SGM3123 white led driver with low dropout current source general description the SGM3123 low-dropout bias supply for white leds is a high-performance alternative to the simple ballast resistors used in conventional white led designs. it is optimized for low power keypad and portable backlighting applications. the SGM3123 uses an internal resistor to set the bias current for four leds, which are matched to 5%. the SGM3123's advantages over ballast resistors include much lower bias variation with supply voltage variation, significantly lower dropou t voltage, and in some applications, significantly improved efficiency. the SGM3123 requires only a 40mv dropout voltage at a 20ma load on each output to match the led brightness. the SGM3123 is available in green tqfn-33-16l package. it operates over an ambient temperature range of -40 to +85 . features support up to 4 leds low 40mv dropout at 20ma less than 5% led current matching simple led brightness control low shutdown current 2.5v to 5.0v supply voltage range thermal shutdown protection operating temperature range: -40 to +85 available in green tqfn-33-16l package applications wireless handsets mp3, mp4, and pmp cellular phones portable communication devices digital cameras, camcorders pdas, palmtops, and handy terminals led/display back light driver leds for camera flash battery-powered equipment rev. a. 2 sg micro corp www.sg-micro.com
white led driver with low dropout current source 2 SGM3123 sg micro corp www.sg-micro.com package/ordering information model order number package description specified temperature range package option marking information SGM3123 SGM3123ytq16g/tr tqfn-33-16l -40c to +85c tape and reel, 3000 3123tq absolute maximum ratings v in to gnd??????.????...?..? .????.-0.3v to 6v the other pins to gnd??????....?????.. -0.3v to 6v storage temperature range...?.?.??..?.... -65 to +150 junction temperature?????.???.???.???...150 operating temperature range...???.?.??. -40 to +85 power dissipation (1) , p d @ t a = 25 tqfn-33-16l ?.............................................................1.47w package thermal resistance (1) tqfn-33-16l, ja ????.?.???????..?.?.68 /w lead temperature (soldering 10 sec) ?????????????...??.??.?....????.. 260 esd susceptibility hbm???????????????.????..???4000v mm????????????????.???..????400v notes: 1. the thermal resistance figures are for general reference only. actual thermal characteristics may vary with the pcb layout, size of metal trace, the therma l conduction path between metal layers and the environment of the system. 2. 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 s pecifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. caution this integrated circuit can be damaged by esd if you don?t pay attention to esd protection. sgmicro recommends that all integrated circuits be handled with appropriate precautions. failure to observe proper handling and installation procedures can cause damage. esd damage can range from subtle performance degradation to complete device failure. precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. sgmicro reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. please contact sgmicro sales office to get the latest datasheet.
white led driver with low dropout current source 3 SGM3123 sg micro corp www.sg-micro.com pin configuration (top view) pgnd vout nc led4 nc nc led3 led1 led2 en gnd en 1234 5 6 7 8 9 10 11 15 14 16 vin nc nc nc 12 13 gnd tqfn-33-16l pin description pin name function 1, 2, 9, 10, 11, 12 nc no internal connection. 3, 4, 5, 6 led1-led4 led1-led4 output pin. connect to led1-led4?s cathode. 20ma constant current output. they are high impedance when en is low. 7 pgnd power ground. 8 vout output voltage source for led1 to led4. 13 vin supply voltage input. 14 gnd analog ground. 15, 16 en enable input (active high). exposed pad gnd exposed pad should be soldered to pcb board and connected to gnd.
white led driver with low dropout current source 4 SGM3123 sg micro corp www.sg-micro.com electrical characteristics (v in = 3.7v, t a = +25c, unless otherwise noted.) parameter symbol conditions min typ max units operation voltage range v in 2.5 5.0 v shutdown supply current i shdn v en < 0.4v 1 a led sink current i led 18 20 22 ma quiescent power supply current i q i led = 0 190 a led dropout voltage i led = 20ma, v led @ i ledn = 90% i led 40 90 mv led current deviation matching d led -5 +5 % opt 150 c opt hysteresis 10 c input high voltage at en v ih v en > v ih for enable ih 1.5 v input low voltage at en v il v en < v il for disable il 0.4 v
white led driver with low dropout current source 5 SGM3123 sg micro corp www.sg-micro.com typical performance characteristics led current vs. input voltage 0 5 10 15 20 25 30 2 2.5 3 3.5 4 4.5 5 5.5 input voltage (v) led current (ma) led1 led2 led3 led4 supply current vs. supply voltage 0 60 120 180 240 1.5 2.5 3.5 4.5 5.5 supply voltage (v) supply current ( a) led current vs. temperature 10 15 20 25 30 -40 -15 10 35 60 85 temperature ( ) led current (ma)
white led driver with low dropout current source 6 SGM3123 sg micro corp www.sg-micro.com typical performance characteristics line transient response time (100s/div) v in = 3.2v to 3.7v v in i led 25ma 1v /div 0ma
white led driver with low dropout current source 7 SGM3123 sg micro corp www.sg-micro.com typical application en led1 led2 led3 led4 gnd pgnd vin SGM3123 1f en vout pwm + _ figure 1. application circuit for backlight application information enable input drive en high to enable the device; drive en low to force led1, led2, led3 and led4 into a high-impedance state. when driven high, en draws190 a to power the ic. driving en low longer than 3ms will disable the device and the typical supply current will be less than 1a. input uvlo an input capacitor at the v cc pin could reduce ripple voltage. it is recommended to use a ceramic 1 f or larger capacitance as the input capacitor. this ic provides an under voltage lockout (uvlo) function to prevent it from unstable issue when startup. the uvlo threshold of input rising voltage is set at 2.1v typically with a hysteresis 0.11v. led brightness dimming control for controlling the led brightness, the SGM3123 can perform the dimming control by applying a pwm signal to en pin. when an external pwm signal is applied to the en pin, brightness of white led is adjusted by the duty cycle. the average led current is proportional to the pwm signal duty cycle. the magnitude of the pwm signal must be higher than the minimum level of enable input high level, in order to let the dimming control perform correctly. the suggested pwm frequency range is 20khz to 200hz.
white led driver with low dropout current source 8 SGM3123 sg micro corp www.sg-micro.com package outline dimensions tqfn-33-16l top view bottom view side view a a2 a1 e e1 b l k d1 d e n1 n5 n16 1.7 1.7 0.7 2.2 3.6 0.5 0.24 recommended land pattern (unit: mm) dimensions in millimeters dimensions in inches symbol min max min max a 0.700 0.800 0.028 0.031 a1 0.000 0.050 0.000 0.002 a2 0.203 ref 0.008 ref d 2.900 3.100 0.114 0.122 d1 1.600 1.800 0.063 0.071 e 2.900 3.100 0.114 0.122 e1 1.600 1.800 0.063 0.071 k 0.200 min 0.008 min b 0.180 0.300 0.007 0.012 e 0.500 typ 0.020 typ l 0.300 0.500 0.012 0.020
white led driver with low dropout current source 9 SGM3123 sg micro corp www.sg-micro.com tape and reel information note: the picture is only for reference. please make the object as the standard. key parameter list of tape and reel package type reel diameter reel width w1 (mm) a0 (mm) b0 (mm) k0 (mm) p0 (mm) p1 (mm) p2 (mm) w (mm) pin1 quadrant tqfn-33-16l 13 12.40 3.35 3.35 1.13 4.00 4.00 2.00 12.00 q1 reel width (w1) reel diameter reel dimensions tape dimensions direction of feed p2 p0 w p1 a0 k0 b0 q1 q2 q4 q3 q3 q4 q2 q1 q3 q4 q2 q1
white led driver with low dropout current source 10 SGM3123 sg micro corp www.sg-micro.com carton box dimensions note: the picture is only for reference. please make the object as the standard. key parameter list of carton box reel type length (mm) width (mm) height (mm) pizza/carton 13 386 280 370 5
|
