ATF-521P8 View Datasheet(PDF) - HP => Agilent Technologies
Part Name
Description
MFG CO.
ATF-521P8
HP => Agilent Technologies
'ATF-521P8' PDF : 24 Pages View PDF
PCB Layout
A recommended PCB pad layout
for the Leadless Plastic Chip
Carrier (LPCC) package used by
the ATF-521P8 is shown in
Figure 10. This layout provides
plenty of plated through hole vias
for good thermal and RF ground-
ing. It also provides a good
transition from microstrip to the
device package. For more de-
tailed dimensions refer to
Section 9 of the data sheet.
Figure 10. Microstripline Layout.
RF Grounding
Unlike SOT packages, ATF-521P8
is housed in a leadless package
with the die mounted directly to
the lead frame or the belly of the
package shown in Figure 11.
Pin 8
Drain
Pin 6
Pin 5
Source
Gate
PPin 3
Source
Bottom View
Figure 11. LPCC Package for ATF-521P8.
This simplifies RF grounding by
reducing the amount of induc-
tance from the source to ground.
It is also recommended to ground
pins 1 and 4 since they are also
connected to the device source.
Pins 3, 5, 6, and 8 are not con-
nected, but may be used to
help dissipate heat from the
package or for better alignment
when soldering the device.
This three-layer board (Figure
12) contains a 10-mil layer and a
52-mil layer separated by a
ground plane. The first layer is
Getek RG200D material with
dielectric constant of 3.8. The
second layer is for mechanical
rigidity and consists of FR4 with
dielectric constant of 4.2.
High Linearity Tx Driver
The need for higher data rates
and increased voice capacity gave
rise to a new third generation
standard know as Wideband
CDMA or UMTS. This new
standard requires higher perfor-
mance from radio components
such as higher dynamic range
and better linearity. For example,
a WCDMA waveform has a very
high peak to average ratio which
forces amplifiers in a transmit
chain to have very good Adjacent
Channel Leakage power Ratio or
ACLR, or else operate in a
backed off mode. If the amplifier
is not backed off then the wave-
form is compressed and the
signal becomes very nonlinear.
This application example pre-
sents a highly linear transmit
drive for use in the 2.14GHz
frequency range. Using the RF
matching techniques described
earlier, ATF-521P8 is matched to
the following input and output
impedances:
C5
R2
R1
R4
R3
Input
Match
50 Ohm
2PL
Output
Match
50 Ohm
S11* = 0.89∠ -169 ΓL = 0.53∠ -176
Figure 13. ATF-521P8 Matching.
C4
C3
J1
C1
L1
short
C6
C7
J2
0
C8
Figure 12. ATF-521P8 demoboard.
17
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