5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
FEATURES
●
Output Current of 5A
●
Fast Transient Response
●
0.04% Line Regulation
●
0.2% Load Regulation
●
Internal Thermal and Current Limiting
●
Adjustable or Fixed Output Voltage(1.5V, 1.8V, 2.5V, 3.3V, 5.0V)
●
Surface Mount Package TO-263 3LD and TO-252 3L
●
100% Thermal Limit Burn-in
●
Low Dropout Voltage 1.5V at 5A Output Current
●
Moisture Sensitivity Level 3
TO-263 PKG
LM1084
TO-252 PKG
APPLICATIONS
●
High Efficiency Linear Regulators / Power Supply
●
High Efficiency "Green" Computer Systems
●
Constant Current Regulators
●
Portable Instrumentation
●
SMPS Post-Regulator
●
Adjustable Power Supplies
●
Powering VGA & Sound Card
1. ADJ / GND
2. OUTPUT
3. INPUT
* Heatsink surface connected to Pin 2.
ORDERING INFORMATION
Device
LM1084R-X.X
LM1084RS-X.X
Package
TO-263 3LD
TO-252 3LD
(X.X=VOUT=1.5V, 1.8V, 2.5V, 3.3V, 5.0V, ADJ)
DESCRIPTION
The LM1084 series of positive adjustable and fixed regulators are designed to provide 5A with high efficient.
All internal circuitry is designed to operate down to 1.3V input to output differential.
On-chip trimming adjusts the reference voltage to 1%.
It's low dropout voltage and fast transient response make it ideal for low voltage microprocessor applications.
Internal current and thermal limiting provides protection against any overload condition that would create
excessive junction temperature.
TEST & TYPICAL APPLICATION CIRCUIT
LM1084-3.3V
LM1084-ADJ
Note
(1) C1 needed if device is far away from filter capacitors.
(2) C2 minimum value required for stability.
V
REF
=V
OUT
-V
ADJ
=1.25V(Typ.)
I
ADJ
=55㎂(Typ.)
V
OUT
= V
REF
x (1+RF2/RF1) + I
ADJ
x RF2
Nov. 2010 - Rev. 1.3.
HTC
-1-
5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
ABSOLUTE MAXIMUM RATINGS
CHARACTERISTIC
Supply Voltage
Operating Junction Temperature Range
Storage Temperature Range
Thermal Resistance Junction to Case TO-263
Thermal Resistance Junction to Ambient TO-263
Lead Temperature (Soldering) 10 sec.
Maximum Output Current
SYMBOL
V
IN
Topr
Tstg
Tjc
Tja
Tsol
Imax
VALUE
12
0 ~ 125
-65 ~ 150
3
60
300
5
LM1084
UNIT
V
℃
℃
C/W
C/W
℃
A
ELECTRICAL CHARACTERISTICS
I
OUT
=100mA, T
A
=25°C, unless otherwise specified.
PARAMETER
1.5V Version
Output Voltage
1.8V Version
Output Voltage
2.5V Version
Output Voltage
3.3V Version
Output Voltage
5.0V Version
Output Voltage
All Voltage Options
Reference Voltage (V
REF
)
Note 1
Min. Load Current
Line Regulation
Note 1
Load Regulation
Dropout Voltage
Note 1
Note1,3
TEST CONDITIONS
0 < I
OUT
< 5A, 3.3V < V
IN
0 < I
OUT
< 5A, 3.75V < V
IN
0 < I
OUT
< 5A, 4.0V < V
IN
0 < I
OUT
< 5A, 4.8V < V
IN
0 < I
OUT
< 5A, 6.5V < V
IN
V
IN
=5V, I
LOAD
= 10mA
1.5V
≤
(V
IN
-V
OUT
)
≤
10V, 10mA
≤
I
OUT
≤
5A
V
IN
=5V, V
ADJ
= 0V
1.5V
≤
V
IN
-V
OUT
≤
10V, I
OUT
=10mA T
J
=25℃
10mA
≤
I
OUT
≤
5A, V
IN
-V
OUT
=1.5V, T
J
=25℃
ΔV
REF
= 1% , I
OUT
= 5A
V
IN
-V
OUT
= 1.5V
1.4V≤(V
IN
-V
OUT
) Adjustable Only
10mA
≤
I
OUT
≤
5A, V
IN
-V
OUT
=1.5V, T
J
=25℃
1.5V
≤
V
IN
-V
OUT
≤
10V, I
OUT
=10mA, T
J
=25℃
V
IN
-V
OUT
= 3V, I
OUT
= 5A
V
IN
-V
OUT
= 1.5V, I
OUT
= 10mA
MIN
1.470
1.764
2.450
3.234
4.900
1.238
1.225
TYP
1.5
1.8
2.5
3.3
5
1.25
1.25
3
0.04
0.2
1.3
MAX
1.530
1.836
2.550
3.366
5.100
1.262
1.275
7
0.2
0.4
1.5
UNIT
V
V
V
V
V
V
mA
%
%
V
A
Current Limit I
OUT
(MAX)
Ground Pin Current
Audust Pin Current
Ripple Rejection
Note 2
Temperature Coefficient
5
6.5
7
0.003
10
mA
uA
dB
60
72
0.005
3
%/℃
Notes :
1 : Low duty pulse testing with Kelvin connections required.
2 : 120Hz input ripple (C
ADJ
for ADJ = 25uF, Cout = 25uF)
3 :
ΔV
OUT
,
ΔV
REF
= 1%
HTC
-2-
5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
TYPICAL PERFORMANCE CHARACTERISTICS
LM1084
Figure 1. Dropout Voltage vs Output Current
Figure 2. Reference Voltage vs Temperature
Figure 3. Load Regulation vs. Output Current
Figure 4. Minimum Load Current
Figure 5. Adjust Pin Current vs Temperature
Figure 6. Ripple Rejection vs. Frequency
(Fixed Versions)
HTC
-3-
5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
LM1084
Figure 7. Ripple Rejection vs. Frequency (Adjustable Versions)
APPLICATIONS INFORMATION
LM1084-ADJ
Figure 8. Resistor Divider Scheme for the Adjustable Version
LM1084-XX
Figure 9. Protection Diode Scheme for Fixed Output Regulators
HTC
-4-
5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
APPLICATION INFORMATION
LM1084
The LM1084 series of adjustable and fixed regulators are easy to use and have all the protection features
expected in high performance voltage regulators : short circuit protection and thermal shut-down.
Pin compatible with older three terminal adjustable regulators, these devices offer the advantage of a lower
dropout voltage, more precies reference tolerance and improved reference stability with temperature.
STABILITY
The circuit design used in the LM1084 series requires the use of an output capacitor as part of the device
frequency compensation.
The addition of 150uF aluminum electrolytic or a 22uF solid tantalum on the output will ensure stability for
all operating conditions. When the adjustment terminal is bypassed with a capacitor to improve the ripple
rejection, the requirement for an output capacitor increases. The value of 22uF tantalum or 150uF aluminum
covers all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal smaller
capacitors can be used with equally good results.
To ensure good transient response with heavy load current changes capacitor values on the order of 100uF
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.
PROTECTION DIODES
Unlike older regulators, the LM1084 family does not need any
protection diodies between the adjustment pin and the output and
from the output tu the input to prevent over-stressing the die.
LM1084
Internal resistors are limiting the internal current paths on the
LM1084 adjustment pin, therfore even with capacitors on the
adjustment pin no protection diode is needed to ensure device
safety under short-circuit conditions.
Diodes between the input and output are not usually needed.
Figure 10.
Microsecond surge currents of 50A to 100A can be handled by
the internal diode between the input and output pins of the device. In norminal operations it is difficult to get
those values of surge currents even with the use of large output capacitances. If high value output capacitors
are used, such as 1000uF to 5000uF 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 LM1084 is used.
Normal power supply cycling or even plugging and unplugging in the system will not generate current large
enough to do any damage.
The adjustment pin can be driven on a transient basis ±25V, with respect to the output without any device
degradation. As with any IC regulator, none the protection circuitry will be functional and the internal
transistors will break diwn if the maximum inout to output voltage differential is exceeded.
HTC
-5-
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