LP2981-N_15_15 Datasheet, PDF (13/29 Pages) Texas Instruments – LP2981-N Micropower 100-mA Ultra-Low Dropout Regulator in SOT-23 Package

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7 Detailed Description
LP2981-N
SNOS773M – MARCH 2000 – REVISED SEPTEMBER 2015
7.1 Overview
The LP2981-N is a 100-mA, fixed-output voltage regulator designed specifically to meet the requirements of
battery-powered applications. Available in assorted output voltages from 2.5 V to 5 V, the device has an output
tolerance of 0.75% for the A grade (1.25% for the non-A version). Using a VIP process, the LP2981-N contains
these features to facilitate battery-powered designs:
• Fixed 5-V, 3.6-V, 3.3-V, 3-V, and 2.5-V output versions
• Very high-accuracy 1.23-V reference
• Low-dropout voltage, typical dropout of 200 mV at 100-mA load current and 7 mV at 1-mA load
• Low ground current, typically 600 μA at 100-mA load and 80 μA at 1-mA load
• A sleep mode feature is available, allowing the regulator to consume only 1 µA (typical) when the ON/OFF pin
is pulled low.
• Overtemperature protection and overcurrent protection circuitry is designed to safeguard the device during
unexpected conditions.
7.2 Functional Block Diagram
7.3 Feature Description
7.3.1 Multiple Voltage Options
To meet the different application requirements, the LP2981-N provides multiple fixed output options from 2.5 V to
5 V.
7.3.2 High-Accuracy Output Voltage
With special careful design to minimize all contributions to the output voltage error, the LP2981-N distinguishes
itself as a very high-accuracy output voltage micropower LDO. This includes a tight initial tolerance (0.75%
typical), extremely good line regulation (0.007%/V typical), and a very low output voltage temperature coefficient,
making the part an ideal low-power voltage reference.
7.3.3 Ultra-Low-Dropout Voltage
Generally speaking, the dropout voltage often refers to the voltage difference between the input and output
voltage (VDO = V_IN – V_OUT), where the main current pass-FET is fully on in the ohmic region of operation and is
characterized by the classic R_DS(ON) of the FET. VDO indirectly specifies a minimum input voltage above the
nominal programmed output voltage at which the output voltage is expected to remain within its accuracy
boundary.
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