LD1085CXX
3 A low-drop, adjustable positive voltage regulator
Features
Typical dropout 1.3 V (at 3 A) Three terminal adjustable output voltage Guaranteed output current up to 3 A Output tolerance 2 % at 25 C and 3 % in full temperature range Internal power and thermal limit Wide operating temperature range -40 C to 125 C Package available: DPAK Pinout compatibility with standard adjustable VREG
DPAK
Description
The LD1085C is a low drop voltage regulator able to provide up to 3 A of output current. Dropout is guaranteed at a maximum of 1.5 V at the maximum output current, decreasing at lower loads. The LD1085C 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 LD1085C quiescent current flows into the load, so increase efficiency. Only a 10 F minimum capacitor is need for stability. The device is supplied in DPAK. On chip trimming allows the regulator to reach a very tight output voltage tolerance, within 2 % at 25 C.
Table 1.
Device summary
Order codes LD1085CDT-R Packages DPAK (tape and reel)
April 2008
Rev 8
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Contents
LD1085CXX
Contents
1 2 3 4 5 6 7 8 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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Diagram
1
Figure 1.
Diagram
Schematic diagram
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Pin configuration
LD1085CXX
2
Figure 2.
Pin configuration
Pin connections (top view)
DPAK
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LD1085CXX
Maximum ratings
3
Table 2.
Maximum ratings
Absolute maximum ratings
Parameter DC input voltage Output current Power dissipation Storage temperature range Operating junction temperature range Value 30 Internally limited Internally limited -55 to +150 -40 to +125 C C Unit V
Symbol VI IO PD TSTG TOP
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. Thermal data
Parameter Thermal resistance junction-case Thermal resistance junction-ambient DPAK 3 62.5 Unit C/W C/W
Table 3.
Symbol RthJC RthJA
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Schematic application
LD1085CXX
4
Figure 3.
Schematic application
Application circuit
R2 V O = V R E F 1 + ------ R 1
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LD1085CXX
Electrical characteristics
5
Table 4.
Symbol VO
Electrical characteristics
Electrical characteristics of LD1085CDT (VI = 4.25 V, CI = CO =10 F, TA = -40 to 125 C, unless otherwise specified).
Parameter Output voltage (1) Test condition IO = 10mA TJ = 25C IO = 10mA to 3A, VI = 2.85 to 30V Line regulation IO = 10mA, VI = 2.85 to 16.5V, TJ = 25C IO = 10mA, VI = 2.85 to 16.5V VO Vd Load regulation Dropout voltage Minimum load current Shor t circuit current Thermal regulation SVR I ADJ IADJ eN S S Supply voltage rejection Adjust pin current Adjust pin current change RMS output noise voltage (% of VO) Temperature stability Long term stability TA = 125C, 1000Hrs IO = 10mA to 5A, TJ = 25C IO = 0 to 5A IO = 5A VI = 30V VI - VO = 5V VI - VO = 25V TA = 25C, 30ms pulse f = 120 Hz, CO = 25F,CADJ = 25 F, IO = 3A, VI = 6.25 3V VI = 4.25V, IO = 10 mA IO = 10mA to 3A, VI = 2.75 to 16.5V (1) TA = 25C, f =10Hz to 10kHz 60 3.2 0.2
(1)
Min. 1.225 1.213
Typ. 1.25 1.25 0.015 0.035 0.1 0.2 1.3 3 4.5 0.5
Max. 1.275 1.288 0.2 0.2 0.3 0.4 1.5 10
Unit V V % % % % V mA A A %/W dB
VO
IO(min) Isc
0.003 0.015 75 55 0.2 0.003 0.5 0.5 120 5
A A % % %
1. See short-circuit current curve for available output current at fixed dropout.
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Typical application
LD1085CXX
6
Figure 4.
Typical application
(Unless otherwise specified TJ = 25 C, CI = CO = 10 F) Output voltage vs temperature Figure 5. Output voltage vs temperature
Figure 6.
Output voltage vs temperature
Figure 7.
Short circuit current vs dropout voltage
Figure 8.
Line regulation vs temperature
Figure 9.
Load regulation vs temperature
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LD1085CXX
Typical application
Figure 10. Dropout voltage vs temperature
Figure 11. Dropout voltage vs output current
Figure 12. Adjust pin current vs temperature
Figure 13. Quiescent current vs temperature
Figure 14. Line regulation vs temperature
Figure 15. Supply voltage rejection vs output current
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Typical application
LD1085CXX
Figure 16. Supply voltage rejection vs frequency
Figure 17. Supply voltage rejection vs temperature
Figure 18. Minimum load current vs temperature
Figure 19. Stability
Figure 20. Stability
Figure 21. Line transient
VI=12 to 13V, IO=200mA, CI = 1F(tant), CO=10F(tant), CADJ=1F
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LD1085CXX
Typical application
Figure 22. Line transient
Figure 23. Load transient
VI=12 to 13V, IO=200mA, CI = 1F(tant), CO=10F(tant), CADJ=1F
VI=12V, IO=0.12 to 3A, CI = 1F(tant), CO=10F(tant), CADJ=1F
Figure 24. Load transient
VI=12V, IO=0.12 to 3A, CI = 1F(tant), CO=10F(tant), CADJ=1F
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Package mechanical data
LD1085CXX
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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.
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Package mechanical data
DPAK mechanical data
mm. Dim. Min. A A1 A2 B b4 C C2 D D1 E E1 e e1 H L (L1) L2 L4 R V2 2.2 0.9 0.03 0 .64 5.2 0 .45 0.48 6 5.1 6.4 4.7 2.28 4.4 9.35 1 2.8 0.8 0.6 0. 2 0 8 0 1 0.023 0.008 8 4.6 10.1 0.173 0.368 0.039 0.110 0.031 0.039 6.6 0.252 0.185 0.090 0.181 0.397 Typ. Max. 2.4 1.1 0.23 0 .9 5.4 0.6 0.6 6.2 Min. 0.086 0.035 0.001 0.025 0.204 0.017 0.019 0.236 0.200 0.260 Typ. Max. 0.094 0.043 0.009 0.035 0.212 0.023 0.023 0.244 inch.
0068772-F
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Package mechanical data
LD1085CXX
Tape & reel DPAK-PPAK mechanical data
mm. Dim. Min. A C D N T Ao Bo Ko Po P 6.80 10.40 2.55 3.9 7.9 6.90 10.50 2.65 4.0 8.0 12.8 20.2 60 22.4 7.00 10.60 2.75 4.1 8.1 0.268 0.409 0.100 0.153 0.311 0.272 0.413 0.104 0.157 0.315 13.0 Typ. Max. 330 13.2 0.504 0.795 2.362 0.882 0.2.76 0.417 0.105 0.161 0.319 0.512 Min. Typ. Max. 12.992 0.519 i nch.
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Revision history
8
Table 5.
Date
Revision history
Document revision history
Revision 6 7 8 Mistake in Table 1. Order codes updated. Modified: Table 1 on page 1. Changes
07-Oct-2004 03-Jul-2007 09-Apr-2008
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LD1085CXX
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