February 2012 Doc ID 2150 Rev 13 1/22
22
L79xxAC
2 % negative voltage regulators
Features
■Output current to 1.5 A
■Output voltages of -5; -12; -15 V
■Thermal overload protection
■Short circuit protection
■Output transition SOA protection
Description
The L79xxAC series of three-terminal negative
regulators is available in TO-220 and D²PAK
packages and several fixed output voltages.
These regulators can provide local on-card
regulation, eliminating the distribution problems
associated with single point regulation;
furthermore, having the same voltage option as
the L78xxA positive standard series, they are
particularly suited for split power supplies. If
adequate heat sinking is provided, they can
deliver over 1.5 A output current. Although
designed primarily as fixed voltage regulators,
these devices can be used with external
components to obtain adjustable voltages and
currents.
D²PAK
TO-220
Table 1. Device summary
Part numbers
Order codes Output
voltages
TO-220 D²PAK
L7905AC L7905ACV L7905ACV-DG (1) L7905ACD2T-TR -5 V
L7912AC L7912ACV L7912ACV-DG (1) -12 V
L7915AC L7915ACV L7915ACV-DG (1) -15 V
1. TO-220 Dual Gauge frame.
www.st.com
Contents L79xxAC
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Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
L79xxAC Diagram
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1 Diagram
Figure 1. Schematic diagram
Pin configuration L79xxAC
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2 Pin configuration
Figure 2. Pin connections (top view)
D²PAK
TO-220
L79xxAC 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 input voltage for VO= -5 to -18V -35 V
for VO= -20, -24V -40
IOOutput current Internally limited
PDPower dissipation Internally limited
TSTG Storage temperature range -65 to 150 °C
TOP Operating junction temperature range 0 to 125 °C
Table 3. Thermal data
Symbol Parameter D²PAK TO-220 Unit
RthJC Thermal resistance junction-case 3 5 °C/W
RthJA Thermal resistance junction-ambient 62.5 50 °C/W
Application L79xxAC
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4 Application
Figure 3. Application circuit
L79xxAC Electrical characteristics
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5 Electrical characteristics
Refer to the test circuits, TJ = 0 to 125 °C, VI = -10 V, IO = 500 mA, CI = 2.2 µF, CO = 1 µF
unless otherwise specified.
Table 4. Electrical characteristics of L7905AC
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage TJ = 25°C -4.9 -5 -5.1 V
VOOutput voltage IO = -5 mA to -1 A, PO ≤ 15 W
VI = -8 to -20 V -4.8 -5 -5.2 V
ΔVO(1) Line regulation VI = -7 to -25 V, TJ = 25°C 100 mV
VI = -8 to -12 V, TJ = 25°C 50
ΔVO(1) Load regulation IO = 5 mA to 1.5 A, TJ = 25°C 100 mV
IO = 250 to 750 mA, TJ = 25°C 50
IdQuiescent current TJ = 25°C 3 mA
ΔIdQuiescent current change IO = 5 mA to 1 A 0.5 mA
VI = -8 to -25 V 1.3
ΔVO/ΔT Output voltage drift IO = 5 mA -0.4 mV/°C
eN Output noise voltage B = 10Hz to 100kHz, TJ = 25°C 100 µV
SVR Supply voltage rejection ΔVI = 10 V, f = 120Hz 54 60 dB
VdDropout voltage IO = 1 A, TJ = 25°C, ΔVO = 100 mV 1.4 V
Isc Short circuit current 2.1 A
Iscp Short circuit peak current TJ = 25°C 2.5 A
1. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be
taken into account separately. Pulse testing with low duty cycle is used.
Electrical characteristics L79xxAC
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Refer to the test circuits, TJ = 0 to 125 °C, VI = -19 V, IO = 500 mA, CI = 2.2 µF, CO = 1 µF
unless otherwise specified.
Table 5. Electrical characteristics of L7912AC
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage TJ = 25°C -11.75 -12 -12.25 V
VOOutput voltage IO = -5 mA to -1 A, PO ≤ 15 W
VI = -15.5 to -27 V -11.5 -12 -12.5 V
ΔVO(1) Line regulation VI = -14.5 to -30 V, TJ = 25°C 240 mV
VI = -16 to -22 V, TJ = 25°C 120
ΔVO(1) Load regulation IO = 5 mA to 1.5 A, TJ = 25°C 240 mV
IO = 250 to 750 mA, TJ = 25°C 120
IdQuiescent current TJ = 25°C 3 mA
ΔIdQuiescent current change IO = 5 mA to 1 A 0.5 mA
VI = -15 to -30 V 1
ΔVO/ΔT Output voltage drift IO = 5 mA -0.8 mV/°C
eN Output noise voltage B = 10Hz to 100kHz, TJ = 25°C 200 µV
SVR Supply voltage rejection ΔVI = 10 V, f = 120Hz 54 60 dB
VdDropout voltage IO = 1 A, TJ = 25°C, ΔVO = 100 mV 1.1 V
Isc Short circuit current 1.5 A
Iscp Short circuit peak current TJ = 25°C 2.5 A
1. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be
taken into account separately. Pulse testing with low duty cycle is used.
L79xxAC Electrical characteristics
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Refer to the test circuits, TJ = 0 to 125 °C, VI = -23 V, IO = 500 mA, CI = 2.2 µF, CO = 1 µF
unless otherwise specified.
Table 6. Electrical characteristics of L7915AC
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage TJ = 25°C -14.7 -15 -15.3 V
VOOutput voltage IO = -5 mA to -1 A, PO ≤ 15 W
VI = -18.5 to -30 V -14.4 -15 -15.6 V
ΔVO(1) Line regulation VI = -17.5 to -30 V, TJ = 25°C 300 mV
VI = -20 to -26 V, TJ = 25°C 150
ΔVO(1) Load regulation IO = 5 mA to 1.5 A, TJ = 25°C 300 mV
IO = 250 to 750 mA, TJ = 25°C 150
IdQuiescent current TJ = 25°C 3 mA
ΔIdQuiescent current change IO = 5 mA to 1 A 0.5 mA
VI = -18.5 to -30 V 1
ΔVO/ΔT Output voltage drift IO = 5 mA -0.9 mV/°C
eN Output noise voltage B = 10Hz to 100kHz, TJ = 25°C 250 µV
SVR Supply voltage rejection ΔVI = 10 V, f = 120Hz 54 60 dB
VdDropout voltage IO = 1 A, TJ = 25°C, ΔVO = 100 mV 1.1 V
Isc Short circuit current 1.3 A
Iscp Short circuit peak current TJ = 25°C 2.5 A
1. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be
taken into account separately. Pulse testing with low duty cycle is used.
Application information L79xxAC
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6 Application information
1. To specify an output voltage, substitute voltage value for "XX".
2. Required for stability. For value given, capacitor must be solid tantalum. If aluminium electrolytic are used,
at least ten times value should be selected. C1 is required if regulator is located an appreciable distance
from power supply filter.
3. To improve transient response. If large capacitors are used, a high current diode from input to output
(1N4001 or similar) should be introduced to protect the device from momentary input short circuit.
(*) Against potential latch-up problems.
Figure 4. Fixed output regulator
Figure 5. Split power supply (± 15 V - 1 A)
L79xxAC Application information
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C3 Optional for improved transient response and ripple rejection.
Figure 6. Circuit for increasing output voltage
VXX/R2 > 3Id
VO=VXX(R1+R2)/R2
IN OUT
GND
IN OUT
GND
Figure 7. High current negative regulator (-5 V / 4 A with 5 A current limiting)
IN OUT
GND
IN OUT
GND
Package mechanical data L79xxAC
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7 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.
Note: In spite of some difference in tolerances, the packages are compatible.
Table 7. TO-220 mechanical data
Dim.
Type STD - ST Dual Gauge Type STD - ST Single Gauge
mm. mm.
Min. Typ. Max. Min. Typ. Max.
A 4.40 4.60 4.40 4.60
b 0.61 0.88 0.61 0.88
b1 1.14 1.70 1.14 1.70
c 0.48 0.70 0.48 0.70
D 15.25 15.75 15.25 15.75
D1 1.27
E 10.00 10.40 10.00 10.40
e 2.40 2.70 2.40 2.70
e1 4.95 5.15 4.95 5.15
F 1.23 1.32 0.51 0.60
H1 6.20 6.60 6.20 6.60
J1 2.40 2.72 2.40 2.72
L 13.00 14.00 13.00 14.00
L1 3.50 3.93 3.50 3.93
L20 16.40 16.40
L30 28.90 28.90
∅P 3.75 3.85 3.75 3.85
Q 2.65 2.95 2.65 2.95
L79xxAC Package mechanical data
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Figure 8. Drawing dimension TO-220 (type STD-ST Dual Gauge)
0015988_S
Package mechanical data L79xxAC
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Figure 9. Drawing dimension TO-220 (type STD-ST Single Gauge)
8174627_B
L79xxAC Package mechanical data
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Figure 10. Drawing dimension tube for TO-220 Dual Gauge (mm.)
Figure 11. Drawing dimension tube for TO-220 Single Gauge (mm.)
Package mechanical data L79xxAC
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Figure 12. Drawing dimension D²PAK (type STD-ST)
0079457/L
L79xxAC Package mechanical data
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Figure 13. Drawing dimension D²PAK (type WOOSEOK-subcon.)
0079457/L
Package mechanical data L79xxAC
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Note: The D²PAK package coming from the subcontractor WOOSEOK is fully compatible with the
ST's package suggested footprint.
Table 8. D²PAK mechanical data
Dim.
Type STD-ST Type WOOSEOK-subcon.
mm. mm.
Min. Typ. Max. Min. Typ. Max.
A 4.40 4.60 4.30 4.70
A1 0.03 0.23 0 0.20
b 0.70 0.93 0.70 0.90
b2 1.14 1.70 1.17 1.37
c 0.45 0.60 0.45 0.50 0.60
c2 1.23 1.36 1.25 1.30 1.40
D 8.95 9.35 9 9.20 9.40
D1 7.50 7.50
E 10 10.40 9.80 10.20
E1 8.50 7.50
e2.54 2.54
e1 4.88 5.28 5.08
H 15 15.85 15 15.30 15.60
J1 2.49 2.69 2.20 2.60
L 2.29 2.79 1.79 2.79
L1 1.27 1.40 1 1.40
L2 1.30 1.75 1.20 1.60
R0.4 0.30
V2 0° 8° 0° 3°
L79xxAC Package mechanical data
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Figure 14. D²PAK footprint recommended data
Table 9. Footprint data
Values
Dim. mm. inch.
A 12.20 0.480
B 9.75 0.384
C 16.90 0.665
D 3.50 0.138
E 1.60 0.063
F 2.54 0.100
G 5.08 0.200
Package mechanical data L79xxAC
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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
L79xxAC Revision history
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8 Revision history
Table 10. Document revision history
Date Revision Changes
22-Jun-2004 7 Order codes updated.
12-Dec-2007 8 Added:
Ta b le 1
.
18-Feb-2008 9 Modified:
Table 1 on page 1
.
28-Jan-2010 10 Modified:
Table 7 on page 12
,
Figure 8 on page 13
,
Figure 9 on page 14
,
Figure 10
and
Figure 11 on page 15
.
12-Nov-2010 11 Modified: RthJC value for TO-220
Table 3 on page 5
.
28-Nov-2011 12 Added: order codes L7912ACV-DG and L7915ACV-DG
Table 1 on page 1
.
09-Feb-2012 13 Added: order code L7905ACV-DG
Table 1 on page 1
.
L79xxAC
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