December 2009 Doc ID 2141 Rev 12 1/23
23
L4940XX5, L4940XX85
L4940XX10, L4940XX12
Very low drop 1.5 A regulator
Features
■Precise 5, 8.5, 10, 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, TO-220FP and
D²PAK packages and with several fixed output
voltages, making it useful in a wide range of
industrial and consumer applications. Thanks to
its very low input/output voltage drop, these
devices are particularly suitable for batteries
powered equipment, reducing consumption and
prolonging battery life. Each type employs internal
current limiting, antisaturation circuit, thermal
shut-down and safe area protection.
D²PAK
TO-220
Table 1. Device summary
Part numbers
Order codes
Output voltages
TO-220 D²PAK
L4940XX5 L4940V5 L4940D2T5-TR 5 V
L4940XX85 L4940V85 8.5 V
L4940XX10 L4940D2T10-TR 10 V
L4940XX12 L4940D2T12-TR 12 V
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Contents L4940XX5, L4940XX85, L4940XX10, L4940XX12
2/23 Doc ID 2141 Rev 12
Contents
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Test circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7 Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Block diagram
Doc ID 2141 Rev 12 3/23
1 Block diagram
Figure 1. Block diagram
Pin configuration L4940XX5, L4940XX85, L4940XX10, L4940XX12
4/23 Doc ID 2141 Rev 12
2 Pin configuration
Figure 2. Pin connections (top view)
TO-220FP
D²PAK
TO-220
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Maximum ratings
Doc ID 2141 Rev 12 5/23
3 Maximum ratings
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
VIForward input voltage 30 V
VIR Reverse input voltage
VO = 5V, RO = 100Ω-15 V
VO = 8.5V, RO = 180Ω-15 V
VO = 10V, RO = 200Ω-15 V
VO = 12V, RO = 240Ω-15 V
IOOutput current Internally Limited mA
PDPower dissipation Internally Limited mW
Tstg Storage temperature range -40 to +150 °C
Top Operating junction temperature range -40 to +150 °C
Table 3. Thermal data
Symbol Parameter TO-220 TO-220FP D²PAK Unit
RthJC Thermal resistance junction-case 3 5 3 °C/W
RthJA Thermal resistance junction-ambient 50 60 62.5 °C/W
Test circuits L4940XX5, L4940XX85, L4940XX10, L4940XX12
6/23 Doc ID 2141 Rev 12
4 Test circuits
Figure 3. DC parameters
Figure 4. Load rejection
Figure 5. Ripple rejection
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Electrical characteristics
Doc ID 2141 Rev 12 7/23
5 Electrical characteristics
Refer to test circuit, VI = 7 V, CI = 0.1 µF, CO = 22 µF, TJ = 25°C, unless otherwise specified.
Table 4. Electrical characteristics of L4940XX5
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 500 mA 4.9 5 5.1 V
VOOutput voltage IO = 5mA to 1.5A, VI = 6.5 to 15 V 4.8 5 5.2 V
VIInput voltage IO = 5 mA 17 V
ΔVOLine regulation VI = 6 to 17 V, IO = 5 mA 4 10 mV
ΔVOLoad regulation IO = 5 mA to 1.5 A 8 25 mV
IO = 0.5 A to 1 A 5 15 mV
IqQuiescent current IO = 5 mA 5 8 mA
IO = 1.5 A, VI = 6.5 V 30 50 mA
ΔIqQuiescent current change IO = 5 mA 3 mA
IO = 1.5 A, VI = 6.5 to 16 V 15 mA
ΔVO/ΔT Output voltage drift 0.5 mV/°C
SVR Supply voltage rejection f = 120 Hz, IO = 1 A 58 68 dB
VdDropout voltage IO = 0.5 A 200 400 mV
IO = 1.5 A 500 900 mV
Isc Short circuit current VI = 14 V 2 2.7 A
VI = 6.5 V 2.2 2.9
Electrical characteristics L4940XX5, L4940XX85, L4940XX10, L4940XX12
8/23 Doc ID 2141 Rev 12
Refer to test circuit, VI = 10.5 V, CI = 0.1 µF, CO = 22 µF, TJ = 25°C, unless otherwise
specified.
Table 5. Electrical characteristics of L4940XX85
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 500 mA 8.3 8.5 8.7 V
VOOutput voltage IO = 5mA to 1.5A, VI = 10.2 to 15V 8.15 8.5 8.85 V
VIInput voltage IO = 5 mA 17 V
ΔVOLine regulation VI = 9.5 to 17V, IO = 5 mA 4 9 mV
ΔVOLoad regulation IO = 5mA to 1.5A 12 30 mV
IO = 0.5A to 1A 8 16 mV
IqQuiescent current IO = 5 mA 4 8 mA
IO = 1.5A, VI = 10.2V 30 50 mA
ΔIqQuiescent current change IO = 5 mA 2.5 mA
IO = 1.5A, VI = 10.2 to 16V 15 mA
ΔVO/ΔT Output voltage drift 0.8 mV/°C
SVR Supply voltage rejection f = 120Hz, IO = 1A 58 66 dB
VdDropout voltage IO = 0.5A 200 400 mV
IO = 1.5A 500 900 mV
Isc Short circuit current VI = 14V 2 2.7 A
VI = 10.2V 2.2 2.9
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Electrical characteristics
Doc ID 2141 Rev 12 9/23
Refer to test circuit, VI = 12V, CI = 0.1 µF, CO = 22 µF, TJ = 25°C, unless otherwise specified.
Table 6. Electrical characteristics of L4940XX10
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 500 mA 9.8 10 10.2 V
VOOutput voltage IO = 5 mA to 1.5 A, VI = 11.7 to 15 V 9.6 10 10.4 V
VIInput voltage IO = 5 mA 17 V
ΔVOLine regulation VI = 11 to 17 V, IO = 5 mA 3 8 mV
ΔVOLoad regulation IO = 5 mA to 1.5 A 15 35 mV
IO = 0.5 A to 1 A 10 20 mV
IqQuiescent current IO = 5 mA 5 8 mA
IO = 1.5 A, VI = 11.7 V 30 50 mA
ΔIqQuiescent current change IO = 5 mA 2 mA
IO = 1.5 A, VI = 11.7 to 16 V 13 mA
ΔVO/ΔT Output voltage drift 1 mV/°C
SVR Supply voltage rejection f = 120 Hz, IO = 1 A 56 62 dB
VdDropout voltage IO = 0.5 A 200 400 mV
IO = 1.5 A 500 900 mV
Isc Short circuit current VI = 14 V 2 2.7 A
VI = 11.7 V 2.2 2.9
Electrical characteristics L4940XX5, L4940XX85, L4940XX10, L4940XX12
10/23 Doc ID 2141 Rev 12
Refer to test circuit, VI = 14 V, CI = 0.1 µF, CO = 22 µF, TJ = 25°C, unless otherwise specified.
Table 7. Electrical characteristics of L4940XX12
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 500 mA 11.75 12 12.25 V
VOOutput voltage IO = 5 mA to 1.5 A, VI = 13.8 to 15 V 11.5 12 12.5 V
VIInput voltage IO = 5 mA 17 V
ΔVOLine regulation VI = 13 to 17 V, IO = 5 mA 3 7 mV
ΔVOLoad regulation IO = 5 mA to 1.5 A 15 35 mV
IO = 0.5 A to 1 A 10 25 mV
IqQuiescent current IO = 5 mA 4 8 mA
IO = 1.5 A, VI = 13.8 V 30 50 mA
ΔIqQuiescent current change IO = 5 mA 1.5 mA
IO = 1.5 A, VI = 13.8 to 16 V 10 mA
ΔVO/ΔT Output voltage drift 1.2 mV/°C
SVR Supply voltage rejection f = 120 Hz, IO = 1 A 55 61 dB
VdDropout voltage IO = 0.5 A 200 400 mV
IO = 1.5 A 500 900 mV
Isc Short circuit current VI = 14 V 2 2.7 A
ZOOutput impedance f = 120 Hz, IO = 0.5 A 40 mΩ
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Typical application
Doc ID 2141 Rev 12 11/23
6 Typical application
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
(L4940V10)
Figure 11. Output voltage vs. temperature
(L4940V12)
Typical application L4940XX5, L4940XX85, L4940XX10, L4940XX12
12/23 Doc ID 2141 Rev 12
Figure 12. Quiescent current vs. temperature
(L4940V5)
Figure 13. Quiescent current vs. input voltage
(L4940V5)
Figure 14. Quiescent current vs. output
current (L4940V5)
Figure 15. Short circuit current vs.
temperature (L4940V5)
Figure 16. Peak output current vs.
input/output differential voltage
(L4940V5)
Figure 17. Low voltage behavior (L4940V5)
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Typical application
Doc ID 2141 Rev 12 13/23
Figure 18. Low voltage behavior (L4940V85) Figure 19. Low voltage behavior (L4940V10)
Figure 20. Low voltage behavior (L4940V12) Figure 21. Supply voltage rejection vs.
frequency (L4940V5)
Figure 22. Supply voltage rejection vs. output
current (L4940V5)
Figure 23. Lad dump characteristics
(L4940V5)
Typical application L4940XX5, L4940XX85, L4940XX10, L4940XX12
14/23 Doc ID 2141 Rev 12
Figure 24. Line transient response (L4940V5) Figure 25. Total power dissipation
Figure 26. Load transient response
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Schematic application
Doc ID 2141 Rev 12 15/23
7 Schematic application
Note: Advantages of these application 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.
Figure 27. Distributed supply with on-card L4940 and L4941 low drop regulator
Figure 28. Distributed supply with on-card L4940 and L4941 low drop regulator
Schematic application L4940XX5, L4940XX85, L4940XX10, L4940XX12
16/23 Doc ID 2141 Rev 12
Note: Advantages of this configuration are:
Very high regulation (line and load on both the output voltage.
12 V output short circuit and thermally protected.
Very high efficiency on the 12 V output due to the low drop regulator.
Figure 29. Distributed supply with on-card L4940 and L4941 low drop regulator
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Package mechanical data
Doc ID 2141 Rev 12 17/23
8 Package mechanical data
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.
Package mechanical data L4940XX5, L4940XX85, L4940XX10, L4940XX12
18/23 Doc ID 2141 Rev 12
Dim. mm. inch.
Min. Typ. Max. Min. Typ. Max.
A 4.40 4.60 0.1730.181
C1.231.32 0.0480.051
D 2.40 2.72 0.094 0.107
D1 1.27 0.050
E0.490.70 0.0190.027
F 0.61 0.88 0.024 0.034
F1 1.14 1.70 0.044 0.067
F2 1.14 1.70 0.044 0.067
G4.95 5.15 0.194 0.203
G1 2.4 2.7 0.094 0.106
H2 10.0 10.40 0.393 0.409
L2 16.4 0.645
L4 13.0 14.0 0.511 0.551
L5 2.65 2.95 0.104 0.116
L6 15.25 15.75 0.600 0.620
L7 6.2 6.6 0.244 0.260
L93.5 3.93 0.137 0.154
DIA. 3.75 3.85 0.147 0.151
TO-220 mechanical data
P011C
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Package mechanical data
Doc ID 2141 Rev 12 19/23
Dim. mm. inch.
Min. Typ Max. Min. Typ. Max.
A 4.40 4.60 0.1730.181
B 2.5 2.7 0.098 0.106
D 2.5 2.75 0.098 0.108
E 0.45 0.70 0.017 0.027
F 0.75 1 0.0300.039
F1 1.15 1.50 0.045 0.059
F2 1.15 1.50 0.045 0.059
G4.95 5.2 0.194 0.204
G1 2.4 2.7 0.094 0.106
H 10.0 10.40 0.393 0.409
L2 16 0.630
L328.6 30.6 1.126 1.204
L4 9.810.6 0.3850.417
L5 2.93.6 0.114 0.142
L6 15.916.4 0.626 0.645
L7 99.30.354 0.366
DIA. 33.2 0.1180.126
TO-220FP mechanical data
7012510A-
H
Package mechanical data L4940XX5, L4940XX85, L4940XX10, L4940XX12
20/23 Doc ID 2141 Rev 12
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A 4.4 4.6 0.1730.181
A1 2.492.690.098 0.106
A2 0.030.230.001 0.009
B 0.7 0.93 0.027 0.036
B2 1.14 1.7 0.044 0.067
C 0.45 0.6 0.017 0.023
C2 1.231.36 0.0480.053
D8.959.350.352 0.368
D1 80.315
E 10 10.4 0.393 0.409
E1 8.5 0.335
G4.88 5.280.192 0.208
L 15 15.85 0.590 0.624
L2 1.27 1.4 0.050 0.055
L31.4 1.75 0.055 0.068
M2.4 3.2 0.094 0.126
R 0.4 0.016
V2 0° 8°0° 8°
D2PAK mechanical data
P011P6G
L4940XX5, L4940XX85, L4940XX10, L4940XX12 Package mechanical data
Doc ID 2141 Rev 12 21/23
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A180 7.086
C 12.813.0 13.2 0.504 0.512 0.519
D 20.2 0.795
N60 2.362
T 14.4 0.567
Ao 10.50 10.6 10.70 0.4130.417 0.421
Bo 15.70 15.80 15.90 0.6180.622 0.626
Ko 4.80 4.90 5.00 0.189 0.193 0.197
Po 3.94.0 4.1 0.1530.157 0.161
P 11.912.0 12.1 0.4680.472 0.476
Tape & reel D2PAK-P2PAK-D2PAK/A-P2PAK/A mechanical data
Revision history L4940XX5, L4940XX85, L4940XX10, L4940XX12
22/23 Doc ID 2141 Rev 12
9 Revision history
Table 8. Document revision history
Date Revision Changes
04-Feb-2005 6 Add new package D²PAK/A.
18-Sep-2006 7 Order codes has been updated and new template.
31-May-2007 8 Order codes has been updated.
19-Sep-2007 9 Add Ta b l e 1 in 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 7 on page 10.
L4940XX5, L4940XX85, L4940XX10, L4940XX12
Doc ID 2141 Rev 12 23/23
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