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LTC1149-3.3 Dataheets PDF



Part Number LTC1149-3.3
Manufacturers Linear Technology
Logo Linear Technology
Description High Efficiency Synchronous Step-Down Switching Regulators
Datasheet LTC1149-3.3 DatasheetLTC1149-3.3 Datasheet (PDF)

LTC1149 LTC1149-3.3/LTC1149-5 High Efficiency Synchronous Step-Down Switching Regulators FEATURES s s s DESCRIPTIO s s s s s s s Operation to 48V Input Voltage Ultrahigh Efficiency: Up to 95% Current Mode Operation for Excellent Line and Load Transient Response High Efficiency Maintained over Wide Current Range Logic-Controlled Micropower Shutdown Short-Circuit Protection Very Low Dropout Operation: 100% Duty Cycle Synchronous FET Switching for High Efficiency Adaptive Nonoverlap Gate Drives .

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LTC1149 LTC1149-3.3/LTC1149-5 High Efficiency Synchronous Step-Down Switching Regulators FEATURES s s s DESCRIPTIO s s s s s s s Operation to 48V Input Voltage Ultrahigh Efficiency: Up to 95% Current Mode Operation for Excellent Line and Load Transient Response High Efficiency Maintained over Wide Current Range Logic-Controlled Micropower Shutdown Short-Circuit Protection Very Low Dropout Operation: 100% Duty Cycle Synchronous FET Switching for High Efficiency Adaptive Nonoverlap Gate Drives Available in 16-Pin Narrow SO Package The LTC ®1149 series is a family of synchronous stepdown switching regulator controllers featuring automatic Burst ModeTM operation to maintain high efficiencies at low output currents. These devices drive external complementary power MOSFETs at switching frequencies up to 250kHz using a constant off-time current-mode architecture. Special onboard regulation and level-shift circuitry allow operation at input voltages from dropout to 48V (60V absolute max). The constant off-time architecture maintains constant ripple current in the inductor, easing the design of wide input range converters. Current mode operation provides excellent line and load transient response. The operating current level is user-programmable via an external current sense resistor. The LTC1149 series incorporates automatic power saving Burst Mode operation when load currents drop below the level required for continuous operation. Standby power is reduced to only about 8mW at VIN = 12V. In shutdown, both MOSFETs are turned off. APPLICATI s s s s s s S Notebook and Palmtop Computers Portable Instruments Battery-Operated Digital Devices Industrial Power Distribution Avionics Systems Telecom Power Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. TYPICAL APPLICATI 1N4148 CAP 0.068µF VIN VIN 1N4148 PGATE PDRIVE 0.047µF D1 1N5819 P-CHANNEL IRFR9024 L* 62µH + CIN 100µF 100V + VCC 3.3µF VCC EFFICIENCY (%) LTC1149-5 0V = NORMAL >2V = SHUTDOWN 3300µF 1k CT 470pF SHDN1 SHDN2 ITH CT SGND SENSE + SENSE – NGATE P, RGNDS 1000pF RSENSE** 0.05Ω VOUT 5V/2A N-CHANNEL IRFR024 + COUT 220µF 60 0.02 1149 F01 *COILTRONICS CTX62-2-MP **KRL SL-1-C1-0R050J Figure 1. High Efficiency Step-Down Regulator U LTC1149-5 Efficiency 100 FIGURE 1 CIRCUIT VIN = 12V 90 VIN = 24V 80 70 0.2 LOAD CURRENT (A) 2 1149 TA01 UO UO 1 LTC1149 LTC1149-3.3/LTC1149-5 ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW PGATE VIN VCC PDRIVE VCC CT ITH SENSE – 1 2 3 4 5 6 7 8 16 CAP 15 SHDN2 14 RGND 13 NGATE 12 PGND 11 SGND VFB / 10 SHDN1* 9 SENSE + S PACKAGE 16-LEAD PLASTIC SO Input Supply Voltage (Pin 2)...................... – 15V to 60V VCC Output Current (Pin 3) .................................. 50mA VCC Input Voltage (Pin 5)........................................ 16V Continuous Output Current (Pins 4, 13) .............. 50mA Sense Voltages (Pins 8, 9) VIN ≥ 12.7V .......................................... 13V to – 0.3V VIN < 12.7V ............................. (VCC + 0.3V) to – 0.3V Shutdown Voltages (Pins 10, 15) ............................. 7V Operating Temperature Range .................... 0°C to 70°C Extended Commercial Temperature Range ............................... – 40°C to 85°C Junction Temperature (Note 1) ............................ 125°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C ORDER PART NUMBER LTC1149CN LTC1149CN-3.3 LTC1149CN-5 LTC1149CS LTC1149CS-3.3 LTC1149CS-5 N PACKAGE 16-LEAD PDIP *FIXED OUTPUT VERSIONS TJMAX = 125°C, θJA = 70°C/ W (N) TJMAX = 125°C, θJA = 110°C/ W (S) Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL V10 I10 VOUT PARAMETER Feedback Voltage (LTC1149 Only) Feedback Current (LTC1149 Only) Regulated Output Voltage LTC1149-3.3 LTC1149-5 Output Voltage Line Regulation Output Voltage Load Regulation LTC1149-3.3 LTC1149-5 Burst Mode Output Ripple I2 Input DC Supply Current (Note 3) Normal Mode Burst Mode Shutdown VCC V2 – V3 VIN – V1 Internal Regulator Voltage (Sets MOSFET Gate Drive Levels) VCC Dropout Voltage P-Gate to Source Voltage (Off) VIN = 9V TA = 25°C, VIN = 12V, V10 = 0V (Note 2), unless otherwise noted. MIN q q CONDITIONS TYP 1.25 0.2 MAX 1.29 1 3.43 5.2 40 65 100 UNITS V µA V V mV mV mV mVP-P 1.21 VIN = 9V ILOAD = 700mA ILOAD = 700mA VIN = 9V to 48V, ILOAD = 50mA 5mA < ILOAD < 2A 5mA < ILOAD < 2A ILOAD = 0A VIN = 12V VIN = 48V VIN = 12V VIN = 48V VIN = 12V, V15 = 2V VIN = 48V, V15 = 2V VIN = 12V to 48V I3 = 20mA VIN = 5V, I3 = 10mA VIN = 12V VIN = 48V q q 3.23 4.9 – 40 3.33 5.05 0 40 60 50 2.0 2.2 0.6 0.8 135 300 ∆VOUT q q 2.8 3.0 0.9 1.1 170 390 11 250 q 9.75 10.25 200 q q – 0.2 – 0.2 0 0 2 U mA mA mA mA µA µA V mV V V W U U W W W LTC1149 LTC1149-3.3/LTC1149-5 ELECTRICAL CHARACTERISTICS SYMBOL V 9 – V8 PARAMETER Current Sense Threshold V.


LTC1149 LTC1149-3.3 LTC1149-5


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