September 2006 Rev. 5 1/17
17
L4941
Very low drop 1A regulator
Feature summary
■Low dropout voltage (450mV typ. at 1A)
■Very low quiescent current
■Thermal shutdown
■Short circuit protection
■Reverse polarity protection
Description
The L4941 is a three terminal 5V positive
regulators available in TO-220 and DPAK
packages, 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 battery
powered equipments, reducing consumption and
prolonging battery life. It employs internal current
limiting, antisaturation circuit, thermal shut-down
and safe area protection.
DPAK
TO-220
www.st.com
Order code
Part number Package
L4941BV TO-220
L4941BDT-TR DPAK
L4941
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Contents
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Test circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7 Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
L4941 Block diagram
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1 Block diagram
Figure 1. Block diagram
Pin configuration L4941
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2 Pin configuration
Figure 2. Pin connections (top view)
DPAK
TO-220
L4941 Maximum ratings
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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 1. Absolute maximum ratings
Symbol Parameter Value Unit
VIForward input voltage 30 V
VIR Reverse input voltage (RO=100Ω)-15V
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 2. Thermal Data
Symbol Parameter TO-220 DPAK Unit
RthJC Thermal resistance junction-case 3 8 °C/W
RthJA Thermal resistance junction-ambient 50 100 °C/W
Test circuits L4941
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4 Test circuits
Figure 3. DC Parameters
Figure 4. Load rejection
Figure 5. Ripple rejection
L4941 Electrical characteristics
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5 Electrical characteristics
Table 3. Electrical characteristics (refer to test circuit, VI=7V, CI = 0.1µF, CO = 22µF, TJ = 25°C,
unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 5mA to 1A, VI = 6 to 14V 4.8 5 5.2 V
VIInput voltage IO = 5 mA 16 V
∆VOLine regulation VI = 6 to 16V, IO = 5 mA 5 20 mV
∆VOLoad regulation IO = 5mA to 1A 8 20 mV
IO = 0.5A to 1A 5 15 mV
IqQuiescent current IO = 5 mA, VI = 6V 4 8 mA
IO = 1A, VI = 6V 20 40 mA
∆IqQuiescent current change IO = 5 mA, VI = 6 to 14V 3 mA
IO = 1A, VI = 6 to 14V -10 mA
VdDropout voltage IO = 0.5A 250 450 mV
IO = 1A 450 700 mV
∆VO/∆T Output voltage drift 0.6 mV/°C
SVR Supply voltage rejection f = 120Hz, IO = 1A 58 68 dB
Isc Short circuit current VI = 14V 1.6 2.0 A
VI = 6V 1.8 2.2
ZOOutput impedance f = 1KHz, IO = 0.5A 30 mΩ
eNOutput noise voltage B = 100Hz to 100KHz 30 µV/VO
Typical application L4941
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6 Typical application
Figure 6. Dropout voltage vs output current Figure 7. Dropout voltage vs temperature
Figure 8. Output voltage vs temperature Figure 9. Quiescent current vs temperature
Figure 10. Quiescent current vs input voltage Figure 11. Quiescent current vs output current
L4941 Typical application
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Figure 12. Short circuit current vs temperature Figure 13. Peak output current vs input/output
differential voltage
Figure 14. Low voltage behavior Figure 15. Supply voltage rejection vs
frequency
Figure 16. Supply voltage rejection vs output
current
Figure 17. Load dump characteristics
Typical application L4941
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Figure 18. Line transient response Figure 19. Total power dissipation
Figure 20. Load transient response
L4941 Schematic application
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7 Schematic application
ADVANTAGES OF THESE APPLICATION ARE:
On card regulation with short-circuit and thermal protection on each output.
Vary high total system efficiency due to the switching preregulation and very low-drop postregulation.
Figure 21. Distributed supply with On-card L4940 and L4941 low drop regulator
Figure 22. Distributed Supply with On-card L4940 and L4941 low drop regulator
Package mechanical data L4941
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8 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
L4941 Package mechanical data
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DIM. mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
A 4.40 4.60 0.173 0.181
C 1.23 1.32 0.048 0.051
D 2.40 2.72 0.094 0.107
D1 1.27 0.050
E 0.49 0.70 0.019 0.027
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
G 4.95 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
L9 3.5 3.93 0.137 0.154
DIA. 3.75 3.85 0.147 0.151
TO-220 MECHANICAL DATA
P011C
Package mechanical data L4941
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DIM.
mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
A 2.2 2.4 0.086 0.094
A1 0.9 1.1 0.035 0.043
A2 0.03 0.23 0.001 0.009
B 0.64 0.9 0.025 0.035
b4 5.2 5.4 0.204 0.212
C 0.45 0.6 0.017 0.023
C2 0.48 0.6 0.019 0.023
D 6 6.2 0.236 0.244
D1 5.1 0.200
E 6.4 6.6 0.252 0.260
E1 4.7 0.185
e 2.28 0.090
e1 4.4 4.6 0.173 0.181
H 9.35 10.1 0.368 0.397
L 1 0.039
(L1) 2.8 0.110
L2 0.8 0.031
L4 0.6 1 0.023 0.039
R 0.2 0.008
V2 0° 8° 0° 8°
DPAK MECHANICAL DATA
0068772-F
L4941 Package mechanical data
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DIM.
mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.0 13.2 0.504 0.512 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.80 6.90 7.00 0.268 0.272 0.2.76
Bo 10.40 10.50 10.60 0.409 0.413 0.417
Ko 2.55 2.65 2.75 0.100 0.104 0.105
Po 3.9 4.0 4.1 0.153 0.157 0.161
P 7.9 8.0 8.1 0.311 0.315 0.319
Tape & Reel DPAK-PPAK MECHANICAL DATA
Revision history L4941
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9 Revision history
Table 4. Revision history
Date Revision Changes
21-Jun-2004 4 Document updating.
15-Sep-2006 5 Order Codes has been updated and new template.
L4941
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