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AT9919 Dataheets PDF



Part Number AT9919
Manufacturers Supertex
Logo Supertex
Description High Brightness LED Driver
Datasheet AT9919 DatasheetAT9919 Datasheet (PDF)

Supertex inc. AT9919 Hysteretic, Buck, High Brightness LED Driver with High-Side Current Sensing Features ►► Hysteretic control with high-side current sensing ►► Wide input voltage range: 4.5 to 40V ►► >90% Efficiency ►► Typical ±5% LED current accuracy ►► Up to 2.0MHz switching frequency ►► Adjustable constant LED current ►► Analog or PWM control signal for PWM dimming ►► Over-temperature protection ►► -40ºC to +125ºC operating temperature range ►► AEC-Q100 compliant Applications ►► Automoti.

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Supertex inc. AT9919 Hysteretic, Buck, High Brightness LED Driver with High-Side Current Sensing Features ►► Hysteretic control with high-side current sensing ►► Wide input voltage range: 4.5 to 40V ►► >90% Efficiency ►► Typical ±5% LED current accuracy ►► Up to 2.0MHz switching frequency ►► Adjustable constant LED current ►► Analog or PWM control signal for PWM dimming ►► Over-temperature protection ►► -40ºC to +125ºC operating temperature range ►► AEC-Q100 compliant Applications ►► Automotive LED lighting applications General Description The AT9919 is a PWM controller IC designed to drive high brightness LEDs using a buck topology. It operates from an input voltage of 4.5 to 40VDC and employs hysteretic control with a high-side current sense resistor to set the constant output current. The operating frequency range can be set by selecting the proper inductor. Operation at high switching frequency is possible since the hysteretic control maintains accuracy even at high frequencies. This permits the use of small inductors and capacitors minimizing space and cost in the overall system. LED brightness control is achieved with PWM dimming from an analog or PWM input signal. Unique PWM circuitry allows true constant color with a high dimming range. The dimming frequency is programmed using a single external capacitor. The AT9919 comes in a small, 8-Lead DFN package and is qualified for automotive LED lighting applications. Typical Application Circuit CIN RSENSE L 0 - 2.0V Doc.# DSFP-AT9919 A061212 CS VIN RAMP VDD ADIM GATE DIM GND AT9919 Supertex inc. www.supertex.com AT9919 Ordering Information Part Number Package AT9919K7-G 8-Lead DFN -G indicates package is RoHS compliant (‘Green’) Packing 3000/Reel Pin Description CS 1 VIN 2 RAMP 3 GND 8 GATE 7 GND 6 VDD ADIM 4 5 DIM Absolute Maximum Ratings Parameter VIN, CS to GND Value -0.3 to +45V 8-Lead DFN (K7) (top view) Product Marking VDD, GATE, RAMP, DIM, ADIM to GND CS to VIN Continuous power dissipation, (TA = +25°C) Operating temperature range Junction temperature -0.3 to +6.0V -1.0 to +0.3V 1.6W -40°C to +125°C +150°C 9919 YWLL Y = Last Digit of Year Sealed W = Code for Week Sealed L = Lot Number = “Green” Packaging 8-Lead DFN (K7) Storage temperature range -65°C to +150°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Typical Thermal Resistance Package θja 8-Lead DFN 37OC/W Mounted on FR-4 board, 25mm x 25mm x 1.57mm Electrical Characteristics (VIN = 12V, VDIM = VDD, VRAMP = GND, CVDD = 1.0µF, RCS = 0.5Ω, TA = TJ = -40OC to +125OC* unless otherwise noted) Sym Description Min Typ Max Units Conditions VIN Input DC supply voltage range 4.5 - 40 V DC input voltage VDD Internally regulated voltage 4.5 - 5.5 V VIN = 6.0 to 40V IIN Supply current - - 1.5 mA GATE open IIN, SDN Shutdown supply current - - 900 µA DIM < 0.7V IIN, LIM Current limit - 30 - mA VIN = 4.5V, VDD = 0V - 8.0 - VIN = 4.5V, VDD = 4.0V fOSC Oscillator frequency - - 2.0 MHz --- UVLO VDD Undervoltage lockout threshold - - 4.5 V VDD rising ΔUVLO VDD Undervoltage lockout hysteresis - 500 - mV VDD falling * Guaranteed by design and characterization, 100% tested at TA = 25OC. Typical characteristics are given at TA = 25OC. Doc.# DSFP-AT9919 A061212 Supertex inc. 2 www.supertex.com AT9919 Electrical Characteristics (VIN = 12V, VDIM = VDD, VRAMP = GND, CVDD = 1.0µF, RCS = 0.5Ω, TA = TJ = -40OC to +125OC* unless otherwise noted) Sym Description Min Typ Max Units Conditions Sense Comparator VCS(HI) VCS(LO) VCS(AVG) tDPDH Sense voltage threshold high Sense voltage threshold low Average reference voltage Propagation delay to output high 198 230 257 mV (VIN - VCS) rising 147 170 195 mV (VIN - VCS) falling 186 200 214 mV VCS(AVG) = 0.5VCS(HI) + 0.5VCS(LO) - 70 - ns Falling edge of (VIN - VCS) = VRS(LO) - 70mV tDPDL Propagation delay to output low ICS Current-sense input current VCS(HYS) Current-sense threshold hysteresis DIM Input - - 70 - ns Rising edge of (VIN - VCS) = VRS(HI) + 70mV - 1.0 µA (VIN - VCS) = 200mV 56 80 mV --- VIH Pin DIM input high voltage VIL Pin DIM input low voltage tON Turn-on time 2.2 - - V --- - - 0.7 V --- - 100 - ns DIM rising edge to VGATE = 0.5 x VDD, CGATE = 2.0nF tOFF Turn-off time - 100 - ns DIM falling edge to VGATE = 0.5 x VDD, CGATE =2.0nF Gate Driver GATE current, source† IGATE GATE current, sink† TRISE GATE output rise time TFALL GATE output fall time VGATE(HI) GATE high output voltage VGATE(LO) GATE low output voltage Over-Temperature Protection TOT Over temperature trip limit† ∆THYST Temperature hysteresi.


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