LM3420 Datasheet, PDF (18/26 Pages) Texas Instruments – 8.4-V Li-Ion Battery Charge Controller

LM3420
SNVS116E – MAY 1998 – REVISED DECEMBER 2014
11 Layout
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11.1 Layout Guidelines
For best overall performance, place all the circuit components on the same side of the circuit board and as near
as practical to the respective pin connections. Place ground return connections to the input and output capacitor,
and to the regulator ground pin as close to each other as possible, connected by a wide, component-side, copper
surface. The use of vias and long traces to create circuit connections is strongly discouraged and negatively
affects system performance. This grounding and layout scheme minimizes inductive parasitic, and thereby
reduces load-current transients, minimizes noise, and increases circuit stability. A ground reference plane is also
recommended and is either embedded in the PCB itself or located on the bottom side of the PCB opposite the
components. This reference plane serves to assure accuracy of the output voltage, shield noise, and behaves
similar to a thermal plane to spread heat from the device. In most applications, this ground plane is necessary to
meet thermal requirements.
11.2 Layout Example
VIN
INPUT
OUTPUT
ADJ
C
B
E
VOUT
GND
C
B
E
Figure 22. LM3420 Layout
12 Device and Documentation Support
12.1 Trademarks
SIMPLE SWITCHER is a registered trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.2 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
12.3 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
18
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