LP38853_15 Datasheet, PDF (19/30 Pages) Texas Instruments – LP38853 3A Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start

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LP38853
SNVS335E – DECEMBER 2006 – REVISED NOVEMBER 2015
9 Power Supply Recommendations
The LP38853 device is designed to operate from an input voltage supply range from 3 V and 5.5 V. The input
voltage range provides adequate headroom in order for the device to have a regulated output. This input supply
must be well regulated. An input capacitor of at least 10 μF is required.
10 Layout
10.1 Layout Guidelines
For best overall performance, place all circuit components on the same side of the circuit board and as near as
practical to the respective LDO pin connections. Place ground return connections to the input and output
capacitor, and to the LDO ground pin as close as possible to each other, connected by a wide, component side,
copper surface. The use of vias and long traces to create LDO 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 similarly to a thermal plane to spread heat from the LDO device when
connected to the PowerPAD. In most applications, this ground plane is necessary to meet thermal requirements.
10.2 Layout Examples
12 34567
CSS
CBIAS
V_IN
CIN
COUT
V_OUT
Figure 31. LP38853 DDPAK/TO-263 and TO-220 Layout Example
12 34567
CSS
CBIAS
V_IN
CIN
COUT
V_OUT
Figure 32. LP38853 SO PowerPAD Layout Example
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