AP139-28WL-7 Diodes Zetex, AP139-28WL-7 Datasheet - Page 5

• Manufacturer Part Number: AP139-28WL-7
• Description: IC REG LDO 300MA 2.8V SOT-25
• Manufacturer: Diodes Zetex

Specifications of AP139-28WL-7

• Regulator Topology: Positive Fixed
• Voltage - Output: 2.8V
• Voltage - Input: Up to 5.5V
• Number Of Regulators: 1
• Current - Output: 300mA (Max)
• Current - Limit (min): 300mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Dropout (typical): -
• Other names: AP139-28WLDITR

Functional Description
The AP139 of CMOS regulators contain a PMOS pass transistor,
voltage reference, error amplifier, over-current protection,
thermal shutdown.
The P-channel pass transistor receives data from the error
amplifier, over-current protection, and thermal protection circuits.
During normal operation, the error amplifier compares the output
voltage to a precision reference. The over-current and thermal
shutdown circuits become active when the junction temperature
exceeds 130
shutdown, the output voltage remains low. Normal operation is
restored when the junction temperature drops below 110
The AP139 switches from voltage mode to current mode when
the load exceeds the rated output current. This prevents
over-stress.
AP139 Rev. 6
Typical Performance Characteristics
4 0 0
3 5 0
3 0 0
2 5 0
2 0 0
1 5 0
1 0 0
1.0E+00
-10
-20
-30
-40
-50
-60
-70
-80
-90
0
5 0
0
3 .5
BP=0
o
C, or the current exceeds 300mA. During thermal
1.0E+01
Power Supply Rejection Ratio
4
V c c V s S h o r t C u r r e n t
1.0E+02 1.0E+03
Frequency (Hz)
4 .5
V c c ( V )
1.0E+04
5
T o p to b o tto m
V o u t= 1 .5 V
V o u t= 1 .8 V
V o u t= 2 .5 V
V o u t= 3 .3 V
1.0E+05
5 .5
www.diodes.com
o
C.
100mA
10mA
1mA
1.0E+06
5 of 7
6
Enable
The enable pin normally floats high. When actively, pulled low,
the PMOS pass transistor shuts off, and all internal circuits are
powered down. In this state, the quiescent current is less than
2μA. This pin behaves much like an electronic switch.
External Capacitor
The AP139 is stable with a low ESR output capacitor to ground of
1.0μF or greater. It can keep stable even with higher ESR
capacitors. A second capacitor is recommended between the
input and ground to stabilize V
larger than 0.1μF to have a beneficial effect. All capacitors should
be placed in close proximity to the pins. A “quiet” ground
termination is desirable.
(Continued)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.5
300mA LOW-NOISE CMOS LDO
1.8
Vout Vs Current Limit
2
2.5
Vout (V)
IN
. The input capacitor should be
2.8
©
FEBRUARY 2009
3
Diodes Incorporated
AP139
3.3
Vcc=5V
3.5