Datasheet LT3845A (Analog Devices) - 4
| 制造商 | Analog Devices |
| 描述 | High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency |
| 页数 / 页 | 26 / 4 — ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply … |
| 文件格式/大小 | PDF / 295 Kb |
| 文件语言 | 英语 |
ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply over the full operating
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LT3845A
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 20V, VCC = BOOST = BURST_EN = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE– = SENSE+ = 10V, SGND = PGND = SW = SYNC = 0V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
TG, BG Drive On Voltage (Note 7) CLOAD = 3300pF 9.8 V TG, BG Drive Off Voltage CLOAD = 3300pF 0.1 V TG, BG Drive Rise/Fall Time 10% to 90% or 90% to 10%, CLOAD = 3300pF 50 ns Minimum TG Off Time l 350 650 ns Minimum TG On Time l 250 400 ns Gate Drive Nonoverlap Time TG Fall to BG Rise 200 ns BG Fall to TG Rise 150 ns
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
VIN voltages below the start-up threshold (7.5V) are only may cause permanent damage to the device. Exposure to any Absolute supported when the VCC is externally driven above 6.5V. Maximum Rating condition for extended periods may affect device
Note 5:
Operating range is dictated by MOSFET absolute maximum VGS. reliability and lifetime.
Note 6:
Supply current specification does not include switch drive
Note 2:
The LT3845A includes overtemperature protection that is intended currents. Actual supply currents will be higher. to protect the device during momentary overload conditions. Junction
Note 7:
DC measurement of gate drive output “ON” voltage is typically temperature will exceed 125°C when overtemperature protection is active. 8.6V. Internal dynamic bootstrap operation yields typical gate “ON” Continuous operation above the specified maximum operating junction voltages of 9.8V during standard switching operation. Standard operation temperature may impair device reliability. gate “ON” voltage is not tested but guaranteed by design.
Note 3:
The LT3845AE is guaranteed to meet performance specifications
Note 8:
The –2V absolute maximum on the SW pin is a transient condition. from 0°C to 125°C junction temperature. Specifications over the –40°C It is guaranteed by design and not subject to test. to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT3845AI is guaranteed over the full –40°C to 125°C operating junction temperature range. The LT3845AMP is 100% tested and guaranteed over the –55°C to 125°C temperature range. 3845afa 4 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 20V, VCC = BOOST = BURST_EN = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE– = SENSE+ = 10V, SGND = PGND = SW = SYNC = 0V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
TG, BG Drive On Voltage (Note 7) CLOAD = 3300pF 9.8 V TG, BG Drive Off Voltage CLOAD = 3300pF 0.1 V TG, BG Drive Rise/Fall Time 10% to 90% or 90% to 10%, CLOAD = 3300pF 50 ns Minimum TG Off Time l 350 650 ns Minimum TG On Time l 250 400 ns Gate Drive Nonoverlap Time TG Fall to BG Rise 200 ns BG Fall to TG Rise 150 ns
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
VIN voltages below the start-up threshold (7.5V) are only may cause permanent damage to the device. Exposure to any Absolute supported when the VCC is externally driven above 6.5V. Maximum Rating condition for extended periods may affect device
Note 5:
Operating range is dictated by MOSFET absolute maximum VGS. reliability and lifetime.
Note 6:
Supply current specification does not include switch drive
Note 2:
The LT3845A includes overtemperature protection that is intended currents. Actual supply currents will be higher. to protect the device during momentary overload conditions. Junction
Note 7:
DC measurement of gate drive output “ON” voltage is typically temperature will exceed 125°C when overtemperature protection is active. 8.6V. Internal dynamic bootstrap operation yields typical gate “ON” Continuous operation above the specified maximum operating junction voltages of 9.8V during standard switching operation. Standard operation temperature may impair device reliability. gate “ON” voltage is not tested but guaranteed by design.
Note 3:
The LT3845AE is guaranteed to meet performance specifications
Note 8:
The –2V absolute maximum on the SW pin is a transient condition. from 0°C to 125°C junction temperature. Specifications over the –40°C It is guaranteed by design and not subject to test. to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT3845AI is guaranteed over the full –40°C to 125°C operating junction temperature range. The LT3845AMP is 100% tested and guaranteed over the –55°C to 125°C temperature range. 3845afa 4 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Application Related Parts