The BH4138FV is an IC developed for use with digital cellular phones. This IC contains a 2nd mixer and IF amplifier.

FEATUREs
1) Mixer circuit, IF amplifier, and RSSI circuit are builtin.
2) Mixer input frequency response 10MHz to 200MHz.
3) The recommended IF amplifier frequencies are 450kHz and 455kHz.
4) High gain IF amplifier (100dB).
5) Battery saving function.
6) Buffer amplifier for RSSI.
7) Low voltage operation (2.3V to 5.5V).

APPLICATIONs
    Digital cellular phones