Version : A.003 Issue Date : 2007/12/12 File Name Total Pages : 20 : SP--A.003.doc 16-bit Constant Current LED Driver 新竹市科學園區展業一路 9 號 7 樓之 1 9-7F-1, Prosperity Road I, Science Based Industrial Park, Hsin-Chu, Taiwan 300, R.O.C. Tel:886-3-5645656 Fax:886-3-5645626
16-bit Constant Current LED Driver General Description is a constant-current sink driver specifically designed for LED display applications. The device incorporates shift registers, data latches, and constant current circuitry on the silicon CMOS chip. The maximum output current value of all 16 channels is adjustable by a single external resistor. Features Constant-current outputs: 3mA to 60mA adjustable by one external resistor Maximum output voltage: 17V Maximum clock frequency: 25MHz Power supply voltage: 3.3V to 5V In-rush current control Bit-to-bit skew : ± 3 % Chip-to-chip skew : ± 6 % Package and pin assignment compatible to conventional LED drivers (ST2221C, DM134/5/6) Applications Indoor/Outdoor LED Video Display LED Variable Message Signs (VMS) System Package Types PDIP24, SOP24, SOP24B, SSOP24 16-bit Constant Current LED Driver Version:A.003 Page 1
Block Diagram 16-bit Constant Current LED Driver Version:A.003 Page 2
Pin Connection GND DAI DCK LAT OUT0 OUT1 OUT2 OUT3 OUT4 1 2 3 4 5 6 7 8 9 DIP24 SOP24 SSOP24 TSSOP24 24 23 22 21 20 19 18 17 16 VDD REXT DAO EN OUT15 OUT14 OUT13 OUT12 OUT11 OUT5 OUT6 10 11 15 14 OUT10 OUT9 OUT7 12 (top view) 13 OUT8 Pin Description PIN No. PIN NAME FUNCTION DIP24/SOP24/SSOP24: 1 GND Ground terminal. DIP24/SOP24/SSOP24: 2 DAI Serial data input terminal. DIP24/SOP24/SSOP24: 3 DCK Synchronous clock input terminal for serial data transfer. Data is sampled at the rising edge of DCK. DIP24/SOP24/SSOP24: 4 LAT Input terminal of data strobe. Data on shift register goes through at the high level of LAT (level trigger). Otherwise, data is latched. DIP24/SOP24/SSOP24: 5~20 OUT0~15 Sink constant-current outputs (open-drain). DIP24/SOP24/SSOP24: 21 EN Output enable terminal: H for all outputs are turned off, L for all outputs are active. DIP24/SOP24/SSOP24: 22 DAO Serial data output terminal. DIP24/SOP24/SSOP24: 23 DIP24/SOP24/SSOP24: 24 REXT VDD External resistors connected between REXT and GND for output current value setting. Supply voltage terminal. 16-bit Constant Current LED Driver Version:A.003 Page 3
Equivalent Circuit of Inputs and Outputs 1. DCK, DAI, LAT, EN terminals 2. DAO terminals 16-bit Constant Current LED Driver Version:A.003 Page 4
Maximum Ratings *1 (Ta=25 C, Tj(max) = 150 C) CHARACTERISTIC SYMBOL RATING UNIT Supply Voltage VDD -0.3 ~ 7.0 V Input Voltage VIN -0.3 ~ VDD+0.3 V Output Current IOUT 70 ma Output Voltage VOUT -0.3 ~ 17 V Input Clock Frequency FDCK 25 MHz GND Terminal Current IGND 1500 ma Power Dissipation (4 layer PCB) Thermal Resistance PD Rth(j-a) 1.90 ( PDIP24 : Ta=25 C) 1.20 ( SOP24 : Ta=25 C) TBD( SOP24B : Ta=25 C) 1.05 ( SSOP24 : Ta=25 C) 50.0 (PDIP24 ) TBD ( SOP24B) 79.2 (SOP24 ) 90.2 (SSOP24 ) Operating Temperature Top -40 ~ 85 C Storage Temperature Tstg -55 ~ 150 C Recommended Operating Condition CHARACTERISTIC SYMBOL CONDITION MIN. TYP. MAX. UNIT Supply Voltage VDD 3.3 5.0 5.5 V Output Voltage VOUT Driver On *2 1.0 0.5VDD Output Voltage VOUT Driver Off *3 17 Output Current Input Voltage IO OUTn 5 60 IOH VOH = VDD 0.2 V +1.2 IOL VOL = 0.2 V -1.4 VIH 0.8VDD VDD VDD = 3.3 V ~ 5.5V VIL 0.0 0.2VDD Input Clock Frequency FDCK Single Chip Operation 25 MHz LAT Pulse Width tw LAT 15 DCK Pulse Width tw DCK 15 Set-up Time for DAI tsetup(d) 10 VDD = 5.0V Hold Time for DAI thold(d) 10 Set-up Time for LAT tsetup(l) 10 Hold Time for LAT thold(l) 10 W C/W V ma V ns *1 Stress beyond those listed under Maximum Ratings may cause permanent damage to the device. These are stress ratings only; it s not implied functional operation condition. Exposure to Maximum Ratings conditions for extended periods may affect device reliability and life time. *2 Notice that the power dissipation is limited to its package and ambient temperature. *3 The driver output voltage including any overshoot stress has to be compliant with the maximum voltage (17V). 16-bit Constant Current LED Driver Version:A.003 Page 5
Electrical Characteristics (VDD = 5.0 V, Ta = 25 C unless otherwise noted) CHARACTERISTIC SYMBOL CONDITION MIN. TYP. MAX. UNIT Input Voltage H Level VIH CMOS logic level 0.8VDD VDD Input Voltage L Level VIL CMOS logics2 level GND 0.2VDD V Output Leakage Current IOL VOH = 17 V ±1.0 ua Output Voltage (DAO) VOL IOL = 1.5 ma 0.2 VOH IOH= 1.4 ma VDD-0.2 V Output Current Skew (Channel-to-Channel) *1 IOL1 ±3 % VOUT = 1.0 V Rrext = 2.2KΩ Output Current Skew (Chip-to-Chip) *2 IOL2 ±6 % Output Voltage Regulation % / VOUT Rrext = 2.2KΩ VOUT = 1 V ~ 3 V ±0.1 ±0.5 % / V Supply Voltage Regulation % / VDD Rrext = 2.2 KΩ ±1 ±4 I DD(off) power on all pins are open unless VDD and GND 3 4 I DD(off) input signal is static Rrext = 2.9 KΩ all outputs turn off 5 6 Supply Current *3 I DD(on) input signal is static Rrext = 2.9 KΩ all outputs turn on 5 6 ma I DD(off) input signal is static Rrext = 1.05K Ω all outputs turn off 9 10 I DD(on) input signal is static Rrext = 1.05K Ω all outputs turn on 9 10 *1 Channel-to-channel skew is defined as the ratio between (any Iout average Iout) and average Iout, where average Iout = (Imax + Imin) / 2. *2 Chip-to-Chip skew is defined as the range into which any output current of any IC falls. *3 IO excluded. 16-bit Constant Current LED Driver Version:A.003 Page 6
Switching Characteristics (VDD = 5.0V, Ta = 25 C unless otherwise noted) CHARACTERISTIC SYMBOL CONDITION MIN. TYP. MAX. UNIT Propagation Delay EN-to-OUT0 52 LAT-to-OUT0 tplh 49 ( L to H ) DCK-to-DAO VIH = VDD 20 EN-to-OUT0 VIL = GND Propagation Delay 22 LAT-to-OUT0 tphl Rrext = 2.2KΩ 75 ( H to L ) DCK-to-DAO VL = 5.0 V 19.5 Output Current Rise Time tor CL *1 = 13 pf 33.5 Output Current Fall Time tof 6 ns Output Delay Time (OUT(n)-to-OUT(n+1)) tod 5 Switching Characteristics (VDD = 3.3V, Ta = 25 C unless otherwise noted) CHARACTERISTIC SYMBOL CONDITION MIN. TYP. MAX. UNIT Propagation Delay ( L to H ) Propagation Delay ( H to L ) EN-to-OUT0 51 LAT-to-OUT0 tplh 21.5 DCK-to-DAO VIH = VDD 12 EN-to-OUT0 VIL = GND 23 LAT-to-OUT0 tphl Rrext = 2.2KΩ 49 DCK-to-DAO VL = 5.0 V 11.5 ns Output Current Rise Time tor 35 CL *1 = 13 pf Output Current Fall Time tof 10 Output Delay Time (OUT(n)-to-OUT(n+1)) tod 10 *1 CL means the probe capacitance of oscilloscope. 16-bit Constant Current LED Driver Version:A.003 Page 7
Timing Diagram 1. DCK-DAI, DAO 2. DCK-LAT 3. LAT-OUT0 16-bit Constant Current LED Driver Version:A.003 Page 8
4. EN-OUT0 5. OUTn+1-OUTn 16-bit Constant Current LED Driver Version:A.003 Page 9
Constant-Current Output Constant-current value of each output channel is set by an external resistor connected between the REXT pin and GND. Varying the resistor value can adjust the current scale ranging from 3mA to 60mA. The reference voltage of REXT terminal (Vrext) is approximately 1.2V. The output current value is calculated roughly by the following equation: Iout(mA) 3 5 10 20 30 40 50 M 55 54.1 50 46.6 45 43.3 41.6 Output Current as a Function of Rrext value Iout(mA) 60 55 50 45 40 35 30 25 20 15 10 5 0 Iout (ma) ~ Vrext (V) Rrext (KΩ) M 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Rext (kω) Output Current as a Function of Output Voltage Iout(mA) 60 55 50 45 40 35 30 25 20 15 10 5 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 Vout(V) In order to obtain a good performance of constant-current output, a suitable output voltage is necessary. Users can get related information about the minimum output voltage above. 16-bit Constant Current LED Driver Version:A.003 Page 10
Serial Data Interface The serial-in data (DAI) will be clocked into 16 bit shift register synchronized on the rising edge of the clock (DCK). The data 1 represents the corresponding current output ON, while the data 0 stands for OFF. The data will be transferred into the 16 bit latch register when the strobe signal (LAT) is H (level trigger); otherwise, the data will be held. The trigger timing of the serial-out data (DAO) will be shifted out on synchronization to the rising edge of the clock. All outputs are turned off while enable terminal (EN) is kept at high level. And they are active when EN shifts to low. 16-bit Constant Current LED Driver Version:A.003 Page 11
Outputs Delay Large in-rush currents will occur when the system activates all the outputs at once. To reduce this effect, is designed to have a constant unit of delay (around 5ns) between outputs. The delay sequence for every output goes like this: OUT0 (no delay) OUT15 OUT1 OUT14 OUT2 OUT13 OUT3 OUT12 OUT4 OUT11 OUT5 OUT10 OUT6 OUT9 OUT7 OUT8 (the largest delay). Global Brightness Control has no built-in global brightness control feature. In order to obtain a lower resolution of global brightness control effect, two methods could be utilized. One is providing PWM signal synchronized on latch pulse to modulate the output enable terminal (EN pin). The other is to adjust the Rrext value or voltage drop across the external resistor. Please see the reference circuit below: 16-bit Constant Current LED Driver Version:A.003 Page 12
Power Dissipation The power dissipation of a semiconductor chip is limited to its package and ambient temperature, in which the device requires the maximum output current calculated for given operating conditions. The maximum allowable power consumption can be calculated by the following equation: Pd(max)(Watt) = Tj(junction temperature)(max)( C) Ta(ambient temperature)( C) Rth(junction-to-air thermal resistance)( C/Watt) The relationship between power dissipation and operating temperature can be refer to the figure below: 3 Tj(max)=150 C 2.5 PDIP24 Rth(PDIP24)=50.0 C/Watt Rth(SOP24)=79.2 C/Watt Power Dissipation Pd(W) 2 1.5 1 SOP24 SSOP24 Rth(SSOP24)=90.2 C/Watt 0.5 0 0 20 40 60 80 100 120 140 160 Ambient Temperature Ta ( ) The power consumption of IC can be determined by the following equation and should be less than the maximum allowable power dissipation: 16-bit Constant Current LED Driver Version:A.003 Page 13
Typical Application 16-bit Constant Current LED Driver Version:A.003 Page 14
Package Outline Dimension PDIP24 D 24 13 E1 E E2 1 12 L A1 A2 A SEATING PLANE b1 e b DIMENSIONS IN INCH DIMENSIONS IN MM SYMBOLS MIN. MAX. MIN. MAX. A - 0.210-5.334 A1 0.015-0.381 - A2 0.125 0.135 3.175 3.429 b 0.060TYP. 1.524TYP. b1 0.018TYP. 0.457TYP. D 1.230 1.280 31.242 32.521 E 0.300TYP. 7.620TYP. E1 0.253 0.263 6.426 6.680 E2 0.335 0.375-8.509 9.525 e 0.100TYP. 2.540TYP. L 0.115 0.150 2.921 3.810 Θ 0 15 0 15 16-bit Constant Current LED Driver Version:A.003 Page 15
Package Outline Dimension SSOP24 D 24 13 E E1 1 12 A C GAUGE PLANE A2 A b e 0.004 SEATING PLANE L L1 A1 DETAIL A DIMENSIONS IN INCH DIMENSIONS IN MM SYMBOLS MIN. MAX. MIN. MAX. A 0.053 0.069 1.346 1.753 A1 0.004 0.010 0.102 0.254 A2-0.059-1.499 b 0.008 0.012 0.203 0.305 C 0.007 0.010 0.178 0.254 D 0.337 0.344 8.560 8.738 E 0.228 0.244 5.791 6.198 E1 0.150 0.157 3.810 3.988 e 0.025TYP. 0.635TYP. L 0.016 0.050 0.406 1.270 L1 0.041TYP. 1.041TYP. Θ 0 8 0 8 16-bit Constant Current LED Driver Version:A.003 Page 16
Package Outline Dimension SOP24 E H b e D A 0.01 inch L 0.004MAX. A1 GAUGE PLANE SEATING PLANE DIMENSIONS IN INCH DIMENSIONS IN MM SYMBOLS MIN. MAX. MIN. MAX. A 0.093 0.104 2.362 2.642 A1 0.004 0.012 0.102 0.305 b 0.016TYP. 0.406TYP. D 0.599 0.614 15.215 15.596 E 0.291 0.299 7.391 7.595 e 0.050TYP. 1.270TYP. H 0.394 0.419 10.008 10.643 L 0.016 0.050 0.406 1.270 Θ 0 8 0 8 16-bit Constant Current LED Driver Version:A.003 Page 17
Package Outline Dimension SOP24B A X B B2 B1 A1 A2 A3 C3 C2 C1 D1 D 3 4 R2 R1 C4 2 1 DETAIL X DIMENSIONS IN INCH DIMENSIONS IN MM SYMBOLS MIN. MAX. MIN. MAX. A 0.508 0.516 12.9 13.1 A1 0.012 0.020 0.30 0.50 A2 0.039TYP. 1.00TYP. A3 0.031 0.80TYP. B 0.299 0.323 7.60 8.20 B1 0.232 0.240 5.90 6.10 B2 0.300TYP. 7.62TYP. C - 0.087-2.20 C1 0.067 0.075 1.70 1.90 C2 0.006 0.012 0.15 0.30 C3 0.002 0.008 0.05 0.20 C4 0.031TYP. 0.80TYP. D 0.037TYP. 0.95TYP. D1 0.013 0.029 0.33 0.73 R1 0.008TYP. 0.20TYP. R2 0.008TYP. 0.20TYP. Θ1 8 TYP 8 TYP Θ2 10 TYP 10 TYP Θ3 4 TYP 4 TYP Θ4 5 TYP 5 TYP 16-bit Constant Current LED Driver Version:A.003 Page 18
The products listed herein are designed for ordinary electronic applications, such as electrical appliances, audio-visual equipment, communications devices and so on. Hence, it is advisable that the devices should not be used in medical instruments, surgical implants, aerospace machinery, nuclear power control systems, disaster/crime-prevention equipment and the like. Misusing those products may directly or indirectly endanger human life, or cause injury and property loss. Silicon Touch Technology, Inc. will not take any responsibilities regarding the misusage of the products mentioned above. Anyone who purchases any products described herein with the above-mentioned intention or with such misused applications should accept full responsibility and indemnify. Silicon Touch Technology, Inc. and its distributors and all their officers and employees shall defend jointly and severally against any and all claims and litigation and all damages, cost and expenses associated with such intention and manipulation. 16-bit Constant Current LED Driver Version:A.003 Page 19