Layout best practices for the TPD3S713x-Q1 device
are listed as follows:
- Considerations for input and output power
traces:
- Make the power traces as short as possible.
- Make the power traces as wide as possible.
- Considerations for input-capacitor traces:
- For all applications, TI recommends 10-µF and 0.1-µF
low-ESR ceramic capacitors, placed close to the IN pin.
- The resistors attached to the ILIM_HI and ILIM_LO
pins of the device have several requirements:
- TI recommends to use 1% low-temperature-coefficient
resistors.
- The trace routing between these two pins and GND must
be as short as possible to reduce parasitic effects on current limit.
These traces must not have any coupling to switching signals on the
board.
- Locate all TPD3S713x-Q1 pullup resistors for
open-drain outputs close to their connection pin. Pullup resistors must be 100
kΩ.
- If a particular open-drain output is not used or needed
in the system, tie it to GND.
- ESD considerations:
- The TPD3S713x-Q1 device has built-in ESD protection for
DP_IN and DM_IN. Keep trace lengths minimal from the USB connector to
the DP_IN and DM_IN pins on the TPD3S713x-Q1 device, and use minimal
vias along the traces.
- The capacitor on BIAS helps to improve the IEC ESD
performance. A 2.2-µF capacitor must be placed close to BIAS, and the
current path from BIAS to GND across this capacitor must be as short as
possible. Do not use vias along the connection traces.
- A 10-µF output capacitor must be placed close to the
BUS pin and TVS.
- See the ESD Protection Layout
Guide for additional information.
- TVS Considerations (BUS, DP_IN and DM_IN exceed 18 V):
- For BUS, a TVS like SMAJ18 must be placed near the BUS
pin.
- For BIAS, a TVS like SMAJ18 must be placed close to the
BIAS pin, but behind the 2.2-µF capacitor.
- The whole path from BUS to GND or BIAS to GND across
the TVS must be as short as possible.
- DP_IN, DM_IN, DP_OUT, and DM_OUT routing considerations
- Route these traces as microstrips with nominal
differential impedance of 90 Ω.
- Minimize the use of vias on the high-speed data
lines.
- Keep the reference GND plane devoid from cuts or splits
above the differential pairs to prevent impedance discontinuities.
- For more USB 2.0 high-speed D+ and D– differential
routing information, see the High Speed USB Platform Design
Guideline from Intel.
- Thermal Considerations:
- When properly mounted, the thermal-pad package provides
significantly greater cooling ability than an ordinary package. To
operate at rated power, the thermal pad must be soldered to the board
GND plane directly under the device. The thermal pad is at GND potential
and can be connected using multiple vias to inner-layer GND. Other
planes, such as the bottom side of the circuit board, can be used to
increase heat sinking in higher-current applications. See the PowerPad™ Thermally Enhanced Package application
report) and (PowerPAD™ Made Easy
application brief) for more information on using this
thermal pad package.