LP2951-33-Q1 Datasheet, PDF (16/30 Pages) Texas Instruments – Adjustable Micropower Voltage Regulators With Shutdown

LP2951-33-Q1, LP2951-50-Q1
SLVSAW6E – JUNE 2011 – REVISED NOVEMBER 2014
8 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LP2951-xx-Q1 devices are used as low-dropout regulators with a wide range of input voltages.
8.2 Typical Application
330 kΩ
V_OUT = 5 V
1 PF
V_{OUT 1}
2 ^SENSE
3 ^SHUTDOWN
GND ₄
LP2951-50
8 ^VIN
7 ^FEEDBACK
6 ^VTAP
5 ^ERROR
V_IN = 12 V
1 PF
Figure 34. 12-V to 5-V Converter
8.2.1 Design Requirements
8.2.1.1 Input Capacitor (C_IN)
A 1-μF (tantalum, ceramic, or aluminum) electrolytic capacitor should be placed locally at the input of the
LP2951-xx-Q1 device if there is, or will be, significant impedance between the ac filter capacitor and the input; for
example, if a battery is used as the input or if the ac filter capacitor is located more than 10 in away. There are
no ESR requirements for this capacitor, and the capacitance can be increased without limit.
8.2.1.2 Output Capacitor (C_OUT)
As with most PNP LDOs, stability conditions require the output capacitor to have a minimum capacitance and an
ESR that falls within a certain range.
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