AP1187S7 [ANACHIP]
1A Ultra Low Dropout Positive Adjustable Regulator; 1A超低漏失正可调稳压器
| 型号： | AP1187S7 |
| 厂家： | 
ANACHIP CORP |
| 描述： | 1A Ultra Low Dropout Positive Adjustable Regulator |
| 文件： | 总6页 (文件大小：179K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Features
General Description
• Adjustable output voltage
• 0.6V Maximum Dropout voltage at 1.0A Load
current
AP1187 is a 1A 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 a
switcher can be achieved without the cost and
complexity associated with switching regulator. One
such application is the new graphic chip sets that
require anywhere from 2.4V to 2.7V supply.
• Built-in Thermal Shutdown
• Output Current Limiting
• Fast transient response
• Good noise rejection
• Package: SOP-7L
Applications
• PC Motherboard
• LCD Monitor
• Graphic Card
• DVD-Video Player
• NIC/Switch
• Telecom Equipment
• ADSL Modem
• Printer and other Peripheral Equipment
Pin Assignments
Pin Descriptions
Name
Description
( Top View )
A resistor divider from this pin to the VOUT
pin and ground sets the output voltage.
This pin is the positive side of the
reference that allows remote load
sensing to achieve excellent load
regulation. A minimum of 10uF capacitor
must be connected from this pin to
ground to insure stability.
ADJ
ADJ
VSENSE
VIN
7 NC
1
2
3
4
VSENSE
VOUT
6
5
AP1187
SOP-7L
VIN
The input of the regulator.
VCTRL
VIN
This pin is the supply pin for the internal
VCTRL control circuit as well as the base drive
for the pass transistor.
NC
VOUT
Not used.
The output of the regulator.
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev.1.1 Aug 23, 2005
1/6
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Ordering Information
AP 1187
X
X
X
Low Dropout Regulator
Lead Free
Packing
Package
S7:SOP-7L
Blank : Normal
Blank : Tube
A : Taping& Reel
L : Lead Free Package
Block Diagram
VIN
VOUT
VSENSE
VCTRL
+
+
+
-
1.25V
+
Current
Limit
Thermal
Shutdown
ADJ
Absolute Maximum Ratings (Note 1)
Symbol
Parameter
Rating
Unit
VIN
VCTRL
PD
Input Voltage
Control Input Voltage
Power Dissipation
16
18
V
V
Internally limited
o
o
TST
TOP
Storage Temperature
Operating Junction Temperature Range
-65 to +150
0 to +150
C
C
NOTE1:
AP1187-ADJ incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the
allowable maximum junction temperature.
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Aug 23, 2005
2/6
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Electrical Characteristics
Unless otherwise specified, these specifications apply over, CIN=1uF, COUT=10uF, and TJ=0 to 150oC. Typical value refer to TJ=25oC.
V
OUT = VSENSE
.
Sym.
Parameter
Test Condition
Min. Typ. Max. Unit
VREF Reference Voltage TJ=25oC,(VIN-VOUT)=0.5V, IO=10mA VCTRL =VIN+1V
1.225 1.250 1.275
0.2
V
%
Line Regulation
IO=10mA, VOUT+0.5V<VIN<12V VCTRL =VIN+1V
0mA<IO<1.0A, TJ=25oC, (VIN – VOUT) = 2V,
Load Regulation
1
%
V
V
CTRL = VIN + 1V
Dropout Voltage VADJ =0V for all conditions below.
1.5
0.5
1.7
0.6
(VCTRL-VOUT
)
V
V
IN =2.05V, IO=1.0A
Dropout Voltage
ADJ =0V for all conditions below.
V
A
(VIN-VOUT
)
VCTRL =3V, IO=1.0A
Current Limit
VCTRL =3V, VIN =2.05V, ∆VO=100mV, VADJ=0V
1.1
60
Minimum Load
VCTRL =5V, VIN =3.3V, VADJ =0V
5
10
mA
Current
Thermal
30ms Pulse
0.01 0.02 %W
Regulation
VCTRL =5V, VIN =5V, IO=1.0A, VADJ =0V, TJ =25,
Ripple Rejection
70
dB
V
RIPPLE=1Vpp at 120Hz
Control Pin
Current
VADJ =0V for all conditions below.
6
10
mA
µA
V
CTRL =2.75V, VIN =2.05V, IO=1.0A
Adjust Pin Current VCTRL =2.75V, VIN =2.05,VADJ=0
Thermal
50
120
Resistance
SOP-7: Control Circuitry/Power Transistor
20
1
OC/W
Junction-to-Case
Package: SOP-7L, with heat sink or amount of copper
board needed.
Power Dissipation
2
W
Typical Application Circuit
3.3V
121
+
ohm
470uF
ADJ
VSENSE
VIN
NC
VOUT
VOUT
121
ohm
2.5V/1A
+
5V
VCTRL
VIN
470uF
+
AP1187
470uF
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Aug 23, 2005
3/6
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Function Description
Introduction
The AP1187 keeps a constant 1.25V between the
VSENSE pin and the ADJ pin. By placing a resistor R1
across these two pins and connecting the VSENSE
and VOUT pin together, a constant current flows
through R1, adding to the IADJ current and into the
R2 resistor producing a voltage equal to the
(1.25/R1)*R2 + IADJ*R2. This voltage is then added
to the 1.25V to set the output voltage. This is
summarized in the above equation.
The AP1187 regulator is a 7-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 AP1187 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 AP1187-ADJ 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.
Since the minimum load current requirement of the
AP1187 is 10mA, R1 is typically selected to be a
121Ω resistor so that it automatically satisfies this
condition. Notice that since the IADJ is typically in the
range of 50uA it only adds a small error to the
output voltage and should be considered when very
precise output voltage setting is required.
Load Regulation
Since the AP1187 has separate pins for the output
(VOUT) and the sense (VSENSE), it is ideal for
providing true remote sensing of the output voltage
at the load. This means that the voltage drops due
to parasitic resistance such as PCB traces between
the regulator and the load are compensated for
using remote sensing. Figure following shows a
typical application of the AP1187 with remote
sensing.
The AP1187 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.
VOUT
VIN
VIN
AP1187-ADJ
ADJ
VSENSE
VCTRL
VCTRL
R1
R2
RL
Output Voltage Setting
Stability
The AP1187 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:
The AP1187 requires the use of an output capacitor
as part of the frequency compensation in order to
make the regulator stable. Typical designs for the
microprocessor
applications
use
standard
electrolytic capacitors with typical ESR in the range
of 50 to 100mΩ and an output capacitance of
100uF to 1000uF. Fortunately as the capacitance
increases, the ESR decreases resulting in a fixed
RC time constant. The AP1187 takes advantage of
the phenomena in making the overall regulator loop
stable.
VOUT=VREF(1+R2/R1)+IADJ*R2 where: VREF=1.25V & IADJ=50uA Typically
V
VOUT
IN
AP1187-ADJ
VSENSE
VREF
VCTRL
R1+
R2+
ADJ
IADJ=50uA
For most applications
a minimum of 100uF
aluminum electrolytic capacitor insures both
stability and good transient response.
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Aug 23, 2005
4/6
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Function Description (Continued)
Assuming, the following conditions:
Thermal Design
V
V
V
OUT =2.5V
IN =3.3V
CTRL=5V
The AP1187 incorporates an internal thermal
shutdown that protects the device when the junction
temperature exceeds the allowable maximum
junction temperature. Although this device can
operate with junction temperatures in the range of
150℃, it is recommended that the selected heat
sink be chosen such that during maximum
continuous load operation the junction temperature
is kept below this number. The example below
shows the steps in selecting the proper surface
mount package.
IOUT =1A DC Avg.
Calculate the maximum power dissipation using the
following equation:
PD= IOUT *(VIN -VOUT) + (IOUT/60) * (VCTRL - VOUT
)
PD =1*(3.3-2.5) + (1/60)*(5-2.5) =0.84W
Using table below select the proper package and
the amount of copper board needed.
Package
SOP7
Copper Area
1.0” X 1.0”
ΘJA (oC / W)
Max Pd (Ta=25oC) Max Pd (Ta=45oC)
65
1.7W
1.4W
Note: Above table is based on the maximum junction temperature of 135oC.
As shown in the above table, any of the two packages will do the job. For low cost applications the SOP7 package is
recommended.
Marking Information
(Top View)
7
5
Logo
Blank: normal
Part number
AP1187
L: Lead Free Package
YY WW X X
ID code: internal
Xth week: 01~52
Year: "01" =2001
"02" =2002
1
4
SOP-7L
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Aug 23, 2005
5/6
AP1187
1A Ultra Low Dropout Positive Adjustable Regulator
Package Information
Package Type: SOP-7L
C2
C3
B1 B2
A
E
e
C1
C
D
β
F
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min.
Nom.
Max.
Min.
Nom.
Max.
A
B1
B2
C
5.79
3.83
3.78
4.80
1.57
0.32
1.17
0.19
5.99
3.91
3.86
4.87
1.67
0.4
1.27
0.22
1.04REF
0.68
1.45
7o
6.19
3.99
3.94
4.94
1.77
0.48
1.37
0.25
0.228
0.151
0.149
0.189
0.062
0.013
0.046
0.007
0.236
0.154
0.152
0.192
0.066
0.016
0.050
0.009
0.041REF
0.027
0.057
7o
0.244
0.157
0.155
0.194
0.070
0.019
0.054
0.010
C1
C2
C3
D
E
e
0.48
1.35
0.88
1.55
0.019
0.053
0.035
0.061
F
β
Anachip Corp.
www.anachip.com.tw
Rev.1.1 Aug 23, 2005
6/6
相关型号：
AP1187S7L
Adjustable Positive LDO Regulator, 1.25V Min, 15.5V Max, 0.6V Dropout, PDSO7, LEAD FREE, SOP-7
ICT
AP1187S7LA
Adjustable Positive LDO Regulator, 1.25V Min, 15.5V Max, 0.6V Dropout, PDSO7, LEAD FREE, SOP-7
ICT
©2020 ICPDF网 联系我们和版权申明