LTC1159 LTC1159-3.3/LTC1159-5 High Efficiency Synchronous Step-Down Switching Regulators FEATURES DESCRIPTIO n Operation from 4V to 40V Input Voltage The LTC 1159 series is a family of synchronous step-down n Ultrahigh Efficiency: Up to 95% switching regulator controllers featuring automatic Burst TM n 20m A Supply Current in Shutdown Mode operation to maintain high efficiencies at low n High Efficiency Maintained Over Wide Current Range output currents. These devices drive external complemen- n Current Mode Operation for Excellent Line and Load tary power MOSFETs at switching frequencies up to 250kHz Transient Response using a constant off-time current-mode architecture. n Very Low Dropout Operation: 100% Duty Cycle A separate pin and on-board switch allow the MOSFET n Short-Circuit Protection driver power to be derived from the regulated output n Synchronous FET Switching for High Efficiency voltage providing significant efficiency improvement when n Adaptive Non-Overlap Gate Drives operating at high input voltages. The constant off-time n Available in SSOP and SO Packages current-mode architecture maintains constant ripple cur- rent in the inductor and provides excellent line and load U transient response. The output current level is user pro- APPLICATIO S grammable via an external current sense resistor. n Step-Down and Inverting Regulators The LTC1159 automatically switches to power saving n Notebook and Palmtop Computers Burst Mode operation when load current drops below n Portable Instruments approximately 15% of maximum current. Standby current n Battery-Operated Digital Devices is only 300m A while still regulating the output and shut- n Industrial Power Distribution down current is a low 20m A. n Avionics Systems , LTC and LT are registered trademarks of Linear Technology Corporation. n Telecom Power Supplies Burst Mode is a trademark of Linear Technology Corporation. TYPICAL APPLICATIO V IN + C IN 1N4148 100m F V LTC1159-5 Efficiency IN 100V CAP P-GATE Si9435DY 100 0.15m F FIGURE 1 CIRCUIT V 0.1m F V = 10V CC IN + P-DRIVE 3.3m F V CC 90 EXTV CC D1 L* R SENSE MBRS140T3 33m H V = 20V 0.05W IN LTC1159-5 1 2 V OUT 5V/2A 3 4 80 + SHDN1 SENSE 0V = NORMAL 0.01m F >2V = SHUTDOWN SHDN2 SENSE I 70 TH + C 3300pF OUT C N-GATE Si9410DY T 220m F C T S-GND P-GND 1k 300pF 60 *COILTRONICS CTX33-4-MP 0.02 0.2 2 LTC1159 F01 LOAD CURRENT (A) LTC1159 TA01 Figure 1. High Efficiency Step-Down Regulator 1 EFFICIENCY (%) U ULTC1159 LTC1159-3.3/LTC1159-5 ABSOLUTEXAI U RATI GS (Note 1) Input Supply Voltage (Pin 2) ..................... 15V to 60V Operating Temperature Range V Output Current (Pin 3) .................................. 50mA LTC1159C .............................................. 0 C to 70 C CC Continuous Pin Currents (Any Pin) ...................... 50mA LTC1159I........................................... 40 C to 85 C Sense Voltages ......................................... 0.3V to 13V Extended Commercial Shutdown Voltages................................................... 7V Temperature Range ............................... 40 C to 85 C EXTV Input Voltage ............................................. 15V Storage Temperature Range ................ 65 C to 150 C CC Junction Temperature (Note 2)............................ 125 C Lead Temperature (Soldering, 10 sec)................. 300 C / PACKAGE ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW TOP VIEW NUMBER NUMBER P-GATE 1 20 CAP P-GATE 1 16 CAP V 2 19 SHDN2 IN V 2 15 SHDN2 IN V 3 18 EXTV CC CC LTC1159CG V 3 14 EXTV LTC1159CN CC CC P-DRIVE 4 17 PGND LTC1159CG-3.3 P-DRIVE 4 13 N-GATE LTC1159CN-3.3 P-DRIVE 5 16 N-GATE V 5 12 PGND LTC1159CG-5 LTC1159CN-5 CC V 6 15 PGND CC C 6 11 SGND LTC1159CS T V 7 14 SGND CC I 7 10 V (SHDN1)* TH FB LTC1159CS-3.3 + C 8 13 SHDN1 T SENSE 8 9 SENSE LTC1159CS-5 I 9 12 V TH FB LTC1159IS N PACKAGE S PACKAGE + SENSE 10 11 SENSE 16-LEAD PDIP 16-LEAD PLASTIC SO LTC1159IS-3.3 *FIXED OUTPUT VERSIONS G PACKAGE LTC1159IS-5 20-LEAD PLASTIC SSOP T = 125 C, q = 80 C/ W (N) JMAX JA T = 125 C, q = 110 C/ W (S) JMAX JA T = 125 C, q = 135 C/ W JMAX JA Consult LTC Marketing for parts specified with wider operating temperature ranges. LECTR AL CHARACTERIST The l denotes specifications which apply over the full operating E IC ICS temperature range, otherwise specifications are at T = 25 C. V = 12V, V = 0V (Note 3), unless otherwise noted. A IN SHDN1 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Feedback Voltage (LTC1159 Only) l 1.21 1.25 1.29 V FB I Feedback Current (LTC1159 Only) l 0.2 m A FB V Regulated Output Voltage V = 9V OUT IN LTC1159-3.3 I = 700mA l 3.23 3.33 3.43 V LOAD LTC1159-5 I = 700mA l 4.90 5.05 5.20 V LOAD D V Output Voltage Line Regulation V = 9V to 40V 40 0 40 mV OUT IN Output Voltage Load Regulation LTC1159-3.3 5mA < I < 2A l 40 65 mV LOAD LTC1159-5 5mA < I < 2A l 60 100 mV LOAD Burst Mode Output Ripple I = 0A 50 mV LOAD P-P I V Pin Current (Note 4) IN IN Normal Mode V = 12V, EXTV = 5V 200 m A IN CC V = 40V, EXTV = 5V 300 m A IN CC Shutdown V = 12V, V = 2V 15 m A IN SHDN2 = 40V, V = 2V 25 m A V IN SHDN2 I EXTV Pin Current (Note 4) EXTV = 5V, Sleep Mode 250 m A EXTVCC CC CC 2 U WU U W W W