L4955

® L4955 5A ULDO LINEAR REGULATORS FAMILY UP TO 5A OUTPUT CURRENT ±2% PRECISE OUTPUT VOLTAGES FAST TRANSIENT RESPONSE 0.75V TYP. DROP OUT VOLTAGE AT 5A OPERATING INPUT VOLTAGE FROM 4.5V ADJUSTABLE VERSION: • VO = 1.26V • INHIBIT (IQ = 120µA TYP.) • POWER GOOD • PROGRAMMABLE CURRENT LIMIT • HEPTAWATT PACKAGE FIXED VERSION: • 3.3V, 5.1V OUTPUTS • VERSAWATT PACKAGE VERY LOW QUIESCENT CURRENT SHORT CIRCUIT PROTECTION (Foldback function) THERMAL SHUTDOWN APPLICATIONS PENTIUM™ AND POWER PC™ SUPPLIES POST REGULATOR FOR SMPS LOW COST SOLUTION FOR 5V TO 3.3V CONVERSION LOW COST BATTERY CHARGER CONSTANT CURRENT REGULATOR SUITABLE FOR APPLICATION WITH STANDBY FEATURE DESCRIPTION The L4955 is a family of monolithic ultra very low drop linear regulators designed to supply the most recent microprocessors. T YPICAL APPLICATIONS INH VIN IN 1 3 PG 6 7 OUT R1 5 GND ADJ R2 C2 VOUT MULTIPOWER BCD TECHNOLOGY HEPTAWATT ORDERING NUMBERS L4955 L4955V3.3 L4955V5.1 OUTPUT VOLTAGE 1.26V ADJ 3.3V 5.1V VERSAWATT (TO-220) PACKAGE HEPTAWATT VERSAWATT VERSAWATT The dropout voltage is only 0.75V (Typ.) at 5A, directly dependent on the output current conditions. Realized in BCDII technology, it has on board a charge pump to properly drive an N-channel power mos Transistor with 150mΩ of RDSON. It operates from a 4.5V minimum supply, with a very low quiescent current irrespective of the load; a minimum of 22µF output capacitor is required for stability. The on-chip trimming techniques improve the precision of the available output voltages to ±2%. Ancillary functions like power good, inhibit with low power consumption, programmable output voltage and current limiting make the flexible heptawatt version usable in applications where power management, stand-by, features, post regulation and adjustable current generators for battery chargers are important. L4955 C1 CL 2 4 VIN C1 IN 1 L4955VXXX 2 GND 3 OUT VOUT C2 D97IN590 D97IN589 February 1999 1/14 L4955 ABSOLUTE MAXIMUM RATINGS Symbol VIN Supply Input Voltage ADJ and CL pins PG and INH pins PTOT Tst, Ti Power Dissipation @ Tamb = 50°C Power Dissipation @ Tcase = 90°C Storage Temperature Parameter Value 24 -0.3 to 4 0 to VIN 2 15 -40 to +150 Unit V V V W W °C PIN CONNECTIONS (Top views) 7 6 5 4 3 2 1 tab connected to pin 4 D96IN367 OUT PG ADJ GND INH CL IN D96IN369 3 OUT GND 1 IN HEPTAWATT VERSAWATT (TO220) BLOCK DIAGRAM VIN 10µF IN 1(1) VREF= 1.26V FIXED C.L. CHARGE PUMP FOLDBACK PRE REGULATOR + - E/A PROGRAM. C.L. BUFFER POWER DMOS 150mΩ OUT 7(3) R1 ADJ VOUT 22 µF THERMAL SHUTDOWN INH 3 VREF + 2 PIN x = HEPTAWATT PIN (x) = VERSAWATT RCL (1/4W, 1%) CL 4(2) GND 0.9V REF 6 PG D96IN366 1.26V INHIBIT ACTIVE HIGH 5 + - R2 2/14 L4955 PIN FUNCTIONS HW 1 2 3 4 5 6 7 VW 1 – – 2 – – 3 Name IN CL INH GND ADJ PG OUT Function Unregulated input voltage; this pin must be bypassed with a capacitor larger than 10µF. A resistor connected between this pin and ground sets the programmable current limiting value. When the programmable current limiting is not used the pin must be connected to GND. TTL-CMOS input. A logic high level on this input disables the device. An internal pull-down insures full functionally even if the pin is open. Ground. The output is connected directly to this terminal for 1.26V operation; it is connected to the output through a resistive divider for higher voltages. Open drain output, this signal is low when the output voltage is lower than 90%, otherwise is high. Regulated output voltage. A minimum bypass capacitor of 22µF is required to insure stability. THERMAL DATA (HEPTAWATT & VERSAWATT packages) Symbol Rth j-case Rth j-amb Parameter Thermal Resistance Junction-case Thermal Resistance Junction-ambient Thermal Shutdown Thermal Hysteresis Max. Max. Typ. Typ. Value 2.5 50 150 20 Unit °C/W °C/W °C °C L 4955 - ELECTRICAL CHARACTERISTICS (Tj = 25°C, Vin = 12V, unless otherwise specified). • = Specifications referred to TJ from 0°C to +125°C. Symbol VIN VO ∆V O ∆V O VO Parameter Operating Supply Voltage Output Voltage (1) Line regulation Dropout Voltage (1) 0.1A < IO < 5A; 4.5V < VIN 2V pin 2 = G ND *P ulsed tecnique ha s been used 11/14 L4955 DIM. A C D D1 E E1 F F1 G G1 G2 H2 H3 L L1 L2 L3 L4 L5 L6 L7 L9 M M1 V4 Dia mm TYP. inch TYP. MIN. 2.4 1.2 0.35 0.7 0.6 2.34 4.88 7.42 10.05 16.7 21.24 22.27 2.6 15.1 6 2.55 4.83 3.65 2.54 5.08 7.62 16.9 14.92 21.54 22.52 2.8 15.5 6.35 0.2 2.8 5.08 MAX. 4.8 1.37 2.8 1.35 0.55 0.97 0.8 0.9 2.74 5.28 7.82 10.4 10.4 17.1 21.84 22.77 1.29 3 15.8 6.6 3.05 5.33 40° 3.85 MIN. 0.094 0.047 0.014 0.028 0.024 0.095 0.193 0.295 0.396 0.657 0.386 0.877 0.102 0.594 0.236 0.100 0.190 (typ.) 0.144 0.100 0.200 0.300 0.668 0.587 0.848 0.891 0.110 0.610 0.250 0.008 0.110 0.200 MAX. 0.189 0.054 0.110 0.053 0.022 0.038 0.031 0.035 0.105 0.205 0.307 0.409 0.409 0.673 0.860 0.896 0.051 0.118 0.622 0.260 0.120 0.210 0.152 OUTLINE AND MECHANICAL DATA Heptawatt V L E L1 M1 A C D1 L5 L2 L3 E E1 F V V D M H2 V4 L9 H3 H1 Dia. G G1 G2 F L7 L6 L4 H2 F1 HEPTAMEC 12/14 L4955 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 13/14 L4955 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 publicationsupersedes and replaces all information previously supplied. STMicroelectronics products are notauthorizedfor use as critical components in life support devices or systems without express writtenapproval of STMicroelectronics. The ST logois a registered trademark of STMicroelectronics © 1999 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com 14/14