StarChips. Technology. SCT2026 V02_01; Jan/08. In/Parallel Product Description. Features. Pin Configurations

Transcription

1 StarChips Technology V02_01; Jan/08 16-bit Serial-In/Pa In/Parallel rallel-out Constant-Current Current LED Driver Product Description The serial-interfaced LED driver sinks 16 LED clusters with constant current to keep the uniform intensity of LED displays. In applications, an external resistor is used to set the full-scale constant output current from 5mA up to 90mA. The guarantees each output can endure maximum 17V DC voltage stress. The built-in shift registers and data latches making the effective solution in driving LED display. The output enable function gates all 16 outputs on and off, and is fast enough to be used as PWM input for LED intensity control. Since the serial data input rate can be reached up to 25MHz, the will satisfy system which needs high volume data transmission to control the LED display. Features 16 constant-current outputs rate at 17V Constant output current range: 5 90mA Excellent current regulation to load, supply voltage and temperature ±3% Current matching between outputs ±6% Current matching between ICs Fast output current control: Minimum PWM pulse width = 120ns All output current are programmed together using a single external resistor CMOS Schmitt triggered inputs High serial data transfer rate: 25MHz Operating supply voltage range of 4.5V to 5.5V Built-in power on reset and thermal protection function Package: SOP24, SSOP24 and P24 Applications: LED Displays, Variable Message Signs, LED Traffic Signs Pin Configurations 4 21 OUT OUT OUT OUT3 OUT4 OUT5 OUT6 OUT CSOG CSSG CSTG CSDG OUT15 OUT14 OUT13 OUT12 OUT11 OUT10 OUT9 OUT8 OUT OUT CSAG OUT0 OUT OUT13 OUT12 OUT11 OUT10 OUT9 OUT8 OUT7 OUT6 OUT5 OUT4 OUT3 OUT2

2 Terminal Description Pin Name Function 1 Ground terminal. 2 Serial input of data shift register. 3 Clock input of shift register, data is sampled at the rising edge of. 4 Input terminal of data strobe. Data is latched when is low. And data on shift register goes through when is high OUT[0:15] Open-drain, constant-current outputs. 21 Output enable signal. Output is enabled when is forced to low. 22 Output terminal of serial-data output to the of next. 23 Used to connect an external resistor for setting up all output current. 24 Supply voltage terminal. Block Diagram Ordering Information OUT0 OUT1 OUT14 OUT15 Part Package CSOG Pb free SOP24 CSSG Pb free SSOP24 Current Regulator Output Driver CSAG Pb free SSOP24 CSTG Pb free SSOP CSDG Pb free P24 Q ST D D Q C Q ST D D Q C D C Q ST D Q Q ST D D Q C StarChips Technology, Inc. 4F, No.5, Technology Rd.,Science-Based Industrial Park, Hsin-Chu,Taiwan, R.O.C. Tel: # 555 Fax: service@starchips.com.tw Truth Table OUT0 ~ OUT15 H L Dn Dn Dn Dn-14 Dn-15 Dn-15 L L Dn+1 No change Dn-14 H L Dn+2 Dn+2 Dn Dn-12 Dn-13 Dn-13 X L Dn+3 Dn+2 Dn Dn-12 Dn-13 Dn-13 X H Dn+3 Off Dn-13 Page 2 of 14

3 Timing Diagram Data strobed to OUT15 OUT14 OUT1 OUT0 OUT0 OUT1 OUT [2:12] OUT13 OUT14 OUT15 OFF ON OFF ON OFF ON Equivalent Circuits of Inputs (1) Equivalent Circuits of Inputs (2) Equivalent Circuits of Output Page 3 of 14

4 Maximum Ratings (TA = 25 ) Characteristic Symbol Rating Unit Supply Voltage V DD 7.0 V Input Voltage V IN -0.2 ~ V DD +0.2 V Output Current I OUT 90 ma/channel Output Voltage V OUT -0.2 ~ 17.0 V Total Terminals Current I 1200 ma Power Dissipation Thermal Resistance SOP SSOP P D SSOP P SOP24 61 SSOP24 84 R TH(j-a) SSOP P24 60 Operating Temperature T OPR -40~+85 Storage Temperature T STG -55~+150 W /W Stresses beyond those listed under Maximum Ratings may cause permanent damage to the device. Exposure to the maximum rating conditions for extended periods may affect device reliability. Recommended Operating Conditions (TA= -40 to 85 unless otherwise noted) Characteristic Symbol Condition Min. Typ. Max. Unit Supply Voltage V DD V Output Voltage V OUT1 Output OFF V Output Voltage V OUT2 Output ON 1-4 V Output Current I OUT V DD =5V 5-60 ma Input Voltage V IH Input Signals V DD V V IL Input Signals V Pulse Width t W V DD =5V ns Selector Guide Part Number of Max Output Min PWM Pulse Outputs Current (ma) Width (ns) Supply Voltage (V) SCT SCT /5 SCT SCT /5 Page 4 of 14

5 Electrical Characteristics (V DD =5V, TA=25 unless otherwise noted) Characteristic Symbol Condition Min. Typ. Max. Unit Input Voltage V IH V DD V V IL V V OH V DD =5V, I OH = -1mA V Output Voltage V OL V DD =5V, I OL = +1mA V Output Leakage Current I OL V OUT = 17V µa Output Current I OUT V OUT =1V, R EXT =900Ω ma Current Bit Skew(Note 1) di OUT1 V OUT =1V, R EXT =900Ω - ±1 ±3 % Current Chip Skew di OUT2 V OUT =1V, R EXT =900Ω - ±3 ±6 % 4.5V < V I OUT vs. V DD Regulation %/dv DD < 5.5V, DD VOUT > 1V, R EXT =900Ω - - ±2 %/V I OUT vs. VOUT Regulation 1V < VOUT < 4V %/dvout I OUT =21mA, R EXT =900Ω - - ±1 %/V Pull-up Resistor R up KΩ Pull-down Resistor R down KΩ Thermal Shutdown Supply Current OFF T H Junction Temperature T L R I DD (off)1 EXT =Open, V DD = 5V OUT [0:15]=Off R I DD (off)2 EXT = 900Ω, V DD = 5V ma OUT [0:15]=Off R ON I DD (on) EXT = 900 Ω, V DD = 5V OUT [0:15]=On Note 1: Bit Skew=(I OUT -I AVG )/I AVG, where I AVG =(I max + I min )/ Switching Characteristics (TA=25 unless otherwise noted)(note 2) Characteristic Symbol Condition Min. Typ. Max. Unit Propagation Delay Time ( L to H ) Propagation Delay Time ( H to L ) - OUTn t PLH ns - OUTn t PLH ns - OUTn t PLH ns - t PLH ns - OUTn t PHL1 V DD = 5V ns - OUTn t PHL2 V LED = 5V ns - OUTn t V IH = V DD PHL ns V - t IL = PHL ns R EXT = 900 Ω t W() R ns L = 180 Ω t W(L) C L = 10 pf ns Pulse Width t W(OE) 120 ns Hold Time for t H(L) ns Setup Time for t S(L) ns Output Rise Time of IOUT t OR ns Output Fall Time of IOUT t OF ns Slow rise time t R ns Cascade Slow fall time t F ns Note 2: All parameter tested at TA=25. Specifications over temperature are guaranteed by design. Page 5 of 14

6 Test Circuit for Switching Characteristics VIH VIL TR = TF = 10 ns IDD OUT0 OUT1 OUT14 OUT15 I OUT RL CL CL V LED Timing Waveform t W() t SU(D) t H(D) t SU(D) t H(D) t PLH, t PHL t W(L) t H(L) t S(L) LOW = ALL OUTPUTS ENABLED HIGH = OUTPUT OFF OUTn t PLH1, t PHL1 t PLH2, t PHL2 LOW = OUTPUT ON t W(OE) t PHL3 t PLH3 OUTn 90% 90% 10% 10% t OF t OR Page 6 of 14

7 Adjusting Output Current All s output current (I OUT ) are set by one external resistor at pin. The relationship between I OUT and resistance R EXT is shown as the following figure Output Current vs. Resistance ) A ( m T U O I V < V OUT < 4.0V EXT (ohm) Also, when s output voltage is set between 1V and 4V, the output current I OUT can be set by the formula: I OUT = 30(630 / R EXT ) ma. Thus the output currents are all set to 21mA (±6%) by set the reference value R EXT = 900Ω. Load Supply Voltage (VLED) The can be operated very well when VOUT ranging from 1V to 4V. It is recommended to use the lowest possible supply voltage VLED or set a voltage reducer to reduce the VOUT voltage and then reduce the power dissipation of. A voltage reducer lets VOUT = VLED VDROP VF, Resistors or Zener diode can be used in the applications as shown in the following figures. VLED VLED V DROP V DROP VF VF IOUT VOUT IOUT VOUT Page 7 of 14

8 Output Characteristics The current characteristic of output stage is flat. The output current IOUT which less than 90mA can be kept constant regardless of the variations of LED forward voltage when VOUT > 1.2V. The relationship between IOUT and VOUT is shown as below: 100 Output Current Performance vs. Output Voltage ) A m ( T U O I VOUT (V) Power Dissipation The power dissipation (P D ) of a semiconductor chip is limited by its package and ambient temperature. The maximum allowable power dissipation P D(max) is determined by P D(max) =(T j(max) T a )/R th(j-a) where T j(max) : maximum chip junction temperature, usually considered as 150, T a : ambient temperature, R th(j-a) : thermal resistance of the package. The relationship between P D(max) and T a is shown as the below figure: ) (W n a tio isip D e r o w P Max. Power Dissipation at Various Ambient Temperature P24: Rth = 60 /W SOP24: Rth = 61 /W SSOP24-1.0: Rth=68 /W SSOP24: Rth = 84 /W Ambient Temperature T a - Page 8 of 14

9 Limitation on Maximum Output Current The maximum output current vs. duty cycle is estimated by: I OUT(max) =(((T j(max) -T a )/R th(j-a) )-(V DD *I DD ))/V OUT /Duty/N Where T j(max) =150, N=16(all ON) (m a x )(m A ) T U O I O V DD = 5V V OUT = 2V 16 bits active Ta = 85 O C Ta = 25 O C SOP24: Rth = 61 /W (m a x )(m A ) T U O I O V DD = 5V V OUT = 2V 16 bits active Ta = 85 O C Ta = 25 O C SSOP24: Rth = 84 /W Duty Cycle % Duty Cycle % (m a x )(m A ) T U O I O V DD = 5V V OUT = 2V 16 bits active Ta = 85 O C Ta = 25 O C SSOP24-1.0: Rth = 68 /W (m a x )(m A ) T U O I O V DD = 5V V OUT = 2V 16 bits active Ta = 85 O C Ta = 25 O C P24: Rth = 60 /W Duty Cycle % Duty Cycle % Over Temperature Shutdown The contains thermal shutdown scheme to prevent damage from over heat. The internal thermal sensor turns off all outputs when the die temperature exceeds approximately The outputs are enabled again when the die temperature drops below approximately Typical Application Circuits Dynamic Lighting VLED POWER MOSFET ARRAY which is not needed in Static SCAN OUT0 OUT14 OUT1 OUT15 C.U. Page 9 of 14

10 PCB Design Considerations Use the following general guide-line when designing printed circuit boards (PCB) : Decoupling Capacitor Place a decoupling capacitor e.g. 0.1uF between and pins of. Locate the capacitor as close to the as possible. This is normally adequate for static LED driving. For dynamic scan or PWM applications, it is necessary to add an additional capacitor of 4.7uF or more to each supply for every. The necessary capacitance depends on the LED load current, PWM switching frequency, and serial-in data speed. Inadequate decoupling can cause timing problems, and very noisy LED supplies can affect LED current regulation. VLED 22Ω IDD 0.1uF/4.7uF External Resistor () Locate the external resistor as close to the pin as possible to avoid the noise influence. Power and Ground Maximizing the width and minimizing the length of and trace improve efficiency and ground bouncing by effect of reducing both power and ground parasitic resistance and inductance. A small value of resistor e.g. 22Ω series in power input pin of in conjunction with decoupling capacitor shunting the ICs is recommended. Separating and feeding the LED power from another supply terminal VLED is strongly recommended as well to get stable supply voltage at pins of. VLED 20mA 320mA 6.4A 320mA 20mA 320mA 3.2A 320mA LED Driver Board 1 (10 s) LED Driver Board 2 (10 s) Page 10 of 14

11 Package Dimension SOP24 SYMBOL DIMENSION (mm) DIMENSION (mil) MIN NOM MAX MIN NOM MAX A A b b c c D E e 1.27 BSC 50 BSC H h L Y θ Page 11 of 14

12 SSOP24 SYMBOL DIMENSION (mm) DIMENSION (mil) MIN NOM MAX MIN NOM MAX A A A b b c c D E E e BSC 25 BSC h L L ZD REF 33 REF Y θ Page 12 of 14

13 SSOP SYMBOL DIMENSION (mm) DIMENSION (mil) MIN NOM MAX MIN NOM MAX A A A A b b c c D E E e 1.00 BSC 39 BSC L L BSC 37 BSC θ Page 13 of 14

14 P24 SYMBOL DIMENSION (mm) DIMENSION (mil) MIN NOM MAX MIN NOM MAX A A A A b b B BSC 39 BSC c c D E e BSC 70 BSC ea 7.62 BSC 300 BSC eb ec L Revision History Data Sheet Version V02_01 Remark Upgrade spec. Information provided by StarChips Technology is believed to be accurate and reliable. Application circuits shown, if any, are typical examples illustrating the operation of the devices. Starchips can not assume responsibility and any problem raising out of the use of the circuits. Starchips reserves the right to change product specification without prior notice. StarChips Technology, Inc. 4F, No.5, Technology Rd., Science-Based Industrial Park, Hsin-Chu, Taiwan, R.O.C. Tel: # 555 Page 14 of 14