LP3981 Datasheet, PDF (1/8 Pages) National Semiconductor (TI) – Micropower, 300mA Ultra Low-Dropout CMOS Voltage

Preliminary Datasheet
LP3981
300mA,Ultra-low noise, Small Package
Ultra-Fast CMOS LDO Regulator
General Description
The LP3981 is designed for portable RF and
wireless applications with demanding performance
and space requirements. The LP3981 performance
is optimized for battery-powered systems to deliver
ultra low noise and low quiescent current. A noise
bypass pin is available for further reduction of
output noise. Regulator ground current increases
only slightly in dropout, further prolonging the
battery life. The LP3981 also works with low-ESR
ceramic capacitors, reducing the amount of board
space necessary for power applications, critical in
hand-held wireless devices. The LP3981 consumes
less than 0.01µA in shutdown mode and has fast
turn-on time less than 50µs. The other features
include ultra low dropout voltage, high output
accuracy, current limiting protection, and high
ripple rejection ratio. Available in the 5-lead of
SOT23-5 packages.
Ordering Information
LP3981 - □ □ □ □ □
F: Pb-Free
Package Type
B5: SOT23-5
Output Voltage Type
12: 1.2V
15: 1.5V
18: 1.8V
25: 2.5V
28: 2.8V
30: 3.0V
33: 3.3V
50: 5.0V
Typical Application Circuit
Vin
+
1 _IN
3 _SHDN
OUT ⁵
NC ⁴
Vout
+
1uF
Features
Ultra-Low-Noise for RF Application 　
2V- 6.5V Input Voltage Range
Low Dropout : 220mV @ 300mA 　
1.2V, 1.5V, 1.8V, 2.5V, 2.8V 3.0V and 3.3V Fixed
300mA Output Current, 550mA Peak Current
High PSSR:-73dB at 1KHz 
< 0.01uA Standby Current When Shutdown
Available in SOT23-5 Package 　
TTL-Logic-Controlled Shutdown Input 　
Ultra-Fast Response in Line/Load transient 　
Current Limiting and Thermal Shutdown
Protection
Quick start-up (typically 50uS)
Applications
Portable Media Players/MP3 players
Cellular and Smart mobile phone
LCD
DSC Sensor
Wireless Card
Pin Configurations
SOT-25(Top View)
Marking Information
Please see website.
LP3981 – 01 Ver. 1.1 Datasheet Feb.-2008
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