REP007: Driving the IFR3100 IF Demodulator with a Cellular Front-End IC

Rapid engineering prototypes are actual circuits that Maxim application engineers build in the lab and conduct product testing. They are the starting point for new RF engineering designs. They are not intended to be used as assessment testing tools.

Objective: To develop a proper IF matching circuit between a dual-band triple-mode front-end IC and the IFR3100 IF demodulator IC, and measure the front-end performance.

The MAX2323 provides very attractive Icc at varying noise figures and linearities, so this front-end IC replaces other, poorer-performing non-Maxim chips in some applications. The purpose of this application is to provide a properly matched IF port for the MSM-based IFT3100 IF demodulator. It is worth noting that the MAX2323 PCS LNA was tested at a noise figure of 1.9dB, which can be further improved if time permits.

The MAX2323 low-noise amplifier (LNA) and mixer is designed for dual-band CDMA cellular handsets, but it can also be used in dual-band TDMA, GSM, EDGE, or WCDMA. Unlike its predecessor (MAX2320), the MAX2323 adds a third stage "medium gain" amplifier to the cellular band LNA to improve hysteresis margin at the switching point. It also comes in a smaller package (28-QFN) and has a higher 3rd-order input cutoff.

Block diagram of the receive-path application
Schematic of the MAX2323 evaluation kit (PDF, 55kB)
Bill of materials, part 1
Bill of materials, part 2
Performance results of the MAX2323