SD4957F Datasheet PDF - Semicoa Semiconductor

Chip type 2C4957 by Semicoa Semiconductors provides performance similar to these devices.

FEATUREs:  Special Characteristics
    ft = 1.6 GHz (typ) at 2.0 mA/10V

APPLICATIONS:
    Designed for high-gain, low-noise class A amplifiers, oscillators and mixers.