EXAR SPX3940

SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
February 2012
Rev. 1.0.0
GENERAL DESCRIPTION
APPLICATIONS
The SPX 3940 is a 1A, accurate voltage
regulator with a low drop out voltage of
280mV (typical) at 1A.
These regulators are specifically designed for
low voltage applications that require a low
dropout voltage and a fast transient respon
They are fully fault protected against over
current, reverse battery, and positive and
negative voltage transients.
x Power Supp
lies
x LCD Monitors
x Portable Instrumentation
se.
-
The SPX 3940 is offered in 3 - pin SOT223 and
TO- 263 packages. For a 3A version, refer to
the SPX29300 data sheet.
x Medical and Industrial Equipments
FEATURES
x Guaranteed 1.5A Peak Current
x 1% Output Accuracy SPX3940A
x Low Quiescent Current
x Low Dropout Voltage of 280mV at 1A
x Extremely Tight Load and Line
Regulation
x Extremely Fast
Transient Response
x Reverse - battery Protection
x Internal Thermal Protection
x Internal Short Circuit Current Limit
x Replacement for LM
x Standard
TYPICAL APPLICATION
3 940
SOT223 & TO - 263 packages
DIAGRAM
Fig. 1: SPX3940 Application Diagram
Exar Corporation
48720 Kato Road, Fremont CA 94538
, USA
±Fixed Output Linear Regulator
Tel. +1 510 668
www.exar.com
- 70 00 ±Fax. +1 510 668 - 70 01
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
ABSOLUTE MAXIMUM RAT
INGS
These are stress ratings only and functional operation of
the device at these ratings or any other above those
indicated in the operation sections of the specification
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect
reliability.
OPERATING RATINGS
Input Voltage VIN ................................
....................
16V
Junction Temperature Range
....................
- 40°C to 1 25 °C
Package s Thermal Resistance
SOT- 223 Junction to Case (at T A) .....................
15 °C/W
SOT- 223 Junction to Ambient
........................
62.3°C/W
TO- 263 Junction to Case (at T A) .........................
3°C/W
TO- 263 Junction to Ambient
..........................
31.4 °C/W
s
Input Voltage V IN ................................
...................
20 V1
Storage Temperature ..............................
- 65°C to 150°C
Lead Temperature (Soldering,
5 sec) .....................
26 0°C
Note 1: Maximum positive
supply voltage of 20V must be
of limited duration (<100ms) and duty cycle (<1%). The
maximum continuous supply voltage is 16V.
ELECTRICAL SPECIFICA
TIONS
Specifications with standard type are for
an Operating Ambient Temperature of TA = 25°C only; limits a
pplying over the full
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design, or statistical correlation. Typical values represent the most likely parametric norm at T
ided
A = 25°C, and are prov
for reference purposes only. Unless otherwise indicated, V
CIN = 6.8 µF, COUT = 10 µF, TA = 25°C .
IN = V IN +1V , I OUT = 10mA,
Parameter
Min.
Typ.
Max.
Units
Conditions
1.782
1.755
1.764
1.737
1.8
1.8
1.8
1.8
1.818
1.845
1.836
1.863
2.475
2.437
2.450
2.412
2.5
2.5
2.5
2.5
2.525
2.563
2.550
2.588
3.267
3.217
3.234
3.184
3.3
3.3
3.3
3.3
3.333
3.383
3.366
3.416
4.950
4.875
4.900
4.825
5.0
5.0
5.0
5.0
5.050
5.125
5.100
5.175
Line Regulation
0.2
1.0
%
I OUT=10mA, (V
Load Regulation
0.3
1.5
%
VIN = V
20
100
ppm/°C
1.8V version
Output Voltage
-
SPX3940A (1%)
Output Voltage
-
SPX3940 (2%)
-
SPX3940A (1%)
V
V
‡ I OUT=10mA
P$”,
OUT”$9”9
IN ”9
‡
2.5V version
Output Voltage
Output Voltag e -
SPX3940 (2%)
V
V
‡ I OUT=10mA
P$”,
OUT”$9”9
IN ”9
‡
3.3V version
Output Voltage
-
SPX3940A (1%)
Output Voltage
-
SPX3940 (2%)
Output Voltage
-
SPX3940A (1%)
Output Voltage
-
SPX3940 (2%)
V
V
‡ I OUT=10mA
P$”,
OUT”$9”9
IN ”9
‡
5 .0 V version
V
V
‡ I OUT=10mA
P$”,
OUT”$9”9
IN ”9
‡
All Voltage Options
ο௏
ο்
- Output Voltage
temperature Coefficient
Dropout Voltage 2
(except 1.8V version)
Ground Current
3
I GNDDO Ground Pin Current at
Dropout
Current Limit
Output Noise Voltage
© 2012 Exar Corporation
1.5
OUT
OUT
9”9
IN ”9
9P$”,
OUT”$
‡
70
200
mV
280
550
mV
‡ I OUT=100mA
‡ I OUT=1A
12
25
mA
‡ I OUT=750mA, V
IN
=V
OUT
+1V
18
mA
I OUT=1A
1.2
mA
VIN = 0.1V less than specified V
VOUT = 0V
OUT I OUT=10mA,
4
2.2
A
400
µV RMS
10Hz - 100KHz, I L=100mA, C
L=10µF
26 0
µV RMS
10Hz - 100KHz, I L=100mA, C
L=33µF
2/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
Note 2: Dropout voltage is defined as the input to output differential when the output voltage drops to 99% of its normal
value.
Note 3: Ground pin current is the regulator quiescent current. The total current draw
n from the source is the sum of the
load current to the ground current.
Note 4: VIN =V OUT(NOMINAL) +1V. For example, use V
- testing procedures to minimize
IN =4.3V for a 3.3V regulator. Employ pulse
temperature rise.
BLOCK DIAGRAM
Fig. 2: SPX3940 Block Diagram
PIN ASSIGNMENT
Fig. 3: SPX3940 Pin Assign ment
© 2012 Exar Corporation
3/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
ORDERING INFORMATION
Part Number
SPX3940AM3 - L- 1- 8
SPX3940AM3 - L- 1- 8/TR
SPX3940AM3 - L- 2- 5
SPX3940AM3 - L- 2- 5/TR
SPX3940AM3 - L- 3- 3
SPX3940AM3 - L- 3- 3/TR
SPX3940AM3 - L- 5- 0
SPX3940AM3 - L- 5- 0/TR
SPX3940AT - L- 1- 8
SPX3940AT - L- 1- 8/TR
SPX3940AT - L- 3- 3
SPX3940AT - L- 3- 3/TR
SPX3940AT - L- 5- 0
SPX3940AT - L- 5- 0/TR
SPX3940M3 - L- 2- 5
SPX3940M3 - L- 2- 5/TR
SPX3940M3 - L- 3- 3
SPX3940M3 - L- 3- 3/TR
SPX3940M3 - L- 5- 0
SPX3940M3 - L- 5- 0/TR
SPX3940T - L- 3- 3
SPX3940T - L- 3- 3/TR
SPX3940T - L- 5- 0
SPX3940T - L- 5- 0/TR
³<<´
<HDU
±³::´
© 2012 Exar Corporation
Temperature
Range
Marking
3940A
18YYWWL
- ƒ&”7
J”ƒ&
XXX
3940A
25YYWWL
- ƒ&”7
J”ƒ&
XXX
3940A
33YYWWL
- ƒ&”7
J”ƒ&
XXX
3940A
50YYWWL
- ƒ&”7
J”ƒ&
XXX
Package
3- pin
SOT- 223
3- pin
SOT- 223
3- pin
SOT- 223
3- pin
SOT- 223
Packing
Quantity
2.5K /Tape & Reel
Bulk
Bulk
1.8 V Output
Voltage ±1%
Lead Free
2.5V Output
Voltage ±1%
Lead Free
3.3V Output
Voltage ±1%
Lead Free
5.0V Output
Voltage ±1%
Lead Free
1.8V Output
Voltage ±1%
Lead Free
3.3V Output
Voltage ±1%
Lead Free
5.0V Output
Voltage ±1%
Lead Free
2.5V Output
Voltage ±2%
Lead Free
3.3V Output
Voltage ±2%
Lead Free
5.0V Output
Voltage ±2%
Lead Free
3.3V Output
Voltage ±2%
Lead Free
5.0V Output
Voltage ±2%
2.5K/Tape & Reel
Bulk
2.5K/Tape & Reel
Bulk
3- pin
TO- 263
500/Tape & Reel
SPX3940AT
- 40°C ”7
J”ƒ&
33YYWWLX
3- pin
TO- 263
500/Tape & Reel
SPX3940AT
- ƒ&”7
J”ƒ&
50YYWWLX
3- pin
TO- 263
500/Tape & Reel
3940M3
- ƒ&”7
J”ƒ&
25YYWWL
3- pin
SOT- 223
2.5K/Tape & Reel
3940M3
- ƒ&”7
J”ƒ&
33YYWWL
3- pin
SOT- 223
2.5K/Tape & Reel
3940M3
- ƒ&”7
J”ƒ&
50YYWWL
3- pin
SOT- 223
2.5K/Tape & Reel
SPX3940T
- ƒ&”7
J”ƒ&
33YYWWLX
3- pin
TO- 263
500/Tape & Reel
SPX3940T
- ƒ&”7
J”ƒ&
33YYWWLX
3- pin
TO- 263
500/Tape & Reel
Bulk
Bulk
Bulk
Bulk
Bulk
Bulk
Bulk
Bulk
Note 2
Lead Free
2.5K/Tape & Reel
SPX3940AT
- ƒ&”7
J”ƒ&
18YYWWLX
:RUN:H
ek ±³;´
Note 1
/RW1XPEHU
±when applicable.
4/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
TYPICAL PERFORMANCE
CHARACTERISTICS
Schematic and BOM from Application Information section of this datasheet.
Fig. 5: Load Regulation
Fig. 4: Line Regulation
Fig. 7: Ground Current vs Input Voltage
Fig. 6: Ground Current vs Load Current
Fig. 8: Ground Current vs
© 2012 Exar Corporation
Fig. 9: Dropout Voltage
Load Current in Dropout
5/ 11
vs Load Current
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
Fig. 10 : Ground Current vs Temperature
I LOAD =100mA
Fig. 11 : Output Voltage vs Temperature
I LOAD =100mA
Fig. 12 : Ground Current vs Temperature
I LOAD =500mA
Fig. 13 : Ground Current vs Temperature
Dropout, I LOAD =750mA
Fig. 14 : Ground Current vs Temperature
I LOAD =1.5A
Fig. 15 : Ground Current vs Temperature
Dropout, I LOAD =1.5A
© 2012 Exar Corporation
6/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
Fig. 16 : Dropout Voltage vs Temperature
I LOAD =750mA
Fig. 17 : Dropout Voltage vs Temperature
I LOAD =1.5A
Fig. 18 : Enable Current vs Temperature
VEN=16V
© 2012 Exar Corporation
Fig. 19 : Enable Threshold vs Temperature
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Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
THEORY OF OPERATION
TJ = T
The SPX3 940 incorporates protection against
over - current faults, reversed load insertion,
over temperature operation, and positive and
negative transient voltage.
TJ = 50 + 7.5 * (1 + 2 + 3) = 95°C
T HERMAL CONSIDERATIONS
The output capacitor is needed to insure
stabi lity and minimize the output noise. The
value of the capacitor varies with the load.
However, a minimum value of 10
µF aluminum
capacitor will guarantee stability over all load
conditions.
A
tantalum
capacitor
is
recommended if a faster load transient
resp onse is needed.
CAPACITOR R EQUIREMENTS
If the power source has
a high AC impedance,
a 0.1 µF ceramic capacitor between input &
ground is recommended.
M INIMUM
TO - 220 Design Example:
L OAD CURRENT
To ensure a proper behavior of the regulator
under light load, a minimum load of 5mA for
SPX3940 is required.
Assume that V IN = 10V, V OUT = 5V,
I OUT = 1.5A, T A
ƒ&:
LJ
HA= 1°C/W,
LJCH ƒ&:DQGLJ
=
3°C/W.
JC
A
+ P D LJ
HA LJ
CH LJ
JC) or
Reliable operation is insured.
Although the SPX3940 o ffers limiting circuitry
for overload conditions, it is still necessary to
insure
that
the
maximum
junction
temperature is not exceeded in the
application. Heat will flow through the lowest
resistance path, the junction
- to - case path. In
order to insure th e best thermal flow of the
component, proper mount
- ing is required.
Consult heatsink manufacturer for thermal
resistance and design of heatsink.
Where T
A
= ambient temperature
LJHA = heatsink to ambient thermal resistance
LJCH = case to heatsink thermal resistance
LJJC = junction to case thermal resistance
The power calculated under these condition
is:
PD = (V
IN
±VOUT) * I
OUT
s
Fig. 20 : Fixed Output Linear Regulator
= 7.5W.
And the junction temperature is calculated as
© 2012 Exar Corporation
8/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
PACKAGE SPECIFICATIO
N
3 - P IN SOT - 223
© 2012 Exar Corporation
9/ 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
3 - P IN TO - 2 63
© 2012 Exar Corporation
10 / 11
Rev. 1.0.0
SP X 3 9 4 0
1 A L o w D r o p o u t V o l t a g e Re g u l a t o r
REVISION HISTORY
Revision
A
1.0.0
Date
Description
04/14 /200 6
02/29/2012
FOR FURTHER ASSISTAN
Reformat of Datashee t
Package drawing corrections
CE
Email:
[email protected]
Exar Technical Documentation:
http://www.exar.com/TechDoc/default.aspx?
EXAR CORPORATION
H EADQUARTERS AND
SALES O FFICES
48720 Kato Road
Fremont, CA 94538
±USA
Tel.: +1 (510) 66
8- 7000
Fax: +1 (510) 668
-7030
www.exar.com
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve
design, performance or reliability. EXAR Corporation assumes no responsibility for the
use of any circuits described herein,
conveys no license under any patent or other right, and makes no representation that the circuits are free of patent
infringement. Charts and schedules contained here in are only for illustration purposes and may vary
depending upon a
XVHU¶VVSHFLILFDSSOLFDWLRQ:KLOHWKHLQIRUPDWLRQLQWKLVSXEOLFDWLRQ
,
is assumed for inaccuracies.
EXAR Corporation does not recommend the use of any of its products in life support
applications where the failure or
malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect
its
safety or effectiveness. Products are not authorized for use in such applications unless EXAR
Corporation receives, in
writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all
such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances.
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
© 2012 Exar Corporation
11 / 11
Rev. 1.0.0