ATF-521P8-BLK View Datasheet(PDF) - Avago Technologies
Part Name
Description
MFG CO.
ATF-521P8-BLK
Avago Technologies
'ATF-521P8-BLK' PDF : 23 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 plat‑
ed through hole vias for good thermal and RF ground‑
ing. It also provides a good transition from microstrip to
the device package. For more detailed dimensions refer
to Section 9 of the data sheet.
This simplifies RF grounding by reducing the amount of
inductance from the source to ground. It is also recom‑
mended to ground pins 1 and 4 since they are also con‑
nected to the device source. Pins 3, 5, 6, and 8 are not
connected, 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.
Figure 10. Microstripline Layout.
RF Grounding
Unlike SOT packages, ATF-521P8 is housed in a lead‑
less package with the die mounted directly to the lead
frame or the belly of the package shown in Figure 11.
Pin 8
Pin 7 (Drain)
Pin 6
Pin 5
Pin 1 (Source)
Pin 2 (Gate)
Pin 3
Pin 4 (Source)
Bottom View
Figure 11. LPCC Package for ATF-521P8.
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 performance 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 Ra‑
tio or ACLR, or else operate in a backed off mode. If the
amplifier is not backed off then the waveform is com‑
pressed and the signal becomes very nonlinear.
This application example presents a highly linear trans‑
mit 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:
R2
R4
C4
C3
J1
C1
L1
short
C5
R1
R3
C6
C7
J2
0
C8
Figure 12. ATF-521P8 demoboard.
17
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