MC34268
800 mA, 2.85 V, SCSI−2
Active Terminator, Low
Dropout Voltage Regulator
The MC34268 is a medium current, low dropout positive voltage
regulator specifically designed for use in SCSI−2 active termination
circuits. This device offers the circuit designer an economical
solution for precision voltage regulation, while keeping power losses
to a minimum. The regulator consists of a 1.0 V dropout composite
PNP/NPN pass transistor, current limiting, and thermal limiting.
These devices are packaged in the SOIC−8 and DPAK−3 and
SOT−223 surface mount power packages.
Applications include active SCSI−2 terminators and post
regulation of switching power supplies.
Features
• 2.85 V Output Voltage for SCSI−2 Active Termination
• 1.0 V Dropout
• Output Current in Excess of 800 mA
• Thermal Protection
• Short Circuit Protection
• Output Trimmed to 1.4% Tolerance
• No Minimum Load Required
• Space Saving DPAK−3, SOT−223 and SOIC−8 Surface Mount
Power Packages
• Pb−Free Packages are Available
Simplified Block Diagram
Input
Thermal
Limiting
Control
Circuit
Current
Limit
Output
Ground
http://onsemi.com
MARKING
DIAGRAMS
8
8
1
SOIC−8
D SUFFIX
CASE 751
34268
ALYW
1
A = Assembly Location
L = Wafer Lot
Y = Year
W = Work Week
GND 1
2
Output
3
Input 4
8 NC
7
Output
6
5 NC
(Top View)
1
3
DPAK−3
DT SUFFIX
CASE 369A
34268
ALYWW
1
3
SOT−223
ST SUFFIX
CASE 318E
AYW
268ST
4
Pin 1. Ground
2. Output
3. Input
1 23
4. Output
(Top View)
Heatsink surface (shown as terminal 4 in
case outline drawing) is connected to Pin 2.
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 3 of this data sheet.
Semiconductor Components Industries, LLC, 2005
1
April, 2005 − Rev. 6
Publication Order Number:
MC34268/D