Datasheet LT3922 (Analog Devices) - 7

LT3922
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 50 – V 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) 3922 G19 3922 G20 3922 G21
LED Current (100% Regulation) LED Current (5% Regulation) ISMON Voltage
350 200 1000 150°C 150°C –40°C 25°C 25°C 25°C 300 –40°C –40°C 125°C 160 800 N = 355 250 N = 355 120 600 200 150 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) 3922 G22 3922 G23 3922 G24 VCTRL = 2V VCTRL = 0.3V VISP = 24V VISP = 24V
Peak SW Current Limit LED Current Line Regulation LED Current vs VOUT
2.6 400 400 fSW = 2MHz V 2.5 L = 4.7µH PEAK SW CURRENT LIMITED FB OVERVOLTAGE PROTECTION LIMITED 350 350 2.4 300 300 2.3 250 250 2.2 (mA) (mA) 200 I LED 200 I LED 2.1 V PEAK SW CURRENT (A) 150 150 IN = 8V 2.0 fSW = 2MHz fSW = 2MHz RSNS = 0.3Ω 1.9 12 LEDs (V 100 100 OUT ~ 36V) RSNS = 0.3Ω RFB_TOP = 1M 6 LEDs (VOUT ~ 18V) 11 LEDs (VOUT ~33V) RFB_BOT = 34.8k 1.8 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) 3922 G25 3922 G26 3922 G27 3922fa For more information www.linear.com/LT3922 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 Revision History Typical Application Related Parts