Datasheet LT3922-1 (Analog Devices) - 7

LT3922-1
TYPICAL PERFORMANCE CHARACTERISTICS VIN = 12V, TA = 25°C, unless otherwise noted. LED Current (Analog CTRL) LED Current (Digital CTRL) LED Voltage Limit
125 125 125 PULSE FREQUENCY AT CTRL PIN = 20kHz VCTRL = 2V 100 100 100 75 (mV) 75 (mV) 75 (mV) ISN ISN ISN – V – V 50 50 – V 50 V ISP V ISP V ISP 25 25 25 0 0 0 0 0.25 0.50 0.75 1 1.25 1.50 1.75 2 0 12.5 25 37.5 50 62.5 75 87.5 100 1.17 1.18 1.19 1.20 1.21 1.22 VCTRL (V) DCTRL (%) VFB (V) 39221 G19 39221 G20 39221 G21
LED Current (100% Regulation) LED Current (5% Regulation) ISMON Voltage
350 200 1000 150°C 150°C –40°C 25°C 300 25°C 25°C –40°C –40°C 160 125°C 800 N = 355 250 N = 355 200 120 600 150 80 400 ISMON (mV) NUMBER OF UNITS 100 NUMBER OF UNITS 40 200 50 0 0 0 98.6 99.3 100 100.7 101.4 4.2 4.6 5 5.4 5.8 0 20 40 60 80 100 ISP–ISN VOLTAGE (mV) ISP–ISN VOLTAGE (mV) VISP – VISN (mV) V 39221 G22 39221 G23 39221 G24 CTRL = 2V VCTRL = 0.3V VISP = 24V VISP = 24V
Peak SW Current Limit LED Current Line Regulation LED Current vs VOUT
3.0 400 400 fSW = 2MHz 2.9 L = 4.7µH PEAK SW CURRENT LIMITED VFB OVERVOLTAGE PROTECTION LIMITED 350 350 2.8 300 300 2.7 2.6 250 250 2.5 (mA) (mA) 200 I LED 200 I LED 2.4 2.3 150 V 150 IN = 8V PEAK SW CURRENT (A) fSW = 2MHz 2.2 fSW = 2MHz R 100 SNS = 0.3Ω 10 LEDs (V R 100 2.1 OUT ~ 30V) SNS = 0.3Ω RFB_TOP = 1M 5 LEDs (V 11 LEDs (V OUT ~ 15V) OUT ~33V) RFB_BOT = 34.8k 2.0 50 50 10 20 30 40 50 60 70 80 90 100 0 3 6 9 12 15 18 21 24 27 30 9 15 21 27 33 39 DUTY CYCLE (%) VIN (V) VOUT (V) 39221 G25 39221 G26 39221 G27 Rev 0 For more information www.analog.com 7 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION TYPICAL APPLICATION RELATED PARTS