LP38859_15 Datasheet, PDF (10/25 Pages) Texas Instruments – 3A Fast-Response High-Accuracy LDO Linear Regulator With Soft Start

LP38859
SNVS337F – JUNE 2006 – REVISED SEPTEMBER 2015
7 Detailed Description
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7.1 Overview
The LP38559 is a fast-response, high-current, low-dropout regulator, available in output voltages are 0.8 V and
1.2 V. This part is capable of delivering 3-A continuous load current. Standard regulator features, such as
overcurrent and over temperature protection, are also included. The LP38559 contains several features:
• Low dropout voltage, typical 240 mV at 3-A load.
• The bias voltage(V_BIAS) provides voltage to drive the gate of the N-MOS power transistor.
• The input voltage(V_IN) is the input voltage which supplies power to the load.
• Programmable soft-start time.
7.2 Functional Block Diagram
IN
BIAS
LP38859-x.x
Undervoltage
Lockout
Thermal
Shutdown
OUT
r_SS
SS
V_REF
I_LIMIT
0.6 V
GND
7.3 Feature Description
7.3.1 Input Voltage
The input voltage (V_IN) is the high current external voltage rail that is regulated down to a lower voltage, which is
applied to the load. The input voltage must be at least V_OUT + V_DO, and no higher than whatever values is used
for V_BIAS.
7.3.2 Bias Voltage
The bias voltage (V_BIAS) is a low current external voltage rail required to bias the control circuitry and provide
gate drive for the N-FET pass transistor. The bias voltage must be in the range of 3 V to 5.5 V to ensure proper
operation of the device.
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