AP1184 Ver la hoja de datos (PDF) - Anachip Corporation
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AP1184 Datasheet PDF : 11 Pages
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4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
AP1184
Electrical Characteristics(Continued)
Unless otherwise specified, these specifications apply over, Cin=1uF, Cout=10uF, and Tj=0 to 150oC. Typical value refer to Tj=25oC.
Vout=Vsense.
Sym. Parameter
Test Condition
Min. Typ. Max. Unit
Thermal Regulation 30mS Pulse
0.01 0.02 %/W
Ripple Rejection
Vctrl =5V, Vin=5V, Io=4A, Vadj=0V, Tj=25, Vripple=1Vpp at
120Hz
60 70
dB
Vadj=0V for all conditions below.
Control Pin Current
Vctrl =2.75V, Vin=2.05V, Io=1.5A
Vctrl =2.75V, Vin=2.05V, Io=3A
Vctrl=2.75V, Vin=2.05V, Io=4A
6
25
30 60 mA
33 70
Iadj Adjust Pin Current Vctrl=2.75V, Vin=2.05,Vadj=0
θ JC
Thermal Resistance
Junction-to-Case
TO-263: Control Circuitry/Power Transistor
TO-220: Control Circuitry/Power Transistor
SOP-7: Control Circuitry/Power Transistor
50 150 µA
3.5
OC/W
2.5
OC/W
20
OC/W
NOTE:
AP1184-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable
maximum junction temperature.
Package
TO263/TO220
SOP7
Max Pd.
2.4W~4.4W
1W~2W
Remarks
With heat sink or amount of copper board needed.
With heat sink or amount of copper board needed.
Functional Descriptions
Introduction
The AP1184 regulator is 5 terminal device designed
specifically to provide extremely low dropout
voltages comparable to the PNP type without the
disadvantage of the extra power dissipation due to
the base current associated with PNP regulators.
This is done by bringing out the control pin of the
regulator that provides the base current to the
power NPN and connecting it to a voltage that is
greater than the voltage present at the Vin pin. This
flexibility makes the AP1184 ideal for applications
where dual inputs are available such as a computer
motherboard with an ATX style power supply that
provides 5V and 3.3V to the board. One such
application is the new graphic chip sets that require
anywhere from 2.4V to 2.7V supply. The AP1184
can easily be programmed with the addition of two
external resistors to any voltages within the range
of 1.25V to 15.5V. Another major requirement of
these graphic chips is the need to switch the load
current from zero to several amps in tens of
nanoseconds at the processor pins, which
translates to an approximately 300 to 500ns of
current step at the regulator. In addition, the output
voltage tolerances are also extremely tight and they
include the transient response as part of the
specification.
The AP1184 is specifically designed to meet the
fast current transient needs as well as providing an
accurate initial voltage, reducing the overall system
cost with the need for fewer number of output
capacitors. Another feature of the device is its true
remote sensing capability that allows accurate
voltage setting at the load rather than at the device.
Output Voltage Setting
The AP1184-ADJ can be programmed to any
voltages in the range of 1.25V to 15.5V with the
addition of R1 and R2 external resistors according
to the following formula:
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Sep 7, 2004
4/11
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