B4251

Features:

•  Maximum Output Current:  250 mA.
•  Highly Accurate Output Voltage +/- 1.4%
•  Only 19µA Power Consumption MAX 
•  Shutdown Supply Current 1µA
•  Ground Current of Less than 5µA
•  Very Low Dropout  0.12V at 100mA  0.23V at 250mA   
•  Shutdown Mode for Power Savings
•  With ON/OFF & BYPASS Features
•  Offered in SOT-89 & SOT-25 Packages
•  PIN-to-PIN S-818 


Application

•  Battery Powered Equipment
•  Notebook PC, Palmtops, PDA
•  Portable Cameras and Video Recorders
•  Reference Voltage Sources
•  Cellular / GSM / PCS Phones


Pinout




Specifications

Parameter		Symbol	Ratings	Units
Input Voltage		VIN	12	V
Output Current		IOUT	500	mA
Output Voltage		VOUT	VSS -0.3 to VIN 0.3	V
On/Off Voltage		On/Off	VSS -0.3 to VIN+ 0.3	V
Continual Total Power Dissipation	SOT-25 SOT-89	Pd	150 300	mW
Operating Ambient Temperature		TOPR	-30 to 80	°C
Storage Temperature		TSTG	-40 to 125	°C

Description

The B4251 series are a group of positive output voltage, five-pin regulators, which provide a high current even when the input/output voltage differential is small.  Low power consumption and high accuracy is achieved though CMOS and programmable fuse technologies.  Output voltage:  2.0V to 6.0V in 0.1V increments.
 
The B4251 consists of a high-precision voltage reference, an error correction circuit, and a current limited output driver. Key features include a Shutdown Pin that reduces supply current to 0.5µA max and a 470pF Bypass input to ground reduces noise present on the internal reference, which in turn significantly reduce output noise. If output noise is not concern, this input maybe left unconnected. Larger capacitor values cap be used, but results in longer time period to rated B4251 when power initially applied. 
 
The ON/OFF pin enables the output to be turned off, resulting in reduced power consumption. Provided in SOT-25 (150mW) packages minimizes the usage of board real state.