General Description
The TC57 is a low dropout regulator controller that operates with an external PNP pass transistor, allowing the user to tailor the LDO characteristics to suit the application at hand. This results in lower dropout operation (and often lower cost) compared with traditional linear regulators with on-board pass transistors. The maximum output current of a TC57-based regulator circuit is limited only by the characteristics of the external pass transistor. For example, a maximum output current of 650mA (with a dropout voltage of 100mV) results when an FZT749 pass transistor is used, while a Darlington configuration can deliver up to 4A.
Flexibility, and superior performance make this family of regulator controllers the ideal choice in applications where low dropout voltage and low installed cost are key.

Features
• Low Dropout Voltage: 100mV @ 650mA with
   FZT749 PNP Transistor
• 2.7V to 8V Supply Range
• Low Operating Current: 50A Operating,
   0.2A Shutdown
• Low True Chip Enable
• Output Accuracy < ±2%
• Small Package: 5-Pin SOT-23A

Applications
• Battery Operated Systems
• Portable Instruments
• High-Efficiency Linear Regulator
• Post-Regulator for SMPS
• Power Supply or Battery Back-Up Supply for Memory