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Электронный компонент: FAN1537B

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www.fairchildsemi.com
REV. 1.1.1 3/20/02
Features
Low dropout voltage
Load regulation: 0.05% typical
On-chip thermal limiting
SO-8 and 5-lead SPAK and TO-252 DPAK packages
Fixed 3.3V, and adjustable or 2.5V or 1.8V fixed
Stable with low ESR output capacitors
Applications
Hard Disk Drives, CD-ROMs, DVDs
High efficiency linear regulators
Post regulators for switching supplies
ADSL and Cable Modems
5V to 3.3V and 2.5V linear regulators
Motherboard with multiple supplies
Description
The FAN1537 provides 2 output voltages: 3.3V, and either
adjustable or 2.5V or 1.8V fixed with 1.0A each output
current capability. These devices have been optimized for
low voltage where transient response and minimum input
voltage are critical.
Current limit features protect the outputs against short circuit
currents. On-chip thermal limiting provides protection
against any combination of overload and ambient tempera-
ture that would create excessive junction temperatures.
The FAN1537 series regulators are available in SO-8 and
5-lead SPAK and TO-252 DPAK power packages.
Typical Applications
V2 = V
REF
(1 + R1/R2)
22
F
2.5V at 1.0A
3.3V at 1.0A
22
F
V
IN
= 5V
+
+
V
IN
V1
NC GND
V2
FAN1537A
22
F
+
22
F
2.5V at 1.0A
3.3V at 1.0A
+
22
F
+
22
F
3.3V at 1.0A
22
F
V
IN
= 5V
+
+
V
IN
V1
GND
FB
V2
FAN1537B
22
F
+
22
F
R1
54.9
R2
124
1.8V at 1.0A
3.3V at 1.0A
+
22
F
+
FAN1537
Dual 1A Adjustable/Fixed Low Dropout
Linear Regulators
FAN1537
PRODUCT SPECIFICATION
2
REV. 1.1.1 3/20/02
Pin Assignments
Pin Descriptions
Absolute Maximum Ratings
Pin Name
SO-8
SPAK
DPAK
Pin Function
V
IN
1
1
Input supply voltage
NC/FB
2
2
For V2 fixed, no connect. For V2 adjustable, feedback voltage.
V1
3
4/5
Output #1
V2
4
5/4
Output #2
GND
5, 6, 7, 8
3
Ground
Parameter
Min.
Max.
Unit
V
IN
10
V
Operating Junction Temperature Range
0
150
C
Storage Temperature Range
-65
150
C
Lead Temperature (Soldering, 10 sec.)
300
C
TOP VIEW
GND
GND
GND
GND
1
1
2
3
4 5
2
3
4
8
7
6
5
V
IN
NC
V1
V2
8-Lead Plastic SO-8
JC
=25
C/W
FAN1537PB
FRONT VIEW
FB
V2
GND
V
IN
V1
5-Lead SPAK
JC
=2
C/W
FAN1537PA
FAN1537PC
FRONT VIEW
NC
V1
GND
V
IN
V2
NC
V1
GND
V
IN
V2
FB
V2
GND
V
IN
V1
5-Lead SPAK
JC
=2
C/W
1
2
3
4 5
FRONT VIEW
FAN1537DA
FAN1537DC
FRONT VIEW
FAN1537DB
5-Lead Plastic TO-252 DPAK
JC
=3
C/W Tab is GND
1
2
3
4
5
1
2
3
4
5
PRODUCT SPECIFICATION
FAN1537
REV. 1.1.1 3/20/02
3
Electrical Characteristics
(Operating Conditions: V
IN
7V, T
J
=25C unless otherwise specified.)
The denotes specifications which apply over the specified operating temperature range of 0C to 125C junction temperature.
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. 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. ESR = 0.2
.
4. For adjust only, V
OUT
= V
REF
(1 + R1/R2)
Parameter
Conditions
Min.
Typ.
Max. Units
Output Voltages
10mA
I
OUT
1A
4.75V
V
IN
7V
1.764
1.742
2.450
2.420
3.234
3.200
1.8
1.8
2.500
2.500
3.300
3.300
1.836
1.858
2.550
2.580
3.366
3.400
V
Output Voltage
3.3V Output, V
IN
= 4.5V, I
OUT
= 1A
3.2
V
Time to Output Voltages Valid
From V
IN
4.75V
5
msec
Reference Voltage, V
REF
10mA
I
OUT
1A
4.75V
V
IN
7V
1.225
1.210
1.250
1.250
1.275
1.290
V
Line Regulation
1,2
(both outputs)
4.75V
V
IN
7V, I
OUT
= 10mA
0.005
0.5
%
Load Regulation
1,2
(both outputs)
V
IN
= 4.75V, 10mA
I
OUT
1A
0.05
0.5
%
Dropout Voltage
(3.3V output)
V
OUT
= 1%, I
OUT
= 1A
1.100 1.300
V
Current Limit
(both outputs)
V
IN
= 5V
1.3
1.5
A
Minimum Load Current
(both outputs)
4.75V
V
IN
7V
10
mA
Quiescent Current
V
IN
= 7V
6
15
mA
Ripple Rejection
3
(both outputs)
f = 120Hz, C
OUT
= 22F Tantalum,
V
IN
= 5V, I
OUT
= 1A
60 dB
Long-Term Stability
T
A
= 125C, 1000 hrs.
0.03
1.0
%
RMS Output Noise (% of V
OUT
) T
A
= 25C, 10Hz
f
10kHz
0.003
%
Thermal Resistance, Junction to
Case
SO-8
50
C/W
TO-252 DPAK
3
C/W
SPAK
2
C/W
Thermal Shutdown
155
C
Thermal Shutdown Hysteresis
Junction Temperature
10
C
FAN1537
PRODUCT SPECIFICATION
4
REV. 1.1.1 3/20/02
Application Hints
External Capacitors
Like any low-dropout regulator, the FAN1537 requires
external capacitors for stability.
Input Capacitor
A Tantalum input capacitor of 22F is recommended. This
capacitor must be located at a distance of no more than 0.5"
from the input pin of the device and returned to a clean ana-
log ground.
Output Capacitor
The FAN1537 is designed to work with Ceramic or Tantalum
load capacitors.
A value of 22F is recommended on each output, but the
value can be reduced to 10F to save space.
Additional capacitance can be added without limit for better
performance, e.g. improved transient response and lower
noise.
When a Ceramic multilayer capacitor is used, the X7R
dielectric is recommended which holds the capacitance
within 15%. The output capacitor should be located not
more than 0.5" from the output pins of the device and
returned to a clean analog ground.
PRODUCT SPECIFICATION
FAN1537
REV. 1.1.1 3/20/02
5
Mechanical Dimensions
8-Lead SOIC Package
8
5
1
4
D
A
A1
C
ccc C
LEAD COPLANARITY
SEATING
PLANE
e
B
L
h x 45
C
E
H
A
.053
.069
1.35
1.75
Symbol
Inches
Min.
Max.
Min.
Max.
Millimeters
Notes
A1
.004
.010
0.10
0.25
.020
0.51
B
.013
0.33
C
.0075
.010
0.20
0.25
E
.150
.158
3.81
4.01
e
.228
.244
5.79
6.20
.010
.020
0.25
0.50
H
.050 BSC
1.27 BSC
h
L
.016
.050
0.40
1.27
0
8
0
8
3
6
5
2
2
N
8
8

ccc
.004
0.10
--
--
D
.189
.197
4.80
5.00
Notes:
1.
2.
3.
4.
5.
6.
Dimensioning and tolerancing per ANSI Y14.5M-1982.
"D" and "E" do not include mold flash. Mold flash or
protrusions shall not exceed .010 inch (0.25mm).
"L" is the length of terminal for soldering to a substrate.
Terminal numbers are shown for reference only.
"C" dimension does not include solder finish thickness.
Symbol "N" is the maximum number of terminals.