AMC DOC. #: AMC1084_B
November 2002
Copyright 2002, ADD Microtech Corp. 1 www.addmtek.com
AMC1084
5A LOW DROPOUT REGULATOR
DESCRIPTION FEATURES
The AMC1084 is a high performance low dropout regulator
rated for 5A output current with fixed 1.8V/2.5V/3.3V/5.0V and
adjustable output. It is designed for use in applications requiring
low dropout characteristics over the rated current range.
On chip trimming adjusts the reference voltage to 1%. These
features are ideal for low voltage microprocessor applications
requiring a regulated 1.8V to 3.6V power supply.
In addition, the AMC1084 provides the device protections
including over current and thermal shutdown. Also, reverse
battery protection scheme limits the reverse current when the
input voltage falls below the output.
! Input-Output differential of
typical 1.1V at 5A and low
quiescent current
! Output current is excess of 5A
# Fast transient response
# Reverse battery protection
# Short circuit protection
# Internal thermal overload protection
# Available in 3L plastic TO-220 and
surface mount 3L TO-263/252
packages
# Pin assignment identical to EZ1084,
LT1084, and LT1585 series.
APPLICATIONS PACKAGE PIN OUT
! Pentium Processor Supplies
! PowerPCTM Supplies
! Computer Add-On Cards
! Other Applications Requiring
Lower Dropout Voltage
$ Voltage Options:
AMC1084-1.8 – 1.8V Fixed
AMC1084-2.5 – 2.5V Fixed
AMC1084-3.3 – 3.3V Fixed
AMC1084-5.0 – 5.0V Fixed
AMC1084-ADJ – Adjustable
ORDER INFORMATION
TO-220 TO-263 TO-252
TA (°C) T 3-pin ST 3-pin SJ 3-pin
0 to 70 AMC1084-X.XT AMC1084-X.XST AMC1084-X.XSJ
0 to 70 AMC1084-ADJT AMC1084-ADJST AMC1084-ADJSJ
Note: All surface-mount packages are available in Tape & Reel. Append the letter “T” to part number (i.e.,
AMC1084-X.XSTT, AMC1084-X.XSJT ).
3-Pin Plastic TO-220
(Top View)
1.ADJ/GND
3.VIN
2.VOUT
3-Pin Plastic TO-252
Surface Mount
(Top View)
3.VIN
2.VOUT
1.ADJ/GND
A
AA
ADD MICROTECH CORP.
3.VIN
2.VOUT
1.ADJ/GND
3-Pin Plastic TO-263
Surface Mount
(Top View)
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 2 www.addmtek.com
TYPICAL APPLICATION
AMC1084-X.X application schematic
AMC1084-ADJ application schematic
AMC1084
-X.X VOUT
1.8V/2.5V/3.3V/5V
C2
22µF
C1
10µF
VIN ≥ 3V
VOUT = VREF (1+(R2/R1)) + IADJR2
* REQUIRED IF REGULATOR IS
LOCATED FAR FROM POWER
SUPPLY FILTER
** DESIGN C2 AS CLOSE TO VOUT PIN
AS POSSIBLE
AMC1084 -
ADJ VOUT
**C2
22µF
*C1
10µF
VIN
R1
1%
R2
1%
A
DJ
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 3 www.addmtek.com
ABSOLUTE MAXIMUM RATINGS (Note)
Input Voltage (VIN) 11V
Operating Junction temperature 150°C
Storage Temperature Range -65°C to 150°C
Lead temperature (Soldering, 10 seconds) 300°C
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground.
Currents are positive into, negative out of the specified terminal.
POWER DISSIPATION TABLE
Package θJA
(°C /W )
Derating factor
( mW/°C ), TA≥ 25OC
TA≤ 25°C
Power rating(mW)
TA=70°C
Power rating(mW)
TA= 85°C
Power rating (mW)
T 45 22.2 2775 1776 1443
ST/ST3 45 22.2 2775 1776 1443
SJ 80 12.5 1562 1000 812
Note: TJ = TA + (PD × θJA)
PD: Power dissipation.
θJA: Thermal resistance from Junction to Ambient.
D
F : Derating factor, θJA = 1 / DF
For T and ST/ST3 packages, θJT = 3.0 °C / W.
For SJ package, θJT = 7.0 °C / W.
TJ = TTAB + (PD × θJT)
TTAB: Tab temperature.
θJT: Thermal resistance from junction to tab of the package.
1. The θJA numbers are guidelines for the thermal performance of the device/PC-board system.
2. All of the above assume no ambient airflow.
3. If power consumption is over above rating, adequate heat sink is required to dissipate heat.
RECOMMENDED OPERATING CONDITIONS
Recommended Operating Conditions
Parameter Symbol
Min. Typ. Max.
Units
Input Voltage VIN 2.75 10 V
Load Current (with adequate heatsinking) IO 0.010 5 A
Input Capacitor (VIN to GND) 1 µF
Output Capacitor with ESR of 10Ω max., (VOUT to GND) 10
µF
Operating Ambient Temperature Range 0 70 °C
Operating junction temperature TJ 125 °C
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 4 www.addmtek.com
BLOCK DIAGRAM
AMC1084 circuit schematic
ADJ
1.25
V
VREF
VIN
THERMAL
LIMIT
VOUT
R1
R2
For fixed output
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 5 www.addmtek.com
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, VIN = VOUT + 2V, IO = 10mA. These specifications apply operating ambient temperature
range, and are for DC characteristics only. (Low duty cycle pulse testing techniques are used which maintains
junction and case temperatures equal to the ambient temperature.)
AMC1084
Parameter Symbol Test Conditions Min. Typ. Max. Units
AMC1084-1.8 1.782 1.800 1.818
AMC1084-2.5 2.475 2.500 2.525
AMC1084-3.3 3.267 3.300 3.333
Output Voltage
AMC1084-5.0
VOUT TA = 25°C
4.950 5.000 5.050
V
AMC1084-1.8 1.771 1.800 1.829 V
AMC1084-2.5 2.460 2.500 2.540
AMC1084-3.3 3.247 3.300 3.353
Output Voltage
AMC1084-5.0
VOUT I
O = 10mA to 5A
4.920 5.000 5.080
V
(Note 1) 1.238 1.250 1.262
Reference
Voltage AMC1084-ADJ VREF IO = 10mA to 5A, (Note 1) 1.230 1.250 1.270 V
Line Regulation (Note 2) VOI (1.5V + VOUT) ≤ VIN ≤ 10V 0.04 0.2 %
Load regulation (Note 2) VOL I
O = 10mA to 5A 0.08 0.3 %
IO = 10mA 1.00 1.15
Dropout Voltage V (Note 3) IO = 5A 1.15 1.30 V
Quiescent Current
( for AMC1084-X.X) IQ VIN ≤ 10V, IO = 10mA to 5A 6 13 mA
Adjust Pin Current
( for AMC1084-ADJ) IADJ 50 120 µA
Current Limit ICL 5.1 6.8 A
Minimum Load Current (Note 4) Imin 5 10 mA
Ripple Rejection (Note 5) RR VRIPPLE = 1VPP, IO = 100mA,
fO=120Hz 60 80 dB
Note 1 Output voltage is set to 2.5V.
Note 2:
Line and load regulations are guaranteed up to maximum power dissipation determined by input/output
differential and the output current. However, the maximum power will not be available over the full
input/output voltage range.
Note 3: The specifications represent the minimum input/output voltage required to maintain 1% regulation.
Note 4: The minimum load current is the minimum current required to maintain regulation. Normally the current in
the resistor divider used to set the output voltage is selected to meet the minimum load current requirement.
Note 5: These parameters, although guaranteed, are not tested in production prior to shipment
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 6 www.addmtek.com
CHARACTERIZATION CURVES
CIN=10uF, COUT=22uF, TA=25°C, unless otherwise specified.
1.5
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
1.95
2
012345
Load Regulation
Output Current (A)
Output Voltage (V )
VIN =3.8V, VOUT =1.8V
2.4
2.42
2.44
2.46
2.48
2.5
2.52
2.54
2.56
2.58
2.6
012345
Load Regulation
Output Voltage (V )
VIN =4.5V,VOUT =2.5V
Output Current (A)
3
3.05
3.1
3.15
3.2
3.25
3.3
3.35
3.4
3.45
3.5
012345
Load Regulation
Output Voltage (V )
VIN =5.3V, VOUT =3.3V
Output Current (A)
4.7
4.75
4.8
4.85
4.9
4.95
5
5.05
5.1
5.15
5.2
012345
Load Regulation
Output Voltage (V )
VIN =7.0V, VOUT =5.0V
Output Current (A)
1.75
1.76
1.77
1.78
1.79
1.8
1.81
1.82
1.83
1.84
1.85
45678910
Line Regulation
Input Voltage (V)
Output Voltage (V )
IO=10mA
IO=5A
VOUT =1.8V
2.4
2.42
2.44
2.46
2.48
2.5
2.52
2.54
2.56
2.58
2.6
45678910
Line Regulation
Input Voltage (V )
Output
V
o
l
tage
(
V
)
IO=10mA
IO=5A
VOUT =2.5V
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 7 www.addmtek.com
CHARACTERIZATION CURVES (continued)
CIN=10uF, COUT=22uF, TA=25°C, unless otherwise specified.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
012345
Dropout Voltage vs. Output Current
Output Current (A)
Dropout Voltage (V)
Quiescent Current vs. Output Current
4.5
4.6
4.7
4.8
4.9
5
5.1
5.2
5.3
5.4
5.5
5.6
012345
Output Current (A)
Quiescent Current(mA)
3.1
3.15
3.2
3.25
3.3
3.35
3.4
4.5 5.5 6.5 7.5 8.5 9.5
Line Regulation
Input Voltage (V)
Output Voltage (V )
IO=10mA
IO=5A
VOUT =3.3V
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
-40 -20 0 20 40 60 80 100 120
Dropout Voltage vs. Temperature
IO=1A
IO=5A
Temperature (°C)
Dropout Voltage (mV)
2.4
2.42
2.44
2.46
2.48
2.5
2.52
2.54
2.56
2.58
2.6
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
Output Voltage vs. Temperature
VIN =5V, VOUT=2.5V
VOUT(V)
IO=10mA
IO=5A
4.8
4.85
4.9
4.95
5
5.05
5.1
5.15
5.2
78910
Line Regulation
Input Voltage (V)
Output Voltage V)
IO=10mA
IO=5A
VOUT =5.0V
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 8 www.addmtek.com
CHARACTERIZATION CURVES (continued)
VIN=5V, CIN=10uF, COUT=22uF, TA=25°C, unless otherwise specified.
Load Transient Response
With IO=1A, VOUT=3.3V
IO
VOUT
10mV/Div 1A/Div
Time: 20μs/ Div
Load Transient Response
With IO=5A, VOUT=3.3V
IO
VOUT
10mV/Div 5A/Div
Time: 20μs/ Div
Load Transient Response
With IO=1A, VOUT=2.5V
IO
VOUT
10mV/Div 1A/Div
Time: 20μs/ Div
Load Transient Response
With IO=5A, VOUT=2.5V
IO
VOUT
10mV/Div 5A/Div
Time: 20μs/ Div
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 9 www.addmtek.com
Application Note:
The maximum power dissipation of a single-output regulator:
PD(MAX) = [(VIN(MAX) - VOUT(NOM))] × IOUT(NOM) + VIN(MAX) × IQ
VOUT(NOM) = the nominal output voltage
IOUT(NOM) = the nominal output current
IQ = the quiescent current at IOUT(MAX)
VIN(MAX) = the maximum input voltage
Thermal consideration:
The AMC1084 series have internal power and thermal limiting circuitry designed to protect the device under
overload conditions. However maximum junction temperature ratings should not be exceeded under continuous
normal load conditions. The thermal protection circuit of AMC1084 series will prevent the device from damage due
to excessive power dissipation. When the device temperature rises to approximately 150°C, the regulator will be
turned off.
When power consumption is over about 1.2W (for TO-220/ TO-263 package, 687mW for TO-252 package,
at TA=70°C), additional heat sink is required to control the junction temperature below 125°C.
The junction temperature is: TJ = PD (θJT + θCS + θSA ) + TA
PD:Dissipated power.
θJT:Thermal resistance from the junction to the mounting tab of the package.
θCS:Thermal resistance through the interface between the IC and the surface on which it is mounted.
(typically, θCS < 1.0°C / W)
θSA : Thermal resistance from the mounting surface to ambient (thermal resistance of the heat sink).
If PC Board copper is going to be used as a heat sink, below table can be used to determine the appropriate size of
copper foil required. For multi-layered PCB, these layers can also be used as a heat sink. They can be connected with
several through hole vias.
PCB θSA (°C / W ) 59 45 38 33 27 24 21
PCB heat sink size (mm2) 500 1000 1500 2000 3000 4000 5000
Recommended figure of PCB area used as a heat sink.
(Top View) (Bottom View)
through hole vias
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 10 www.addmtek.com
3-Pin Plastic TO-220 (T)
INCHES MILLIMETERS
MIN TYP MAX MIN TYP MAX
A 0.140 - 0.190 3.56 - 4.83
b1 0.045 - 0.070 1.14 - 1.78
b 0.020 - 0.045 0.51 - 1.14
c 0.012 - 0.045 0.30 - 1.14
D 0.560 - 0.650 14.22 - 16.51
E 0.380 - 0.420 9.65 - 10.67
e 0.090 - 0.110 2.29 - 2.79
e1 0.190 - 0.210 4.83 - 5.33
F 0.020 0.055 0.51 - 1.40
H1 0.230 - 0.270 5.84 - 6.86
J1 0.080 - 0.115 2.03 - 2.92
L 0.500 - 0.580 12.7 - 14.73
P 0.139 - 0.161 3.53 - 4.09
Q 0.100 - 0.135 2.54 - 3.43
L1 - - 0.250 - - 6.35
E
b
e1
P
e
b1
Q
D
L
cJ1
F
A
H1
SEATING PLAN
L1
3-Pin Surface Mount TO-263 (ST)
INCHES MILLIMETERS
MIN TYP MAX MIN TYP MAX
A 0.160 - 0.190 4.06 - 4.83
b 0.020 - 0.039 0.51 - 0.99
b2 0.045 - 0.055 1.14 - 1.40
c 0.015 TYP. 0.38 TYP.
c2 0.045 - 0.055 1.14 - 1.40
D 0.340 - 0.380 8.64 - 9.65
E 0.380 - 0.405 9.65 - 10.29
e 0.100 B S C 2.54 BS C
L 0.575 - 0.625 14.61 - 15.88
L1 0.090 - 0.110 2.29 - 2.79
L2 - - 0.115 - - 2.92
L3 0.050 - 0.070 1.27 - 1.78
E
b
b2
e
L
L1
c
D
L3
c2
A
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 11 www.addmtek.com
3-Pin Surface Mount TO-252 (SJ)
INCHES MILLIMETERS
MIN TYP MAX MIN TYP MAX
A 0.086 - 0.094 2.18 - 2.39
A1 0.040 - 0.050 1.02 - 1.27
b - 0.024 - - 0.61 -
b2 0.205 - 0.215 5.21 - 5.46
c 0.018 - 0.023 0.46 - 0.58
c1 0.018 - 0.023 0.46 - 0.58
D 0.210 - 0.220 5.33 - 5.59
E 0.250 - 0.265 6.35 - 6.73
e 0.090 B S C 2.29 BS C
e1 0.180 BSC 4.58 BS C
H 0.370 - 0.410 9.40 - 10.41
L 0.020 - - 0.51 - -
L1 0.025 - 0.040 0.64 - 1.02
L2 0.060 - 0.080 1.52 - 2.03
b2
E
L2
D
b
ee1
L1
SEATING PLAN
H
L
c
c1
A1
A
AMC DOC. #: AMC1084_B AMC1084
November 2002 5A L OW DROPOUT REGULATOR
Copyright 2002, ADD Microtech Corp. 12 www.addmtek.com
IMPORTANT NOTICE
ADD Microtech (ADDM) reserves the right to make changes to its products or to discontinue any integrated circuit
product or service without notice, and advises its customers to obtain the latest version of relevant information to
verify, before placing orders, that the information being relied on is current.
A few applications using integrated circuit products may involve potential risks of death, personal injury, or severe
property or environmental damage. ADDM integrated circuit products are not designed, intended, authorized, or
warranted to be suitable for use in life-support applications, devices or systems or other critical applications. Use of
ADDM products in such applications is understood to be fully at the risk of the customer. In order to minimize
risks associated with the customer’s applications, the customer should provide adequate design and operating
safeguards.
ADDM assumes to no liability to customer product design or application support. ADDM warrants the performance
of its products to the specifications applicable at the time of sale.
U.S. Asia Pacific region
ADD Microtech Inc.
492 Altamont Drive
Milpitas, CA 95035
ADD Microtech Corp
3F, 132, Sec. 4, Chung Hsiao E. Rd.,
Taipei, Taiwan
TEL: (408) 9410420 TEL: 2-27760166
FAX: (408) 9410864 FAX: 2-27764208
