LP38859_14 Datasheet, PDF (9/21 Pages) Texas Instruments – 3A Fast-Response High-Accuracy LDO Linear Regulator with Soft-Start

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IN
BIAS
Block Diagram
LP38859
SNVS337D – JUNE 2006 – REVISED OCTOBER 2011
OUT
LP38859-x.x
Under-Voltage
Lock-Out
Thermal
Shut Down
r_SS
SS
V_REF
I_LIMIT
0.6V
GND
APPLICATION INFORMATION
EXTERNAL CAPACITORS
To assure regulator stability, input and output capacitors are required as shown in the Typical Application Circuit.
Output Capacitor
A minimum output capacitance of 10 µF, ceramic, is required for stability. The amount of output capacitance can
be increased without limit. The output capacitor must be located less than 1 cm from the output pin of the IC and
returned to the device ground pin with a clean analog ground.
Only high quality ceramic types such as X5R or X7R should be used, as the Z5U and Y5F types do not provide
sufficient capacitance over temperature.
Tantalum capacitors will also provide stable operation across the entire operating temperature range. However,
the effects of ESR may provide variations in the output voltage during fast load transients. Using the minimum
recommended 10 µF ceramic capacitor at the output will allow unlimited capacitance, Tantalum and/or
Aluminum, to be added in parallel.
Input Capacitor
The input capacitor must be at least 10 µF, but can be increased without limit. It's purpose is to provide a low
source impedance for the regulator input. A ceramic capacitor, X5R or X7R, is recommended.
Tantalum capacitors may also be used at the input pin. There is no specific ESR limitation on the input capacitor
(the lower, the better).
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