ETC FAN1582T

www.fairchildsemi.com
FAN1582
3A Adjustable/Fixed Ultra Low Dropout
Linear Regulator
Features
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 VTT bus termination, where transient response and
minimum input voltage are critical. The FAN1582 is ideal
for low voltage microprocessor applications requiring a regulated 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 VTT 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.
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 standard TO-220 and TO-263 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
Current limit ensures controlled short-circuit current. On-chip
thermal limiting provides protection against any combination
of overload and ambient temperature that would create excessive junction temperatures.
The FAN1582 series regulators are available in the industrystandard 5-Pin TO-220 and TO-263 power packages.
Typical Applications
VIN = 3.0V
+
10µF
VIN = 3.3V
+
10µF
VCNTL = 5V
VIN
+
22µF
2.1V at 3A
VCNTL
Adj
2.5V at 3A
+
GND
1µF
FAN1582
VOUT
VSENSE
FAN1582–2.5
VOUT
VCNTL
VCNTL = 3.3V
VSENSE
VIN
+
124Ω
22µF
VIN = 5.75V
+
86.6Ω
10µF
VCNTL = 12V
VIN
VSENSE
FAN1582
VOUT
5V at 3A
VCNTL
Adj
+
124Ω
22µF
374Ω
Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation.
REV. 1.0.0 1/9/01
FAN1582
PRODUCT SPECIFICATION
Pin Assignments
FAN1582T
FAN1582T-1.5, -2.5
FRONT VIEW
FAN1582M-1.5, -2.5
FAN1582M
FRONT VIEW
FRONT VIEW
1 2
1 2 3 4 5
1 2 3 4 5
S
S
OUT
GND
IN
CNTL
OUT
Adj
S
IN
3 4 5
OUT
Adj
CNTL
FRONT VIEW
3 4 5
1 2
S
IN
OUT
GND
CNTL
IN
CNTL
5-Lead Plastic TP-220
ΘJC=3°C/W*
5-Lead Plastic TP-263
ΘJC=3°C/W*
*With package soldered to 0.5 square inch copper area over backside ground plane or internal
power plane. ΘJA can vary fom 20°C/W to >40°C/W with other mounting techniques.
Pin Definitions
Pin Number
Pin Name
1
VSense
2
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.
3
VOUT
Output Voltage. This pin and the tab are output.
4
VCNTL
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.
5
VIN
Input Voltage.
Internal Block Diagram
4
VCNTL, Control
5 Vin, Power
Thermal
Shutdown
Current
Limit
Vref
2
Voltage Loop
Amplifier
3 Output
1 Sense
2 Adj
REV. 1.0.0 1/9/01
PRODUCT SPECIFICATION
FAN1582
Absolute Maximum Ratings
Parameter
Min.
VIN
VCNTL
Operating Junction Temperature Range
0
Lead Temperature (Soldering, 10 sec.)
Storage Temperature Range
-65
Max.
Unit
7
V
13.2
V
125
°C
300
°C
150
°C
Electrical Characteristics
TJ=25°C, VOUT = VS, VADJ = 0V unless otherwise specified.
The • denotes specifications which apply over the specified operating temperature range.
Parameter
Reference Voltage3
Reference Voltage3
Adjustable Output Voltage
Output Voltage4
Output Voltage5
Line Regulation1,2
Load Regulation1,2
Dropout Voltage Minimum VCNTL
Dropout Voltage Minimum VIN
Dropout Voltage Minimum VIN
Current Limit
Control Pin Current
Adjust Pin Current3
Minimum Load Current
Ripple Rejection
Thermal Resistance, Junction to
Case
Thermal Regulation
Thermal Shutdown
Conditions
VIN = 2.0V, VCNTL = 2.75V,
IOUT = 10mA
2.05V ≤ VIN ≤ 5.5V,
2.7V ≤ VCNTL ≤ 12V,
10mA ≤ IOUT ≤ 3A
3V ≤ VIN ≤ 7V (function of Vout),
10mA ≤ IOUT ≤ 3A
3V ≤ VIN ≤ 7V, 10mA ≤ IOUT ≤ 3A
5.1V ≤ VIN ≤ 7V, 10mA ≤ IOUT ≤ 3A
1.75V ≤ VIN ≤ 5.5V, 2.5V ≤ VCNTL ≤ 12V,
IOUT = 10mA
VIN = 2.1V, VCNTL = 2.75V,
10mA ≤ IOUT ≤ 3A
VIN = 2.05V, ∆VREF = 1%, IOUT = 3A
VCNTL = 2.75V, ∆VREF = 1%,
IOUT = 3A
VCNTL = 2.75V, ∆VREF = 1%,
IOUT = 3A
VIN = 2.05V, VCNTL = 2.75V
VIN = 2.05V, VCNTL = 2.75V,
IOUT = 10mA
VIN = 2.05V, VCNTL = 2.75V
VIN = 3.3V, VCNTL = 5V
VIN = 3.75V, VCNTL = 3.75V, f = 120Hz,
COUT = 22µF Tantalum, IOUT = 1.5A
Min.
1.243
Typ.
1.250
Max.
1.257
Units
V
•
1.237
1.250
1.263
V
•
Vref
1.5
5.7
V
•
•
•
1.47
2.474
1.5
2.5
1
1.53
2.526
3
V
V
mV
•
1
5
mV
•
1.05
0.4
1.18
0.5
V
V
•
0.5
0.6
V
30
120
A
µA
50
5.0
80
120
10
•
•
3.1
•
•
60
3
TA = 25°C, 30ms pulse
0.002
150
mA
mA
dB
°C/W
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. 1.0.0 1/9/01
3
FAN1582
PRODUCT SPECIFICATION
OUTPUT VOLTAGE DEVIATION (%)
Typical Perfomance Characteristics
1.0
DROPOUT VOLTAGE (V)
0.9
0.8
0.7
0.6
T=0°C
0.5
0.4
T=25°C
T=125°C
0.3
0.2
0.1
0.0
0
0.5
1
1.5
2
2.5
3
OUTPUT CURRENT (A)
0.10
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
1.275
3.70
1.270
1.265
1.260
1.255
3.65
3.60
3.55
3.50
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE
Dropout Voltage vs. Output Current
1.250
1.245
1.240
1.235
1.230
1.225
∆Ι=3A
0.05
VOUT set with
1% resistors
3.45
3.40
3.35
3.30
3.25
3.20
-75 -50 -25
0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
VOUT = 3.3V1
-75 -50
100
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
4
-25 0
25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
Output Voltage vs. Temperature
ADJUST PIN CURRENT (µA)
MINIMUM LOAD CURRENT (mA)
Reference Voltage vs. Temperature
Note:
1. FAN1582 Only
Note:
1. FAN1582 Only
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
REV. 1.0.0 1/9/01
PRODUCT SPECIFICATION
FAN1582
Typical Perfomance Characteristics (continued)
90
90
RIPPLE REJECTIONS (dB)
SHORT-CIRCUIT CURRENT (A)
6
5
4
3
70
60
50
40
30
(VIN—VOUT) ≤ 3V
20
0.5V ≤ VRIPPLE ≤ 2V
10
2
IOUT = 3A
0
-75 -50 -25 0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
10
Short-Circuit Current vs.Temeperature
100
1K
10K
FREQUENCY (HZ)
100K
Ripple Rejection vs. Frequency
20
POWER (W)
15
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 threeterminal regulators optimized for GTL+ VTT 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 microprocessor buses like GTL+.
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
REV. 1.0.0 1/9/01
to ensure stability. The frequency compensation of these
devices optimizes the frequency response with low ESR capacitors. In general, it is suggested to use capacitors with an ESR
of <1Ω. It is also recommended to use bypass capacitors such
as a 22µF tantalum or a 100µF aluminum on the adjust pin of
the FAN1582 for low ripple and fast transient response. When
these bypassing capacitors are not used at the adjust pin, smaller
values of output capacitors provide equally good results.
Protection Diodes
In normal operation, the FAN1582 series does not require any
protection diodes. For the FAN1582, internal resistors limit
internal current paths on the adjust pin. Therefore, even with
bypass capacitors on the adjust pin, no protection diode is
needed to ensure device safety under short-circuit conditions.
5
FAN1582
PRODUCT SPECIFICATION
A protection diode between the input and output pins is usually not needed. An internal diode between the input and the
output pins on the FAN1582 series can handle microsecond
surge currents of 50A to 100A. Even with large value output
capacitors it is difficult to obtain those values of surge currents in normal operation. Only with large values of output
capacitance, such as 1000µF to 5000µF, and with the input
pin instantaneously shorted to ground can damage occur. A
crowbar circuit at the input can generate those levels of current;
a diode from output to input is then recommended, as shown
in Figure 1. Usually, normal power supply cycling or system
“hot plugging and unplugging” will not generate current
large enough to do any damage.
The adjust pin can be driven on a transient basis ±7V with
respect to the output, without any device degradation. As with
any IC regulator, exceeding the maximum input-to-output
voltage differential causes the internal transistors to break
down and none of the protection circuitry is then functional.
100Ω and the ripple frequency equals 120Hz, the adjust pin
capacitor should be 22µF. At 10kHz, only 0.22µF is needed.
Output Voltage
The FAN1582 regulator develops a 1.25V reference voltage
between the output pin and the adjust pin (see Figure 2).
Placing a resistor R1 between these two terminals causes a
constant current to flow through R1 and down through R2 to
set the overall output voltage. Normally, this current is the
specified minimum load current of 10mA.
The current out of the adjust pin adds to the current from R1
and is typically 35µA. Its output voltage contribution is
small and only needs consideration when a very precise output voltage setting is required.
Vcntl
Vcntl
VIN
+
D1
1N4002
(OPTIONAL)
VOUT
VIN
Vcntl
+
Vin
VOUT
VREF
C1
10µF
IADJ
50µA
Vsense
+
R1
C2
22µF
R2
VOUT = VREF (1+R2/R1) + IADJ (R2)
FAN1582
C1
10µF
Vsense
FAN1582
Vin Adj Vout
+
Adj Vout
R1
VOUT
C2
22µF
Figure 2. Basic Regulator Circuit
Load Regulation
+
R2
CADJ
The FAN1582 family provides true remote sensing, eliminating output voltage errors due to trace resistance. To utilize
remote sensing, connect the VSENSE pin directly to the
load, rather than at the VOUT pin. If the load is more than 1"
away from the FAN1582, it may be necessary to increase the
load capacitance to ensure stability.
D1
1N4002
(OPTIONAL)
Thermal Considerations
VCNTL
VIN
Vcntl
+
Vsense
FAN1582–1.5, 2.5
C1
10µF
Vin
Gnd Vout
+
VOUT
C2
22µF
Figure 1. Optional Protection Diode
Ripple Rejection
In applications that require improved ripple rejection, a bypass
capacitor from the adjust pin of the FAN1582 to ground
reduces the output ripple by the ratio of VOUT/1.25V. The
impedance of the adjust pin capacitor at the ripple frequency
should be less than the value of R1 (typically in the range of
100Ω to 120Ω) in the feedback divider network in Figure 1.
Therefore, the value of the required adjust pin capacitor is a
function of the input ripple frequency. For example, if R1 equals
6
The FAN1582 series protect themselves under overload conditions with internal power and thermal limiting circuitry.
However, for normal continuous load conditions, do not exceed
maximum junction temperature ratings. It is important to
consider all sources of thermal resistance from junction-toambient. These sources include the junction-to-case resistance,
the case-to-heat sink interface resistance, and the heat sink
resistance. Thermal resistance specifications have been
developed to more accurately reflect device temperature and
ensure safe operating temperatures. The electrical characteristics section provides a separate thermal resistance and
maximum junction temperature for both the control circuitry
and the power transistor. Calculate the maximum junction
temperature for both sections to ensure that both thermal
limits are met.
For example, look at using an FAN1582T-1.5 to generate 3A
@ 1.5V ± 2% from a 3.3V source (3.2V to 3.6V).
REV. 1.0.0 1/9/01
PRODUCT SPECIFICATION
FAN1582
From the specification table,
Assumptions:
•
•
•
•
•
Vin = 3.6V worst case
VOUT = 1.47V worst case
IOUT = 3A continuous
TA = 70°C
Θ Case-to-Ambient = 5°C/W (assuming both a heatsink and
a thermally conductive material)
The power dissipation in this application is:
PD = (VIN - VOUT) * (IOUT) = (3.6-1.47) * (3) = 6.39W
TJ = TA + (PD) * (Θ Case-to-Ambient + ΘJC)
= 70 + (6.39) * (5 + 3) = 121°C
The junction temperature is below the maximum rating.
Junction-to-case thermal resistance is specified from the IC
junction to the bottom of the case directly below the die. This
is the lowest resistance path for heat flow. Proper mounting
ensures the best thermal flow from this area of the package to
the heat sink. Use of a thermally conductive material at the
case-to-heat sink interface is recommended. Use a thermally
conductive spacer if the case of the device must be electrically isolated and include its contribution to the total thermal
resistance.
U1
VIN = 3.3V
10µF
VIN
+
C1
VSENSE
FAN1582
VOUT
2.1V at 3A
VCNTL
VCNTL = 5V
1µF
C4
Adj
10µF
C3
+
R1
86.6Ω
R2
124Ω
100µF
C2
Figure 3. Application Circuit (FAN1582)
Table 1. Bill of Materials for Application Circuit for the FAN1582
Item
Quantity
Manufacturer
Part Number
Description
C1, C3
2
Xicon
L10V10
10µF, 10V Aluminum
C2
1
Xicon
L10V100
100µF, 10V Aluminum
C4
1
Any
1µF Ceramic
R1
1
Generic
86.6Ω, 1%
R2
1
Generic
124Ω, 1%
U1
1
Fairchild
REV. 1.0.0 1/9/01
FAN1582T
3A Regulator
7
FAN1582
PRODUCT SPECIFICATION
U1
VIN = 2.5V
10µF
C1
VIN
+
FAN1582–1.5
VOUT
VCNTL
VCNTL = 3.3V
1µF
VSENSE
1.5V at 3A
+
Adj
C2
100µF
C3
Figure 4. Application Circuit (FAN1582-1.5)
Table 2. Bill of Materials for Application Circuit for the RC1582-1.5
Item
Quantity
Manufacturer
Part Number
Description
C1
1
Xicon
L10V10
10µF, 10V Aluminum
C2
1
Any
C3
1
Xicon
L10V100
100µF, 10V Aluminum
U1
1
Fairchild
FAN1582T-1.5
3A Regulator
1µF Ceramic
U1
VIN = 2.5V
+
10µF
C1
VIN
VSENSE
FAN1582–2.5
VOUT
VCNTL
VCNTL = 3.3V
+
1.5V at 3A
+
Adj
1µF
C2
100µF
C3
Figure 5. Application Circuit (FAN1582-2.5)
Table 3. Bill of Materials for Application Circuit for the RC1582-2.5
Item
8
Quantity
Manufacturer
Part Number
Description
C1
1
Xicon
L10V10
10µF, 10V Aluminum
C2
1
Any
C3
1
Xicon
L10V100
100µF, 10V Aluminum
U1
1
Fairchild
FAN1582T-2.5
3A Regulator
1µF Ceramic
REV. 1.0.0 1/9/01
PRODUCT SPECIFICATION
FAN1582
Mechanical Dimensions
5-Lead TO-263 Package
Symbol
Inches
Notes:
1. Dimensions are exclusive of mold flash and metal burrs.
2. Standoff-height is measured from lead tip with ref. to Datum –B-.
3. Foot length is measured with ref. to Datum –A- with lead surface
(at inner R).
4. Dimension exclusive of dambar protrusion or intrusion.
5. Formed leads to be planar with respect to one another at seating
place –C-.
Millimeters
Min.
Max.
Min.
Max.
A
.380
.405
9.65
10.29
B
.575
.625
14.60
15.88
C
.325
.380
8.25
9.66
D
–
.055
–
1.40
E
.020
.039
.50
.99
F
.060
.072
1.52
1.83
G
0.45
.055
1.14
1.40
H
.160
.190
4.06
4.83
J
.090
0.110
2.28
2.80
K
.018
.029
.457
.736
R
.017
.019
0.43
0.48
A
D
G
C
E-PIN
B
E
R (2PLCS)
F
J
-B-
-A-
H
-C-
REV. 1.0.0 1/9/01
9
FAN1582
PRODUCT SPECIFICATION
Mechanical Demensions (continued)
5-Lead TO-220 Package
Inches
Symbol
Millimeters
Min.
Max.
Min.
Max.
A
b
c1
øP
D
E
e
.140
.025
.190
.040
3.56
.63
4.83
1.02
.140
.139
.560
.380
.062
.220
.161
.650
.420
.072
.356
3.53
14.22
9.65
1.57
.559
4.09
16.51
10.67
1.83
e1
F
H1
J1
L
Q
α
.263
.045
.230
.080
.273
.055
.270
.115
6.68
1.14
5.84
2.04
6.94
1.40
6.87
2.92
.500
.100
3°
.580
.135
7°
12.70
.254
3°
14.73
.343
7°
Notes
Notes:
1. Dimension c1 apply for lead finish.
H1
Q
L
e
e1
E
b
E-PIN
øP
α (5X)
c1
A
J1
F
D
10
REV. 1.0.0 1/9/01
FAN1582
PRODUCT SPECIFICATION
Ordering Information
Product Number
Package
FAN1582M
TO-263
FAN1582T
TO-220
FAN1582M-1.5
TO-263
FAN1582T-1.5
TO-220
FAN1582M-2.5
TO-263
FAN1582T-2.5
TO-220
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user.
2. A critical component in any component of a life support
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