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AMC DOC. #: AMC7580_E (LF)
AMC7580
Feb 2005
7A LOW DROPOUT REGULATOR
Figure 4.
Capaci nce
ta
Effects
ESL
Effects
ESR
Effects
Slope, V/t =
∆I/C
Point at which regulator
takes control
Output Voltage
The AMC7580-ADJ develops a 1.25V reference voltage between the Sense pin and the Adjust pin (Figure 5).
Placing a resistor between these two terminals causes a constant current to flow thought R1 and down though R2 to
set the output voltage. In general R1 is chosen so that this current is the specified minimum load current of 10 mA.
The current out of the Adjust pin is small, typically 50
µA and it adds to the current for R1. For best regulation the
top of the resistor divider should be connected directly to the Sense pin.
Figure 5 Setting Output Voltage
Figure 6. Optional Clamp Diodes Protect
Against Input Crowbar Circuit
D2
D1
R2
R1
ADJ
AMC7580
-ADJ
SENSE
VPOWER
VCONTROL
R2
R1
IADJ = 50µA
ADJ
VREF
AMC7580
-ADJ
SENSE
VOUT
VPOWER
VCONTROL
Copyright
© 2002, ADD Microtech Corp.
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