SKY65006-348LF Datasheet, PDF (12/15 Pages) Skyworks Solutions Inc. – 2.4-2.5 GHz WLAN/Zigbee Power Amplifier

Data Sheet • SKY65006-348LF
Test Board Biasing Procedure
1. Connect the RF input and output ports as labeled on the
engineering evaluation board.
2. Set the input power level from a CW signal generator to
approximately -25 dBm.
3. Apply ground connection from DC voltage supply to all
GND pins before applying any voltage.
4. Adjust the power supply to 3.3 V and set the current limit to
400 mA. Apply voltage to the pin labeled V_CC and note that
there is no current draw from the supply. Be sure to apply
the voltage to V_CC before applying any other voltages to the
test board.
5. Adjust a second power supply output to 3.0 V and set the
current limit to 30 mA. Apply voltage to the pin labeled V_REG
and VDCC. Note that the current draw for V_REG is approxi-
mately 10 mA.
6. Observe that the current on the V_CC supply is in the range
of the quiescent current specification. The SKY65006
should be approximately 50 mA.
7. Observe that the small signal gain is within the range speci-
fied. The SKY65006 should be in the range of 27 dB. This
should verify the proper working conditions for this device,
and further testing can proceed.
8. To observe the detector voltage output, connect a voltmeter
or oscilloscope to the V_DET pin on the evaluation test board.
Set the signal source to CW mode and increase power until
the output voltage begins to increase. The nominal offset
voltage with low or no signal inputs should be approximately
50–200 mV and should increase monotonically to approxi-
mately 700–1000 mV, when driven at an output level of
approximately 18 dBm. The evaluation circuit contains an
external 51K Ω resistor and an equivalent capacitance of
10 pF to ground.
9. Bias the unit off by first removing the V_REG power supply and
finally remove the connection to the V_CC power supply.


Application Information
The Skyworks SKY65006 is a high-performance 2-stage InGaP
power amplifier designed for 2.4–2.5 GHz ISM, IEEE802.11b,
802.11g WLAN and Zigbee^® band applications. The SKY65006
is a high-efficiency linear amplifier designed for single 3.3 V
supply operation, requiring no input and output matching com-
ponents for 50 Ω operation. This device also includes an internal
power detector and integrated harmonic filter for reduced PC
board component count. The integrated low pass filter is also
highly effective in reducing harmonics at their source by local-
izing harmonic rejection to a tiny portion of the PA chip. This
significantly reduces the risk of radiation from a high order filter
design external to the amplifier. Filtering of harmonics in this way
may eliminate the need for an external shield over the PA, and
reduces overall cost. If additional suppression of harmonics is
required, an external low pass filter can be added to the output of
the amplifier. Optional shunt inductor, L3, is included on the appli-
cations board at the input of the amplifier to improve the return
loss. The typical performance data shown includes these optional
components.
The SKY65006 requires a nominal V_CC supply voltage of 3.3 V
and a positive control voltage V_REG1, 2 providing bias for the
first and second stage amplifiers. Nominal control voltage, V_REG,
is 2.5–2.6 V resulting from the stack of two emitter-base junc-
tions of about 1.3 V each for typical GaAs HBT device. To insure
proper reference currents into V_REG1, 2, for normal operation of
the RF stages, drop-in resistors could be used between V_REG1, 2
and a V_REG supply. Bias control would then be set in the range of
2.7–3.5 V allowing added flexibility for both the control voltage
value and desired RF stage currents. If additional output power is
required, V_CC can also be increased 4.0 V. Biasing of each stage
consists of an external resistor of 180 Ω (R₁) and 240 Ω (R₂) for
the recommended typical bias currents of 15 mA and 35 mA for
stage 1 and 2 respectively. In most applications one end of each
of the bias resistors is tied to the V_REG supply, so both amplifier
stages are biased with a single common voltage. Capacitor C₅,
1.8 pF, bypasses the V_REG stage 1 control bias pin and is used to
improve RF rejection of the bias control lines.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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November 19, 2008 • Skyworks Proprietary Information. • Products and product information are subject to change without notice. • 200122 Rev. H