LT3150 Fast Transient Response, Low Input Voltage, Very Low Dropout Linear Regulator Controller FEATURES DESCRIPTIO n Fast Transient Response Optimized with The LT 3150 drives a low cost external N-channel MOSFET Ceramic Output Capacitors as a source follower to produce a fast transient response, n FET R Defines Dropout Voltage very low dropout voltage linear regulator. Selection of the DS(ON) n 1% Reference Tolerance Over Temperature N-channel MOSFET R allows dropout voltages below DS(ON) n Multifunction LDO Shutdown Pin with Latchoff 300mV for low V to low V applications. IN OUT n Fixed Frequency 1.4MHz Boost Converter Generates The LT3150 includes a fixed frequency boost regulator MOSFET Gate Drive that generates gate drive for the N-channel MOSFET. The n Internally Compensated Boost Converter Uses Tiny internally compensated current mode PWM architecture Capacitors and Inductor combined with the 1.4MHz switching frequency permits n Independent Boost Converter Shutdown Control the use of tiny, low cost capacitors and inductors. Permits LDO Output Voltage Supply Sequencing n The LT3150s transient load performance is optimized 16-Lead SSOP Package with ceramic output capacitors. A precision 1.21V refer- U ence accommodates low voltage supplies. APPLICATIO S Protection includes a high side current limit amplifier that n Microprocessor, ASIC and I/O Supplies activates a fault timer circuit. A multifunction shutdown n Very Low Dropout Input-to-Output Conversion pin provides either current limit time-out with latchoff, n Logic Termination Supplies overvoltage protection or thermal shutdown. Independent , LTC and LT are registered trademarks of Linear Technology Corporation. shutdown control of the boost converter provides on/off and sequencing control of the LDO output voltage. TYPICAL APPLICATIO 1.8V to 1.5V, 4A Very Low Dropout Linear Regulator Transient Response for (Typical Dropout Voltage = 65mV at I = 4A) OUT 0.1A to 4A Output Load Step MBR0520L + L1 C1 6.19k LT3150 10H 50mV/DIV 4.7F 1% V SW IN2 FB1 V IN1 1.37k SHDN2 SHDN1 V 1% IN SWGND I POS 1.8V C + IN GND I NEG 5.1 220F 2A/DIV Si4410 GND GATE 2.5V V OUT 2 FB2 1.5V COMP 243 4A 1% 2.2F 10 1.5k X5R CERAMIC 3150 TA02 6800pF 50pF 1020 20m s/DIV 0805 CASE 1% C : PANASONIC SP SERIES EEFUE0E221R 20% IN C1: AVX TAJA475M020R 20V 20% 3150 TA01 L1: MURATA LQH32CN100K11 OR SUMIDA CDRH3D16100 3150f 1 U ULT3150 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) V , SHDN1 Voltage .............................................. 10V TOP VIEW ORDER PART IN1 SW Voltage .............................................. 0.4V to 36V SW 1 NUMBER 16 FB1 FB1 Voltage ................................................ V + 0.3V SWGND 2 15 GND IN1 LT3150CGN Current into FB1, FB2 Pin .................................... 1mA V 3 14 SHDN1 IN1 4 V , I , I ....................................................... 22V SHDN2 13 I POS IN2 POS NEG 5 V 12 I SHDN2.................................................................... V IN2 NEG IN2 6 GND 11 GATE Operating Ambient Temperature Range ..... 0 C to 70 C GN PART 7 NC 10 NC Junction Temperature (Note 2)........................... 125 C MARKING 8 FB2 9 COMP Storage Temperature Range ................ 65 C to 150 C 3150 GN PACKAGE Lead Temperature (Soldering, 10 sec)................. 300 C 16-LEAD PLASTIC SSOP T = 125 C, q = 130 C/W, q = 40 C/W JMAX JA JC Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. A V = 1.5V, V = V , V = 12V, GATE = 6V, I = I = 5V, V = 0.75V unless otherwise noted. IN1 SHDN1 IN1 IN2 POS NEG SHDN2 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Boost Switching Regulator V Minimum Operating Voltage 0.9 1.1 V IN1 V Maximum Operating Voltage 10 V IN1 V FB1 Reference Voltage l 1.20 1.23 1.255 V FB1 FB1 Input Bias Current Current Flows into Pin l 27 80 nA I V Quiescent Current V = 1.5V 3 4.5 mA Q1 IN1 SHDN1 V Quiescent Current in Shutdown V = 0V, V = 2V 0.01 0.5 m A IN1 SHDN1 IN1 V = 0V, V = 5V 0.01 1.0 m A SHDN1 IN1 FB1 Reference Line Regulation 1.5V V 10V 0.02 0.2 %/V IN1 Switching Frequency l 1 1.4 1.9 MHz Maximum Duty Cycle l 82 86 % Switch Current Limit (Note 3) 550 800 mA Switch V I = 300mA 300 350 mV CESAT SW Switch Leakage Current V = 5V 0.01 1 m A SW SHDN1 Input Voltage High 1 V SHDN1 Input Voltage Low 0.3 V SHDN1 Input Bias Current V = 3V, Current Flows into Pin 25 50 m A SHDN1 V = 0V, Current Flows into Pin 0.01 0.1 m A SHDN1 Linear Regulator Controller I V Quiescent Current l 512 19 mA Q2 IN2 V FB2 Reference Voltage 1.203 1.210 1.217 V FB2 l 1.198 1.210 1.222 V FB2 Line Regulation 10V V 20V l 0.01 0.03 %/V IN2 FB2 Input Bias Current FB2 = V , Current Flows out of Pin l 0.6 4 m A FB2 3150f 2 U WWW