Datasheet LT3477 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | 3A, DC/DC Converter with Dual Rail-to-Rail Current Sense |
| Páginas / Página | 22 / 1 — FeaTures. DescripTion. Dual 100mV Rail-to-Rail Current Sense Amplifiers. … |
| Formato / tamaño de archivo | PDF / 585 Kb |
| Idioma del documento | Inglés |
FeaTures. DescripTion. Dual 100mV Rail-to-Rail Current Sense Amplifiers. Wide Input Voltage Range: 2.5V to 25V
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LT3477 3A, DC/DC Converter with Dual Rail-to-Rail Current Sense
FeaTures DescripTion
n
Dual 100mV Rail-to-Rail Current Sense Amplifiers
The LT®3477 is a current mode, 3A DC/DC step-up converter n
Wide Input Voltage Range: 2.5V to 25V
with dual rail-to-rail current sense amplifiers and an internal n
3A, 42V Internal Switch
3A, 42V switch. It combines a traditional voltage feedback n
High Efficiency Power Conversion: Up to 93%
loop and two unique current feedback loops to operate n
Drives LEDs in Boost, Buck-Boost or Buck Mode
as a constant-current, constant-voltage source. Both cur- n Frequency Set by External Resistor: 200kHz to 3.5MHz rent sense voltages are set at 100mV and can be adjusted n Programmable Soft-Start independently using the IADJ1 and IADJ2 pins. Efficiency n Low VCESAT Switch: 0.3V at 2.5A of up to 93% can be achieved in typical applications. The n Capable of Positive and Negative Output Voltages LT3477 features a programmable soft-start function to (Boost, Inverting, SEPIC, Flyback) limit inductor current during start-up. Both inputs of the n Available in Thermally Enhanced 20-Lead error amplifier are available externally allowing positive (4mm × 4mm) QFN and 20-Lead TSSOP Packages and negative output voltages (boost, inverting, SEPIC, Flyback). The switching frequency is programmable from
applicaTions
200kHz to 3.5MHz through an external resistor. n Available in thermally enhanced 20-pin (4mm × 4mm) High Power LED Driver n QFN and 20-pin TSSOP packages, the LT3477 provides a DSL Modems n complete solution for both constant-voltage and constant- Distributed Power n current applications. Input/Output Current Limited Boost, SEPIC, Inverting, Flyback Converters , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Constant-Voltage, Constant-Current Source
Typical applicaTion 330mA LED Driver With Open LED Protection Efficiency
10µH V 90 IN 5V 3.3µF 3.3µF 85 I 200k SP1 ISN1 SW 80 VIN FBN IADJ1 75 I 10k ADJ2 70 SHDN SHDN LT3477 ISP2 65 0.3Ω EFFICIENCY (%) VC ISN2 60 VREF RT 55 1k FBP GND SS 330mA 50 0 0.1 0.2 0.3 0.4 33nF 22k I 4.7nF OUT (A) 3477 TA01b 3477 TA01a 3477fd For more information www.linear.com/LT3477 1 Document Outline Description Typical Application Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Pin Functions Package Description Typical Application Related Parts
FeaTures DescripTion
n
Dual 100mV Rail-to-Rail Current Sense Amplifiers
The LT®3477 is a current mode, 3A DC/DC step-up converter n
Wide Input Voltage Range: 2.5V to 25V
with dual rail-to-rail current sense amplifiers and an internal n
3A, 42V Internal Switch
3A, 42V switch. It combines a traditional voltage feedback n
High Efficiency Power Conversion: Up to 93%
loop and two unique current feedback loops to operate n
Drives LEDs in Boost, Buck-Boost or Buck Mode
as a constant-current, constant-voltage source. Both cur- n Frequency Set by External Resistor: 200kHz to 3.5MHz rent sense voltages are set at 100mV and can be adjusted n Programmable Soft-Start independently using the IADJ1 and IADJ2 pins. Efficiency n Low VCESAT Switch: 0.3V at 2.5A of up to 93% can be achieved in typical applications. The n Capable of Positive and Negative Output Voltages LT3477 features a programmable soft-start function to (Boost, Inverting, SEPIC, Flyback) limit inductor current during start-up. Both inputs of the n Available in Thermally Enhanced 20-Lead error amplifier are available externally allowing positive (4mm × 4mm) QFN and 20-Lead TSSOP Packages and negative output voltages (boost, inverting, SEPIC, Flyback). The switching frequency is programmable from
applicaTions
200kHz to 3.5MHz through an external resistor. n Available in thermally enhanced 20-pin (4mm × 4mm) High Power LED Driver n QFN and 20-pin TSSOP packages, the LT3477 provides a DSL Modems n complete solution for both constant-voltage and constant- Distributed Power n current applications. Input/Output Current Limited Boost, SEPIC, Inverting, Flyback Converters , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Constant-Voltage, Constant-Current Source
Typical applicaTion 330mA LED Driver With Open LED Protection Efficiency
10µH V 90 IN 5V 3.3µF 3.3µF 85 I 200k SP1 ISN1 SW 80 VIN FBN IADJ1 75 I 10k ADJ2 70 SHDN SHDN LT3477 ISP2 65 0.3Ω EFFICIENCY (%) VC ISN2 60 VREF RT 55 1k FBP GND SS 330mA 50 0 0.1 0.2 0.3 0.4 33nF 22k I 4.7nF OUT (A) 3477 TA01b 3477 TA01a 3477fd For more information www.linear.com/LT3477 1 Document Outline Description Typical Application Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Pin Functions Package Description Typical Application Related Parts