先对照下面的checklist来看看是否满足下面的要求
The checklist below provides important RF PCB design considerations to be followed, and it
is highly recommended that the designers verify their designs with the suggested points
below. Following these points in the checklist will help to achieve optimum performance from
the designs.
1 Ensure that you follow the datasheet layout recommendation unique to the part
(CCXXXX).
2 0603(mils) discrete parts are not recommended because of size and parasitic
values.
3 Verify that bypassing capacitors are as close as possible to the power supply pins
that they are meant to bypass.
4 Ensure each decoupling capacitor only decouples the specific pins recommended
on the reference design and that the capacitor is correct value and type.
5 Ensure that decoupling is done pin<>capacitor<>via.
6 Verify the stack-up matches the reference design. If the design is a 4-layer PCB;
verify that ground plane is layer two right below top/component side.
7 Changing the layer spacing/stack-up will affect the matching in the RF signal path
and should be carefully accounted for as explained in AN068 [2].
8 Verify that the ground plane matches the reference design. There should be a
solid ground plane below the device and the RF path. There should be no ground
plane below the antenna unless you are using an antenna whose manufacturer
recommends a ground plane (for example, a whip antenna).
9 Verify that RF signal path matches the reference design as closely as possible.
Components should be arranged in a very similar way and oriented the same way
as the reference design.
10 The crystal oscillator should be as close as possible to the oscillator pins of the
part. Long lines to the oscillator should be avoided if possible.
11 Verify that the top ground pours are stitched to the ground plane layer and bottom
layer with many vias around the RF signal path. Compare to the reference design.
Vias on the rest of the board should be no more than λ/10 apart.
12 If the part has a differential output, ensure that the traces in the differential section
are symmetrical as in the reference design.
13 If the design uses a battery (such as a coin cell), the battery will act as a ground
plane and should therefore not be placed under the antenna.
14 If the reference design specifies using T-Lines (Transmission Lines), it is very
critical to ensure that the T-Lines match the reference design exactly.
15 Verify that the under-the-device power pad layout is correct. The solder pads and
mask should match and the opening size should ensure correct amount of paste.
Vias should be the correct number and masked/tented to ensure that they don’t
suck up all the solder, leaving none to solder the chip to pad. (Refer to the
datasheet for layout recommendation for the corresponding part.)
16 The board should specify impedance controlled traces. That is, the layer spacing
and FR4 permittivity should be controlled and known.
Important considerations for Antennas:
17 If using an antenna from a TI reference design, be sure to copy the design exactly
and check if the stack-up in the reference design matches your stack-up.
18 Changes to feed line length of antenna will change input impedance match.
19 Any metal in close proximity, plastic enclosure, and human body will change the
antenna’s input impedance and resonance frequency, which must be considered in
the design.
20 For multiple antenna on same board, use antenna polarization and directivity to
isolate.
21 For chip antennas verify that the spacing from and orientation with respect to the
ground plane is correct as specified in antenna’s datasheet.
22 It is a good practice to add a pi-network after the balun filter network for antenna
impedance matching. Component values can be calculated after the PCB is
fabricated and impedance measurement looking into antenna and the balun
network as made at the desired frequency. If not required, the shunt components
can be left un-mounted and a 0 ohm resistor can be used as series component.
先对照下面的checklist来看看是否满足下面的要求
The checklist below provides important RF PCB design considerations to be followed, and it
is highly recommended that the designers verify their designs with the suggested points
below. Following these points in the checklist will help to achieve optimum performance from
the designs.
1 Ensure that you follow the datasheet layout recommendation unique to the part
(CCXXXX).
2 0603(mils) discrete parts are not recommended because of size and parasitic
values.
3 Verify that bypassing capacitors are as close as possible to the power supply pins
that they are meant to bypass.
4 Ensure each decoupling capacitor only decouples the specific pins recommended
on the reference design and that the capacitor is correct value and type.
5 Ensure that decoupling is done pin<>capacitor<>via.
6 Verify the stack-up matches the reference design. If the design is a 4-layer PCB;
verify that ground plane is layer two right below top/component side.
7 Changing the layer spacing/stack-up will affect the matching in the RF signal path
and should be carefully accounted for as explained in AN068 [2].
8 Verify that the ground plane matches the reference design. There should be a
solid ground plane below the device and the RF path. There should be no ground
plane below the antenna unless you are using an antenna whose manufacturer
recommends a ground plane (for example, a whip antenna).
9 Verify that RF signal path matches the reference design as closely as possible.
Components should be arranged in a very similar way and oriented the same way
as the reference design.
10 The crystal oscillator should be as close as possible to the oscillator pins of the
part. Long lines to the oscillator should be avoided if possible.
11 Verify that the top ground pours are stitched to the ground plane layer and bottom
layer with many vias around the RF signal path. Compare to the reference design.
Vias on the rest of the board should be no more than λ/10 apart.
12 If the part has a differential output, ensure that the traces in the differential section
are symmetrical as in the reference design.
13 If the design uses a battery (such as a coin cell), the battery will act as a ground
plane and should therefore not be placed under the antenna.
14 If the reference design specifies using T-Lines (Transmission Lines), it is very
critical to ensure that the T-Lines match the reference design exactly.
15 Verify that the under-the-device power pad layout is correct. The solder pads and
mask should match and the opening size should ensure correct amount of paste.
Vias should be the correct number and masked/tented to ensure that they don’t
suck up all the solder, leaving none to solder the chip to pad. (Refer to the
datasheet for layout recommendation for the corresponding part.)
16 The board should specify impedance controlled traces. That is, the layer spacing
and FR4 permittivity should be controlled and known.
Important considerations for Antennas:
17 If using an antenna from a TI reference design, be sure to copy the design exactly
and check if the stack-up in the reference design matches your stack-up.
18 Changes to feed line length of antenna will change input impedance match.
19 Any metal in close proximity, plastic enclosure, and human body will change the
antenna’s input impedance and resonance frequency, which must be considered in
the design.
20 For multiple antenna on same board, use antenna polarization and directivity to
isolate.
21 For chip antennas verify that the spacing from and orientation with respect to the
ground plane is correct as specified in antenna’s datasheet.
22 It is a good practice to add a pi-network after the balun filter network for antenna
impedance matching. Component values can be calculated after the PCB is
fabricated and impedance measurement looking into antenna and the balun
network as made at the desired frequency. If not required, the shunt components
can be left un-mounted and a 0 ohm resistor can be used as series component.
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