AMS317A [ADMOS]
1A LOW DROPOUT VOLTAGE REGULATOR; 1A低压差稳压器
| 型号： | AMS317A |
| 厂家： | 
ADVANCED MONOLITHIC SYSTEMS |
| 描述： | 1A LOW DROPOUT VOLTAGE REGULATOR |
| 文件： | 总8页 (文件大小：82K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Advanced
Monolithic
Systems
AMS317
1A LOW DROPOUT VOLTAGE REGULATOR
FEATURES
APPLICATIONS
· Three Terminal Adjustable or Fixed Voltages*
1.8V, 2.5V, 2.85V, 3.3V and 5.0V
· Output Current of 1A
· High Efficiency Linear Regulators
· Post Regulators for Switching Supplies
· 5V to 3.3V Linear Regulator
· Battery Chargers
· Operates Down to 1V Dropout
· Line Regulation: 0.2% Max.
· Active SCSI Terminators
· Load Regulation: 0.4% Max.
· TO-220, TO-263, TO-252 and SOT-223 package available
· Power Management for Notebook
· Battery Powered Instrumentation
GENERAL DESCRIPTION
The AMS317 series of adjustable and fixed voltage regulators are designed to provide 1A output current and to operate down
to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.3V at maximum output
current, decreasing at lower load currents.
On-chip trimming adjusts the reference voltage to 1%. Current limit is also trimmed, minimizing the stress under overload
conditions on both the regulator and power source circuitry.
The AMS317 devices are pin compatible with other three-terminal regulators and are offered in 3 lead TO-220 package, in
the 2 & 3 Lead TO-263 (Plastic DD), in the TO-252 (D PAK) and in the low profile surface mount SOT-223 package.
ORDERING INFORMATION:
OUTPUT
PACKAGE TYPE
3 Lead TO-220 2 &3 Lead TO-263 TO-252
OPERATING JUNCTION
TEMPERATURE RANGE
SOT-223
AMS317A
AMS317
VOLTAGE
ADJUSTABLE AMS317ACT
AMS317CT
AMS317ACM
AMS317CM
AMS317ACD
AMS317CD
-40 to +125° C
0 to 125° C
FIXED*
AMS317ACT-X
AMS317CT-X
AMS317ACM-X
AMS317CM-X
AMS317ACD-X AMS317A-X
-40 to +125° C
0 to 125° C
AMS317CD-X
AMS317-X
X= 1.8V, 2.5V, 2.85V, 3.3V and 5.0V.
*For additional available fixed voltages contact factory.
SOT-223 Top View
PIN CONNECTIONS
TO-263 FRONT VIEW
FIXED VERSION
ADJUSTABLE VERSION
3
TAB IS
OUTPUT
2
1
1- Ground
2- VOUT
3- VIN
1- Adjust
2- VOUT
3- VIN
1
2
3
TO-252 FRONT VIEW
3
2L TO-263 FRONT VIEW
TO-220 FRONT VIEW
3
2
1
TAB IS
OUTPUT
TAB IS
OUTPUT
3
2
1
TAB IS
OUTPUT
2
1
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
ABSOLUTE MAXIMUM RATINGS (Note 1)
Power Dissipation
Internally limited
Thermal Resistance
TO-220 package
TO-263 package
TO-252 package
SOT-223 package
Input Voltage
25V
j
j
j
JA= 50°C/W
JA= 30°C/W
JA= 80°C/W
JA= 90°C/W*
Operating Junction Temperature
AMS317A
AMS317
-40°C to +125°C
0°C to +125°C
j
* With package soldering to copper area over backside ground
Storage temperature
Soldering information
Lead Temperature (10 sec)
- 65°C to +150°C
plane or internal power plane j can vary from 46°C/W to
JA
>90°C/W (for SOT-223) (20°C/W to >40°C/W for TO-263)
depending on mounting technique and the size of the copper
area.
300°C
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IOUT = 10 mA, (VIN - VOUT) = 5V, and TJ = +25°C unless otherwise specified.
Parameter
Device
Conditions
AMS317A
Min Typ
AMS317
Max Min Typ
Units
Max
Reference Voltage
(Note 2)
AMS317
IOUT = 10 mA
10mA £ IOUT £ IMAX, 3V£ (VIN - VOUT) £ 25V
1.238
1.225
1.250
1.250
1.262
1.270
1.225
1.20
1.250
1.250
1.270
1.30
V
V
Output Voltage
(Note 2)
AMS317-1.8
AMS317-2.5
AMS317-2.85
AMS317-3.3
AMS317-5.0
AMS317
1.782
1.764
1.800
1.800
1.818
1.836
1.764
1.746
1.800
1.800
1.836
1.854
V
V
0 £ IOUT £ IMAX, 3.3V£ VIN £ 25V
0 £ IOUT £ IMAX , 4.0V£ VIN £ 25V
0 £ IOUT £ IMAX , 4.35V£ VIN £ 25V
0 £ IOUT £ IMAX, 4.75V £ VIN £ 25V
2.475
2.460
2.500
2.500
2.525
2.560
2.450
2.425
2.500
2.500
2.550
2.575
V
V
2.82
2.793
2.850
2.850
2.88
2.907
2.793
2.765
2.850
2.850
2.907
2.935
V
V
3.267
3.235
3.300
3.300
3.333
3.365
3.235
3.201
3.300
3.300
3.365
3.399
V
V
4.950
4.900
5.000
5.000
5.050
5.100
4.900
4.850
5.000
5.000
5.100
5.150
V
V
0 £ IOUT £ IMAX , 6.5V £ VIN £ 25V
Line Regulation
0.015
0.035
0.2
0.2
0.015
0.035
0.2
0.2
%
%
ILOAD = 10 mA , 3V£ (VIN - VOUT) £ 25V
Load Regulation
(Notes 2, 3)
AMS317
0.1
0.3
0.5
1.0
0.1
0.3
0.5
1.0
%
%
10mA £ IOUT £ IMAX
Current Limit
AMS317/-1.8/-
2.5/-2.85/-3.3/-5.0
(VIN - VOUT) = 5V
A
1.5
5
2.0
1.5
5
2.0
Minimum Load
Current
AMS317
(VIN - VOUT) = 25V
mA
10
10
Thermal Regulation
Adjust Pin Current
AMS317
AMS317
TA = 25°C, 20ms pulse
0.04
40
0.07
0.04
40
0.07
%W
mA
mA
100
5
100
5
Adjust Pin Current
Change
AMS317
AMS317
0.2
1.0
0.2
1.0
10mA £ IOUT £ IMAX , 3V£ (VIN - VOUT) £ 25V
TMIN £ TJ £ TMAX
mA
Temperature
Stability
%
Long Term Stability
Ripple Rejection
TA =125°C, 1000Hrs
0.3
1
0.3
1
%
dB
66
80
66
80
f =120Hz , COUT = 25mF Tantalum,
(VIN-VOUT ) = 3V, CADJ =10mF
RMS Output Noise
0.003
0.003
%
TA = 25°C , 10Hz £ f £ 10kHz
(% of VOUT
)
Thermal Resistance
Junction-to-Case
TO-252 Package
5
23.5
5
5
23.5
5
°C/W
°C/W
°C/W
SOT-223 Package
TO-220 / TO-263 Package
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and test conditions, see the
Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Parameters identified with boldface type apply over the full
operating temperature range.
Note 2: Line and Load regulation are guaranteed up to the maximum power dissipation of 1.2 W. Power dissipation is determined by the input/output differential
and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range.
Note 3: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constant junction
temperature by low duty cycle pulse testing. Load regulation is measured at the output lead ~1/8” from the package.
Note 4: Minimum load current is defined as the minimum output current required to maintain regulation. When 3V £ (VIN - VOUT) £ 25V the device is guaranteed
to regulate if the output current is greater than 10mA.
APPLICATION HINTS
The AMS317 series of adjustable and fixed regulators are easy to
use and are protected against short circuit and thermal overloads.
Thermal protection circuitry will shut-down the regulator should
the junction temperature exceed 165°C at the sense point.
Pin compatible with older three terminal adjustable regulators,
these devices offer the advantage of a lower dropout voltage,
more precise reference tolerance and improved reference stability
with temperature.
output capacitors are used, such as 1000mF to 5000mF and the
input pin is instantaneously shorted to ground, damage can occur.
A diode from output to input is recommended, when a crowbar
circuit at the input of the AMS317 is used (Figure 1).
D1
Stability
AMS317
IN OUT
ADJ
VOUT
COUT
VIN
The circuit design used in the AMS317 series requires the use of
an output capacitor as part of the device frequency compensation.
The addition of 150mF aluminum electrolytic or a 22mF solid
tantalum on the output will ensure stability for all operating
conditions.
+
R1
R2
m
F
150
CADJ
m
F
10
When the adjustment terminal is bypassed with a capacitor to
improve the ripple rejection, the requirement for an output
capacitor increases. The value of 22mF tantalum or 150mF
aluminum covers all cases of bypassing the adjustment terminal.
Without bypassing the adjustment terminal smaller capacitors can
be used with equally good results.
Figure 1.
Output Voltage
To ensure good transient response with heavy load current
changes capacitor values on the order of 100mF are used in the
output of many regulators. To further improve stability and
transient response of these devices larger values of output
capacitor can be used.
The AMS317 series develops a 1.25V reference voltage between
the output and the adjust terminal. Placing a resistor between
these two terminals causes a constant current to flow through R1
and down through R2 to set the overall output voltage. This
current is normally the specified minimum load current of 10mA.
Because IADJ is very small and constant it represents a small
error and it can usually be ignored.
Protection Diodes
Unlike older regulators, the AMS317 family does not need any
protection diodes between the adjustment pin and the output and
from the output to the input to prevent over-stressing the die.
Internal resistors are limiting the internal current paths on the
AMS317 adjustment pin, therefore even with capacitors on the
adjustment pin no protection diode is needed to ensure device
safety under short-circuit conditions.
AMS317
IN OUT
ADJ
VOUT
VIN
VREF
R1
R2
IADJ
50
A
m
Diodes between the input and output are not usually needed.
Microsecond surge currents of 50A to 100A can be handled by the
internal diode between the input and output pins of the device. In
normal operations it is difficult to get those values of surge
currents even with the use of large output capacitances. If high
value
VOUT = VREF (1+ R2/R1)+IADJR2
Figure 2. Basic Adjustable Regulator
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
APPLICATION HINTS
Load Regulation
The thermal resistance from the junction to the tab for the
AMS317 is 15°C/W; thermal resistance from tab to ambient can
be as low as 30°C/W. The total thermal resistance from junction
to ambient can be as low as 45°C/W. This requires a reasonable
sized PC board with at least on layer of copper to spread the heat
across the board and couple it into the surrounding air.
Experiments have shown that the heat spreading copper layer
does not need to be electrically connected to the tab of the device.
The PC material can be very effective at transmitting heat
between the pad area, attached to the pad of the device, and a
ground plane layer either inside or on the opposite side of the
board. Although the actual thermal resistance of the PC material
is high, the Length/Area ratio of the thermal resistance between
layers is small. The data in Table 1, was taken using 1/16” FR-4
board with 1 oz. copper foil, and it can be used as a rough
guideline for estimating thermal resistance.
True remote load sensing it is not possible to provide, because the
AMS317 is a three terminal device. The resistance of the wire
connecting the regulator to the load will limit the load regulation.
The data sheet specification for load regulation is measured at the
bottom of the package. Negative side sensing is a true Kelvin
connection, with the bottom of the output divider returned to the
negative side of the load.
The best load regulation is obtained when the top of the resistor
divider R1 is connected directly to the case not to the load. If R1
were connected to the load, the effective resistance between the
regulator and the load would be:
RP x ( R2+R1 ) , RP = Parasitic Line Resistance
R1
For the TO-252 package, if the maximum allowable value is
found to be ³ 92°C/W, no heat sink is needed since the package
alone will dissipate enough heat to satisfy these requirements. If
the calculated value for qJA falls bellow these limits, a heat sink
is required.
For each application the thermal resistance will be affected by
thermal interactions with other components on the board. To
determine the actual value some experimentation will be
necessary.
Connected as shown , RP is not multiplied by the divider ratio
RP
PARASITIC
LINE RESISTANCE
AMS317
V
IN
OUT
ADJ
IN
RL
R1*
R2*
The power dissipation of the AMS317 is equal to:
PD = ( VIN - VOUT )( IOUT
)
Maximum junction temperature will be equal to:
TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient))
Maximum junction temperature must not exceed 125°C.
Ripple Rejection
The ripple rejection values are measured with the adjustment pin
bypassed. The impedance of the adjust pin capacitor at the ripple
frequency should be less than the value of R1 (normally 100W to
200W) for a proper bypassing and ripple rejection approaching
the values shown. The size of the required adjust pin capacitor is
a function of the input ripple frequency. If R1=100W at 120Hz
the adjust pin capacitor should be >13mF. At 10kHz only 0.16mF
is needed.
*CONNECT R1 TO CASE
CONNECT R2 TO LOAD
Figure 3. Connections for Best Load Regulation
In the case of fixed voltage devices the top of R1 is connected
Kelvin internally, and the ground pin can be used for negative
side sensing.
The ripple rejection will be a function of output voltage, in
circuits without an adjust pin bypass capacitor. The output ripple
will increase directly as a ratio of the output voltage to the
reference voltage (VOUT / VREF ).
Thermal Considerations
The AMS317 series have internal power and thermal limiting
circuitry designed to protect the device under overload conditions.
However maximum junction temperature ratings of 125°C should
not be exceeded under continuous normal load conditions.
Careful consideration must be given to all sources of thermal
resistance from junction to ambient. For the surface mount
package SOT-223 additional heat sources mounted near the
device must be considered. The heat dissipation capability of the
PC board and its copper traces is used as a heat sink for the
device.
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
Table 1.
COPPER AREA
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
TOP SIDE*
2500 Sq. mm
BACK SIDE
2500 Sq. mm
BOARD AREA
2500 Sq. mm
45°C/W
45°C/W
53°C/W
59°C/W
52°C/W
55°C/W
1000 Sq. mm
225 Sq. mm
100 Sq. mm
1000 Sq. mm
1000 Sq. mm
2500 Sq. mm
2500 Sq. mm
2500 Sq. mm
1000 Sq. mm
0
2500 Sq. mm
2500 Sq. mm
2500 Sq. mm
1000 Sq. mm
1000 Sq. mm
* Tab of device attached to topside copper.
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Operating Current
Short-Circuit Current
(Adjustable Device)
12
1.25
1.00
0.75
0.50
0.25
0
TJ = 125°C
TJ = 25°C
9
TJ =
125°C
TJ = 25°C
6
3
0
0
5
10
15
20
0
5
10
15
INPUT/OUTPUT DIFFERENTIAL
INPUT/OUTPUT DIFFERENTIAL (V)
Load Regulation
Ripple Rejection vs. Current
0.10
0.05
100
90
80
70
60
50
40
30
20
10
0
D
ILOAD = 1A
fRIPPLE = 120Hz
VRIPPLE£3Vp-p
0
fRIPPLE = 20Hz
-0.05
£
VRIPPLE 0.5Vp-p
-0.10
-0.15
-0.20
VOUT = 5V
CADJ = 25
COUT = 25
mF
m
F
-50
-25
0
25
50
75
100
125
0
0.2
0.4
0.6
0.8
TEMPERATURE (°C)
OUTPUT CURRENT (A)
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
TYPICAL PERFORMANCE CHARACTERISTICS (Continued).
Adjust Pin Current
Temperature Stability
2.0
1.0
0
100
90
80
70
60
50
40
30
20
10
0
-1.0
-2.0
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
125
150
TEMPERATURE (°C)
TEMPERATURE (°C)
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.
3 LEAD TO-220 PLASTIC PACKAGE (T)
0.147-0.155
0.165-0.180
(4.191-4.572)
0.390-0.415
(9.906-10.541)
(3.734-3.937)
0.045-0.055
(1.143-1.397)
DIA
0.230-0.270
(5.842-6.858)
0.570-0.620
(14.478-15.748)
0.460-0.500
(11.684-12.700)
0.330-0.370
(8.382-9.398)
0.980-1.070
(24.892-27.178)
0.218-0.252
(5.537-6.401)
0.520-0.570
(13.208-14.478)
0.090-0.110
(2.286-2.794)
0.050
(1.270)
TYP
0.013-0.023
(0.330-0.584)
0.095-0.115
(2.413-2.921)
0.028-0.038
(0.711-0.965)
T (TO-220) AMS DRW# 042193
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).
3 LEAD TO-263 PLASTIC DD (M)
0.165-0.180
(4.191-4.572)
0.060
(1.524)
0.390-0.415
(9.906-10.541)
0.045-0.055
(1.143-1.397)
TYP
+0.008
-0.004
+0.203
0.004
0.330-0.370
(8.382-9.398)
(
)
0.102
-0.102
0.095-0.115
(2.413-2.921)
0.108
(2.74)
0.199-0.218
(5.05-5.54 )
TYP
0.90-0.110
(2.29-2.79)
0.090-0.110
(2.286-2.794)
0.032
(0.81)
TYP
0.013-0.023
(0.330-0.584)
M (DD3) AMS DRW# 042191R1
2 LEAD TO-263 PLASTIC DD (M)
0.165-0.180
(4.191-4.572)
0.060
(1.524)
0.390-0.415
(9.906-10.541)
0.045-0.055
(1.143-1.397)
TYP
+0.008
-0.004
+0.203
0.004
0.330-0.370
(8.382-9.398)
(
)
0.102
-0.102
0.0295
0.095-0.115
0.108
(2.74)
TYP
(0.7495)
(2.413-2.921)
0.199-0.218
(5.05-5.54 )
TYP
0.90-0.110
(2.29-2.79)
0.090-0.110
(2.286-2.794)
0.032
(0.81)
TYP
0.013-0.023
(0.330-0.584)
M (DD2) AMS DRW# 072191
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS317
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).
TO-252 PLASTIC PACKAGE (D)
0.258-0.262
(6.553-6.654)
0.208-0.212
(5.283-5.384)
0.020-0.030
0.085-0.095
(0.508-0.762)
0.033-0.037
(2.159-2.413)
0.030-0.034
(0.762-0.863)
0.020-0.030
(0.508-0.762)
(0.838-0.939)
0.038-0.042
(0.965-1.066)
7.0°
0.023-0.027
(0.584-0.685)
45.0°
0.175-0.180
(4.191-4.445)
0.235-0.245
(5.969-6.223)
0.057-0.067
(0.144-0.170)
DIA
0.025
(0.635)
TYP
0.038
(0.965)
TYP
0.038-0.042
(0.965-1.066)
0.099-0.103
(2.514-2.615)
0.024±0.002
(0.610±0.0508)
0.088-0.092
(2.235-2.336)
0.030
(0.762)
TYP
0.018-0.022
(0.451-0.558)
D (D3) AMS DRW# 042891
3 LEAD SOT-223 PLASTIC PACKAGE
0.248-0.264
(6.30-6.71)
0.116-0.124
(2.95-3.15)
0.264-0.287
(6.71-7.29)
0.130-0.146
(3.30-3.71)
0.033-0.041
(0.84-1.04)
0.090
(2.29)
NOM
10°-16°
10°
MAX
0.071
(1.80)
MAX
0.010-0.014
(0.25-0.36)
10°-16°
0.012
(0.31)
MIN
0.025-0.033
(0.64-0.84)
0.025-0.033
(0.64-0.84)
(SOT-223 ) AMS DRW# 042292
0.181
(4.60)
NOM
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
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