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L4957A Up to 5A ULDO linear regulator General features 1.5V, 1.8V, 2.5V and 3.3V fixed output voltage 3V to 14V input voltage range 200m RDS(on) typical @ tJ = 125C 0.6V max. drop-out at 2A Excellent load regulation 0.6mA quiescent current at any load Short circuit protection Thermal shutdown 3 1 D2PAK Description The L4957AD devices are Ultra Low Drop Output linear regulators with an internal N-channel MOSFET of 200m particulary suitable for low voltage/low dropout applications. Operating with a input voltage from 3V to 14V they are capable to deliver up to 5A. The devices are ideal for use as one of the suppliesrequired by processor, for example they are the cost effective and efficient solution for conversion from 3.3V (rail bus) to 2.5V @ 2.5A or to 1.5V with high current rating. Fast response transient minimise the output capacitor value. A minimum of 22F assures the stability in all load conditions. The on-chip trimming technique offers a tighter voltage reference tolerance (with 2% including line and load variation) beside to ensure a controlled short circuit current. Thermal shutdown provides protection against overload conditions that creates excessive junction temperature. Applications Mother boards Processor I/O & supplies Low voltage memory & chip set supplies Graphic & sound cards Low voltage logic supplies Post regulator for SMPS Order codes Part number Tube L4957AD1.5 L4957AD1.8 L4957AD2.5 L4957AD3.3 April 2006 Rev 6 Tape and Reel L4957AD1.5TR L4957AD1.8TR L4957AD2.5TR L4957AD3.3TR 1/12 www.st.com 12 Contents L4957A Contents 1 2 Block diagram and typical application . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 2.2 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 3.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 5 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2/12 L4957A Block diagram and typical application 1 Block diagram and typical application Figure 1. Block diagram VIN 10F IN 1 CHARGE PUMP VREF CURRENT LIMIT PRE REGULATOR + - E/A BUFFER POWER DMOS 200m OUT RX 3 VOUT 22F THERMAL SHUTDOWN RY 2 GND D00IN1108A Figure 2. Typical application 3V to 14V IN 1 3 OUT VOUT L4957AD C1 2 GND D00IN1107B C2 3/12 Pin description L4957A 2 2.1 Pin description Pin connection Figure 3. Pin connection (top view) 3 2 1 GND OUT IN D98IN933A D2PAK 2.2 Pin description Table 1. Pin description Name 1 2 3 Pin N IN GND OUT Description Unregulated input voltage; this pin must be bypassed with a capacitor larger than 10F. To connect to Ground to get 1.5V, 1.8V, 2.5V or 3.3V output. Regulated output voltage. A minimum bypass capacitor of 22F is required to insure stability. 4/12 L4957A Maximum ratings 3 3.1 Maximum ratings Absolute maximum ratings Table 2. Absolute maximum ratings Symbol VIN TJ TSTG Supply input voltage Junction temperature Storage temperature Parameter Value 16 -40 to +150 -40 to +150 Unit V C C 3.2 Thermal data Table 3. Thermal data Symbol RthJC RthJA Parameter Maximum thermal resistance junction-case Maximum thermal resistance junction-ambient Thermal Shutdown Thermal Hysteresis Typ. Typ. Value 3 60 150 29 Unit C/W C/W C C 5/12 Electrical characteristics L4957A 4 Electrical characteristics Table 4. Electrical Characteristcs (TJ = 25C, VIN = 5V, unless otherwise specified) Symbol VIN VO Parameter Operating Supply Voltage Output Voltage 3.15V < VIN < 5.25V; IO = 0.1A VIN = 3.3V 5%; 0.1A < IO < 5A (1) VIN = 3.3V 5% IO = 0.1A VIN = 5V 5% VIN = 3.3V 5% (0.1A < IO< 4.5A) (1) VIN = 5V 5% 0.1A < IO< 5A VIN = 3.3V 5% IO = 0.1A VIN = 5V 5% VIN = 3.3V 5% (0.1A < IO< 2.2A) (1) VIN = 5V 5% 0.1A < IO< 5A VIN = 5V 5% IO = 0.1A VIN = 5V 5% 0.1A < IO< 5A (1) RDS(on) IO IQ Drain-Source ON Resistance Current Limiting Quiescent Current Ripple Rejection (1) (1) Test condition Min 3 1.485 1.47 1.782 Typ Max 14 Unit V V V V 1.5 1.5 1.8 1.515 1.53 1.818 1.764 1.8 1.836 V 2.475 2.5 2.525 V 2.45 3.267 3.234 2.5 3.3 3.3 2.55 3.333 3.366 300 V V V m A mA dB 5.1 6.3 0.6 7.5 2 3V < VIN< 14V (1) f = 120Hz, IO = 1A VIN = 5V VIN = 2V PP 60 75 1. Specifications referred to TJ from 0C to +125C. 6/12 L4957A Electrical characteristics Figure 4. 5 O u tp u t V o lta g e D e v ia tio n [m V ] 4 .5 4 3 .5 3 2 .5 2 1 .5 1 0 .5 0 -4 0 -2 0 Line regulation vs. junction temperature Figure 5. Load regulation O u tp u t V o lta g e D e v ia tio n [m V ] 5 4 3 2 1 0 -1 -2 -3 -4 3 V < V in < 6 .5 V Io u t = 1 0 m A V in = 5 V T j = 2 5 C ( P u ls e d te c h n iq u e h a s b e e n u s e d ) V o u t = 1 .5 V 0 20 40 60 80 100 120 140 160 T j [ C ] -5 0 1 2 Io u t [A ] 3 4 5 Figure 6. Maximum output current vs. junction temperature Figure 7. DC operating area O u tp u t C u rre n t [A ] 10 9 8 7 6 5 4 3 2 1 0 -4 0 -2 0 0 20 40 60 80 100 120 140 160 T j [ C ] (V in -V o u t) > 2 V p in 2 = G N D O u tp u t C u r re n t [A ] 8 7 6 R d son lim it V in > 2 .8 V T j= 1 2 5 C C u rre n t L im ita tio n P o w e r D issip a tio n L im it T c =2 5 C P d m a x= 40 W 5 4 3 D C O p e ra tin g A re a T c= 7 0C P dm a x= 22 W 2 1 0 0 1 2 3 4 5 (V in - V o u t) [V ] 6 7 8 * P u ls e d te c n iq u e h a s b e e n u s e d 7/12 Electrical characteristics Figure 8. Ripple rejection vs. frequency Figure 9. L4957A Output voltage vs. output current (VOUT = 1.5V) D00IN1109 R ip p le R e je c tio n [d B ] 100 90 80 70 60 50 40 30 20 10 0 10 100 1k F re q u e n c y [ H z ] 10k 10 0 k C in = 2 2 u F C o u t= 2 2 u F V o u t= 1 .5 V V in m in = 3 V Io u t= 5 A V rip p le = 3 V p - p V r ip p le = 0 .5 V p -p VOUT (V) 6.3 IOUT(A) Figure 10. Maximum output current vs. junction temperature Io [A ] 5 4 .5 4 3 .5 3 2 .5 2 1 .5 1 0 .5 0 0 0 .2 0 .4 0 .6 0 .8 1 1 .2 1 .4 1 .6 1 .8 2 V = V in - V o m a x im u m R o n lim its T j = 2 5 C Tj = 125C Tj = 100C 8/12 L4957A Package mechanical data 5 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK(R) 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 9/12 Package mechanical data Table 5. D 2PAK Mechanical data mm. Dim. Min A A1 A2 B B2 C C2 D E G L L2 L3 R V2 0 4.30 2.49 0.03 0.70 1.25 0.45 1.21 8.95 10.00 4.88 15.00 1.27 1.40 0.40 8 0 1.40 0.60 1.36 9.35 10.28 5.28 15.85 1.40 1.75 Typ Max 4.60 2.69 0.23 0.93 Min 0.169 0.098 0.001 0.027 0.049 0.017 0.047 0.352 0.393 0.192 0.590 0.050 0.055 0.016 0.055 Typ inch L4957A Max 0.181 0.106 0.009 0.037 0.024 0.054 0.368 0.405 0.208 0.624 0.055 0.069 8 Figure 11. Package dimensions 10/12 L4957A Revision history 6 Revision history Table 6. Revision history Date 12-Feb-2002 20-Apr-2006 Revision 5 6 Changes Removed the L4957AV part number and its references in the whole document New template 11/12 L4957A 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. 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Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. (c) 2006 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 12/12 |
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