LM2940-N_16 Datasheet, PDF (17/37 Pages) Texas Instruments – 1A Low Dropout Regulator

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LM2940-N, LM2940C
SNVS769J – MARCH 2000 – REVISED DECEMBER 2014
9 Power Supply Recommendations
The device is designed to operate from an input voltage supply range between V_OUT + 1 V up to a maximum of
26 V. This input supply must be well regulated and free of spurious noise. To ensure that the LM2940 output
voltage is well regulated, the input supply should be at least V_OUT + 2 V.
10 Layout
10.1 Layout Guidelines
The dynamic performance of the LM2940 is dependent on the layout of the PCB. PCB layout practices that are
adequate for typical LDOs may degrade the PSRR, noise, or transient performance of the LM2940. Best
performance is achieved by placing C_IN and C_OUT on the same side of the PCB as the LM2940, and as close as
is practical to the package. The ground connections for C_IN and C_OUT should be back to the LM2940 ground pin
using as wide and short of a copper trace as is practical.
10.2 Layout Examples
Ground
CIN
VIN
1
5
2
6
GND
3
7
4
8
COUT
VOUT
Figure 30. LM2940 WSON Layout
4
CIN
VIN
COUT
VOUT
Ground
Figure 31. LM2940 SOT-223 Layout
4
CIN
VIN
123
COUT
VOUT
Ground
Figure 32. TO-263 Layout
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