3 A low drop positive voltage regulator adjustable and fixed
Features
■ Typical dropout 1.3 V (at 3 A)
■ Three terminal adjustable or fixed output
voltage 1.5 V, 1.8 V, 2.5 V, 3.3 V, 5 V, 12 V.
■ Automotive grade product: adjustable V
only in TO-220 full pack package
■ Guaranteed output current up to 3 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, TO-220FP,
2
DPAK, D
■ Pinout compatibility with standard adjustable
PAK, D2PAK/A
VREG
Description
The LD1085xx is a low drop voltage regulator
able to provide up to 3 A of output current.
Dropout is guaranteed at a maximum of 1.2 V at
the maximum output current, decreasing at lower
loads. The LD1085xx is pin to pin compatible with
the older 3-terminal adjustable regulators, but has
better performances in term of drop and output
tolerance.
A 2.85 V output version is suitable for SCSI-2
active termination. Unlike PNP regulators, where
a part of the output current is wasted as quiescent
current, the LD1085xx quiescent current flows
OUT
LD1085xx
TO-220
D2PAKDPAK
into the load, so increase efficiency. Only a 10 µF
minimum capacitor is need for stability.
The device is supplied in TO-220, TO-220FP,
DPAK, D
2
PAK and D2PAK/A. On chip trimming
allows the regulator to reach a very tight output
voltage tolerance, within ± 1 % at 25 °C.
The LD1085xx is available as automotive grade in
TO-220FP package only, for the option of
adjustable output voltage whose commercial part
number is shown in the Table 11: Order codes.
This device is qualified according to the
specification AEC-Q100 of the automotive
market, in the temperature range -40 °C to
125 °C, and the statistical tests PAT, SYL, SBL are
performed.
VI = 4.5 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 4.Electrical characteristics of LD1085#15
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO =3 A 1.31.5V
d
Quiescent currentVI ≤ 30 V510mA
I
q
I
Short circuit current
sc
(1)
Thermal regulationT
SVRSupply voltage rejection
eN
RMS output noise voltage (%
)
of V
O
IO = 0 mA, TJ = 25°C1.4851.51.515V
= 0 to 3 A, VI = 3.1 to 30 V1.471.51.53V
I
O
I
= 0 mA, VI = 3.1 to 18 V, TJ = 25°C0.24mV
O
I
= 0 mA, VI = 3.1 to 15 V0.44mV
O
I
= 0 to 3 A, TJ = 25°C210mV
O
= 0 to 3 A 420mV
I
O
V
- VO = 5 V3.24.5A
I
V
- VO = 25 V0.20.5A
I
= 25°C, 30ms pulse0.0080.04%/W
A
f = 120 Hz, C
= 7.5 ± 3 V
V
I
T
= 25°C, f =10 Hz to 10 kHz0.003%
A
= 25 µF, IO = 3 A
O
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000Hrs0.5%
A
Doc ID 6738 Rev 257/28
Electrical characteristicsLD1085xx
VI = 4.8 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 5.Electrical characteristics of LD1085#18
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO = 3 A 1.31.5V
d
Quiescent currentVI ≤ 30 V510mA
I
q
I
Short circuit current
sc
(1)
Thermal regulationT
SVRSupply voltage rejection
eN
RMS output noise voltage (% of
)
V
O
IO = 0 mA, TJ = 25°C1.7821.81.818V
= 0 to 3 A, VI = 3.4 to 30 V1.7641.81.836V
I
O
I
= 0 mA, VI = 3.4 to 18 V TJ = 25°C0.24mV
O
= 0 mA, VI = 3.4 to 15 V0.44mV
I
O
I
= 0 to 3 A, TJ = 25°C210mV
O
I
= 0 to 3 A 420mV
O
V
- VO = 5 V3.24.5A
I
- VO = 25 V0.20.5A
V
I
= 25°C, 30 ms pulse0.0080.04%/W
A
f = 120 Hz, C
VI = 7.5 ± 3 V
= 25°C, f =10 Hz to 10 kHz0.003%
T
A
= 25 µF, IO = 3 A
O
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
8/28 Doc ID 6738 Rev 25
LD1085xxElectrical characteristics
VI = 5.5 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 6.Electrical characteristics of LD1085#25
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO = 3 A 1.31.5V
d
Quiescent currentVI ≤ 30 V510mA
I
q
I
Short circuit current
sc
(1)
Thermal regulationT
SVRSupply voltage rejection
eN
RMS output noise voltage (%
)
of V
O
IO = 0 mA, TJ = 25°C2.4752.52.525V
= 0 to 3 A, VI = 4.1 to 30 V2.452.52.55V
I
O
I
= 0 mA, VI = 4.1 to 18 V, TJ = 25°C0.24mV
O
= 0 mA, VI = 4.1 to 18 V0.44mV
I
O
I
= 0 to 3 A, TJ = 25°C210mV
O
I
= 0 to 3 A 420mV
O
V
- VO = 5 V3.24.5A
I
- VO = 25 V0.20.5A
V
I
= 25°C, 30ms pulse0.0080.04%/W
A
f = 120 Hz, C
VI = 7.5 ± 3 V
= 25°C, f =10 Hz to 10 kHz0.003%
T
A
= 25µF, IO = 3 A
O
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
Doc ID 6738 Rev 259/28
Electrical characteristicsLD1085xx
VI = 6.3 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 7.Electrical characteristics of LD1085#33
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO = 3 A1.31.5V
d
Quiescent currentVI ≤ 30 V510mA
I
q
I
Short circuit current
sc
(1)
Thermal regulationT
SVRSupply voltage rejection
eN
RMS output noise voltage (%
)
of V
O
IO = 0 mA, TJ = 25°C3.2673.33.333V
= 0 to 3 A, VI = 4.9 to 30 V3.2343.353.366V
I
O
I
= 0 mA, VI = 4.9 to 18 V, TJ = 25°C0.56mV
O
= 0 mA, VI = 4.9 to 18 V16mV
I
O
I
= 0 to 3 A, TJ = 25°C315mV
O
I
= 0 to 3 A720mV
O
V
- VO = 5 V3.24.5A
I
- VO = 25 V0.20.5A
V
I
= 25°C, 30 ms pulse0.0080.04%/W
A
f = 120 Hz, C
VI = 8.3 ± 3 V
= 25°C, f =10 Hz to 10 kHz0.003%
T
A
= 25 µF, IO = 3 A
O
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
10/28 Doc ID 6738 Rev 25
LD1085xxElectrical characteristics
VI = 8 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 8.Electrical characteristics of LD1085#50
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO = 3 A1.31.5V
d
Quiescent currentVI ≤ 30 V510mA
I
q
I
Short circuit current
sc
(1)
Thermal regulationT
SVRSupply voltage rejection
eN
RMS output noise voltage (%
)
of V
O
IO = 0 mA, TJ = 25°C4.9555.05V
= 0 to 3 A, VI = 6.6 to 30 V4.955.1V
I
O
I
= 0 mA, VI = 6.6 to 20 V, TJ = 25°C0.510mV
O
= 0 mA, VI = 6.6 to 20 V110mV
I
O
I
= 0 to 3 A, TJ = 25°C510mV
O
I
= 0 to 3 A1035mV
O
V
- VO = 5 V3.24.5A
I
- VO = 25 V0.20.5A
V
I
= 25°C, 30 ms pulse0.0080.04%/W
A
f = 120 Hz, C
VI = 10 ± 3 V
= 25°C, f = 10 Hz to 10 kHz0.003%
T
A
= 25 µF, IO = 3 A
O
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
Doc ID 6738 Rev 2511/28
Electrical characteristicsLD1085xx
VI = 4.25 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 9.Electrical characteristics of LD1085#
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
I
O(min)
I
sc
Output voltage
O
Line regulation
O
Load regulation
O
Dropout voltageIO = 3 A1.31.5V
d
Minimum load currentVI = 30 V310mA
Short circuit current
(1)
Thermal regulationT
SVRSupply voltage rejection
I
ΔI
eN
Adjust pin currentVI = 4.25 V, IO = 10 mA55120µA
ADJ
Adjust pin current change
ADJ
RMS output noise voltage (%
)
of V
O
IO = 10 mA TJ = 25°C1.2371.251.263V
= 10 mA to 3 A, VI = 2.85 to 30 V1.2251.251.275V
I
O
= 10 mA, VI = 2.85 to 16.5 V,
I
O
TJ = 25°C
= 10 mA, VI = 2.85 to 16.5 V0.0350.2%
I
O
I
= 10 mA to 3 A, TJ = 25°C0.10.3%
O
= 0 to 3 A0.20.4%
I
O
V
- VO = 5 V5.56.5A
I
- VO = 25 V0.50.7A
V
I
= 25°C, 30ms pulse0.003 0.015%/W
A
f = 120 Hz, C
= 25 µF,C
O
= 25 µF,
ADJ
IO = 3 A, VI = 6.25 ± 3 V
(1)
IO = 10 mA to 3 A, VI = 2.85 to 16.5 V0.25µA
= 25°C, f =10 Hz to 10 kHz0.003%
T
A
0.0150.2%
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
12/28 Doc ID 6738 Rev 25
LD1085xxElectrical characteristics
VI = 4.25 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified.
Table 10.Electrical characteristics of LD1085PY (Automotive Grade)
SymbolParameterTest conditionMin.Typ.Max.Unit
V
ΔV
ΔV
V
I
O(min)
I
sc
Output voltage
O
Line regulationIO = 10 mA, VI = 2.85 to 16.5 V0.0350.2%
O
Load regulationIO = 0 to 3 A0.20.4%
O
Dropout voltageIO = 3 A1.31.5V
d
Minimum load currentVI = 30 V310mA
Short circuit current
(1)
Thermal regulationT
SVRSupply voltage rejection
I
ΔI
eN
Adjust pin currentVI = 4.25 V, IO = 10 mA55120µA
ADJ
Adjust pin current change
ADJ
RMS output noise voltage (%
)
of V
O
IO = 10 mA TA = 25°C1.2371.251.263V
= 10 mA to 3 A, VI = 2.85 to 30 V1.2251.251.275V
I
O
V
- VO = 5 V, TA = 25°C5.56.5A
I
- VO = 25 V, TA = 25°C0.50.7A
V
I
= 25°C, 30 ms pulse0.003 0.015%/W
A
f = 120 Hz, C
= 25 µF,C
O
IO = 3 A, VI = 6.25 ± 3 V, TA = 25°C
(1)
IO = 10 mA to 3 A, VI = 2.85 to 16.5 V0.25µA
= 25°C, f =10 Hz to 10 kHz0.003%
T
A
= 25 µF,
ADJ
6072dB
STemperature stability0.5%
SLong term stabilityT
1. See short-circuit current curve for available output current at fixed dropout.
= 125°C, 1000 Hrs0.5%
A
Doc ID 6738 Rev 2513/28
Typical applicationLD1085xx
6 Typical application
Unless otherwise specified TJ = 25 °C, CI = CO = 10 µF.
Figure 4.Output voltage vs. temperatureFigure 5.Output voltage vs. temperature
Figure 6.Output voltage vs. temperatureFigure 7.Short circuit current vs. dropout
Figure 8.Line regulation vs. temperatureFigure 9.Load regulation vs. temperature
voltage
14/28 Doc ID 6738 Rev 25
LD1085xxTypical application
Figure 10. Dropout voltage vs. temperatureFigure 11. Dropout voltage vs. output current
Figure 12. Adjust pin current vs. temperature Figure 13. Quiescent current vs. temperature
Figure 14. Line regulation vs. temperatureFigure 15. Supply voltage rejection vs. output
Doc ID 6738 Rev 2515/28
current
Typical applicationLD1085xx
Figure 16. Supply voltage rejection vs.
frequency
Figure 18. Minimum load current vs.
temperature
Figure 17. Supply voltage rejection vs.
temperature
Figure 19. Stability, VO = 1.8 V
Figure 20. Stability, VO = 12 VFigure 21. Line transient
VI=12 to 13V, IO=200mA, CI = 1µF(tant), CO=10µF(tant),
C
=1µF
ADJ
16/28 Doc ID 6738 Rev 25
LD1085xxTypical application
Figure 22. Line transientFigure 23. Load transient
VI=12 to 13V, IO=200mA, CI = 1µF(tant), CO=10µF(tant),
C
=1µF
ADJ
Figure 24. Load transient
VI=12V, IO=0.12 to 3A, CI = 1µF(tant), CO=10µF(tant),
C
=1µF
ADJ
VI=12V, IO=0.12 to 3A, CI = 1µF(tant), CO=10µF(tant),
C
=1µF
ADJ
Doc ID 6738 Rev 2517/28
Package mechanical dataLD1085xx
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
Tape & reel D2PAK-P2PAK-D2PAK/A-P2PAK/A mechanical data
Dim.
mm.inch.
Min.Typ.Max.Min.Typ.Max.
A1807.086
C12.813.013.20.5040.5120.519
D20.20.795
N602.362
T14.40.567
Ao10.5010.610.700.4130.4170.421
Bo15.7015.8015.900.6180.6220.626
Ko4.804.905.000.1890.1930.197
Po3.94.04.10.1530.1570.161
P11.912.012.10.4680.4720.476
Doc ID 6738 Rev 2525/28
Order codesLD1085xx
8 Order codes
Table 11.Order codes
Packages
TO-220TO-220FPD
2
PAKDPAK (T&R)D2PAK/A (T&R)
LD1085DT15R1.5 V
LD1085D2M18R1.8 V
LD1085D2M25R2.5 V
LD1085D2T33RLD1085D2M33R3.3 V
LD1085V505.0 V
LD1085VLD1085PLD1085D2T-RLD1085D2M-RADJ
LD1085PY
1. Automotive Grade products.
(1)
Output
voltage
ADJ
26/28 Doc ID 6738 Rev 25
LD1085xxRevision history
9 Revision history
Table 12.Document revision history
DateRevisionChanges
07-Oct-200412Mistake order codes - Table 1.
08-Feb-200513Mistake U.M. load regulation - V ==> mV.
01-Mar-200514Version 1.2 V removed.
22-May-200615Order codes has been updated and new template.
10-Nov-200616Add package DPAK, typo on V
04-Apr-200717Order codes updated.
07-Jun-200718Order codes updated.
05-Dec-200719Modified: Ta b le 1 1.
29-Jan-200820
Added new order codes for Automotive grade products see Table 11 on
page 26.
18-Feb-200821Modified: Table 11 on page 26.
09-Apr-200822Modified: Table 11 on page 26.
test value in tables 3, 4 and 11.
O
14-Jul-200823Modified: Table 11 on page 26.
22-Aug-200824Modified: Table 3 on page 5.
28-Jul-200925Modified: Table 11 on page 26.
Doc ID 6738 Rev 2527/28
LD1085xx
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