www.fairchildsemi.com
FAN1582
3A Adjustable/Fixed Ultra Low Dropout
Linear Regulator
Features
•
•
•
•
•
•
•
Ultra Low dropout voltage, 0.4V typical at 3A
Remote sense operation
Fast transient response
Load regulation: 0.05% typical
0.5% initial accuracy
On-chip thermal limiting
5-Pin SPAK, TO-252 DPAK, and TO-263 packages
Description
The FAN1582, FAN1582-1.5, and FAN1582-2.5 are ultra-low
dropout regulators with 3A output current capability. These
devices have been optimized for low voltage applications
including V
TT
bus termination, where transient response and
minimum input voltage are critical. The FAN1582 is ideal
for low voltage microprocessor applications requiring a reg-
ulated output from 1.3V to 5.7V with a power input supply
of 1.75V to 6.5V. The FAN1582-1.5 offers fixed 1.5V with
3A current capabilities for GTL+ bus V
TT
termination. The
FAN1582-2.5 offers fixed 2.5V with 3A current capability
for logic IC operation and processors while minimizing the
overall power dissipation.
Current limit ensures controlled short-circuit current. On-chip
thermal limiting provides protection against any combination
of overload and ambient temperature that would create exces-
sive junction temperatures.
The FAN1582 series regulators are available in the 5-Pin
SPAK, TO-252 DPAK, and TO-263 power packages.
Applications
•
•
•
•
•
•
•
Pentium
®
Processors
PowerPC
™
, AMD K5 and K6 processors
Pentium support of GTL+ bus supply
Low voltage logic supply
Embedded Processor supplies
Split plane regulator
New 2.5V and 1.8V Logic Families
Typical Applications
V
IN
= 3.3V
+
10µF
V
IN
= 3.3V
+
10µF
V
CNTL
= 5V
V
CNTL
= 5V
+
1µF
2.1V at 3A
+
124Ω
22µF
V
IN
= 5.75V
+
86.6Ω
10µF
V
CNTL
= 12V
V
IN
V
SENSE
V
IN
V
SENSE
FAN1582–2.5
V
OUT
V
CNTL
GND
2.5V at 3A
+
22µF
V
IN
V
SENSE
FAN1582
V
OUT
V
CNTL
Adj
FAN1582
V
OUT
V
CNTL
Adj
124Ω
+
22µF
5V at 3A
374Ω
Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation.
REV. 1.1.2 2/26/03
FAN1582
PRODUCT SPECIFICATION
Pin Assignments
FAN1582M-1.5, -2.5
FRONT VIEW
FAN1582M
FRONT VIEW
FAN1582P
FRONT VIEW
FAN1582P-1.5, -2.5
FRONT VIEW
FAN1582D
FRONT VIEW
FAN1582D-1.5, -2.5
FRONT VIEW
1 2 3 4 5
1 2 3 4 5
1 2 3
4 5
1 2 3
4 5
1
2
3
4
5
1
2
3
4
5
CNTL
IN
S
GND
OUT
S
GND
OUT
CNTL
IN
S
ADJ
OUT
CNTL
IN
CNTL
IN
S
ADJ
OUT
ADJ
CNTL
GND
CNTL
S
OUT
IN
S
OUT
5-Lead Plastic TO-263
Θ
JC
=3°C/W*
Tab is out.
5-Lead Plastic SPAK
Θ
JC
=2°C/W*
Tab is out.
5-Lead Plastic TO-252 DPAK
Θ
JC
=3°C/W*
Tab is out.
*With package soldered to 0.5 square inch copper area over backside ground plane or internal
power plane,
θ
JA
can vary from 30
°C/W
to more than 40
°C/W.
Other mounting techniques
can provide a thermal resistance lower than 30
°C/W.
Pin Definitions
Pin Number
1
Pin Name
VSense
ADJ/GND
Pin Function Descrition
Remote Voltage Sense
. Connect this pin to the load to permit true
remote sensing and avoid trace drops.
Adjust or Ground.
On the FAN1582, this pin forms the feedback to
determine the output voltage. On the FAN1582-1.5 and -2.5, connect this
pin to ground.
Output Voltage.
This pin and the tab are output.
Control Voltage.
This pin draws small-signal power to control the
FAN1582 circuitry. Connect to a voltage higher than VIN, as shown in the
applications circuits.
Input Voltage.
2
3
4
VOUT
VCNTL
5
VIN
Internal Block Diagram
4
V
CNTL
, Control
5 Vin, Power
Thermal
Shutdown
Current
Limit
3 Output
1 Sense
2 Adj
Vref
Voltage Loop
Amplifier
2
REV. 1.1.2 2/26/03
IN
PRODUCT SPECIFICATION
FAN1582
Absolute Maximum Ratings
Parameter
V
IN
V
CNTL
Operating Junction Temperature Range
Lead Temperature (Soldering, 10 sec.)
Storage Temperature Range
-65
0
Min.
Max.
7
13.2
125
300
150
Unit
V
V
°C
°C
°C
Electrical Characteristics
T
J
=25°C, V
OUT
= V
S
, V
ADJ
= 0V unless otherwise specified.
The • denotes specifications which apply over the specified operating temperature range.
Parameter
Reference Voltage
3
Reference Voltage
3
Conditions
V
IN
= 2.0V, V
CNTL
= 2.75V,
I
OUT
= 10mA
2.05V
≤
V
IN
≤
5.5V,
2.7V
≤
V
CNTL
≤
12V,
10mA
≤
I
OUT
≤
3A
3V
≤
V
IN
≤
7V (function of Vout),
10mA
≤
I
OUT
≤
3A
3V
≤
V
IN
≤
7V, 10mA
≤
I
OUT
≤
3A
5.1V
≤
V
IN
≤
7V, 10mA
≤
I
OUT
≤
3A
1.75V
≤
V
IN
≤
5.5V, 2.5V
≤
V
CNTL
≤
12V,
I
OUT
= 10mA
V
IN
= 2.1V, V
CNTL
= 2.75V,
10mA
≤
I
OUT
≤
3A
V
IN
= 2.05V,
∆
V
REF
= 1%, I
OUT
= 3A
V
CNTL
= 2.75V,
∆
V
REF
= 1%,
I
OUT
= 3A
V
CNTL
= 2.75V,
∆
V
REF
= 1%,
I
OUT
= 3A
V
IN
= 2.05V, V
CNTL
= 2.75V
V
IN
= 2.05V, V
CNTL
= 2.75V,
I
OUT
= 10mA
V
IN
= 2.05V, V
CNTL
= 2.75V
V
IN
= 3.3V, V
CNTL
= 5V
V
IN
= 3.75V, V
CNTL
= 3.75V, f = 120Hz,
C
OUT
= 22µF Tantalum, I
OUT
= 1.5A
TO-263/TO-252
SPAK
T
A
= 25°C, 30ms pulse
Min.
1.243
•
1.237
Typ.
1.250
1.250
Max.
1.257
1.263
Units
V
V
Adjustable Output Voltage
Output Voltage
4
Output Voltage
5
Line Regulation
1,2
Load Regulation
1,2
Dropout Voltage Minimum
(V
CNTL
–V
OUT
)
Dropout Voltage Minimum
(V
IN
–V
OUT
)
Dropout Voltage Minimum V
IN
Current Limit
Control Pin Current
Adjust Pin Current
3
Minimum Load Current
Ripple Rejection
Thermal Resistance, Junction to
Case
Thermal Regulation
Thermal Shutdown
•
•
•
•
•
•
Vref
1.47
2.474
1.5
1.5
2.5
1
1
1.05
0.4
5.7
1.53
2.526
3
5
1.18
0.5
0.6
V
V
V
mV
mV
V
V
V
A
mA
µA
mA
dB
°C/W
•
•
•
•
•
60
3.1
0.5
2
50
5.0
80
3
2
0.002
150
6
120
10
0.02
%/W
°C
Notes:
1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are
measured at a constant junction temperature by low duty cycle pulse testing.
2. Line and load regulation are guaranteed up to the maximum power dissipation (18W). Power dissipation is determined by
input/output differential and the output current. Guaranteed maximum output power will not be available over the full input/
output voltage range.
3. FAN1582 only.
4. FAN1582-1.5 only.
5. FAN1582-2.5 only.
REV. 1.1.2 2/26/03
3
FAN1582
PRODUCT SPECIFICATION
Typical Perfomance Characteristics
OUTPUT VOLTAGE DEVIATION (%)
1.0
0.9
DROPOUT VOLTAGE (V)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
0.5
1
1.5
OUTPUT CURRENT (A)
Dropout Voltage vs. Output Current
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
-75 -50 -25
0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Load Regulation vs. Temperature
∆Ι=3A
T=0°C
T=25°C
T=125°C
2
2.5
3
1.275
REFERENCE VOLTAGE
OUTPUT VOLTAGE (V)
1.270
1.265
1.260
1.255
1.250
1.245
1.240
1.235
1.230
1.225
-75 -50 -25
0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Reference Voltage vs. Temperature
3.70
3.65
3.60
3.55
3.50
3.45
3.40
3.35
3.30
3.25
3.20
V
OUT
set with
1% resistors
V
OUT
= 3.3V
1
-75 -50
Note:
1. FAN1582 Only
-25 0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Output Voltage vs. Temperature
MINIMUM LOAD CURRENT (mA)
10
8
6
4
2
0
-75 -50 -25 0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Mimimum Load Current vs. Temperature
ADJUST PIN CURRENT (µA)
100
90
80
70
60
50
40
30
20
10
0
-75 -50
-25
0
25 50
75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Adjust Pin Current vs. Temperature
Note:
1. FAN1582 Only
4
REV. 1.1.2 2/26/03
PRODUCT SPECIFICATION
FAN1582
Typical Perfomance Characteristics (continued)
6
SHORT-CIRCUIT CURRENT (A)
90
90
5
RIPPLE REJECTIONS (dB)
70
60
50
40
30
20
10
2
-75 -50 -25 0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Short-Circuit Current vs.Temeperature
20
0
10
100
1K
10K
FREQUENCY (HZ)
100K
(V
IN
—V
OUT
)
≤
3V
0.5V
≤
V
RIPPLE
≤
2V
I
OUT
= 3A
4
3
Ripple Rejection vs. Frequency
15
POWER (W)
10
5
0
25
45
65
85
105
CASE TEMPERATURE
125
Maximum Power Dissipation
General
The FAN1582, FAN1582-1.5, and FAN1582-2.5 are three-
terminal regulators optimized for GTL+ V
TT
termination and
logic applications. These devices are short-circuit protected,
and offer thermal shutdown to turn off the regulator when the
junction temperature exceeds about 150°C. The FAN1582
series provides low dropout voltage and fast transient
response. Frequency compensation uses capacitors with low
ESR while still maintaining stability. This is critical in
addressing the needs of low voltage high speed microproces-
sor buses like GTL+.
sequencing problems. The output voltage will not turn on
until both supplies are operating. If the control voltage
comes up first, the output current will be typically limited to
about 3.0 mA until the power input voltage comes up. If the
power input voltage comes up first the output will not turn on
at all until the control voltage comes up. The output can
never come up unregulated.
The FAN1582 can also be used as a single supply device
with the control and power inputs tied together. In this mode,
the dropout is determined by the minimum control voltage.
V
IN
and V
CNTL
Functions
The FAN1582 utilizes a dual supply approach to maximize
efficiency. The collector of the power device is brought out
to the V
IN
pin to minimize internal power dissipation under
high current loads. V
CNTL
provides power for the control
circuitry and the drive for the output NPN transistor. V
CNTL
should be at least 1.2 V higher than the output voltage.
Special care was taken to ensure there are no supply-
REV. 1.1.2 2/26/03
Stability
The FAN1582 series requires an output capacitor as a part of
the frequency compensation. It is recommended to use a 22µF
solid tantalum or a 100µF aluminum electrolytic on the output
to ensure stability. The frequency compensation of these
devices optimizes the frequency response with low ESR capaci-
tors. In general, it is suggested to use capacitors with an ESR
of <0.3Ω. It is also recommended to use bypass capacitors
such as a 22µF tantalum or a 100µF aluminum on the adjust
5
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