Datasheet LT3508 (Analog Devices) - 3

link to page 2 link to page 9 LT3508
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage, VIN1 l 3.4 3.7 V Minimum Operating Voltage, VIN2 VIN1 = 12V l 2.5 3.0 V VIN1 Quiescent Current Not Switching 4.3 5.2 mA VIN2 Quiescent Current Not Switching 320 500 µA Shutdown Current (VIN1 + VIN2) VSHDN = 0.3V 0.1 2 µA FB Voltage 0.790 0.800 0.814 V l 0.784 0.816 V FB Pin Bias Current (Note 3) VFB = 0.800V, VC = 0.5V l 50 300 nA FB Voltage Line Regulation 5V < VIN < 40V 0.01 %/V Error Amp Transconductance 300 µS Error Amp Voltage Gain 600 V/V VC to Switch Current Gain 2.5 A/V Switching Frequency RT = 33.2k l 0.92 1 1.06 MHz Switching Phase RT = 33.2k 150 180 210 Deg Maximum Duty Cycle (Note 4) RT = 33.2k l 84 90 % RT = 7.50k 80 % RT = 169k 98 % Foldback Frequency RT = 33.2k, VFB = 0V 120 kHz Switch Current Limit (Note 5) Duty Cycle = 15% l 2.0 2.6 3.2 A Switch VCESAT ISW = 1.5A 300 mV Switch Leakage Current 0.01 1 µA Minimum Boost Voltage 1.7 2.5 V Boost Pin Current ISW = 1.5A, VBOOST = 17V 35 50 mA TRACK/SS Pin Current VTRACK/SS = 0V 0.8 1.2 2.2 µA PG Threshold Offset VFB Rising 56 75 110 mV PG Voltage Output Low VFB = 0.6V, IPG = 250µA 0.13 0.4 V PG Pin Leakage VPG = 2V 0.01 1 µA SHDN Threshold Voltage 2.53 2.63 2.73 V SHDN Input Current (Note 6) VSHDN = 60mV Above Threshold Voltage 6 8 10 µA SHDN Threshold Current Hysteresis 5.5 7.5 9.5 µA SYNC Threshold Voltage 1 1.25 1.5 V SYNC Input Frequency 0.25 2.5 MHz
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
Current flows out of pin. may cause permanent damage to the device. Exposure to any Absolute
Note 4:
VBOOST =12V. Circuitry increases the maximum duty cycle of the Maximum Rating condition for extended periods may affect device LT3508 when VBOOST > VIN + 2.5V. See Minimum Operating Voltage in the reliability and lifetime. Applications Information section for details.
Note 2:
The LT3508E is guaranteed to meet performance specifications
Note 5:
Current limit is guaranteed by design and/or correlation to static from 0°C to 125°C junction temperature. Specifications over the –40°C test. Slope compensation reduces current limit at higher duty cycles. to 125°C operating junction temperature range are assured by design,
Note 6:
Current flows into pin. characterization and correlation with statistical process controls. The LT3508I is guaranteed over the full –40°C to 125°C operating junction
Note 7:
This IC includes overtemperature protection that is intended temperature range. The LT3508H is guaranteed over the full –40°C to to protect the device during momentary overload conditions. Junction 150°C operating junction temperature range. High junction temperatures temperature will exceed the maximum operating junction temperature degrade operating lifetimes. Operating lifetime is derated at junction range when overtemperature protection is active. Continuous operation temperatures greater than 125°C. above the specified maximum operating junction temperature may impair device reliability. Rev. E For more information www.analog.com 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts