View RT4533GJ6_8935063.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

rt4533/a ? ds4533/a-02 september 2015 www.richtek.com 1 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. marking information ordering information note : richtek products are : ? rohs compliant and compatible with the current require- ments of ipc/jedec j-std-020. ? suitable for use in snpb or pb-free soldering processes. simplified application circuit applications ? cellular phones ? digital cameras ? probable instruments asynchronous boost converter for 10 wleds general description the rt4533/a is a highly integrated led driver ic capable of driving 10 wleds in series. it is composed of a current mode boost converter integrated with a 36.5v/1.2a power switch. the rt4533/a supports a wide input voltage range from 2.5v to 5.5v and runs at a fixed frequency of 1.1mhz. the led current is set via an external resistor and the feedback voltage is regulated to 200mv / 300mv. for brightness dimming, the rt4533/a supports pwm dimming which determines the feedback reference voltage. features ? ? ? ? ? 2.5v to 5.5v input voltage range ? ? ? ? ? 36.5v open led protection for 10 wleds ? ? ? ? ? pwm dimming brightness control ? ? ? ? ? 200mv / 300mv reference voltage with 2% accuracy ? ? ? ? ? 1.1mhz switching frequency ? ? ? ? ? built-in soft-start ? ? ? ? ? over-temperature protection ? ? ? ? ? internal compensation ? ? ? ? ? current limit ? ? ? ? ? rohs compliant and halogen free 0r=dnn 0r= : product code dnn : date code lx fb gnd rt4533/a vin en l v in vout v out enable d RT4533GJ6 rt4533agj6 1l=dnn 1l= : product code dnn : date code rt4533/a package type j6 : tsot-23-6 lead plating system g : green (halogen free and pb free) feedback voltage rt4533 : 200mv rt4533a : 300mv
2 rt4533/a www.richtek.com ds4533/a-02 september 2015 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. functional pin description pin no. pin name pin function 1 lx switch node. 2 gnd ground. 3 fb feedback voltage input. put a resistor to gnd to setting the current. 4 en enable control input (pwm dimming). 5 vout output voltage pin. 6 vin supply voltage input. tsot-23-6 (top view) pin configurations lx gnd fb vin vout en 4 23 5 6
3 rt4533/a ds4533/a-02 september 2015 www.richtek.com ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. function block diagram operation the rt4533/a is a constant frequency, current mode boost led driver. in normal operation, the n-mosfet is turned on when the pwm control circuit is set by the oscillator and is turned off when the current comparator resets the pwm control circuit. while the n-mosfet is turned off, the inductor current conducts through the external diode. uvlo when the input voltage is lower than the uvlo threshold (2.37v typ.), the driver will turn off. there is a 80mv for the uvlo hysteresis control. soft-start when the device is enabled, the comp ramps up to the target voltage in a specific time. this ensures that the output voltage rises slowly to reduce the input inrush current. en dimming the en pin is used for the control input for both pwm dimming mode and digital dimming mode. shutdown delay when the en voltage is logic low for more than specific time, the driver will be shut down. logic control, minimum on time current- sense ocp driver - + + slope compensation + - pwm ea gm lpf 20ms shutdown enable logic ovp otp uvlo v ref lx gnd fb vout vin en internal compensation internal soft-start pwm oscillator reference voltage bias current ocp the driver provides cycle-by-cycle current limit function to control the current on power switch. the boost switch turns off when the inductor current reaches this current threshold and it remains off until the beginning of the next switching cycle. this protects the rt4533/a and external component under overload conditions. ovp the over voltage protection is detected by a resistor divider circuit from vout. once vout goes over the ovp voltage, lx pin stops switching and the power n-mosfet will be turned off. then, the vout will be discharged by external resistor. ovp will be released until en goes from lo to hi again. otp as the die temperature is higher than 160 c, the chip also will enter protection mode. the power mosfet will be turned off during protection mode to prevent abnormal operation. the device is released from shutdown automatically when the junction temperature decreases by 15 c.
4 rt4533/a www.richtek.com ds4533/a-02 september 2015 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. electrical characteristics recommended operating conditions (note 4) ? supply input voltage, v in ------------------------------------------------------------------------------------------ 2.5v to 5.5v ? junction temperature range -------------------------------------------------------------------------------------- ? 40 c to 125 c ? ambient temperature range -------------------------------------------------------------------------------------- ? 40 c to 85 c (v in = 3.6v, c in = 4.7 f, c out = 1 f, l = 22 h, f sw = 1.1mhz, t a = 25 c, unless otherwise specified) absolute maximum ratings (note 1) ? vin ---------------------------------------------------------------------------------------------------------------------- ? 0.3v to 6v ? en, fb to gnd ------------------------------------------------------------------------------------------------------- ? 0.3v to (v in + 0.3v) ? lx to gnd ------------------------------------------------------------------------------------------------------------- ? 0.3v to 38v ? v out to gnd ---------------------------------------------------------------------------------------------------------- ? 0.3v to 40v ? power dissipation, p d @ t a = 25 c tsot-23-6 ------------------------------------------------------------------------------------------------------------- 0.5w ? package thermal resistance (note 2) tsot-23-6, ja ------------------------------------------------------------------------------------------------------- 197.4 c/w ? junction temperature ----------------------------------------------------------------------------------------------- 150 c ? lead temperature (soldering, 10 sec.) ------------------------------------ ------------------------------------- 260 c ? storage temperature range -------------------------------------------------------------------------------------- ? 65 c to 150 c ? esd susceptibility (note 3) hbm (human body model) ---------------------------------------------------------------------------------------- 2kv mm (ma chine model) ----------------------------------------------------------------------------------------------- 200v parameter symbol test conditions min typ max unit power supply ic operating current (switching) i q_sw v fb = 0v 0.25 0.8 1.5 ma ic quiescent current (non-switching) i q v fb = 0.4v 0.25 0.35 0.5 ma vin pin shutdown current i sd en = gnd -- 0.3 1 ? a under-voltage lockout threshold, uvlo vin rising edge 2.25 2.37 2.5 v under-voltage lockout hysteresis u vlo_hys vin falling edge -- 80 -- mv enable and reference control logic-high v ih 1.4 -- -- en input voltage logic-low v il -- -- 0.4 v en pull low resistance r en -- 300 -- k ? en minimum shut down pulse width t off 20 -- -- ms en minimum logic high pulse width t high_min 0.5 -- -- ? s en minimum logic low pulse width t low 1 -- 10000 ? s internal comp resistance r comp -- 7 -- m ? pwm minimum duty d pwm min -- 3 -- % pwm frequency f pw m 5 -- 100 khz
5 rt4533/a ds4533/a-02 september 2015 www.richtek.com ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. note 1. stresses beyond those listed ? 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 may affect device reliability. note 2. ja is measured at t a = 25 c on a high effective thermal conductivity four-layer test board per jedec 51-7. note 3. devices are esd sensitive. handling precaution is recommended. note 4. the device is not guaranteed to function outside its operating conditions. parameter symbol test conditions min typ max unit voltage and current control feedback regulation voltage rt4533 v fb 196 200 204 mv rt4533a 294 300 306 feedback pin bias current i fb -- -- 0.1 ? a oscillator frequency f sw 0.99 1.1 1.21 mhz maximum duty cycle d max -- 93 -- % power switch n-mosfet on-resistance r ds(on) v in = 3.6v -- 0.4 0.7 ? oc and olp peak n-mosfet current limit i lim 1.0 1.2 1.4 a open led protection threshold ovp 35 36.5 38 v thermal shutdown thermal shutdown threshold t sd -- 160 -- c thermal shutdown hysteresis ? t sd -- 15 -- c
6 rt4533/a www.richtek.com ds4533/a-02 september 2015 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. typical application circuit timing diagram lx fb gnd rt4533/a vin en 4.7f l 10h to 22h 1f / 50v v in 1 6 vout c out v out 3 5 enable c in 4 2 r set 10 wleds d fb 5khz < f pwm < 100khz t shdn > 20ms en period1 period2 on-time1 on-time2 duty1 x 200mv duty1 x 300mv duty2 x 200mv duty2 x 300mv duty1 : on-time1/period1 duty2 : on-time2/period2
7 rt4533/a ds4533/a-02 september 2015 www.richtek.com ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. oscillator frequency vs. temperature 1.00 1.05 1.10 1.15 1.20 1.25 -50 -25 0 25 50 75 100 125 temperature (c) oscillator frequency (mhz) 1 typical operating characteristics operating quiescent current vs. input voltage 0.60 0.70 0.80 0.90 1.00 1.10 1.20 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5 input voltage (v) quiescent current (ma ) switching quiescent current efficiency vs. input voltage 0 10 20 30 40 50 60 70 80 90 100 2.533.544.555.5 input voltage (v) efficiency (%) load = 30ma load = 20ma v out = 30v efficiency vs. output current 0 10 20 30 40 50 60 70 80 90 100 0 0.005 0.01 0.015 0.02 0.025 0.03 output current (a) efficiency (%) v out = 30v 5.5v 4.2v 3.7v i led vs. duty 0 5 10 15 20 25 30 35 0 102030405060708090100 duty (%) i led (ma) rt4533a pwm frequency = 10khz reference voltage vs. output current 199.8 199.9 200 200.1 200.2 200.3 200.4 200.5 0 3 6 9 12 15 18 21 24 27 30 output current (ma) reference voltage (mv) 4.2v 3.7v rt4533
8 rt4533/a www.richtek.com ds4533/a-02 september 2015 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. application information soft-start the rt4533/a includes a soft-start function to avoid high inrush current during start-up. the soft-start function is achieved by clamping the output voltage of the error amplifier with another voltage source that is increased slowly from zero to near vin. led current the loop control of the boost converter keeps vfb equal to a reference voltage, v ref . therefore, when r set is connected between the fb pin and gnd, the led current will be determined by the current through r set , which is equal to v fb / r set . current limit the current flowing through the inductor during a charging period is detected by a current sensing circuit. if the value exceeds the current limit, the n-mosfet will be turned off. the inductor will then be forced to leave charging stage and enter discharging stage. therefore, the inductor current will not increase to reach current limit. shutdown delay when the en voltage is in logic low for 20ms during pwm dimming, the system will enter shutdown. pwm dimming when the en pin is constantly high, the fb voltage is regulated to 200mv / 300mv typically. the rt4533/a allows a pwm signal from en pin to reduce the regulation voltage; and achieve led brightness dimming. the relationship between the duty cycle and fb voltage is given by ? fb ref v = dutyv where duty = duty cycle of the pwm signal v ref = internal reference voltage (200mv / 300mv typ.) the rt4533/a choose the internal 200mv reference voltage via the duty cycle of the pwm signal. therefore, although a pwm signal is used for brightness dimming, only the led dc current is modulated, which is often referred as analog dimming. this eliminates the audible noise which often occurs when the led current is pulsed in replica of the frequency and duty cycle of pwm control. for optimum performance, use the pwm dimming frequency in the range of 5khz to 100khz, and the pwm dimming frequency is strongly suggested to be over than 20khz to avoid audio noise. inductor selection the recommended value of inductor for 10 leds or high brightness led applications is 10 h to 22 h. smaller size and better efficiency are the major concerns for portable devices. the inductor should have low core loss at 1mhz and low dcr for better efficiency. the inductor saturation current rating should be considered to cover the inductor peak current. table 1 lists the recommended inductor for the rt4533/a. capacitor selection for low ripple voltage, ceramic capacitors with low esr are recommended. x5r and x7r types are suitable because of their wide voltage range and good operating temperature characteristics. for the application of the rt4533/a to drive 10 leds in series, a 4.7 f for input capacitor, an 1 f / 50v for output capacitor. thermal considerations for continuous operation, do not exceed absolute maximum operation junction temperature. the maximum power dissipation depends on the thermal resistance of ic package, pcb layout, the rate of surroundings airflow and temperature difference between junction to ambient. the maximum power dissipation can be calculated by following formula : p d(max) = ( t j(max) ? t a ) / ja part number l ( ? h) dcr max (m ? ) saturation current (a) size (l x w x h mm) vendor nr4018t100m 10 216 1.2 4 x 4 x 1.8 taiyo nr4018t220m 22 432 0.8 4 x 4 x 1.8 taiyo table 1
9 rt4533/a ds4533/a-02 september 2015 www.richtek.com ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. figure 1. derating curve of maximum power dissipation 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0 25 50 75 100 125 ambient temperature (c) maximum power dissipation (w) 1 four-layer pcb layout consideration for best performance of the rt4533/a, the following guide lines must be strictly followed. ? input and output capacitors should be placed close to the ic and connected to ground plane to reduce noise coupling. ? the gnd and exposed pad should be connected to a strong ground plane for heat sinking and noise protection. ? keep the main current traces as possible as short and wide. ? lx node of dc/dc converter is with high frequency voltage swing. it should be kept at a small area. ? place the feedback components as close as possible to the ic and keep away from the noisy devices. where t j(max) is the maximum operation junction temperature, t a is the ambient temperature and the ja is the junction to ambient thermal resistance. for recommended operating condition specifications, the maximum junction temperature is 125 c. the junction to ambient thermal resistance, ja , is layout dependent. for tsot-23-6 package, the thermal resistance, ja , is 197.4 c/w on the standard jedec 51-7 four-layer thermal test board. the maximum power dissipation at t a = 25 c can be calculated by following formula : p d(max) = (125 c ? 25 c) / (197.4 c/w) = 0.5w for tsot-23-6 package the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance ja . the derating curve in figure 1 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed.
10 rt4533/a www.richtek.com ds4533/a-02 september 2015 ? copyright 2015 richtek technology corporation. all rights reserved. is a registered trademark of ric htek technology corporation. figure 2. pcb layout guide r set v in gnd wleds the inductor should be placed as close as possible to the switch pin to minimize the noise coupling into other circuits. lx node copper area should be minimized for reducing emi. fb node copper area should be minimized and keep far away from noise sources (lx pin) and rs should be as close as possible to fb pin. c in should be placed as closed as possible to vin pin for good filtering. the c out should be connected directly from the output schottky diode to ground rather than across the wleds 4 2 3 5 6 1 vin vout en lx gnd fb l d c in c out it recommended to add 100 ohm between ic's v out and wled's anode for improving system esd level.
11 rt4533/a ds4533/a-02 september 2015 www.richtek.com richtek technology corporation 14f, no. 8, tai yuen 1 st street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 richtek products are sold by description only. richtek reserves the right to change the circuitry and/or specifications without notice at any time. customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a richtek product. information furnish ed by richtek is believed to be accurate and reliable. however, no responsibility is assumed by richtek or its subsidiaries for its use; nor for any infringeme nts of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of r ichtek or its subsidiaries. outline dimension tsot-23-6 surface mount package dimensions in millimeters dimensions in inches symbol min max min max a 0.700 1.000 0.028 0.039 a1 0.000 0.100 0.000 0.004 b 1.397 1.803 0.055 0.071 b 0.300 0.559 0.012 0.022 c 2.591 3.000 0.102 0.118 d 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 h 0.080 0.254 0.003 0.010 l 0.300 0.610 0.012 0.024 a a1 e b b d c h l

▲Up To Search▲

Price & Availability of RT4533GJ6

	To Download RT4533GJ6 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .