RF5300 Datasheet, PDF (4/6 Pages) RF Micro Devices – 3V, 5GHz LINEAR POWER AMPLIFIER

RF5300
Theory of Operation
The RF5300 is a three-stage device with a nominal gain of 28dB to 30dB in the 4.9GHz to 5.850GHz ISM band. The
RF5300 is designed primarily for IEEE802.11a/n WLAN applications where the available supply voltage and current are
limited. This amplifier will operate to (and below) the lowest expected voltage made available by a typical PCMCIA slot in
a laptop PC, and will maintain required linearity at decreased supply voltages.
The RF5300 requires only a single positive supply of 3.0V nominal (or greater) to operate to full specifications. Power
control is provided through two bias control input pins (VREG1, VREG2, and VREG3), but in most applications these are
tied together and used as a single control input.
There is no external matching required on the input and output of the part, thus allowing minimal bill of material (BOM)
parts count in end applications. Both the input and the output of the device are DC-blocked.
For best results, the PA circuit layout from the evaluation board should be copied as closely as possible, particularly the
ground layout and ground vias. Other configurations may also work, but the design process is much easier and quicker if
the layout is copied from the RF5300 evaluation board. Gerber files of our designs are available on request.
The RF5300 is not a difficult part to implement, but care in circuit layout and component selection is always advisable
when designing circuits to operate at 5GHz.
It is important to isolate VCC1 from other RF and low-frequency bypass capacitors on this supply line. This can be
accomplished using a suitably-long transmission line which is RF shorted on the other end as described above. Ideally
the length of this line will be a quarter wavelength, but it only needs to be long enough so that the effects of other supply
bypass capacitors on the VCC1 line are minimized. If board space is a concern, this isolation can also be accomplished
with an RF choke inductor or ferrite bead.
The RF5300 has primarily been characterized with a voltage on VREG1, VREG2, and VREG3 of 2.8V_DC. However, the
RF5300 will operate from a wide range of control voltages. If you prefer to use a control voltage that is significantly differ-
ent than 2.8V_DC, contact RFMD Sales or Applications Engineering for additional data and guidance.
2-658
Rev A8 051107