LTC3442EDE#PBF Linear Technology, LTC3442EDE#PBF Datasheet

Page 1

... The LTC3442 is available in a low profile, thermally en- hanced 12-lead (4mm × 3mm × 0.75mm) DFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6404251, 6166527. V OUT 3 ...

Page 2

LTC3442 ABSOLUTE AXI U RATI GS (Note Voltage........................................... – 0 OUT SW1, SW2 Voltage DC ................................................................. – 0 Pulsed <100ns ............................................... – 0 SHDN/SS, BURST Voltage ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T PARAMETER Burst Current Ratio Input Current Ratio R Threshold LIM SHDN/SS Threshold SHDN/SS Input Current Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the ...

Page 4

LTC3442 W U TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current (Fixed Frequency Mode) 4.0 3.5 2.0 MHz 3.0 1.5 MHz 2.5 1.0 MHz 2.0 1.5 0.5 MHz 1.0 NO SWITCHING 0.5 0.0 3.0 3.5 4.5 2.5 4.0 ...

Page 5

W U TYPICAL PERFOR A CE CHARACTERISTICS Switch Pins in Buck-Boost Mode SW1 2V/DIV SW2 2V/DIV 3442 G16 50ns/DIV 3.3V AT 500mA OUT Load Transient Response in Fixed Frequency Mode, No Load to 1A ...

Page 6

LTC3442 CTIO S SHDN/SS (Pin 1): Combined Soft-Start and Shutdown. Applied voltage <0.4V shuts down the IC. Tie to >1.4V to enable the IC and >2.4V to ensure the error amp is not clamped from ...

Page 7

W SI PLIFIED BLOCK DIAGRA – 10 LIM – – 2. OSC SHUTDOWN SOFT-START SHDN/ SW1 ...

Page 8

LTC3442 U OPERATIO The LTC3442 provides high efficiency, low noise power for applications such as portable instrumentation. The LTC proprietary topology allows input voltages above, below or equal to the output voltage by properly phasing the output switches. The error ...

Page 9

U OPERATIO Reverse Current Limit During fixed frequency operation, the LTC3442 operates in forced continuous conduction mode. The reverse cur- rent limit amplifier monitors the inductor current from the output through switch D. Once the negative inductor current exceeds 500mA ...

Page 10

LTC3442 U OPERATIO Boost Region (V < OUT Switch A is always on and switch B is always off during this mode. When the internal control voltage, V voltage V3, switch pair CD will alternately switch to ...

Page 11

U OPERATIO current in Amps. Do not use values of R 250k. For automatic operation, a filter capacitor should also be connected from BURST to ground to prevent ripple on BURST from causing the IC to oscillate in and out ...

Page 12

LTC3442 U OPERATIO response, Type 3 compensation is also recommended to broad band the control loop and roll off past the two pole response of the output LC filter. (See Closing the Feedback Loop.) Soft-Start The soft-start function is combined ...

Page 13

U U APPLICATIO S I FOR ATIO COMPONENT SELECTION SHDN/ SGND R 10 LIM 4 SW1 PGND V 8 OUT 6 SW2 BURST 7 MULTIPLE ...

Page 14

LTC3442 U U APPLICATIO S I FOR ATIO The output capacitance is usually many times larger than the minimum value in order to handle the transient re- sponse requirements of the converter. For a rule of thumb, the ratio of ...

Page 15

U U APPLICATIO S I FOR ATIO where f = switching frequency in MHz. Therefore fre- quency selection is a compromise between the optimal efficiency and the smallest solution size. Closing the Feedback Loop The LTC3442 incorporates voltage mode PWM ...

Page 16

LTC3442 U TYPICAL APPLICATIO S 2. 10µF Li-Ion Multi-Input 3.3V at 600mA Boost Converter for Portable Applications with Automatic Burst Mode Operation and Average Input Current Limit for USB Powered Devices Li-Ion USB/ 10µF ...

Page 17

U TYPICAL APPLICATIO S High Efficiency Li-Ion Powered Constant Current LED Driver V IN 2.5V TO 4.2V 10µF OPEN LED VOLTAGE LIMIT = (R4+R5)*0.95/R4 * NOTE: THE SHDN/SS VOLTAGE MUST BE NO MORE THAN 0.5V BELOW with Open-LED Protection 3.3µH ...

Page 18

LTC3442 U U TYPICAL APPLICATIO S TYPICAL APPLICATIO S High Current LED Driver with Low/High Current Range for Pulsed Applications; LED Current is 0.5A with 1.5A Pulse R5 7.87k V IN 2.7V TO 4.2V *OFF ON 10µF 6. ...

Page 19

... SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. U UE/DE Package 12-Lead Plastic DFN (4mm × ...

Page 20

... Synchronous Buck-Boost DC/DC Converter OUT LTC3443 1. 600kHz Synchronous Buck-Boost DC/DC Converter OUT LT3467 1. 1.3MHz, High Efficiency Step-Up DC/DC Converter SW ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● COMMENTS V IN ...