8-Pin N-FET Linear Regulator Controller
UCC1837 UCC2837 UCC3837
FEATURES • On Board Charge Pump to Drive
External N-MO...
8-Pin N-FET Linear
Regulator Controller
UCC1837 UCC2837 UCC3837
FEATURES On Board Charge Pump to Drive
External N-MOSFET
Input Voltage as Low as 3V
Duty Ratio Mode Over Current Protection
Extremely Low Dropout Voltage
Low External Parts Count
Output Voltages as Low as 1.5V
DESCRIPTION
The UCC3837 Linear
Regulator Controller includes all the features required for an extremely low dropout linear
regulator that uses an external N-channel MOSFET as the pass
transistor. The device can operate from input voltages as low as 3V and can provide high current levels, thus providing an efficient linear solution for custom processor voltages, bus termination voltages, and other logic level voltages below 3V. The on board charge pump creates a gate drive voltage capable of driving an external N-MOSFET which is optimal for low dropout voltage and high efficiency. The wide versatility of this IC allows the user to optimize the setting of both current limit and output voltage for applications beyond or between standard 3-terminal linear
regulator ranges.
This 8-pin controller IC features a duty ratio current limiting technique that provides peak transient loading capability while limiting the average power dissipation of the pass
transistor during fault conditions. See the Application Section for detailed information.
BLOCK DIAGRAM
VDD 1
CS 8
CAP 2
140mV
CHARGE PUMP
CURRENT SENSE AMPLIFIER
LEVEL SHIFT
5 VOUT
ERROR AMPLIFIER 6 FB
100mV
UVLO CURRENT SENSE COMPARATOR
TI...