Datasheet LT3957A (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | Boost, Flyback, SEPIC and Inverting Converter with 5A, 40V Switch |
| Páginas / Página | 28 / 1 — FEATURES. DESCRIPTION. Wide Input Voltage Range: 3V to 40V. Single … |
| Formato / tamaño de archivo | PDF / 567 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTION. Wide Input Voltage Range: 3V to 40V. Single Feedback Pin for Positive or Negative. Output Voltage
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LT3957A Boost, Flyback, SEPIC and Inverting Converter with 5A, 40V Switch
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 3V to 40V
The LT®3957A is a wide input range, current mode DC/DC n
Single Feedback Pin for Positive or Negative
converter which is capable of generating either positive or
Output Voltage
negative output voltages. It can be configured as either a n
Internal 5A/40V Power Switch
boost, flyback, SEPIC or inverting converter. It features n Current Mode Control Provides Excellent Transient an internal low side N-channel power MOSFET rated for Response 40V at 5A and driven from an internal regulated 5.2V n Programmable Operating Frequency (100kHz to supply. The fixed frequency, current-mode architecture 1MHz) with One External Resistor results in stable operation over a wide range of supply n Synchronizable to an External Clock and output voltages. n Low Shutdown Current < 1μA The operating frequency of LT3957A can be set with an n Internal 5.2V Low Dropout Voltage Regulator external resistor over a 100kHz to 1MHz range, and can n Programmable Input Undervoltage Lockout with be synchronized to an external clock using the SYNC pin. Hysteresis A minimum operating supply voltage of 3V, and a low n Programmable Soft-Start shutdown quiescent current of less than 1μA, make the n Thermally Enhanced QFN (5mm × 6mm) Package LT3957A ideally suited for battery-powered systems. The LT3957A features soft-start and frequency foldback
APPLICATIONS
functions to limit inductor current during start-up. The n Automotive LT3957A has improved load transient performance com- n Telecom pared to the LT3957. n Industrial L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No RSENSE and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7825665.
TYPICAL APPLICATION High Efficiency Output Boost Converter Efficiency vs Output Current
10μH VOUT V 100 IN 24V V 4.5V TO 16V IN = 12V 600mA 10μF 10μF 200k 95 VIN SW w2 EN/UVLO GND 90 95.3k LT3957A 85 SGND SENSE1 SYNC SENSE2 226k EFFICIENCY (%) 80 FBX RT SS V INTV C CC 15.8k 75 41.2k 300kHz 0.33μF 6.8k 4.7μF 70 0 100 200 300 400 500 600 22nF OUTPUT CURRENT (mA) 3957A TA01b 3957A TA01a 3957afa 1
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 3V to 40V
The LT®3957A is a wide input range, current mode DC/DC n
Single Feedback Pin for Positive or Negative
converter which is capable of generating either positive or
Output Voltage
negative output voltages. It can be configured as either a n
Internal 5A/40V Power Switch
boost, flyback, SEPIC or inverting converter. It features n Current Mode Control Provides Excellent Transient an internal low side N-channel power MOSFET rated for Response 40V at 5A and driven from an internal regulated 5.2V n Programmable Operating Frequency (100kHz to supply. The fixed frequency, current-mode architecture 1MHz) with One External Resistor results in stable operation over a wide range of supply n Synchronizable to an External Clock and output voltages. n Low Shutdown Current < 1μA The operating frequency of LT3957A can be set with an n Internal 5.2V Low Dropout Voltage Regulator external resistor over a 100kHz to 1MHz range, and can n Programmable Input Undervoltage Lockout with be synchronized to an external clock using the SYNC pin. Hysteresis A minimum operating supply voltage of 3V, and a low n Programmable Soft-Start shutdown quiescent current of less than 1μA, make the n Thermally Enhanced QFN (5mm × 6mm) Package LT3957A ideally suited for battery-powered systems. The LT3957A features soft-start and frequency foldback
APPLICATIONS
functions to limit inductor current during start-up. The n Automotive LT3957A has improved load transient performance com- n Telecom pared to the LT3957. n Industrial L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No RSENSE and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7825665.
TYPICAL APPLICATION High Efficiency Output Boost Converter Efficiency vs Output Current
10μH VOUT V 100 IN 24V V 4.5V TO 16V IN = 12V 600mA 10μF 10μF 200k 95 VIN SW w2 EN/UVLO GND 90 95.3k LT3957A 85 SGND SENSE1 SYNC SENSE2 226k EFFICIENCY (%) 80 FBX RT SS V INTV C CC 15.8k 75 41.2k 300kHz 0.33μF 6.8k 4.7μF 70 0 100 200 300 400 500 600 22nF OUTPUT CURRENT (mA) 3957A TA01b 3957A TA01a 3957afa 1