www.fairchildsemi.com A Adjustable/Fixed Low Dropout Linear Regulator Features Low dropout voltage Load regulation:.5% typical Trimmed current limit On-chip thermal limiting Standard SOT-223, TO-22, and TO-252 packages Three-terminal adjustable or fixed.8, 2.5, 2.85, 3.3, 5 Applications Active SCSI terminators High efficiency linear regulators Post regulators for switching supplies Battery chargers 2 to 5 linear regulators Motherboard clock supplies Description The and -.8, -2.5, -2.85, -3.3 and -5 are low dropout three-terminal regulators with A output current capability. These devices have been optimized for low voltage where transient response and minimum input voltage are critical. The 2.85 version is designed specifically to be used in Active Terminators for SCSI bus. Current limit is trimmed to ensure specified output current and controlled short-circuit current. On-chip thermal limiting provides protection against any combination of overload and ambient temperatures that would create excessive junction temperatures. Unlike PNP type regulators where up to % of the output current is wasted as quiescent current, the quiescent current of the flows into the load, increasing efficiency. The series regulators are available in the industry-standard SOT-223, TO-22, and TO-252 (DPAK) power packages. Typical Applications IN = 2 + IN OUT 9 at A + µf 22µF R ADJ 24Ω OUT = REF ( + R2/R) + I ADJ R2 R2 768Ω -5 IN = 2 IN + OUT + µf 22µF GND 5 at A RE... /7/3
Pin Assignments Front iew Tab is OUT Front iew Tab is OUT Front iew 2 3 Tab is OUT 3 2 IN OUT 2 3 ADJ/GND ADJ/ GND OUT IN ADJ/ OUT IN GND 4-Lead Plastic SOT-223 Θ JC = 5 C/W* 3-Lead Plastic TO-252 Θ JC = 3 C/W* 3-Lead Plastic TO-22 Θ JC = 3 C/W* *With package soldered to.5 square inch copper area over backside ground plane or internal power plane, Θ JA can vary from 3 C/W to more than 5 C/W. Other mounting techniques may provide better thermal resistance than 3 C/W. Absolute Maximum Ratings Parameter Min. Max. Unit IN 8 ( IN OUT ) * I OUT See Figure Operating Junction Temperature Range 25 C Storage Temperature Range -65 5 C Lead Temperature (Soldering, sec.) 3 C.2. I OUT (A).8.6.4.2 2 4 6 8 2 4 6 8 2 IN OUT () Figure. Absolute Maximum Safe Operating Area 2 RE... /7/3
PRODUCT SPECIFICATION Electrical Characteristics Operating Conditions: IN 7, T J = 25 C unless otherwise specified. The denotes specifications which apply over the specified operating temperature range. Parameter Conditions Min. Typ. Max. Units Reference oltage 3.5 ( IN OUT ) 7, ma I OUT A Output oltage 4 ma I OUT A -.8, 3.3 IN 8.8-2.5, 4 IN 9.5-2.85, 4.35 IN 9.85-3.3, 4.8 IN.3-5, 6.5 IN 2.225 (-2%).25.275 (+2%) Notes:. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant junction temperature by low duty cycle pulse testing. 2. Line and load regulation are guaranteed up to the maximum power dissipation (8W). Power dissipation is determined by input/output differential and the output current. Guaranteed maximum output power will not be available over the full input/ output voltage range. 3. only. 4. Output current must be limited to meet the absolute maximum ratings of the part..764 2.45 2.793 3.234 4.9.8 2.5 2.85 3.3 5..836 2.55 2.97 3.366 5. Line Regulation,2 ( OUT +.5) IN 2, I OUT = ma.5.2 % Load Regulation,2 ( IN OUT ) = 2, ma I OUT A.5.5 % Dropout oltage REF = %, I OUT = A..2 Current Limit ( IN OUT ) = 2..5 A Adjust Pin Current 3 35 2 µa Adjust Pin Current Change 3,4.5 ( IN OUT ) 7,.2 5 µa ma I OUT A Minimum Load Current.5 ( IN OUT ) 5 ma Quiescent Current IN = OUT +.25 4 3 ma Ripple Rejection f = 2Hz, C OUT = 22µF Tantalum, ( IN OUT ) = 3, I OUT = A 6 72 db Thermal Regulation T A = 25 C, 3ms pulse.4.2 %/W Temperature Stability.5 % Long-Term Stability T A = 25 C, hrs..3. % RMS Output Noise T A = 25 C, Hz f khz.3 % (% of OUT ) Thermal Resistance, Junction SOT-223 5 C/W to Case TO-252, TO-22 3 C/W Thermal Shutdown Junction Temperature 55 C Thermal Shutdown Hysteresis C RE... /7/3 3
Typical Performance Characteristics DROPOUT OLTAGE ().5..4.3.2...9.8.7.6.5 T J = 25 C T J = C T J = 25 C -.2.2.4.6.8. -75-5 -25 25 5 75 25 5 75 OUTPUT CURRENT (A) DROPOUT OLTAGE DEIATION (%).5 -.5 -. -.5 I = A Figure 2. Dropout oltage vs. Output Current Figure 3. Load Regulation vs. Temperature REFERENCE OLTAGE ().26 3.7 OUT SET WITH % RESISTORS.255 3.65 OUT = 3.6.25.245.24.235.23.225.22.25.2 3.6 3.55 3.5 3.45 3.4 3.35 3.3 3.25 3.2 OUT = 3.3 Note:. Only -75-5 -25 25 5 75 25 5 75-75 -5-25 25 5 75 25 5 75 REFERENCE OLTAGE () Figure 4. Reference oltage vs. Temperature Figure 5. Output oltage vs. Temperature MINIMUM LOAD CURRENT (ma) 5 4 3 2-75 -5-25 25 5 75 25 5 75 ADJUST PIN CURRENT (µa) 9 Note:. Only 8 7 6 5 4 3 2-75 -5-25 25 5 75 25 5 75 Figure 6. Minimum Load Current vs. Temperature Figure 7. Adjust Pin Current vs. Temperature 4 RE... /7/3
PRODUCT SPECIFICATION Typical Performance Characteristics (continued) 2. 9 SHORT-CIRCUIT CURRENT (A).75.5.25. -75-5 -25 25 5 75 25 5 75 RIPPLE REJECTION (db) 8 7 6 5 4 3 2 ( IN - OUT ) = 3.5 < RIPPLE < 2 I OUT = A K K K FREQUENCY (Hz) Figure 8. Short-Circuit Current vs. Temperature Figure 9. Ripple Rejection vs. Frequency 5 IN = 2 ma < I OUT < I MAX POWER (W) 7.5 5 2.5 SOT-223 TO-252, TO-22 OUTPUT CAP'S ESR (mω) 4 3 2 Instability region IN = 5 Region of Stability (SOA) 25 45 65 85 5 25 CASE TEMPERATURE ( C) 2 3 4 5 6 7 8 9 OUT () Figure. Maximum Power Dissipation Figure. Stability Region (SOA) vs. ESR of the C OUT RE... /7/3 5
Mechanical Dimensions 4-Lead SOT-223 Package Symbol Inches Millimeters Min. Max. Min. Max. Notes A.7 A.8 B.25.33 c.9 D.248.264 E.3.48.8 4.8.64.84 2.29 6.3 6.7 3.3 3.7 e.5.24 2.95 3.5 F.33.4.84.4 H.264.287 6.7 7.29 I.2.3 J K 6 6 L.8.4.23.8 M 6 6 N..4.25.36 D e K H E A J M N B I L A c F 6 RE... /7/3
PRODUCT SPECIFICATION Mechanical Dimensions (continued) 3-Lead TO-22 Package Symbol Inches Millimeters Min. Max. Min. Max. A.4.9 3.56 4.83 b.5.4.38.2 b.45.7.4.78 c.4.22.36.56 øp.39.6 3.53 4.9 D.56.65 4.22 6.5 E.38.42 9.65.67 e.9. 2.29 2.79 e.9.2 4.83 5.33 e3.45.4 F.2.55.5.4 H.23.27 5.94 6.87 J.8.5 2.4 2.92 L.5.58 2.7 4.73 L.25 BSC 6.35 BSC Q..35 2.54 3.43 α 3 7 3 7 Notes Notes:. Dimension c apply for lead finish. H L Q e3 b e e E b L E-PIN øp c α (5X) J A D F RE... /7/3 7
Mechanical Dimensions (continued) 3-Lead TO-252 Package 6.73 6.35 5.46 5.2 A 6. MIN L3 4 6.5 MIN D.2.84 6.25 C 2 3 3 3. MIN (.59).89.54.25 M A M C 4.57.4.78 2.29.4 MIN 2.3 4.8 LAND PATTERN RECOMMENDATION B SEE NOTE D E 4 2.38 2.8.58.48 D SEE DETAIL A.4 9.4 3 2. B.6.48 GAGE PLANE.78.4 2.9 DETAIL A (ROTATED 9 SCALE 2X.27 MAX.5 SEATING PLANE (.54) NOTES: UNLESS OTHERWISE SPECIFIED A) ALL DIMENSIONS ARE IN MILLIMETERS. B) THIS PACKAGE CONFORMS TO JEDEC, TO-252, ISSUE C. ARIATION AA & AB, DATED NO. 999. C) DIMENSIONING AND TOLERANCING PER ASME Y4.5 994. D) HEAT SINK TOP EDGE COULD BE IN CHAMFERED CORNERS OR EDGE PROTRUSION. E) DIMENSIONS L3, D, E & D TABLE: L3 D E D OPTION AA OPTION AB.89.27.52 2.3 5.97 6.22 5.33 5.59 4.32 MIN 3.8 MIN 5.2 MIN 4.57 MIN 8 RE... /7/3
Ordering Information Product Number DX SX D8X S8X D25X S25X D285 S285 D33X S33X T T8 T25 T33 D5X S5X Package TO-252 SOT-223 TO-22 TO-22 TO-22 TO-22 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com /7/3.m 7 Stock#DS37A 23 Fairchild Semiconductor Corporation