ADS5263_15 Datasheet, PDF (72/84 Pages) Texas Instruments – Quad Channel 16-Bit, 100-MSPS High-SNR ADC

ADS5263
SLAS760D – MAY 2011 – REVISED NOVEMBER 2015
11 Layout
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11.1 Layout Guidelines
As for all switching power supplies, the layout is an important step in the design, especially at high peak currents
and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as
well as EMI problems.
1. Use wide and short traces for the main current path and for the power ground tracks without using vias if possible. If vias
are unavoidable, use many vias in parallel to reduce resistance and inductance.
2. At each power-supply pin (AVDD, DVDD, or AVDDD3V), keep a 0.1-µF de-coupling capacitor close to the device. A
separate de-coupling capacitor group consisting of a parallel combination of 10-µF, 1-µF, and 0.1-µF capacitors can be
kept close to the supply source.
3. Use of a ground plane is recommended.
4. Keep digital outputs away from the analog inputs. When these digital outputs exit the pinout, the digital output traces
must not be kept parallel to the analog input traces because this configuration can result in coupling from the digital
outputs to the analog inputs and degrade performance. All digital output traces to the receiver [such as a field-
programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)] must be matched in length to avoid
skew among outputs.
Since ADS5263 provides charging current and system power with internal linear regulators, users need to
consider thermal condition.
1. PowerPAD should be soldered to a thermal land on the PCB.
2. Vias on the thermal land of the PCB are necessary. This is a thermal path through the other side of the PCB.
3. A thermal pad of the same size is required on the other side of the PCB. All thermal pads should be connected by vias.
4. A metal layer should cover all of the PCB if possible.
5. Place vias to connect other sides to create thermal paths.
With these steps, the thermal resistance of ADS5263 can be lowered.
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