MRFIC0904

6

MOTOROLA RF DEVICE DATA

APPLICATIONS INFORMATION

DESIGN PHILOSOPHY

The MRFIC0904 is a versatile driver amplifier designed to

operate in the 800 MHz to 1 GHz frequency range for cellular

phone and Industrial, Scientific, and Medical (ISM) applica-

tions. The amplifier is designed using depletion mode GaAs

MESFETs to perform at high efficiency at battery voltages of

3.6 and 4.8 Volts. While designed as a driver amplifier for a

discrete transistor final stage, the device can act as a power

amplifier for lower power systems such as ISM applications

in telemetry and cordless telephones.

THEORY OF OPERATION

The MRFIC0904 has various control features making it ver-

satile and applicable to both linear and saturated applications.

The BIAS pin allows the setting of drain quiescent current. For

non–linear applications such as GSM cellular, the pin can be

grounded. For better gain and linearity, a positive voltage up

to about 0.6 Volts can be applied. The PCNTRL pin allows

the control of the output power over a wide dynamic range

with low AM to AM distortion such as is required in GSM and

other cellular systems. As shown in Figures 6 through 9,

PCNTRL affects both the output power and the drain current

thus maintaining good efficiency over a range of output pow-

er. The ENABLE pin is used to control the on–off state of the

device and is useful as a reduced current standby control. A

logic high signal of more than 2.5 Volts turns the device on. A

logic low signal of less than 0.5 Volts reduces total supply

current to typically less than 200

µA.

EVALUATION BOARDS

Evaluation boards are available for RF Monolithic Inte-

grated Circuits by adding a “TF” suffix to the device type.

For a complete list of currently available boards and ones

in development for newly introduced product, please con-

tact your local Motorola Distributor or Sales Office.