Features
TO-220
LD1084
5 A low-drop positive voltage regulator adjustable
Datasheet - production data
LD1084 quiescent current flows into the load, so
to increase the efficiency. A minimum capacitor of
10 µF is needed for stability.
The device is supplied in TO-220. The on-chip
trimming allows the regulator to reach a very tight
output voltage tolerance, within ± 1% at 25 °C.
Table 1. Device summary
Order code Output voltage
LD1084V adjustable
• Typical dropout 1.3 V (at 5 A)
• Three-terminal adjustable output voltage
• Guaranteed output current up to 5 A
• Output tolerance ± 1% at 25 °C and ± 2% in full
temperature range
• Internal power and thermal limit
• Wide operating temperature range -40 °C to
125 °C
• Package available: TO-220
• Pinout compatibility with standard adjustable
VREG
Description
The LD1084 is a low-drop voltage regulator
providing up to 5 A of output current. Dropout is
guaranteed at a maximum of 1.5 V at the
maximum output current, decreasing at lower
loads. The LD1084 is pin-to-pin compatible with
the older 3-terminal adjustable regulators, but it
has better performances in terms of drop and
output tolerance.
Unlike PNP regulators, where a part of the output
current is wasted as quiescent current, the
September 2013 DocID9035 Rev 10 1/16
This is information on a product in full production.
www.st.com
16
Contents LD1084
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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LD1084 Diagram
1 Diagram
Figure 1. Schematic diagram
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Pin configuration LD1084
$'-
287387
,1387
2 Pin configuration
Figure 2. Pin connections (top view)
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LD1084 Maximum ratings
3 Maximum ratings
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
DC input voltage 30 V
Output current Internally limited mA
Power dissipation Internally limited mW
Storage temperature range -55 to +150 °C
Operating junction temperature range -40 to +125 °C
T
P
T
V
I
I
O
D
STG
OP
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 Unit
R
R
thJC
thJA
Thermal resistance junction-case 3 °C/W
Thermal resistance ju nction-ambient 50 °C/W
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Schematic application LD1084
VOV
REF
1
R
2
R
1
------ -+
⋅=
4 Schematic application
Figure 3. Application circuit
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LD1084 Electrical characterist ics
5 Electrical characteristics
VI = 4.25 V, CI = CO = 10 µF, TA = -40 to 125 °C, unless otherwise specified.
Symbol Parameter Test conditions Min. Typ. Max. Unit
Table 4. LD1084 electrical characteristics
V
ref
ΔV
ΔV
V
I
O(min)
I
sc
Reference voltage
Line regulation
O
Load regulation
O
Dropout voltage IO = 5 A 1.3 1.5 V
d
(1)
Minimum load current VI = 30 V 3 10 mA
Short-circuit current
Thermal regulation T
IO = 10 mA TJ = 25 °C 1.237 1.25 1.263 V
I
= 10 mA to 3 A, VI = 2.85 to 30 V 1.225 1.25 1.275 V
O
I
= 10 mA, VI = 2.85 to 16.5V, TJ =
O
25 °C
= 10 mA, VI = 2.85 to 16.5 V 0.035 0.2 %
I
O
= 10 mA to 5 A, TJ = 25 °C 0.1 0.3 %
I
O
0.015 0.2 %
IO = 0 to 5 A 0.2 0.4 %
V
- VO = 5 V 5.5 6.5 A
I
V
- VO = 25 V 0.5 0.7 A
I
= 25 °C, 30 ms pulse 0.003 0.015 %/W
A
f = 120 Hz, CO = 25 µF,
SVR Supply voltage rejection
C
= 25 µF, IO = 5 A,
ADJ
60 72 dB
VI = 6.25 ± 3 V
I
ΔI
Adjust pin current VI = 4.25 V, IO = 10 mA 55 120 μA
ADJ
Adjust pin current change
ADJ
RMS output noise voltage
eN
(% of V
)
O
(1)
IO = 10 mA to 5 A,
V
= 2.85 to 16.5 V
I
0.2 5 μA
TA = 25 °C, f = 10 Hz to 10 kHz 0.003 %
S Temperature stability 0.5 %
S Long term stability T
1. See short-circuit current curve for available output current at fixed dropout.
= 125 °C, 1000 hrs 0.5 %
A
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Typical performance characteristics LD1084
6 Typical performance characteristics
Unless otherwise specified TJ = 25 °C, CI = 10 µF (tant.), CO = 22 µF (tant.)
Figure 4. Short-circuit current vs. dropout
Figure 6. Quiescent current vs. temperature Figure 7. Output voltage vs. temperature
voltage
Figure 5. Line regulation vs. temperature
Figure 8. Load regulation vs. temperature Figure 9. Quiescent current vs. output voltage
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LD1084 Typical performance characteristics
Figure 10. Quiescent current vs. input voltage Figure 11. Dropout voltage vs. output current
Figure 12. Supply voltage rejection vs. output
current
Figure 14. Supply voltage rejection vs.
temperature
Figure 13. Dropout voltage vs. temperature
Figure 15. Supply voltage rejection vs.
frequency
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Typical performance characteristics LD1084
Figure 16. Adjust pin current vs. output current Figure 17. Reference voltage vs. temperature
Figure 18. Load regulation vs. temperature Figure 19. Adjust pin current vs. temperature
Figure 20. Line regulation vs. temperature Figure 21. Minimum load current vs.
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temperature
LD1084 Typical performance characteristics
Figure 22. Supply voltage rejection vs.
temperature
Figure 24. Stability Figure 25. Supply voltage rejection vs. output
Figure 23. Supply voltage rejection vs.
frequency
current
Figure 26. Stability Figure 27. Line transient
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VI=14 to 15 V , IO=200 mA, CI = 1 µF (tant), CO= 10 µF (tant),
= tf = 5 µs
t
s
Typical performance characteristics LD1084
Figure 28. Line transient Figure 29. Load transient
VI=12 to 13 V, IO = 200 mA, CI = 1 µF (tant), CO= 10 µF
(tant), No C
= tf = 5 µs
ADJ ts
Figure 30. Load transient Figure 31. Line transient
VI =15 V, IO = 0.1 to 5 A, CI = 1 µF (tant), CO= 10 µF (tant)
VI = 15 V, IO= 0.1 to 5 A, CI = 1 µF (tant), CO= 10 µF (tant),
No C
ADJ
Figure 32. Load transient
VI=12 to 13 V , IO= 200 mA, CI = 1 µF (tant), CO= 10 µF(tant),
C
ADJ
VI=13 V, IO= 0.1 to 5 A, CI = 1 µF(tant), CO=10 µF (tant)
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= 1µF , ts = tf = 5 µs
LD1084 Package mechanical data
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.
Table 5. TO-220 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
E 10 10.40
e 2.40 2.70
e1 4.95 5.15
F 0.51 0.60
H1 6.20 6.60
J1 2.40 2.72
L13 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 mechanical data LD1084
BUHY'
Figure 33. TO-220 drawings
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LD1084 Revision history
8 Revision history
Table 6. Document revision history
Date Revision Changes
07-Oct-2004 3 Mistake order codes - Table 1.
08-Feb-2005 4 Mistake U.M. Load Regulation - V ==> mV.
16-Jun-2005 5 Order codes updated.
04-Apr-2007 6 Order code updated.
07-Jun-2007 7 Order codes updated.
08-Apr-2008 8
29-Jul-2009 9 Modified: Table 1 on page 1.
04-Sep-2013 10
Modified: Table 1 on page 1. Removed: packages D²PAK, D²PAK/A and
mechanical data.
RPN LD1084XX changed to LD1084.
Updated the Description in cover page, Section 7: Package mechanical data,
Figure 2: Pin connections (top view) and Figure3: Applicati on circ ui t.
Minor text changes.
DocID9035 Rev 10 15/16
LD1084
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