VGA + I/Q Demodulator Rx ASIC for Portable Phone Applications

The CX74005 Application-Specific Integrated Circuit (ASIC) is a Variable Gain Amplifier (VGA) and I/Q demodulator, intended for use in Code Division Multiple Access (CDMA) portable phones in both cellular and Personal Communications System (PCS) bands. As a trimode IC, it can be used in CDMA mode or Advanced Mobile Phone System (AMPS) mode.

The device incorporates a VGA and the In-Phase and Quadrature (I/Q) demodulator stages. The intermediate frequencies (IF) are combined through separate buffers at the input of the VGA depending on the selected mode. The VGA has a gain control range greater than 90 dB.

Features

• Supports CDMA/AMPS/PCS1900 modes

• Three battery cell operation (2.7 V < VCC < 3.3 V).

• IF inputs and I/Q outputs

• On-chip 100 to 640 MHz oscillators

• Low power operation: <25 mA

• 32-pin Land Grid Array (LGA) 5 x 5 mm package

Applications

• Tri-mode handsets

• CDMA and AMPS modes in the cellular band:

− AMPS

− CDMA-US

− CDMA-Japan

• CDMA mode in the PCS band:

− PCS-US

− PCS-Korea