DESCRIPTION
The SA9503 is an integrated CDMA/AMPS low noise amplifier (LNA) plus a downconverter, for both the 900 MHz Cellular band and the 1.9 GHz PCS band. The LNA incorporates 5 settings of digitally selected stepped gain in the Cellular band and in the PCS band. One of the modes (high linearity mode) in each of the Cellular and PCS bands, includes a high IP3 setting in order to meet the 1-tone CDMA desensitization test. The gain, noise figure and IP3 for the remaining 4 low current modes in the Cellular band, are designed in order to have sufficient separation between the antenna power levels at which the LNA gains are changed, based on multi-tone interference levels. A 3 dB overlap is allowed in the antenna power levels for the adjacent modes. Table 1 indicates a typical scenario

FEATURES
Versatile step gain LNA
• Can meet single tone CDMA desensitization requirements
• Can meet CDMA two tone interference requirements
• Cellular
• PCS
• Separate, selectable IF outputs to suit FM and CDMA bandwidth
• Buffered Cellular and PCS LO inputs
• Integrated frequency doubler for PCS mixer LO
• Differential (Tx) LO output buffer (can be switched on or off)
• Low voltage operation down to 2.7 volts
• Mixers current consumption with (Tx) LO buffer on:
    – Cellular FM: 16.8 mA
    – Cellular CDMA: 23 mA
    – PCS: 26 mA
• Low standby current in sleep mode: <50 µA
• BCC32++™ package

APPLICATIONS
• 800 MHz analog FM and CDMA digital receivers
• 1900 MHz PCS band CDMA digital receivers
• Supports dual-band and triple-mode operation
• Digital mobile communications equipment
• Portable, low power radio equipment