Reference Circuit 444

REP007: Cellular Front-End IC Drives IFR3100 IF Demodulator



Rapid Engineering Prototypes are real circuits that Maxim application engineers have built and measured in our labs. They can provide a starting point for new RF designs. They are not available as evaluation kits.


Click here for an overview of the wireless components used in a typical radio transceiver.
Click here for an overview of the wireless components used in a typical radio transceiver.


Objective: To develop a suitable IF match between this dual-band triple-mode front-end IC and the IFR3100 IF demodulator IC, and to measure the front-end performance. 

The MAX2323 offers very attractive Icc versus noise figure and linearity, so this front-end IC is found in applications replacing poorer-performing ICs from other non-Maxim chipsets. This application was developed to match the IF port to the MSM-based IFT3100 IF demodulator. Note that the MAX2323 PCS LNA was measured at a 1.9dB noise figure, which could likely be improved further given the time.

The MAX2323 low-noise amplifier (LNA) plus mixer is designed for dual-band CDMA cellular-phone handsets, but it can also be used in dual-band TDMAGSMEDGE, or WCDMA applications. It differs from its predecessor (the MAX2320) by adding a third "mid-gain" state for the cellular-band LNA that improves switchover hysteresis margin. It also comes in a smaller package (28-QFN) and offers increased third-order input intercept.

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

 
Status:
Package:
Temperature:

MAX2323
Triple/Dual-Mode CDMA LNA/Mixers

  • 2.7V Operation
  • Dual Band, Triple Mode
  • Three LNA Gain Settings (Cellular)