LTC1147-3.3 LTC1147-5/LTC1147L High Efficiency Step-Down Switching Regulator Controllers DESCRIPTIO FEATURES n Very High Efficiency: Over 95% Possible The LTC 1147 series are step-down switching regulator TM n Wide V Range: 3.5V* to 16V controllers featuring automatic Burst Mode operation to IN n Current Mode Operation for Excellent Line and Load maintain high efficiencies at low output currents. These Transient Response devices drive an external P-channel power MOSFET at n High Efficiency Maintained Over Three Decades of switching frequencies exceeding 400kHz using a constant Output Current off-time current mode architecture providing constant n Low 160m A Standby Current at Light Loads ripple current in the inductor. n Logic Controlled Micropower Shutdown: I < 20m A Q The operating current level is user-programmable via an n Short-Circuit Protection external current sense resistor. Wide input supply range n Very Low Dropout Operation: 100% Duty Cycle allows operation from 3.5V* to 14V (16V maximum). n High Efficiency in a Small Amount of Board Space Constant off-time architecture provides low dropout regu- n Output Can Be Externally Held High in Shutdown lation limited by only the R of the external MOSFET DS(ON) n Available in 8-Pin SO Package and resistance of the inductor and current sense resistor. U The LTC1147 series incorporates automatic power saving APPLICATIO S Burst Mode operation to reduce switching losses when load currents drop below the level required for continuous n Notebook and Palmtop Computers operation. Standby power is reduced to only 2mW at n Portable Instruments V = 10V (at I = 0). Load currents in Burst Mode IN OUT n Battery-Operated Digital Devices operation are typically 0mA to 300mA. n Cellular Telephones n DC Power Distribution Systems For applications where even higher efficiency is required, n GPS Systems refer to the LTC1148 data sheet and Application Note 54. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. *LTC1147L and LTC1147L-3.3 only. TYPICAL APPLICATI LTC1147-5 Efficiency V (5.2V TO 14V) IN 100 + + C IN 1m F 100m F V IN 95 P-CHANNEL V = 6V IN PDRIVE L* R ** Si4431DY SENSE 50m H LTC1147-5 0.05W 90 V 0V = NORMAL OUT SHDN 5V/2A >1.5V = SHUTDOWN V = 10V + IN SENSE 85 1000pF I TH SENSE C + T R C OUT C 80 1k 390m F D1 C T GND MBRD330 C 470pF C 75 3300pF LT1147 F01 70 *COILTRONICS CTX50-2-MP 0.001 0.01 0.1 1 **KRL SL-1-C1-0R050J LOAD CURRENT (A) LT1147 TA01 Figure 1. High Efficiency Step-Down Converter sn1147 1147fds 1 EFFICIENCY (%) UO ULTC1147-3.3 LTC1147-5/LTC1147L ABSOLUTE AXI U RATI GS Input Supply Voltage (Pin 1) .................... 16V to 0.3V Operating Ambient Temperature Range Continuous Output Current (Pin 8) ...................... 50mA LTC1147C ............................................... 0 C to 70 C Sense Voltages (Pins 4, 5) LTC1147I............................................. 40 C to 85 C V 12.7V ...........................................13V to 0.3V Extended Commercial IN V < 12.7V............................... (V + 0.3V) to 0.3V Temperature Range (Note 4) ................. 40 C to 85 C IN IN Junction Temperature (Note 1)............................ 125 C Storage Temperature Range ................ 65 C to 150 C Lead Temperature (Soldering, 10 sec)................. 300 C UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART NUMBER S8 PART MARKING V 1 8 PDRIVE IN LTC1147CN8-3.3 LTC1147IS8-5 11473 C 2 7 GND T SHDN LTC1147CN8-5 LTC1147LCS8 11475 I 3 6 TH (V *) FB LTC1147CS8-3.3 LTC1147LCS8-3.3 1147I3 + SENSE 4 5 SENSE LTC1147CS8-5 LTC1147LIS8 1147I5 N8 PACKAGE S8 PACKAGE LTC1147IS8-3.3 1147L 8-LEAD PLASTIC DIP 8-LEAD PLASTIC SO * ADJUSTABLE OUTPUT VERSION 1147L3 T = 125 C, q = 110 C/W (N) JMAX JA 1147LI T = 125 C, q = 150 C/W (S) JMAX JA Consult factory for Military grade parts. T = 25 C, V = 10V, V = 0V, unless otherwise noted. ELECTRICAL CHARACTERISTICS A IN SHDN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Feedback Voltage (LTC1147L) V = 9V l 1.21 1.25 1.29 V 6 IN I Feedback Current (LTC1147L) l 0.2 1 m A 6 V Regulated Output Voltage V = 9V OUT IN LTC1147-3.3, LTC1147L-3.3 I = 700mA l 3.23 3.33 3.43 V LOAD LTC1147-5 I = 700mA l 4.90 5.05 5.20 V LOAD D V Output Voltage Line Regulation V = 7V to 12V, I = 50mA 40 0 40 mV OUT IN LOAD Output Voltage Load Regulation LTC1147-3.3, LTC1147L-3.3 5mA < I < 2A l 40 65 mV LOAD LTC1147-5 5mA < I < 2A l 60 100 mV LOAD Burst Mode Output Ripple I = 0A 50 mV LOAD P-P I Input DC Supply Current (Note 2) (Note 5) Q LTC1147 Series Normal Mode 4V < V < 12V 1.6 2.1 mA IN Sleep Mode 4V < V < 12V 160 230 m A IN Sleep Mode (LTC1147-5) 5V < V < 12V 160 230 m A IN Shutdown V = 2.1V, 4V < V < 12V 10 20 m A SHDN IN LTC1147L Series Normal Mode 3.5V < V < 12V 1.6 2.1 mA IN Sleep Mode 3.5V < V < 12V 160 230 m A IN Shutdown (LTC1147L-3.3) V = 2.1V, 3.5V < V < 12V 10 20 m A SHDN IN sn1147 1147fds 2 U WWW