RF5722 Datasheet, PDF (6/10 Pages) RF Micro Devices – 3.0V TO 3.6V, 2.4GHz TO 2.5GHz LINEAR POWER AMPLIFIER

RF5722
Theory of Operation and Application Information
The RF5722 is a two-stage power amplifier (PA) with a minimum gain of 24dB minimum gain in the 2.4GHz to 2.5GHz ISM
band. The RF5722 has integrated input, interstage and output matching components thus allowing minimal bill of material
(BOM) parts count in end applications. The RF5722 is designed primarily for IEEE802.11b/g/n WiFi 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 RF5722 requires only a single positive supply of 3.3V nominal (or greater) to operate to full specifications. Power control is
provided through one bias control input pin (V_REG). DC blocking caps are provided internally and the evaluation board circuit
(available from RF Micro Devices, Inc. (RFMD)) is optimized for 3.3V_DC applications.
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. Pin 4 must be left as a no-connect on the PCB in order for the PA to work properly. Other configurations
may also work, but the design process is much easier and quicker if the layout is copied from the RF5722 evaluation board.
Gerber files of RFMD PCBA designs can be provided on request. The RF5722 is a very easy part to implement, but care in cir-
cuit layout and component selection is always advisable when designing circuits to operate at 2.5GHz. The RF5722 evaluation
board layout and schematic are available using 0201 (US) size components which will help shrink the overall size of the total
area of the PA and components of the intended design. Please contact RFMD Sales or Application Engineering for additional
data and guidance.
For best performance, it is important to duplicate (as closely as possible) the layout of the evaluation board. The RF5722 has
primarily been characterized with a voltage on V_REG of 2.8V_DC. If you prefer to use a control voltage that is significantly differ-
ent than 2.8V_DC, or a different frequency than the recommended frequency range, contact RFMD Sales or Applications Engi-
neering for additional data and guidance.
QFN8 Package Area versus Other Small Form Factor Package Areas
Package Type Length (mm) Width (mm) _{Area (mm}²_{) Delta () (mm}²_{) to QFN8}
SOT 23-6
3.1
3.0
9.30
4.46
QFN12
3.0
3.0
9.00
4.16
SOT 23-5
2.9
2.8
8.12
3.28
QFN8
2.2
2.2
4.84
0.00
An application schematic for 2.5GHz operation is included that has two additional components, one shunt inductor, and one
shunt capacitor, on the output for improved second harmonic rejection. This layout provides ~20dB rejecetion at 5GHz with a
minimal BOM count.
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