July 2008 Rev 18 1/23
23
LM2931XX - LM2931AXX33
LM2931AXX50 - LM2931BXX50
Very low drop voltage regulators with inhibit function
Features
■Very low dropout voltage (0.15 V typ. at 10 mA
load)
■Low quiescent current (typ. 2.5 mA, at 100 mA
load)
■Output current up to 100 mA
■Adjustable (from VOUT = 2.5 V only SO-8) and
fixed (3.3 V & 5 V) output voltage version
■Internal current and thermal limit
■Load dump protection up to 60 V
■Reverse transient protection up to -50 V
■Temperature range: -40 to 125 °C
■Package available: TO-92, DPAK, SO-8 (with
inhibit control)
Description
The LM2931xx are very low drop regulators. The
very low drop voltage and the low quiescent
current make them particular suitable for low
noise, low power applications and in battery
powered systems. In the 8 pin configuration (SO-
8), fully compatible to the older L78Lxx family, a
shut down logic control function is available.
This means that when the device is used as a
local regulator is possible to put a part of the
board in stand-by decreasing the total power
consumption. Ideal for automotive application the
LM2931xx is protected from reverse battery
installations or 2 battery jumps. During the
transient, such as a a load dump (60 V) when the
input voltage can exceed the specified maximum
operating input voltage (26 V), the regulator will
automatically shut down to protect both internal
circuit and the load.
TO-92
DPAK
SO-8
Table 1. Device summary
Order codes
Output voltagePackages
DPAK TO-92 (BAG) TO-92 (Ammopak) (1) SO-8
LM2931AZ33R LM2931AD33R 3.3 V
LM2931ADT50R LM2931AZ50R LM2931AD50R 5.0 V
LM2931BZ50R LM2931BZ50AP LM2931BD50R 5.0 V
LM2931D-R 2.5 to 26 V
1. Please note that in these cases pins are shaped according to tape & reel specifications.
www.st.com
Contents LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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Contents
1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Application circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6 Timing diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8 Order code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Diagram
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1 Diagram
Figure 1. Schematic diagram
Pin configuration LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
4/23
2 Pin configuration
Figure 2. Pin connections (top view)
SO-8
DPAK
PIN 1 = VOUT
PIN 2 = GND
PIN 3 = VIN
TO-92 BOTTOM VIEW
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 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 2. Absolute maximum ratings
Symbol Parameter Value Unit
VIDC positive input voltage 40 V
VIDC reverse input voltage -15 V
VITransient input voltage (τ < 100 ms) 60 V
VITransient reverse input voltage (τ < 100 ms) -50 V
VINH Inhibit input voltage 40 V
IOOutput current Internally limited
TSTG Storage temperature range -65 to 150 °C
TOP Operating junction temperature range -40 to 125 °C
Table 3. Thermal data
Symbol Parameter SO-8 DPAK TO-92 Unit
RthJC Thermal resistance junction-case 20 8 °C/W
RthJA Thermal resistance junction-ambient 55 (1) 100 200 °C/W
1. Considering 6 cm2 of copper board heat-sink.
Application circuits LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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4 Application circuits
R1 suggested value = 27 kΩ
VO = VREF (R1 + R2)/R1
Figure 3. Application circuit for fixed output
Figure 4. Application circuit for adjustable output
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Electrical characteristics
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5 Electrical characteristics
Table 4. Electrical characteristics of LM2931Axx33 (refer to the application circuit Figure 3,
TJ = 25 °C, CI = 0.1 µF, CO = 100 µF, VI = 14 V, IO = 10 mA, VINH = 0 V, unless otherwise
specified).
Symbol Parameter Test conditions Min. Typ. Max. Unit
VI
Maximum operating input
voltage IO = 10 mA, TJ = -40 to 125°C 26 37 V
VOOutput voltage 3.135 3.3 3.425 V
VOOutput voltage IO = 100 mA, VI = 6 to 26 V
TJ = -40 to 125°C 3.135 3.3 3.465 V
ΔVOLine regulation VI = 9 to 16 V 2 10 mV
VI = 6 to 26 V 4 33
ΔVOLoad regulation IO = 5 to 100 mA 10 33 mV
VdDropout voltage (1) (2) IO = 10 mA 90 250 mV
IO = 100 mA 250 600
Id
Quiescent current
ON MODE IO = 100 mA 2.5 30 mA
OFF MODE VINH = 2.5 V, RLOAD = 330 Ω0.3 1 mA
ISC Short circuit current 100 300 mA
SVR Supply voltage rejection IO = 100 mA, VI = 14 ± 2 V
f = 120 Hz, TJ = -40 to 125°C 55 78 dB
VIL Control input voltage low TJ = -40 to 125°C 2 1.2 V
VIH Control input voltage high TJ = -40 to 125°C 3.25 2 V
IINH Inhibit input current VINH = 2.5 V 22 50 µA
VITransient input voltage RLOAD = 330 Ω, τ < 100ms 60 70 V
VI
Reverse polarity input
voltage VO = ± 0.3 V, RLOAD = 330 Ω-15 -50 V
VI
Reverse polarity input
voltage transient RLOAD = 330 Ω, τ < 100ms -50 V
eN Output noise voltage B =10 Hz to 100 kHz 330 µVRMS
1. Reference voltage is measured from VOUT to ADJ pin.
2. Vd measured when the output voltage has dropped 100 mV from the nominal value obtained at 14 V.
Electrical characteristics LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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Table 5. Electrical characteristics of LM2931Axx50 (refer to the application circuit Figure 3,
TJ = 25 °C, CI = 0.1 µF, CO = 100 µF, VI = 14 V, IO = 10 mA, VINH = 0 V, unless otherwise
specified).
Symbol Parameter Test conditions Min. Typ. Max. Unit
VI
Maximum operating input
voltage IO = 10 mA, TJ = -40 to 125°C 26 37 V
VOOutput voltage 4.81 5 5.19 V
VOOutput voltage IO = 100 mA, VI = 6 to 26 V
TJ = -40 to 125°C 4.75 5 5.25 V
ΔVOLine regulation VI = 9 to 16 V 2 10 mV
VI = 6 to 26 V 4 30
ΔVOLoad regulation IO = 5 to 100 mA 15 50 mV
VdDropout voltage (1) (2) IO = 10 mA 90 200 mV
IO = 100 mA 250 600
Id
Quiescent current
ON MODE IO = 100 mA 2.5 30 mA
OFF MODE VINH = 2.5 V, RLOAD = 500 Ω0.3 1 mA
ISC Short circuit current 100 300 mA
SVR Supply voltage rejection IO = 100 mA, VI = 14 ± 2 V
f = 120 Hz, TJ = -40 to 125°C 55 75 dB
VIL Control input voltage low TJ = -40 to 125°C 2 1.2 V
VIH Control input voltage high TJ = -40 to 125°C 3.25 2 V
IINH Inhibit input current VINH = 2.5 V 22 50 µA
VITransient input voltage RLOAD = 500 Ω, τ < 100ms 60 70 V
VI
Reverse polarity input
voltage VO = ± 0.3 V, RLOAD = 500 Ω-15 -50 V
VI
Reverse polarity input
voltage transient RLOAD = 500 Ω, τ < 100ms -50 V
eN Output noise voltage B =10 Hz to 100 kHz 500 µVRMS
1. Reference voltage is measured from VOUT to ADJ pin.
2. Vd measured when the output voltage has dropped 100 mV from the nominal value obtained at 14 V.
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Electrical characteristics
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Table 6. Electrical characteristics of LM2931Bxx50 (refer to the application circuit Figure 3,
TJ = 25 °C, CI = 0.1 µF, CO = 100 µF, VI = 14 V, IO = 10 mA, VINH = 0 V, unless otherwise
specified).
Symbol Parameter Test conditions Min. Typ. Max. Unit
VI
Maximum operating input
voltage IO = 10 mA, TJ = -40 to 125°C 26 37 V
VOOutput voltage 4.75 5 5.25 V
VOOutput voltage IO = 100 mA, VI = 6 to 26 V
TJ = -40 to 125°C 4.5 5 5.5 V
ΔVOLine regulation VI = 9 to 16 V 2 10 mV
VI = 6 to 26 V 4 30
ΔVOLoad regulation IO = 5 to 100 mA 15 50 mV
VdDropout voltage (1) (2) IO = 10 mA 90 200 mV
IO = 100 mA 250 600
Id
Quiescent current
ON MODE IO = 100 mA 2.5 30 mA
OFF MODE VINH = 2.5 V, RLOAD = 500 Ω0.3 1 mA
ISC Short circuit current 100 300 mA
SVR Supply voltage rejection IO = 100 mA, VI = 14 ± 2 V
f = 120 Hz, TJ = -40 to 125°C 55 75 dB
VIL Control input voltage low TJ = -40 to 125°C 2 1.2 V
VIH Control input voltage high TJ = -40 to 125°C 3.25 2 V
IINH Inhibit input current VINH = 2.5 V 22 50 µA
VITransient input voltage RLOAD = 500 Ω, τ < 100ms 60 70 V
VI
Reverse polarity input
voltage VO = ± 0.3 V, RLOAD = 500 Ω-15 -50 V
VI
Reverse polarity input
voltage transient RLOAD = 500 Ω, τ < 100ms -50 V
eN Output noise voltage B =10 Hz to 100 kHz 500 µVRMS
1. Reference voltage is measured from VOUT to ADJ pin.
2. Vd measured when the output voltage has dropped 100 mV from the nominal value obtained at 14 V.
Electrical characteristics LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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Table 7. Electrical characteristics of LM2931xx (refer to the application circuit Figure 4 with
R1 = 27 KΩ and R2 = 40.5 kΩ, TJ = 25 °C, CI = 0.1 µF, CO = 100 µF, VI = 14 V, IO = 10 mA,
VINH = 0 V, unless otherwise specified).
Symbol Parameter Test conditions Min. Typ. Max. Unit
VI
Maximum operating input
voltage IO = 10 mA, TJ = -40 to 125°C 26 37 V
VREF Reference voltage (1) 1.14 1.2 1.26 V
VREF Reference voltage (1) IO = 100 mA, TJ = -40 to 125°C 1.08 1.2 1.32 V
ΔVOLine regulation VI = 3.6 to 26 V 0.6 4.5 mV
ΔVOLoad regulation IO = 5 to 100 mA 9 30 mV
VdDropout voltage (1) (2) IO = 10 mA 90 200 mV
IO = 100 mA 250 600
Id
Quiescent current
ON MODE IO = 100 mA 2.5 30 mA
OFF MODE VINH = 2.5 V, RLOAD = 300 Ω0.3 1 mA
ISC Short circuit current 100 300 mA
SVR Supply voltage rejection IO = 100 mA, VI = 14 ± 2 V
f = 120 Hz, TJ = -40 to 125°C 55 80 dB
VIL Control input voltage low TJ = -40 to 125°C 2 1.2 V
VIH Control input voltage high TJ = -40 to 125°C 3.25 2 V
IINH Inhibit input current VINH = 2.5 V 22 50 µA
VITransient input voltage RLOAD = 300 Ω, τ < 100ms 60 70 V
VI
Reverse polarity input
voltage VO = ± 0.3 V, RLOAD = 300 Ω-15 -50 V
VI
Reverse polarity input
voltage transient RLOAD = 300 Ω, τ < 100ms -50 V
eN Output noise voltage B = 10 Hz to 100 kHz 330 µVRMS
1. Reference voltage is measured from VOUT to ADJ pin.
2. Vd measured when the output voltage has dropped 100 mV from the nominal value obtained at 14 V.
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Typical characteristics
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6 Typical characteristics
(unless otherwise specified CI = 0.1 µF, CO = 100 µF)
Figure 5. Output voltage vs temperature Figure 6. Output voltage vs temperature
Figure 7. Reference voltage vs temperature Figure 8. Line regulation vs temperature
Figure 9. Load regulation vs temperature Figure 10. Dropout voltage vs temperature
Typical characteristics LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
12/23
Figure 11. Dropout voltage vs temperature Figure 12. Dropout voltage vs output current
Figure 13. Output voltage vs input voltage Figure 14. Short circuit current vs drop
voltage
Figure 15. Quiescent current vs temperature Figure 16. Quiescent current vs input voltage
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Typical characteristics
13/23
Figure 17. Quiescent current vs output current Figure 18. Supply voltage rejection vs
temperature
Figure 19. Supply voltage rejection vs
frequency
Figure 20. Supply voltage rejection vs output
current
Figure 21. Stability vs COFigure 22. Line transient
VI = 6 to 20 V, RL = 500 Ω, TJ = 25°C, CI = 0, CO = 100 µF,
Rise Fall-Time = 200 ns
Typical characteristics LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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Figure 23. Line transient
VI = 14 V, IO = 100 mA, TJ = 25°C, CI = 0.1 µF, CO = 100 µF,
Rise Time = 500 ns, Fall-Time = 1 µs
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Package mechanical data
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7 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.
Package mechanical data LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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Dim.
mm. mils.
Min. Typ. Max. Min. Typ. Max.
A4.324.95 170.1 194.9
b0.36 0.51 14.2 20.1
D 4.45 4.95 175.2 194.9
E3.303.94 129.9155.1
e 2.41 2.67 94.9105.1
e1 1.14 1.40 44.955.1
L 12.7 15.49500.0 609.8
R 2.16 2.41 85.0 94.9
S1 0.92 1.52 36.2 59.8
W 0.41 0.56 16.1 22.0
α5° 5°
TO-92 mechanical data
0102782/D
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Package mechanical data
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Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A 2.2 2.4 0.086 0.094
A1 0.91.1 0.035 0.043
A2 0.030.230.001 0.009
B 0.64 0.90.025 0.035
b4 5.2 5.4 0.204 0.212
C 0.45 0.6 0.017 0.023
C2 0.480.6 0.0190.023
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
e2.280.090
e1 4.4 4.6 0.1730.181
H9.35 10.1 0.3680.397
L 1 0.039
(L1) 2.80.110
L2 0.80.031
L4 0.6 1 0.0230.039
R 0.2 0.008
V2 0° 8°0° 8°
DPAK mechanical data
0068772-F
Package mechanical data LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
18/23
Dim. mm. inch.
Min. Typ. Max. Min. Typ. Max.
A1.35 1.75 0.0530.069
A1 0.10 0.25 0.04 0.010
A2 1.10 1.65 0.0430.065
B0.33 0.51 0.0130.020
C0.190.25 0.007 0.010
D4.80 5.00 0.189 0.197
E3.80 4.00 0.150 0.157
e 1.27 0.050
H5.80 6.20 0.2280.244
h 0.25 0.50 0.010 0.020
L 0.40 1.27 0.016 0.050
k8° (max.)
ddd 0.1 0.04
SO-8 mechanical data
0016023/C
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Package mechanical data
19/23
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A330 12.992
C12.813.0 13.2 0.504 0.512 0.519
D 20.2 0.795
N60 2.362
T22.40.882
Ao 6.806.90 7.00 0.2680.272 0.2.76
Bo 10.40 10.50 10.60 0.4090.4130.417
Ko 2.55 2.65 2.75 0.100 0.104 0.105
Po 3.94.0 4.1 0.1530.157 0.161
P7.98.0 8.1 0.311 0.315 0.319
Tape & reel DPAK-PPAK mechanical data
Package mechanical data LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
20/23
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A330 12.992
C 12.813.2 0.504 0.519
D 20.2 0.795
N60 2.362
T 22.4 0.882
Ao 8.1 8.5 0.3190.335
Bo 5.5 5.90.216 0.232
Ko 2.1 2.30.082 0.090
Po 3.94.1 0.1530.161
P7.98.1 0.311 0.319
Tape & reel SO-8 mechanical data
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50 Package mechanical data
21/23
Dim. mm. inch.
Min. Typ. Max. Min. Typ. Max.
A1 4.80 0.189
T3.80 0.150
T1 1.60 0.063
T2 2.30 0.091
d0.480.019
P0 12.5 12.90.492 0.508
P2 5.65 7.05 0.222 0.278
F1, F2 2.44 2.54 2.94 0.096 0.100 0.116
delta H ±2 0.079
W 17.5 18.00 19.0 0.689 0.7090.748
W0 5.7 6.30.224 0.248
W1 8.5 9.25 0.335 0.364
W2 0.50 0.20
H18.50 18.70 0.7280.726
H0 15.50 16.50 0.610 0.650
H1 25.00 0.984
D0 3.84.2 0.150 0.165
t0.900.035
L1 30.118
delta P±1 0.039
u50 1.968
Φ1360 14.173
Φ2301.181
Tape & reel for TO-92 mechanical data
W
W1
W0
W2
A1
d
D0
H1
H
H0
L
l1
F1 F2
P2
P0
delta P
delta H
T2 T1
T
t
DRAWING NOT IN SCALE
Revision history LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
22/23
8 Revision history
Table 8. Document revision history
Date Revision Changes
21-Jun-2004 12 Document updated.
16-Jun-2006 13 Order codes updated.
27-Jul-2007 14 Added Ta b le 1 in cover page.
21-Aug-2007 15 Added root part number - (see Ta bl e 1 )
22-Nov-2007 16 Modified: Tabl e 1.
11-Feb-2008 17 Modified: Table 1 on page 1.
10-Jul-2008 18 Removed package TO-220, modified Table 1 on page 1.
LM2931XX - LM2931AXX33 - LM2931AXX50 - LM2931BXX50
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