L4957

® L4957 UP TO 4A ULDO LINEAR REGULATOR 1.5V AND 2.5V FIXED OUTPUT VOLTAGE 3V TO 6.5V INPUT VOLTAGE RANGE 200mΩ Rdson TYPICAL @ Tj = 125 °C 0.6V max. DROP-OUT AT 2A EXCELLENT LOAD REGULATION 0.6mA QUIESCENT CURRENT AT ANY LOAD SHORT CIRCUIT PROTECTION WITH FOLDBACK THERMAL SHUTDOWN APPLICATIONS MOTHER BOARDS PROCESSOR I/O & SUPPLIES LOW VOLTAGE MEMORY & CHIP SET SUPPLIES GRAPHIC & SOUND CARDS LOW VOLTAGE LOGIC SUPPLIES POST REGULATOR FOR SMPS DESCRIPTION The L4957 devices are Ultra Low Drop Output linear regulators with an internal N-channel MOS of 200mΩ particulary suitable for low voltage/low dropout applications. Operating with a input voltage from 3V to 6.5V they are capable to deliver up to 4A at 1.5V or 2.5V fixed output voltages. MULTIPOWER BCD TECHNOLOGY 3 1 Versawatt TO-220 D2PAK ORDERING NUMBERS: L4957V1.5 L4957V2.5 L4957D1.5 L4957D2.5 The devices are ideal for use as one of the supplies required 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 22µF 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. TYPICAL APPLICATION 3V to 6.5V IN 1 3 OUT VOUT=1.5V/2.5V L4957 C1 2 GND D97IN657E C2 February 2000 1/7 L4957 ABSOLUTE MAXIMUM RATINGS Symbol VIN Ti Tstg Supply Input Voltage Junction Temperature Storage Temperature Parameter Value 7 -40 to +150 -40 to +150 Unit V °C °C PINS CONNECTION 3 2 1 D98IN838B OUT GND IN 3 2 1 GND OUT IN D98IN933A Versawatt (TO220) D2PAK BLOCK DIAGRAM VIN 10µF IN 1 CURRENT LIMIT WITH FOLDBACK + CHARGE PUMP VREF PRE REGULATOR E/A BUFFER POWER DMOS 150mΩ OUT RX 3 VOUT 22µF THERMAL SHUTDOWN RY 2 GND D98IN839C 2/7 L4957 PIN FUNCTIONS Pin N° Name 1 2 3 IN GND OUT Function Unregulated input voltage; this pin must be bypassed with a capacitor larger than 10µF. To connect to Ground to get 1.5V or 2.5V output. Regulated output voltage. A minimum bypass capacitor of 22µF is required to insure stability. THERMAL DATA Symbol Rth j-case Rth j-amb Parameter Thermal Resistance Junction-case Thermal Resistance Junction-ambient Thermal Shutdown Thermal Hysteresis Max. Max. Typ. Typ. TO220 2.5 50 150 20 D2PAK 3 60 Unit °C/W °C/W °C °C L 4957 - ELECTRICAL CHARACTERISTICS (Tj = 25°C, VIN = 5V, unless otherwise specified). • = Specifications referred to TJ from 0°C to +125°C. Symbol VIN VO Parameter Operating Supply Voltage (1) Output Voltage (1) For L4957V1.5/D1.5 0.1A < IO < 4A; 3V < VIN < 6.5V 3V < VIN < 6.5V; 0.1A < IO < 4A For L4957V2.5/D2.5 0.1A < IO < 4A; 3V < VIN < 6.5V 3V < VIN < 6.5V; 0.1A < IO < 4A ∆V O R DSON IO IQ Load regulation (1) Drain-Source ON Resistance Current Limiting Short Circuit Current Quiescent Current Ripple Rejection (1) GND connected to ground. Test Condition Min. 3 Typ. Max. 6.5 Unit V • • • • • • 1.47 1.455 2.45 2.425 1.5 1.5 2.5 2.5 2 200 1.53 1.545 2.55 2.575 10 300 7.5 2 V V V V mV mΩ A A mA dB 0.1A < IO < 4A 90% VO VO = 0V 0.1A < IO < 4A 3V < VIN < 6.5V f = 120Hz, IO = 4A VIN = 5V ∆VIN = 2VPP 5.1 0.5 60 6.3 1.8 75 Figure 1: Line Regulation vs. Junction Temperature Output Voltage Deviation [mV] 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 -40 -20 0 20 40 60 80 Tj [° C] 100 120 140 160 3V < Vin < 6.5V Iout = 10mA Figure 2: Load Regulation Output Voltage Deviation [mV] 5 4 3 2 1 0 -1 -2 -3 -4 -5 0 1 2 Iout [A] 3 4 5 Vin = 5V Tj = 25 °C (Pulsed technique has been used) Vout = 1.5V 3/7 L4957 Figure 3: Maximum Output Current vs. Junction Temperature O utput C urrent [A] 10 9 8 7 6 5 4 3 2 1 0 -40 -20 0 20 40 60 80 100 120 140 160 Tj [ °C] (Vin-Vout) > 2V pin 2 = G ND 6 5 4 3 D C O p e ratin g A re a Tc = 70 ° C P d m a x =2 2 W R d s on lim it Figure 4: DC Operating Area O u t p u t C u r r en t [ A ] 8 7 V in > 2 .8V T j= 1 2 5C C u rre nt L im ita tio n Tc =2 5 ° C P dm a x = 40 W P ow er D is s ip ation Lim it 2 1 0 0 1 2 3 4 5 ( Vi n - Vo u t ) [ V ] 6 7 8 * P ulsed tecnique ha s been used Figure 5: Ripple Rejection vs. Frequency R ip p le R e je c t i o n [ d B ] 10 0 90 80 70 60 50 40 30 20 10 0 10 10 0 1k F re q u e n c y [H z ] 10 k 100k C i n = 2 2u F C o u t= 2 2 u F V o u t= 1 . 5 V V i n m in = 3 V Io u t= 5 A V rip p l e = 3 V p -p V r ipp l e = 0 .5 V p - p Figure 6: Output Voltage vs. Output Current. (VOUT = 1.5V) VOUT (V) D98IN846A 80% VOUT 1.8 6.3 IOUT(A) Figure 7: Maximum Output Current vs. Drop-Out Voltage 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 - Vo m a x im u m R o n lim its T j = 2 5°C T j = 1 25°C T j = 1 00°C 4/7 L4957 mm MIN. A C D E F F1 F2 G G1 H2 L2 L4 L5 L6 L7 L9 M Dia 3.75 13.0 2.65 15.25 6.20 3.50 2.6 3.85 0.147 4.40 1.23 2.40 0.49 0.61 1.14 1.14 4.95 2.40 10.0 16.4 14.0 2.95 15.75 6.60 3.93 0.511 0.104 0.600 0.244 0.137 0.102 0.151 TYP. MAX. 4.60 1.32 2.72 0.70 0.88 1.70 1.70 5.15 2.70 10.4 MIN. 0.173 0.048 0.094 0.019 0.024 0.044 0.044 0.194 0.094 0.393 0.645 0.551 0.116 0.620 0.260 0.154 inch TYP. MAX. 0.181 0.051 0.107 0.027 0.034 0.067 0.067 0.203 0.106 0.409 DIM. OUTLINE AND MECHANICAL DATA Versawatt (TO220) M TO220MEC 5/7 L4957 DIMENSIONS REF. Millimeters 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 Typ. Max. Min. 4.60 0.169 2.69 0.098 0.23 0.001 0.93 0.027 0.049 0.055 0.60 0.017 1.36 0.047 9.35 0.352 10.28 0.393 5.28 0.192 15.85 0.590 1.40 0.050 1.75 0.055 0.016 8° 0.024 0.054 0.368 0.405 0.208 0.624 0.055 0.069 Inches Typ. Max. 0.181 0.106 0.009 0.037 OUTLINE AND MECHANICAL DATA D2PAK A E L2 C2 16.90 D L L3 A1 B2 B G A2 2.0 MIN. FLAT ZONE V2 C R 3.70 8.90 10.30 1.30 5.08 6/7 L4957 I nformation furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics © 2000 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com 7/7