Document
AX1184 4A Ultra Low Dropout Positive Linear Regulator
Feature
• • • • • • •
0.7V maximum dropout voltage at 4A load current Built-in Thermal shutdown Output current limiting Adjustable output voltage: 1.250V Fast transient response Good noise rejection Packages: SOP-8L, TO220-5L and TO263-5L
General Description
AX1184 is a 4A regulator with extremely low dropout voltage. This product is specifically designed to provide well regulated supply for applications requiring 2.8V or lower voltages from 3.3V ATX power supplies where high efficiency of the switch can be achieved without the cost and complexity associated with switching regulator. One such application is the new graphic chipsets that requires anywhere from 2.4V to 2.7V supply.
Ordering Information
AX1184 X X
Package S:SOP-8L M5:TO263-5L T5:TO220-5L
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Packing Blank : Tube A : Taping
Typical Application
VIN+2.5V VIN+5V 1 2 4 5 C1 100uF C2 100uF AX1184-ADJ Vsense ADJ/GND Vctrl VIN VOUT 3 R1 100 R2 220 Vout=1.8V
C3 100uF
VOUT = VREF x (1+ R2 ) R1 VREF = 1.250V
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Axelite Confidential Materials, do not copy or distribute without written consent
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Rev.1.0 Jan.16, 2008
cˆgCNãtUFÿmñW3^VÛmw`R•yÑb€g–PQlSø
u5‹Ýÿ 0755-8398 3377 135 9011 2223 http://www.gofotech.com
4A Ultra Low Dropout Positive Linear Regulator
AX1184
Block Diagram
Vin Vctrl CURRENT LIMIT + + 1.25V + THERMAL SHUTDOWN Adj/ GND + Vout Vsense
Pin Configuration
TOP VIEW 5 4 3 2 1 Vsense Vin Vctrl Adj(GND) Vout Vctrl Adj(GND) Vsense Vin 1 2 3 4 TOP VIEW 8 7 6 5 Vout Vout Vout Vout Tab is Vout TOP VIEW 5 4 3 2 1 Vin Vctrl Vout Adj(GND) Vsense
Tab is Vout
(AX1184M5)
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( AX1184S )
(AX1184T5)
Pin Descriptions
Name Adj (GND) Vsense Vin I/O Description A resistor divider from this pin to the Vout pin and ground sets the output voltage. (GND only for fixed mode) This pin is the positive side of the reference that allows remote load sensing to achieve excellent load regulation. The input of the regulator. Typically a large storage capacitor is connected from this pin to ground to insure that the input voltage does not sag below the minimum dropout voltage during the load transient response. This pin must always be higher than Vout in order for the device to regulate. This pin is the supply pin for the internal control circuit as well as the base drive for the pass transistor. This pin must always by higher than the Vout pin in order the device to regulate. A minimum of 100uF capacitor must be connected from this pin to ground to insure stability.
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I I
Vctrl
I
Vout
O
The output of the regulator. A minimum of 100uF capacitor must be connected from this pin to ground to insure stability.
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Axelite Confidential Materials, do not copy or distribute without written consent Rev.1.0 Jan.16, 2008
cˆgCNãtUFÿmñW3^VÛmw`R•yÑb€g–PQlSø
u5‹Ýÿ 0755-8398 3377 135 9011 2223 http://www.gofotech.com
4A Ultra Low Dropout Positive Linear Regulator
AX1.