1
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
1A Low Dropout Voltage Regulator
Fixed Output, Fast Response
SPX2940
DESCRIPTION
FEATURES
Guaranted 1.5A Peak Current
Low Quiescent Current
Low Dropout Voltage of 280mV at 1A
Extremely Tight Load and Line Regulation
Extremely Fast Transient Response
Reverse-battery Protection
Internal Thermal Protection
Internal Short Circuit Current Limit
Replacement for LM2940, MIC2940A,
AS2940
Standard TO-220 and TO-263 packages
The SPX2940 is a 1A, accurate voltage regulators 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 response. They are fully fault protected against over-current,
reverse battery, and positive and negative voltage transients.
The SPX2940 is offered in 3-pin TO-220 & TO-263 packages. For a 3A version, refer to the
SPX29300 data sheet.
SPX2940
V
OUT
V
IN
+
6.8F
+
10F
1
2
3
Figure 1. Fixed Output Linear Regulator.
TYPICAL APPLICATIONS CIRCUIT
APPLICATIONS
Powering VGA & Sound Card
LCD Monitors
USB Power Supply
Power PC
TM
Supplies
SMPS Post-Regulator
PDA or Notebook Computer
High Efficiency Linear Power Supplies
Portable Instrumentation
Constant Current Regulators
Cordless Telephones
Automotive Electronics
Now Available in Lead Free Packaging
1
2
3
SPX2940
3 Pin TO-263
GND
V
IN
V
OUT
2
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
ABSOLUTE MAXIMUM RATINGS
Lead Temperature (soldering, 5 seconds) ................................. 260C
Storage Temperature Range ..................................... -65C to +150C
Operating Junction Temperature Range ................... -40C to +125C
Input Voltage (Note 5) ................................................................... 16V
NOTES:
Note 1: Dropout voltage is defined as the input to output differential when the output voltage drops to 99% of its normal value.
Note 2: V
IN
=V
OUT (NOMINAL)
+ 1V. For example, use V
IN
=4.3V for a 3.3V regulator. Employ pulse-testing procedures to minimize temperature rise.
Note 3: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current to the ground current.
Note 4: Thermal regulation is defined as the change in the output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation
effects.
Note 5: Maximum positive supply voltage of 20V must be of limited duration (<100ms) and duty cycle (<1%). The maximum continuous supply voltage is 16V.
at V
IN
=V
OUT
+ 1V and I
OUT
= 10 mA, C
IN
= 6.8 F, C
OUT
= 10F; T
A
= 25C, unless otherwise specified. The
Boldface applies over the junction temperature range. Adjustable versions are set at 5.0V.
PARAMETER
CONDITIONS
TYP
MIN
MAX
UNITS
1.8V Version
Output Voltage
I
OUT
= 10mA
1.8
1.746
1.854
V
10mAI
OUT
1A, 6VV
IN
16V
1.8
1.710
1.890
2.5V Version
Output Voltage
I
OUT
= 10mA
2.5
2.425
2.575
V
10mAI
OUT
1A, 6VV
IN
16V
2.5
2.375
2.625
3.3V Version
Output Voltage
I
OUT
= 10mA
3.3
3.201
3.399
V
10mAI
OUT
1A, 6VV
IN
16V
3.3
3.135
3.465
5.0V Version
Output Voltage
I
OUT
= 10mA
5.0
4.850
5.150
V
10mAI
OUT
1A, 6VV
IN
16V
5.0
4.750
5.250
All Voltage Options
Line Regulation
I
O
=10mA, (V
OUT
+1V)V
IN
16V
0.2
1.0
%
Load Regulation
V
IN
=V
OUT
+1V, 10mAI
OUT
1A
0.3
1.5
%
V
Output Voltage
20
100
ppm/C
T
Temperature Coef.
Dropout Voltage (Note 1) I
O
=100mA
70
200
mV
(except 1.8V version)
I
O
=1A
280
550
Ground Current (Note 3) I
O
=750mA, V
IN
=V
OUT
, + 1V
12
25
mA
I
O
=1A
18
I
GNDDO
Ground Pin
V
IN
=0.1V less than specified V
OUT
1.2
mA
Current at Dropout
I
OUT
= 10mA
Current Limit
V
OUT
=0V (Note 2)
2.2
1.5
A
Output Noise Voltage
C
L
= 10F
400
V
RMS
10Hz to 100kHz)
I
L
=100mA
C
L
=33F
260
Thermal Resistance
TO-220 Junction to Case, at Tab
3
TO-220 Junction to Ambient
60
C/W
TO-263 Junction to Case, at Tab
3
TO-263 Junction to Ambient
60
ELECTRICAL CHARACTERISTICS
3
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
Figure 2. Line Regulation
Figure 3. Load Regulation
Figure 4. Ground Current vs Load Current
Figure 5. Ground Current vs Input Voltage
Reference
Thermal
Shutdown
IN
OUT
GND
O.V
I
LIMIT
28V
R1
R2
1.240V
+
-
Ibias
BLOCK DIAGRAM
3.320
3.315
3.310
3.305
3.300
3.295
3.290
3.285
3.280
4
6
8
10
12
14
16
V
IN
(V)
V
OUT
(V)
3.3V Device
IL = 10mA
CL = 10F
3.310
3.305
3.300
3.295
3.290
3.285
3.280
IL (A)
V
OUT
(V)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
3.3V Device
V
IN
= 4.3V
CL = 10F
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
IL (A)
IGnd (mA)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
3.3V Device
V
IN
= 4.3V
CL = 10F
300
280
260
240
220
200
180
4
6
8
10
12
14
16
V
IN
(V)
IGnd (mA)
3.3V Device
IL = 10mA
CL = 10F
TYPICAL PERFORMANCE CHARACTERISTICS
4
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
Figure 6. Ground Current vs Current in Dropout
Figure 7. Dropout Voltage vs Load Current
Figure 8. Ground Current vs Temperature at
Figure 9. Output Voltage vs Temperature at
I
LOAD
= 10mA
I
LOAD
=10mA
100
90
80
70
60
50
40
30
20
10
0
IL (A)
IGnd (mA)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
3.3V Device
V
IN
= 3.2V
CL = 10F
600
500
400
300
200
100
0
IL (A)
V
DR
OPOUT
(mV)
0.00
0.25
0.50
0.75
1.00
1.25
1.50
3.3V Device
CL = 10F
280
270
260
250
240
230
220
210
200
190
180
-40
-20
0
20
40
60
80
Temperature (C)
IGnd (
A)
3.3V Device
V
IN
= 4.3V
IL = 10mA
CL = 10F
120
100
3.320
3.310
3.300
3.290
3.280
3.270
3.260
3.250
3.240
3.230
3.220
-40
-20
0
20
40
60
80
Temperature (C)
V
OUT
(V)
3.3V Device
V
IN
= 4.3V
IL = 10mA
CL = 10F
120
100
7.00
6.80
6.60
6.40
6.20
6.00
5.80
5.60
5.40
5.20
5.00
-40
-20
0
20
40
60
80
Temperature (C)
IGnd (mA)
3.3V Device
V
IN
= 4.3V
IL = 500mA
CL = 10F
120
100
Figure 10. Ground Current vs Temperature at
Figure 11. Ground Current vs Temperature in Dropout
I
LOAD
=500mA
at I
LOAD
=750mA
30
29
28
27
26
25
24
23
22
21
20
-40
-20
0
20
40
60
80
Temperature (C)
IGnd (mA)
3.3V Device
V
IN
= 3.2V
IL = 750mA
CL = 10F
120
100
TYPICAL PERFORMANCE CHARACTERISTICS
5
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
52.0
50.0
48.0
46.0
44.0
42.0
40.0
38.0
36.0
-40
-20
0
20
40
60
80
Temperature (C)
IGnd (mA)
3.3V Device
V
IN
= 4.3V
IL = 1.5A
CL = 10F
120
100
Figure 12. Ground Current vs Temperature at I
LOAD
= 1.5A
Figure 13. Ground Current vs Temperature in Dropout
at I
LOAD
=1.5A
100
95
90
85
80
75
70
-40
-20
0
20
40
60
80
Temperature (C)
IGnd (mA)
3.3V Device
V
IN
= 3.2V
IL = 1.5A
CL = 10F
120
100
350
330
310
290
270
250
230
210
190
170
150
-40
-20
0
20
40
60
80
Temperature (C)
V
DR
OPOUT
(mV)
120
100
3.3V Device
IL = 750mA
CL = 10F
Figure 14. Dropout Voltage vs Temperature at
I
LOAD
= 750mA
500
480
460
440
420
400
380
360
340
320
-40
-20
0
20
40
60
80
Temperature (C)
V
DR
OPOUT
(mV)
120
100
3.3V Device
IL = 750A
CL = 10F
Figure 15. Dropout Voltage vs Temperature at
I
LOAD
= 1.5mA
35
30
25
20
15
10
5
0
-40
-20
0
20
40
60
80
Temperature (C)
I
EN
(
A)
120
100
3.3V Device
V
IN
= 3.2V
IL = 750mA
CL = 10F
Figure 16. Enable Current vs Temperature for V
EN
= 16V
2.00
1.90
1.80
1.70
1.60
1.50
1.40
1.30
1.20
1.10
1.00
-40
-20
0
20
40
60
80
Temperature (C)
V
TH
(V)
120
100
3.3V Device
V
IN
= 3.2V
IL = 750mA
CL = 10F
Figure 17. Enable Threshold vs Temperature
TYPICAL PERFORMANCE CHARACTERISTICS
6
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
The SPX2940 incorporates protection against
over-current faults, reversed load insertion, over
temperature operation, and positive and nega-
tive transient voltage.
Thermal Considerations
Although the SPX2940 offers 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 the best
thermal flow of the component, proper mount-
ing is required. Consult heatsink manufacturer
for thermal resistance and design of heatsink.
For example, TO-220 design:
Assume that V
IN
= 10V, V
OUT
= 5V, I
OUT
= 1.5A,
T
A
= 50
C/W,
HA
= 1
C/W,
CH
= 2
C/W, and
JC
= 3
C/W.
Where TA = ambient temperature
HA
= heatsink to ambient thermal resistance
CH
= case to heatsink thermal resistance
JC
= junction to case thermal resistance
The power calculated under these conditions is:
P
D
= (V
IN
- V
OUT
) * I
OUT
= 7.5W.
And the junction temperature is calculated as
T
J
= T
A
+ P
D
* (
HA
+
CH
+
JC
) or
T
J
= 50 + 7.5 * (1 + 2 + 3) = 95
C
Reliable operation is insured.
Capacitor Requirements
The output capacitor is needed to insure stability and minimize the output noise. The value of the
capacitor varies with the load. However, a minimum value of 10
F aluminum capacitor will guarantee
stability over all load conditions. A tantalum capacitor is recommended if a faster load transient
response is needed.
If the power source has a high AC impedance, a 0.1
F ceramic capacitor between input & ground is
recommended.
Minimum Load Current
To ensure a proper behavior of the regulator under light load, a minimum load of 5mA for SPX2940
is required.
SPX2940
V
OUT
V
IN
+
6.8F
+
10F
1
2
3
Figure 18. Fixed Output Linear Regulator.
APPLICATION INFORMATION
7
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
PACKAGE: 3 PIN TO-263
E
D
L1
b2
e
b
.160 - .190
.000 - .010
Dimensions in inches
3-PIN TO-263
JEDEC TO-263
(AA) Variation
.020 - .039
.015 - .029
.070 - .110
-
- -
A
A1
b
c
D
E
E1
L
L1
L2
MIN NOM MAX
e
.100 BSC
.066
-
.330 - .380
D1
.270 - -
.380 - .420
.245
-
-
H
.575 - .625
.070
L3
.010 BSC
1
2
3
c
C2
A
H
SEATING PLANE
L
0-8
See View C
E/2
View C
GAUGE PLANE
A1
SEATING
PLANE
c
WITH PLATING
BASE METAL
b
SECTION B-B
B
B
3 PIN TO-263
8
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
H1
B
SEATING
PLANE
A1
A
CHAMFER
OPTIONAL
C
A2
A
A
E
P
Q
D
D1
E2
E/2
L
L1
C
C
D
D
b
c
WITH PLATING
BASE METAL
b
CONTACT AREA
1
e
e1
.140 - .190
.020 - .055
Dimensions in
(mm)
3 PIN TO-220
JEDEC TO-220
(AB) Variation
.080 - .115
.015 .027 .040
.045 - .070
.480 - .507
A
A1
A2
b
b2
D1
D2
.380 - .420
E
MIN NOM MAX
c
.014 - .024
D
.560 - .650
.330 - .355
E1
.270
-
.350
E2
- - .030
e
.100 BSC
e1
.200 BSC
H1
.230 - .270
L1
- - .250
L2
- - -
P
.139 - .161
Q
.100 -
.135
3 PIN TO-220
PACKAGE: 3 PIN TO-220
9
Date: 5/25/04 SPX2940 1A Low Dropout Voltage Regulator
Copyright 2004 Sipex Corporation
PART NUMBER
ACC.
OUTPUT VOLTAGE
PACKAGE
SPX2940U-1.8
3%
1.8V
3 Lead TO-220
SPX2940U-2.5
3%
2.5V
3 Lead TO-220
SPX2940U-3.3
3%
3.3V
3 Lead TO-220
SPX2940U-5.0
3%
5.0V
3 Lead TO-220
SPX2940T-1.8
3%
1.8V
3 Lead TO-263
SPX2940T-1.8/TR
3%
1.8V
3 Lead TO-263
SPX2940T-2.5
3%
2.5V
3 Lead TO-263
SPX2940T-2.5/TR
3%
2.5V
3 Lead TO-263
SPX2340T-3.3
3%
3.3V
3 Lead TO-263
SPX2340T-3.3/TR
3%
3.3V
3 Lead TO-263
SPX2940T-5.0
3%
5.0V
3 Lead TO-263
SPX2940T-5.0/TR
3%
5.0V
3 Lead TO-263
Corporation
ANALOG EXCELLENCE
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Sipex Corporation
Headquarters and
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
ORDERING INFORMATION
TO-263-3 Package (T)
V
OUT
GND
V
IN
Front View
TAB = GND
1
2
3
Front View
TAB = GND
TO-220-3 Package (U)
V
IN
V
OUT
GND
3
2
1
PACKAGE PINOUTS
Available in lead free packaging. To order add "-L" suffix to part number.
Example: SPX2940T-3.3/TR = standard; SPX2940T-3.3-L/TR = lead free
/TR = Tape and Reel
Pack quantity is 500 for TO-263.
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