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 µF 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. April 2008 Device summary Order codes Packages LD1085CDT-R DPAK (tape and reel) Rev 8 1/16 www.st.com 16 Contents LD1085CXX Contents 1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/16 LD1085CXX Diagram 1 Diagram Figure 1. Schematic diagram 3/16 Pin configuration 2 Pin configuration Figure 2. Pin connections (top view) LD1085CXX DPAK 4/16 LD1085CXX Maximum ratings 3 Maximum ratings Table 2. Absolute maximum ratings Symbol Parameter Value Unit 30 V VI DC input voltage IO Output current Internally limited PD Power dissipation Internally limited TSTG Storage temperature range -55 to +150 °C TOP Operating junction temperature range -40 to +125 °C Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. Table 3. Thermal data Symbol Parameter RthJC Thermal resistance junction-case RthJA Thermal resistance junction-ambient DPAK Unit 3 °C/W 62.5 °C/W 5/16 Schematic application 4 Schematic application Figure 3. Application circuit LD1085CXX R V O = V REF ⋅ ⎛⎝ 1 + ------2-⎞⎠ R1 6/16 LD1085CXX Electrical characteristics 5 Electrical characteristics Table 4. Electrical characteristics of LD1085CDT (VI = 4.25 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified). Symbol VO ΔVO Parameter Output voltage (1) Test condition Min. Typ. Max. Unit 1.225 1.25 1.275 V 1.213 1.25 1.288 V IO = 10mA, VI = 2.85 to 16.5V, TJ = 25°C 0.015 0.2 % IO = 10mA, VI = 2.85 to 16.5V 0.035 0.2 % IO = 10mA to 5A, TJ = 25°C 0.1 0.3 % IO = 0 to 5A 0.2 0.4 % IO = 10mA TJ = 25°C IO = 10mA to 3A, VI = 2.85 to 30V Line regulation (1) ΔVO Load regulation Vd Dropout voltage IO = 5A 1.3 1.5 V Minimum load current VI = 30V 3 10 mA IO(min) Isc Short circuit current VI - VO = 5V 3.2 4.5 A VI - VO = 25V 0.2 0.5 A Thermal regulation TA = 25°C, 30ms pulse SVR Supply voltage rejection f = 120 Hz, CO = 25µF,CADJ = 25 µF, IO = 3A, VI = 6.25 ± 3V IADJ Adjust pin current VI = 4.25V, IO = 10 mA 55 120 µA ΔIADJ Adjust pin current change IO = 10mA to 3A, VI = 2.75 to 16.5V (1) 0.2 5 µA eN RMS output noise voltage (% of VO) TA = 25°C, f =10Hz to 10kHz S Temperature stability S Long term stability TA = 125°C, 1000Hrs 0.003 0.015 60 75 %/W dB 0.003 % 0.5 % 0.5 % 1. See short-circuit current curve for available output current at fixed dropout. 7/16 Typical application LD1085CXX 6 Typical application Figure 4. (Unless otherwise specified TJ = 25 °C, CI = CO = 10 µF) 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 8/16 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 9/16 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 = 1µF(tant), CO=10µF(tant), CADJ=1µF 10/16 LD1085CXX Typical application Figure 22. Line transient Figure 23. Load transient VI=12 to 13V, IO=200mA, CI = 1µF(tant), CO=10µF(tant), CADJ=1µF VI=12V, IO=0.12 to 3A, CI = 1µF(tant), CO=10µF(tant), CADJ=1µF Figure 24. Load transient VI=12V, IO=0.12 to 3A, CI = 1µF(tant), CO=10µF(tant), CADJ=1µF 11/16 Package mechanical data 7 LD1085CXX 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. 12/16 LD1085CXX Package mechanical data DPAK mechanical data mm. inch. Dim. Min. A A1 A2 B b4 C C2 D D1 E E1 e e1 H L (L1) L2 L4 R V2 Typ. 2.2 0.9 0.03 0.64 5.2 0.45 0.48 6 Max. Min. 2.4 1.1 0.23 0.9 5.4 0.6 0.6 6.2 0.086 0.035 0.001 0.025 0.204 0.017 0.019 0.236 6.6 0.252 5.1 6.4 0.260 0.173 0.368 0.039 2.8 0.8 0.181 0.397 0.110 0.031 1 0.023 0.2 0° 0.094 0.043 0.009 0.035 0.212 0.023 0.023 0.244 0.185 0.090 4.6 10.1 0.6 Max. 0.200 4.7 2.28 4.4 9.35 1 Typ. 0.039 0.008 8° 0° 8° 0068772-F 13/16 Package mechanical data LD1085CXX Tape & reel DPAK-PPAK mechanical data mm. inch. Dim. Min. Typ. A Min. Typ. 330 13.0 13.2 Max. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 14/16 Max. 0.504 0.512 22.4 0.519 0.882 Ao 6.80 6.90 7.00 0.268 0.272 0.2.76 Bo 10.40 10.50 10.60 0.409 0.413 0.417 Ko 2.55 2.65 2.75 0.100 0.104 0.105 Po 3.9 4.0 4.1 0.153 0.157 0.161 P 7.9 8.0 8.1 0.311 0.315 0.319 LD1085CXX Revision history 8 Revision history Table 5. Document revision history Date Revision Changes 07-Oct-2004 6 Mistake in Table 1. 03-Jul-2007 7 Order codes updated. 09-Apr-2008 8 Modified: Table 1 on page 1. 15/16 LD1085CXX Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. 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