Datasheet LT3932, LT3932-1 (Analog Devices) - 3

LT3932/LT3932-1
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Reference
VREF Voltage IVREF = 0µA l 1.975 2 2.020 V IVREF = 500µA 1.980 1.998 2.016 V VREF Pin Current Limit VREF = 1.9V, Current Out of Pin 2 mA
LED Current Regulation
CTRL-Off Threshold (Falling) l 200 218 228 mV CTRL-Off Rising Hysteresis 20 mV CTRL Pin Current VCTRL = 2V −100 100 nA Sense Voltage (VISP−VISN) VCTRL = 1.5V (100%), VIN = 36V, VISP = 24V l 98.5 100 101.5 mV (Analog Input) VCTRL = 750mV (50%), VIN = 36V, VISP = 24V l 48.5 50 51.5 mV VCTRL = 300mV (5%), VIN = 36V, VISP = 24V l 4 5 6 mV ISP Pin Current VIN = 36V, VISP = 24V, VCTRL = 2V, Current Into Pin 50 µA ISN Pin Current VIN = 36V, VISN = 23.9V, VCTRL = 2V, Current Into Pin 50 µA ISP/ISN Common Mode Range VIN = 36V (Note 5) 0 36 V Current Error Amplifier Transconductance VIN = 36V, VISP = 24V 200 µA/V
Duty Cycle Control of LED Current
Sense Voltage (VISP−VISN) CTRL Duty = 75% (100%), VIN = 36V, VISP = 24V 99 100 101 mV (Duty Cycle Input) CTRL Duty = 37.5% (50%), VIN = 36V, VISP = 24V 49 50 51 mV CTRL Duty = 15% (5%), VIN = 36V, VISP = 24V 4 5 6 mV CTRL Pulse Input High (VIH) 1.6 V CTRL Pulse Input Low (VIL) 0.4 V CTRL Pulse Input Frequency Range 100 1000 kHz
Voltage Regulation
FB Regulation Voltage VISP = VISN = 6V, VCTRL = 2V l 0.988 1.000 1.012 V FB Pin Current VFB = 1V −100 100 nA Voltage Error Amplifier Transconductance 480 µA/V
Power Stage
Peak Current Limit 3.0 3.6 4.2 A Minimum Off-Time (Note 6) 55 ns Minimum On-Time (Note 6) 55 ns Bottom Switch On-Resistance 90 mΩ Top Switch On-Resistance 90 mΩ
Oscillator
Programmed Switching Frequency (fSW) RT = 45.3k, VSYNC/SPRD = 0V l 1900 2000 2100 kHz RT = 523k, VSYNC/SPRD = 0V l 180 200 230 kHz Spread Spectrum Frequency Range RT = 45.3k, VSYNC/SPRD = 3.3V 1900 2650 kHz RT = 523k, VSYNC/SPRD = 3.3V 180 290 kHz RT Pin Current Limit VRT = 0V, Current Out of Pin 34 µA SYNC/SPRD Threshold (Rising) 1.4 1.5 V SYNC/SPRD Falling Hysteresis 220 mV SYNC/SPRD Pin Current VSYNC/SPRD = 3.3V −100 100 nA
Soft-Start
SS Pin Charging Current VSS = 0V 20 µA Rev B For more information www.analog.com 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Applications Package Description Revision History Typical Application Related Parts