Datasheet LT3756, LT3756-1, LT3756-2 (Analog Devices) - 4

LT3756/LT3756-1/LT3756-2
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 24V, SHDN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Minimum Operating Voltage VIN Tied to INTVCC l 6 V VIN Shutdown IQ SHDN/UVLO = 0V, PWM = 0V 0.1 1 µA SHDN/UVLO = 1.15V, PWM = 0V 5 µA VIN Operating IQ (Not Switching) PWM = 0V 1.4 1.7 mA VREF Voltage 100µA ≤ IVREF ≤ 0µA (E, I, H-Grades) l 1.965 2.00 2.045 V 80µA ≤ IVREF ≤ 0µA (J-Grade only) l 1.965 2.00 2.045 V VREF Line Regulation 6V ≤ VIN ≤ 100V 0.006 %/V SENSE Current Limit Threshold l 98 108 118 mV SENSE Input Bias Current Current Out of Pin 40 µA SS Pull-Up Current Current Out of Pin 8 10 13 µA
Error Amplifier
ISP/ISN Full-Scale Current Sense Threshold FB = 0V, ISP = 48V l 96 100 103 mV J-Grade l 95.5 100 103 mV ISP/ISN Current Sense Threshold at CTRL = 0V CTRL = 0V, FB = 0V, ISP = 48V –12 –9.5 –7 mV CTRL Pin Range for Current Sense Threshold Adjustment l 0 1.1 V CTRL Input Bias Current Current Out of Pin 50 100 nA LED Current Sense Amplifier Input Common Mode Range (VISN) l 2.9 100 V ISP/ISN Short-Circuit Threshold ISN = 0V 115 150 200 mV ISP/ISN Short-Circuit Fault Sensing Common Mode Range (VISN) l 0 3 V ISP/ISN Input Bias Current (Combined) PWM = 5V (Active), ISP = ISN = 48V 55 µA PWM = 0V (Standby), ISP = ISN = 48V 0 0.1 µA LED Current Sense Amplifier gm V(ISP – ISN) = 100mV 120 µS VC Output Impedance 1V < VC < 2V 15000 kΩ VC Standby Input Bias Current PWM = 0V –20 20 nA FB Regulation Voltage (VFB) l 1.220 1.250 1.270 V ISP = ISN 1.232 1.250 1.265 V J-Grade l 1.215 1.250 1.275 V FB Amplifier gm FB = VFB, ISP = ISN 480 µS FB Pin Input Bias Current Current Out of Pin 40 100 nA FB Open LED Threshold OPENLED Falling VFB – VFB – VFB – V (LT3756 and LT3756-2) 65mV 50mV 40mV FB Overvoltage Threshold PWMOUT Falling VFB + VFB + VFB + V 50mV 60mV 75mV VC Current Mode Gain – (∆VVC/∆VSENSE) 4 V/V
Oscillator
Switching Frequency RT = 100k l 90 100 125 kHz RT = 10k 925 1000 1050 kHz Minimum Off-Time 170 ns
Linear Regulator
INTVCC Regulation Voltage 7 7.15 7.3 V Dropout (VIN – INTVCC) IINTVCC = –10mA, VIN = 7V 1 V INTVCC Undervoltage Lockout 3.9 4.1 4.3 V Rev. C 4 For more information www.analog.com 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 Package Description Revision History Typical Application Related Parts