preferable

to bypass the LNA completely, and the PCS LNA supports this

feature.

requirements with margin. The cellular CDMA and PCS mixers

have balanced output to drive the IF SAW filters. The differential

outputs of the AMPS mixer are combined externally to mate to a

single-ended input IF SAW filter.

Variable Gain Amplifier (VGA) _________________________

The high dynamic range required by CDMA handsets is

achieved by the VGA, which is common to all modes. It has

three different inputs and the appropriate signal path is switched

inside the chip. The VGA has a dynamic range of 90 dB with a

control voltage of 0.5 to 2.5 volts. It has a low noise figure at

maximum gain, which allows it to meet the system noise figure

requirements. The balanced output is common for all the modes

and is fed directly to the I/Q Demodulator.

Mixers ____________________________________________

I/Q Demodulator_____________________________________

The CX74001 Rx ASIC has three independent mixers, one for

the PCS band and two for the cellular band (AMPS and CDMA).

The mixers are designed to operate with LO powers of –10

dBm, typical.

The cellular and PCS band mixers have a high gain and IIP3,

and a low noise figure that allow them to meet the system

The VGA stage is internally AC coupled to the I/Q demodulator.

The LO signals are derived from one of the on-chip VCOs, then

fed to a divider block that divides the VCO frequency by two.

The differential I and Q outputs are designed specifically with a

low DC output offset and a low phase and amplitude imbalance

when cascaded with the baseband processor.

2

Skyworks

101134A

Proprietary Information and Specifications are Subject to Change

March 5, 2002

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