SKY65152 Datasheet, PDF (5/12 Pages) Skyworks Solutions Inc. – 2.4-2.5 GHz WLAN Power Amplifier

preliminary Data Sheet • SKY65152
Theory of Operation
The SKY65152 is a three-stage, HBT InGaP device optimized for
high linearity and power efficiency. It contains all of the needed
RF matching and DC biasing circuits. An in-module active bias
circuit is included within the device for all three amplifier stages
providing for excellent gain tracking over temperature and
voltage variations. The first, second and output stages are inde-
pendently supplied using the V_CC1, V_CC2 and V_CC3 supply lines,
pins 16, 14 and 11,respectively. The DC control voltage that
sets the bias for all 3 stages is supplied via V_{C_BIAS}, pin 4. The
evaluation board includes shunt decoupling caps on these pins to
suppress any possible bias affect on the RF at low frequencies.
The bias reference voltages for stages 1, 2 and 3 are supplied
using common lines V_REF1, V_REF2 and V_REF3 (Pins 5, 6 and 7). The
maximum reference voltage at the package pins is 4 V. Resistors
R1, R2 and R3 on the evaluation board set the correct bias to
these pins when attached to a 5 V power supply.
The SKY65152 includes an internal PA Enable control pin (Pin
3) for fast RF On/Off control of < 0.5 µs. Zero volts turns off the
PA while 3–5 V will turn on the PA. The device also provides an
output power detector voltage V_DET at Pin 14. A bias voltage is
required to operate the detector. The detector supply voltage
is supplied via V_{CC_DET} (Pin 15). The maximum voltage at the
package pin is 4 V. Resistor R5 on the evaluation board sets the
correct bias to this pin when attached to a 5 V power supply.
Pin 18 is the RF input and Pin 9 is the RF output. External DC
blocking or RF matching is not required on the RF input and
output. Ground is achieved through several ground pins and the
package backside, center ground.
These features make the device suitable for wideband digital
applications, where PA linearity and power consumption are of
critical importance (e.g., WLANs). The device has been character-
ized with the highest specified data rates for 802.11b (11 Mbps)
and 802.11g (54 Mbps). Under these stringent test conditions,
the device exhibits excellent spectral purity and power efficiency.
Application Circuit Notes
Center Ground. It is extremely important that the device paddle
be sufficiently grounded for both thermal and stability reasons.
Multiple small vias are acceptable and will work well under the
device if solder migration is an issue.
Ground (Pins 1, 2, 8, 10, 17, 19, 20). Attach all ground pins to
the RF ground plane with the largest diameter and lowest induc-
tance via that the layout will allow. Multiple small vias are also
acceptable and will work well under the device if solder migra-
tion is an issue.
PA_ENB (Pin 3). PA_ENB is the internal PA Enable control pin
for fast RF On/Off control of < 0.5 µs. Zero volts turns off the PA
while 3–5 V will turn on the PA.
V_{C_BIAS} (Pin 4). V_{C_BIAS} is the bias supply voltage for stages 1
and 2, typically set to 5 V.
V_REF1 (Pin 5). Bias reference voltage for amplifier stage 1. V_REF1
should be operated over the same voltage range as V_CC, with a
nominal voltage of 5 V.
V_REF2 (Pin 6). Bias reference voltage for amplifier stage 2. V_REF2
should be operated over the same voltage range as V_CC, with a
nominal voltage of 5 V.
V_REF3 (Pin 7). Bias reference voltage for amplifier stage 3. V_REF3
should be operated over the same voltage range as V_CC, with a
nominal voltage of 5 V.
RF_OUT (Pin 9). Amplifier RF Output Pin. Z_O = 50 W. The
module includes an onboard internal DC blocking capacitor. All
impedance matching is provided internal to the module.
V_CC3 (Pin 11). Supply voltage for the output (final) stage collector
bias (typically 5 V). bypassing of V_CC3 is accomplished with C10
and C17 and should be placed in the approximate location shown
on the evaluation board, but placement is not critical.
No Connect (Pin 12). The pin is open and may or may not be
connected to ground.
V_CC2 (Pin 13). Supply voltage for the second stage collector bias
(typically 5 V). Bypassing of V_CC2 is accomplished with C8 and
C16 and should be placed in the approximate location shown on
the evaluation board, but placement is not critical.
V_DET (Pin 14). Output power detector voltage pin. The detector
load and settling time constant are set external to the device.
Inductor L2 and capacitor C7 are set to yield a settling time of
less than 0.5 µs.
V_{CC_DET} (Pin 15). Power detector supply voltage. Proper bias
and bypassing is V_{CC_DET} is accomplished with Resistor R5 and
capacitor C5 provided. V_{CC_DET} may be connected to PA_ENB
supply. The benefit of doing this is the current draw consumed
by the detector will not be wasted with the PA in the “Off” state.
V_CC1 (Pin 16). Supply voltage for the first stage collector bias
(typically 5 V). Bypassing of V_CC1 is accomplished with C5 and
C15 and should be placed in the approximate location shown on
the evaluation board, but placement is not critical.
RF_IN (Pin 18). Amplifier RF Input Pin. Z_O = 50 W. The module
includes an onboard internal DC blocking capacitor. All imped-
ance matching is provided internal to the module.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
200968 Rev. C • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 26, 2009
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