LP3852_15 Datasheet, PDF (14/32 Pages) Texas Instruments – 1.5-A Fast Response Ultra-Low Dropout Linear Regulators

LP3852, LP3855
SNVS174I – FEBRUARY 2003 – REVISED FEBRUARY 2015
10 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.
10.1 Application Information
The LP3852 and LP3855 devices can provide 1.5-A output current with 2.5-V to 7-V input. A minimum 10-uF
output capacitor is required for loop stability. An input capacitor of at least 10 µF is required . Pin SD must be
tied to input if not used. For LP3852, ERROR pin should be pulled high through a pullup resistor. For LP3855, if
the sense option is not required , the SENSE pin must be connected to the OUT pin.
10.2 Typical Applications
INPUT
3.3V ± 10%
C_IN*
10 2F
SD**
IN
OUT
LP3852-2.5
SD
ERROR
GND
ERROR**
V_OUT
2.5V, 1.5A
C_OUT*
10 2F
* TANTALUM OR CERAMIC
Figure 18. LP3852 Typical Application
INPUT
3.3V ± 10%
C_IN*
10 2F
SD**
IN
OUT
LP3855-2.5
SD
SENSE
GND
V_OUT
2.5V, 1.5A
C_OUT*
10 2F
* TANTALUM OR CERAMIC
Figure 19. LP3855 Typical Application
10.2.1 Design Requirements
DESIGN PARAMETERS
Input voltage
Output voltage
Output current
Input capacitor
Output capacitor
ERROR pullup resistor (LP3852 only)
VALUE
3.3 V, ±10%
2.5 V, ±3%
1.5 A (maximum)
10 µF (minimum)
10 µF (minimum)
10 kΩ
10.2.2 Detailed Design Procedure
10.2.2.1 External Capacitors
Like any low dropout regulator, external capacitors are required to assure stability. These capacitors must be
correctly selected for proper performance.
10.2.2.1.1 Input Capacitor
An input capacitor of at least 10 µF is required. Ceramic or tantalum may be used, and capacitance may be
increased without limit.
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