LP2992_15 Datasheet, PDF (15/33 Pages) Texas Instruments – LP2992 Micropower 250-mA Low-Noise Ultralow-Dropout Regulator in SOT-23 and WSON Packages Designed for Use with Very Low-ESR Output Capacitors

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8 Application and Implementation
LP2992
SNVS171H – NOVEMBER 2001 – REVISED JANUARY 2015
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 LP2992 is a 250-mA, fixed-output voltage regulator designed to provide ultralow-dropout and low noise in
battery powered applications. The device is stable with output capacitor equivalent series resistance (ESR) as
low as 5 mΩ which allows the use of ceramic capacitors on the output.
At 250-mA loading, the dropout voltage of the LP2992 is 850 mV maximum over temperature; thus, 1000-mV
headroom is sufficient for operation over input and output voltage accuracy. The efficiency of the LP2992 in this
configuration is V_OUT/V_IN = 76.7%. To achieve the smallest form factor, the SOT-23 package is selected.
Input and output capacitors are selected in accordance with Capacitor Characteristics. Ceramic capacitance of 1
µF for the input and that of 4.7 µF for the output are selected. With efficiency of 76.7% and a 250-mA load
current, the internal power dissipation is 250 mW, which corresponds to 43.55°C junction temperature rise for the
SOT-23 package. To minimize noise, a bypass capacitor (C_BYPASS) of 0.01 µF is selected.
8.2 Typical Application
*ON/OFF input must be actively terminated. Tie to the IN pin if this function is not to be used.
**Minimum capacitance is shown to ensure stability (may be increased without limit). Ceramic capacitor required for
output (see Output Capacitor).
***Reduces output noise (may be omitted if application is not noise critical). Use ceramic or film type with very low
leakage current (see Capacitor Characteristics).
Figure 34. Basic Application Circuit
8.2.1 Design Requirements
DESIGN PARAMETER
Input voltage
Output voltage
Output current
Output capacitor range
VALUE
4.3 V
3.3 V
150 mA (maximum)
1 mA (minimum)
4.7 µF
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