L4940
1.5 A very low drop voltage regulator IC
Datasheet - production data
Table 1. Device summary
Order code
TO-220
D²PAK
L4940V5
L4940D2T5-TR
L4940V85
5V
8.5 V
L4940D2T12-TR
TO-220
Output
voltages
12 V
D²PAK
Features
• Precise 5, 8.5, 12 V outputs
• Low dropout voltage (450 mV typ. at 1 A)
• Very low quiescent current
• Thermal shutdown
• Short-circuit protection
• Reverse polarity protection
Description
The L4940 series of three-terminal positive
regulators is available in TO-220 and D²PAK
packages and with several fixed output voltages,
making it useful in a wide range of industrial and
consumer applications. Thanks to their very low
input/output voltage drop, these devices are
particularly suitable for battery-powered
equipment, reducing consumption and prolonging
battery-life. Each type employs internal current
limiting, anti-saturation circuit, thermal shutdown
and safe area protection.
April 2015
This is information on a product in full production.
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www.st.com
Contents
L4940
Contents
1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Test circuits
5
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6
Performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7
Application circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9
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............................................... 6
8.1
TO-220 (dual gauge) package information . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2
TO-220 (dual gauge) packing information . . . . . . . . . . . . . . . . . . . . . . . . 18
8.3
D²PAK package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.4
D²PAK packing information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
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L4940
1
Block diagram
Block diagram
Figure 1. Block diagram
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25
Pin configuration
2
L4940
Pin configuration
Figure 2. Pin connections (top view)
TO-220
D²PAK
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L4940
3
Maximum ratings
Maximum ratings
Table 2. Absolute maximum ratings
Symbol
VI
VIR
Parameter
Value
Unit
30
V
VO = 5 V, RO = 100 Ω
-15
V
VO = 8.5 V, RO = 180 Ω
-15
V
VO = 12 V, RO = 240 Ω
-15
V
Forward input voltage
Reverse input voltage
IO
Output current
Internally limited
mA
PD
Power dissipation
Internally limited
mW
Tstg
Storage temperature range
-40 to +150
°C
Top
Operating junction temperature range
-40 to +150
°C
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these conditions is not implied.
Table 3. Thermal data
Symbol
Parameter
TO-220
D²PAK
Unit
RthJC
Thermal resistance junction-case
3
3
°C/W
RthJA
Thermal resistance junction-ambient
50
62.5
°C/W
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Test circuits
4
L4940
Test circuits
Figure 3. DC parameters
Figure 4. Load regulation
Figure 5. Ripple rejection
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L4940
5
Electrical characteristics
Electrical characteristics
Refer to test circuit, VI = 7 V, CI = 0.1 µF, CO = 22 µF, TJ = 25 °C, unless otherwise specified.
Table 4. L4940#5 electrical characteristics
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
VO
Output voltage
IO = 500 mA
4.9
5
5.1
V
VO
Output voltage
IO = 5 mA to 1.5 A, VI = 6.5 to 15 V
4.8
5
5.2
V
VI
Maximum input voltage
IO = 5 mA
17
V
ΔVO
Line regulation
VI = 6 to 17 V, IO = 5 mA
4
10
mV
ΔVO
IO = 5 mA to 1.5 A
8
25
mV
Load regulation
IO = 0.5 A to 1 A
5
15
mV
IO = 5 mA
5
8
mA
IO = 1.5 A, VI = 6.5 V
30
50
mA
IO = 5 mA
3
mA
IO = 1.5 A, VI = 6.5 to 16 V
15
mA
Iq
ΔIq
Quiescent current
Quiescent current change
ΔVO / ΔT Output voltage drift
SVR
Supply voltage rejection
Vd
Dropout voltage
Isc
Short-circuit current
f = 120 Hz, IO = 1 A
58
0.5
mV/°C
68
dB
IO = 0.5 A
200
400
mV
IO = 1.5 A
500
900
mV
VI = 14 V
2
2.7
VI = 6.5 V
2.2
2.9
A
Refer to test circuit, VI = 10.5 V, CI = 0.1 µF, CO = 22 µF, TJ = 25 °C, unless otherwise
specified.
Table 5. L4940#85 electrical characteristics
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
VO
Output voltage
IO = 500 mA
8.3
8.5
8.7
V
VO
Output voltage
IO = 5 mA to 1.5 A, VI = 10.2 to 15 V
8.15
8.5
8.85
V
VI
Maximum input voltage
IO = 5 mA
17
V
ΔVO
Line regulation
VI = 9.5 to 17 V, IO = 5 mA
4
9
mV
ΔVO
IO = 5 mA to 1.5 A
12
30
mV
Load regulation
IO = 0.5 A to 1 A
8
16
mV
IO = 5 mA
4
8
mA
IO = 1.5 A, VI = 10.2 V
30
50
mA
IO = 5 mA
2.5
mA
IO = 1.5 A, VI = 10.2 to 16 V
15
mA
Iq
ΔIq
Quiescent current
Quiescent current change
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Electrical characteristics
L4940
Table 5. L4940#85 electrical characteristics (continued)
Symbol
Parameter
Test conditions
Min.
ΔVO / ΔT Output voltage drift
SVR
Supply voltage rejection
Vd
Dropout voltage
Isc
Short-circuit current
f = 120 Hz, IO = 1 A
58
Typ.
Max.
Unit
0.8
mV/°C
66
dB
IO = 0.5 A
200
400
mV
IO = 1.5 A
500
900
mV
VI = 14 V
2
2.7
2.2
2.9
A
VI = 10.2 V
Refer to test circuit, VI = 14 V, CI = 0.1 µF, CO = 22 µF, TJ = 25 °C, unless otherwise
specified.
Table 6. L4940#12 electrical characteristics
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
VO
Output voltage
IO = 500 mA
11.75
12
12.25
V
VO
Output voltage
IO = 5 mA to 1.5 A, VI = 13.8 to 15 V
11.5
12
12.5
V
VI
Maximum input voltage
IO = 5 mA
17
V
ΔVO
Line regulation
VI = 13 to 17 V, IO = 5 mA
3
7
mV
ΔVO
IO = 5 mA to 1.5 A
15
35
mV
Load regulation
IO = 0.5 A to 1 A
10
25
mV
IO = 5 mA
4
8
mA
IO = 1.5 A, VI = 13.8 V
30
50
mA
IO = 5 mA
1.5
mA
IO = 1.5 A, VI = 13.8 to 16 V
10
mA
Iq
ΔIq
ΔVO /ΔT
SVR
Quiescent current
Quiescent current change
Output voltage drift
Supply voltage rejection
55
mV/°C
61
dB
IO = 0.5 A
200
400
mV
IO = 1.5 A
500
900
mV
Short-circuit current
VI = 14 V
2
2.7
A
Output impedance
f = 120 Hz, IO = 0.5 A
40
Vd
Dropout voltage
Isc
ZO
8/25
f = 120 Hz, IO = 1 A
1.2
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mΩ
L4940
6
Performance characteristics
Performance characteristics
Figure 6. Dropout voltage vs. output current
Figure 7. Dropout voltage vs. temperature
Figure 8. Output voltage vs. temperature
(L4940V5)
Figure 9. Output voltage vs. temperature
(L4940V85)
Figure 10. Output voltage vs. temperature
(L4940V12)
Figure 11. Quiescent current vs. temperature
(L4940V5)
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Performance characteristics
L4940
Figure 12. Quiescent current vs. input voltage
(L4940V5)
Figure 13. Quiescent current vs. output current
(L4940V5)
Figure 14. Short-circuit current vs. temperature Figure 15. Peak output current vs. input/output
(L4940V5)
differential voltage (L4940V5)
Figure 16. Low voltage behavior (L4940V5)
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Figure 17. Low voltage behavior (L4940V85)
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L4940
Performance characteristics
Figure 18. Low voltage behavior (L4940V12)
Figure 19. Supply voltage rejection vs.
frequency (L4940V5)
Figure 20. Supply voltage rejection vs. output Figure 21. Load dump characteristics (L4940V5)
current (L4940V5)
Figure 22. Line transient response (L4940V5)
Figure 23. Total power dissipation
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Performance characteristics
L4940
Figure 24. Load transient response
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L4940
7
Application circuits
Application circuits
Figure 25. Distributed power supply with the L4960, L4940 and the L4941
Figure 26. Distributed power supply with the L296, L4940, and the L4941
Note:
Advantages of these applications are:
On-card regulation with short-circuit and thermal protection on each output. Very high total
system efficiency due to the switching pre-regulation and very low drop post-regulation.
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25
Application circuits
L4940
Figure 27. Secondary regulation for switch mode power supply with the L4940
Note:
Advantages of this configuration are:
Very high regulation (line and load on both the output voltage. 12 V output short-circuit and
thermal protection. Very high efficiency on the 12 V output due to the low drop regulator.
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L4940
8
Package information
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
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Package information
8.1
L4940
TO-220 (dual gauge) package information
Figure 28. TO-220 (dual gauge) package outline
BW\SH$B5HYB7
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L4940
Package information
Table 7. TO-220 (dual gauge) mechanical data
mm
Dim.
Min.
Typ.
Max.
A
4.40
4.60
b
0.61
0.88
b1
1.14
1.70
c
0.48
0.70
D
15.25
15.75
D1
1.27
E
10
10.40
e
2.40
2.70
e1
4.95
5.15
F
1.23
1.32
H1
6.20
6.60
J1
2.40
2.72
L
13
14
L1
3.50
3.93
L20
16.40
L30
28.90
∅P
3.75
3.85
Q
2.65
2.95
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Package information
8.2
L4940
TO-220 (dual gauge) packing information
Figure 29. Tube for TO-220 (dual gauge) outline (mm.)
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L4940
8.3
Package information
D²PAK package information
Figure 30. D²PAK package outline
0079457_T
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25
Package information
L4940
Table 8. D²PAK mechanical data
mm
Dim.
Min.
Typ.
A
4.40
4.60
A1
0.03
0.23
b
0.70
0.93
b2
1.14
1.70
c
0.45
0.60
c2
1.23
1.36
D
8.95
9.35
D1
7.50
E
10
E1
8.50
10.40
e
2.54
e1
4.88
5.28
H
15
15.85
J1
2.49
2.69
L
2.29
2.79
L1
1.27
1.40
L2
1.30
1.75
R
V2
20/25
Max.
0.4
0°
8°
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L4940
Package information
Figure 31. D²PAK recommended footprint(a)
16.90
12.20
5.08
1.60
3.50
9.75
Footprint
a. All dimensions are in millimeters.
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Package information
8.4
L4940
D²PAK packing information
Figure 32. D²PAK tape outline
10 pitches cumulative
tolerance on tape +/- 0.2 mm
T
P0
Top cover
tape
P2
D
E
F
B1
K0
For machine ref. only
including draft and
radii concentric around B0
W
B0
A0
P1
D1
User direction of feed
R
Bending radius
User direction of feed
AM08852v1
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L4940
Package information
Figure 33. D²PAK reel outline
T
REEL DIMENSIONS
40mm min.
Access hole
At slot location
B
D
C
N
A
Full radius
G measured at hub
Tape slot
in core for
tape start 25 mm min.
width
AM08851v2
Table 9. D²PAK tape and reel mechanical data
Tape
Reel
mm
mm
Dim.
Dim.
Min.
Max.
A0
10.5
10.7
A
B0
15.7
15.9
B
1.5
D
1.5
1.6
C
12.8
D1
1.59
1.61
D
20.2
E
1.65
1.85
G
24.4
F
11.4
11.6
N
100
K0
4.8
5.0
T
P0
3.9
4.1
P1
11.9
12.1
Base qty
1000
P2
1.9
2.1
Bulk qty
1000
R
50
T
0.25
0.35
W
23.7
24.3
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Min.
Max.
330
13.2
26.4
30.4
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Revision history
9
L4940
Revision history
Table 10. Document revision history
Date
Revision
04-Feb-2005
6
Added new package D²PAK/A.
18-Sep-2006
7
Order codes and new template have been updated.
31-May-2007
8
Order codes have been updated.
19-Sep-2007
9
Added Table 1 to cover page.
20-Feb-2008
10
Modified: Table 1 on page 1.
29-Jul-2009
11
Modified: Table 1 on page 1.
16-Dec-2009
12
Modified: Table 6 on page 8.
04-Nov-2013
13
The L4940XX5, L4940XX85, L4940XX10, L4940XX12 have been changed
into the L4940.
Updated: the title and the description in cover page.
Updated Section 4: Test circuits, Section 5: Electrical characteristics,
Section 6: Performance characteristics and Section 8: Package information.
Added Section 8.4: D²PAK packing information.
Minor text changes.
08-Apr-2015
14
Updated title in Table 1: Device summary.
Updated Section 8: Package information.
Minor text changes.
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Changes
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L4940
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