CAT4008 8-Channel Constant Current LED Driver Description The CAT4008 is an 8 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs. A high−speed 4−wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration. A serial output data pin (SOUT) allows multiple devices to be cascaded and programmed via one serial interface. The device also includes a blanking control pin (BLANK) that can be used to disable all channels independently of the interface. Thermal shutdown protection is incorporated in the device to disable the LED outputs if the die temperature exceeds a set limit. The device is available in the TSSOP package. Features • • • • • • • • • 8 Constant Current−sink Channels Serial Interface up to 25 MHz Clock Frequency 3 V to 5.5 V Logic Supply LED Current Range from 2 mA to 100 mA LED Current set by External RSET Resistor 300 mV LED Dropout at 30 mA Thermal Shutdown Protection Available in 16−lead SOIC (150 and 300 mil wide), and TSSOP Packages These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant Applications • • • • July, 2015 − Rev. 3 MARKING DIAGRAM 1 AB 4008YZZ 3YMXXX TSSOP−16 Y SUFFIX CASE 948AN CAT4008Y−T2 A = Assembly Location 3 = Lead Finish − Matte−Tin B = Product Revision (Fixed as “B”) 4008Y = Device Code Z or ZZ = Leave Blank Y = Production Year (Last Digit) M = Production Month (1-9, A, B, C) XXX or XXXX = Last Three of Four Digits of XXX or XXXX = Assembly Lot Number PIN CONNECTIONS 1 GND SIN SCLK XLAT LED1 LED2 LED3 LED4 VDD RSET SOUT BLANK LED8 LED7 LED6 LED5 16−Lead TSSOP (Y) (Top View) Billboard Display Marquee Display Instrument Display General Purpose Display © Semiconductor Components Industries, LLC, 2015 www.onsemi.com ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 11 of this data sheet. 1 Publication Order Number: CAT4008/D CAT4008 VIN 3 V to 5.5 V 1 mF 20 mA CONTROLLER VDD LED1 LED2 LED8 BLANK LATCH CAT4008 SOUT to next device SIN RSET CLK GND 3.09 kW Figure 1. Typical Application Circuit Table 1. ABSOLUTE MAXIMUM RATINGS Parameter Rating Units 6 V −0.3 V to VDD+0.3 V V 6 V 150 mA Storage Temperature Range −55 to +160 _C Junction Temperature Range −40 to +150 _C 300 _C VDD Supply Voltage Logic input/output voltage (SIN, SOUT, CLK, BLANK, LATCH) LEDn voltage DC output current on LED1 to LED8 Lead Soldering Temperature (10 sec.) Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. Table 2. RECOMMENDED OPERATING CONDITIONS Range Units VDD Parameter 3.0 to 5.5 V Voltage applied to LED1 to LED8 0.4 to 5.5 V LED current RSET control range up to 100 mA Ambient Temperature Range −40 to +85 _C www.onsemi.com 2 CAT4008 Table 3. ELECTRICAL OPERATING CHARACTERISTICS (VDD = 5.0 V, TAMB = 25°C, over recommended operating conditions unless specified otherwise.) Symbol Name Conditions Min Typ Max Units LED Current (any channel) VLED = 1 V, RSET = 3.08 kW 18 20 22 mA VLED = 1 V, RSET = 1.54 kW 36 40 44 DC CHARACTERISTICS ILED−ACC ILED−MAT LED Current Matching (ILED − ILEDAVR) / ILEDAVR VLED = 1 V, RSET = 769 W 80 VLED = 1 V, RSET = 3.08 kW ±1.5 VLED = 1 V, RSET = 1.54 kW −6.0 ±1.5 VLED = 1 V, RSET = 769 W ±2.0 % +6.0 ΔIVDD LED current regulation vs. VDD VDD within 4.5 V and 5.5 V LED current 30 mA ±0.1 %/V ΔIVLED LED current regulation vs. VLED VLED within 1 V and 3 V LED current 30 mA ±0.05 %/V IDDOFF Supply Current (all outputs off) RSET = 3.08 kW 2 RSET = 769 W 5.5 2.5 8 mA 9 mA 1 mA IDDON Supply Current (all outputs on) RSET = 3.08 kW ILKG LEDn output Leakage VLED = 5 V, outputs off RLATCH LATCH Pull−down Resistance 100 180 300 kW RBLANK BLANK Pull−up Resistance 100 180 300 kW VIH VIL Logic high input voltage Logic low input voltage 0.7xVDD VHYS Logic input hysteresis voltage IIL Logic Input leakage current (CLK, SIN) VI = VDD or GND −5 VOH VOL SOUT logic high output voltage SOUT logic low output voltage IOH = −1 mA IOL = 1 mA VCC−0.3 V VRSET RSET Regulated Voltage BLANK high, outputs off 1.17 TSD Thermal Shutdown 160 °C THYST Thermal Hysteresis 20 °C RSET = 769 W 6.2 −1 V 0.3xVDD 0.1xVDD www.onsemi.com 3 0 V 5 mA V 0.3 1.20 1.23 V CAT4008 Table 4. TIMING CHARACTERISTICS (For 3.0 V ≤ VDD ≤ 5.5 V, TAMB = 25°C, unless specified otherwise.) Name Symbol Min (Note 1) Conditions Typ (Note 2) Max (Note 1) Units 25 MHz CLK fclk CLK Clock Frequency tcwh CLK Pulse Width High 20 ns tcwl CLK Pulse Width Low 20 ns tssu Setup time SIN to CLK 4 ns tsh Hold time SIN to CLK 4 ns tlwh LATCH Pulse width 20 ns Tlh Hold time LATCH to CLK 4 ns Tlsu Setup time LATCH to CLK Channel Stagger Delay 400 ns tld LED1 Propagation delay LATCH to LED1 off/on 40 300 ns tls LED Propagation delay stagger LED(n) to LED(n+1) 17 40 ns tlst LED Propagation delay stagger total LED1 to LED8 120 tbd BLANK Propagation delay BLANK to LED(n) off/on 60 300 ns tlr LED rise time (10% to 90%) Pull−up resistor = 50 W to 3.0 V 40 200 ns tlf LED fall time (90% to 10%) Pull−up resistor = 50 W to 3.0 V 30 250 ns tor SOUT rise time (10% to 90%) CL = 15 pF 5 ns tof SOUT fall time (90% to 10%) CL = 15 pF 5 ns tod Propagation delay time SOUT CLK to SOUT SIN LATCH LEDn ns SOUT 8 15 1. All min and max values are guaranteed by design. 2. VDD = 5 V, LED current 30 mA. 1 mF VDD VDD Rp 50 W Rp 50 W CONTROLLER LED1 BLANK LATCH CAT4008 LED8 SIN V1 CLK SOUT RSET GND Cl 15 pF RSET Figure 2. Test Circuit for AC Characteristics www.onsemi.com 4 3V 25 ns CAT4008 1/fclk CLK tssu tsh tcwl tcwh SIN tod SOUT tlh tlsu LATCH tlwh Figure 3. Serial Input Timing Diagram tld LATCH tbd BLANK tls LED1 LED2 tlst = 7 tls LED8 Figure 4. LED Output Timing Diagram www.onsemi.com 5 CAT4008 TYPICAL PERFORMANCE CHARACTERISTICS 70 4.0 60 3.5 SUPPLY CURRENT (mA) LED CURRENT (mA) (VDD = 5.0 V, LED current 30 mA, all LEDs On, TAMB = 25°C unless otherwise specified.) 50 40 30 20 10 0 0.3 0.6 0.9 1.2 ALL LED’s OFF 2.0 1.5 1.5 3.0 3.5 4.0 4.5 5.0 5.5 LED PIN (V) VDD (V) Figure 5. LED Current vs. LED Pin Voltage Figure 6. Supply Current vs. VDD Pin Voltage 31.5 8 7 SUPPLY CURRENT (mA) 31.0 LED CURRENT (mA) 2.5 1.0 0 30.5 30.0 29.5 29.0 6 5 ALL LED’s ON 4 3 ALL LED’s OFF 2 1 0 28.5 3.0 3.5 4.0 4.5 5.0 0 5.5 0.5 1.0 1.5 VDD (V) RSET CURRENT (mA) Figure 7. LED Current vs. VDD Pin Voltage Figure 8. Supply Current vs. RSET Current 2.0 100 1.30 80 LED CURRENT (mA) 1.25 RSET PIN (V) ALL LED’s ON 3.0 1.20 1.15 60 40 20 1.10 0 3.0 3.5 4.0 4.5 5.0 5.5 0.1 1 10 VDD (V) RSET (kW) Figure 9. RSET Voltage vs. VDD Pin Voltage Figure 10. LED Current vs. RSET Resistor www.onsemi.com 6 100 CAT4008 TYPICAL PERFORMANCE CHARACTERISTICS (VDD = 5.0 V, LED current 30 mA, all LEDs On, TAMB = 25°C unless otherwise specified.) 1.30 31.5 31.0 LED CURRENT (mA) RSET PIN (V) 1.25 1.20 1.15 30.5 30.0 29.5 29.0 0 50 100 28.5 −50 150 0 50 100 150 TEMPERATURE (°C) TEMPERATURE (°C) Figure 11. RSET Voltage vs. Temperature Figure 12. LED Current vs. Temperature 30 30 25 25 PULL−UP CURRENT (mA) PULL−DOWN CURRENT (mA) 1.10 −50 20 15 10 5 0 20 15 10 5 0 0 1 2 3 4 5 0 1 2 3 4 LATCH VOLTAGE (V) BLANK VOLTAGE (V) Figure 13. Internal Pull−Down Current (LATCH Pin) Figure 14. Internal Pull−Up Current (BLANK Pin) 100 DUTY CYCLE (%) 80 60 40 20 0 0 5 10 15 20 25 30 LED CURRENT (mA) Figure 15. PWM Dimming on BLANK Pin (f = 10 kHz) Figure 16. BLANK Transient Response www.onsemi.com 7 5 CAT4008 Table 5. PIN DESCRIPTION Name Function GND Ground SIN Serial data input pin CLK Serial clock input pin LATCH LED1−LED8 Latch serial data to output registers LED channel 1 to 8 cathode terminals BLANK Enable / disable all channels SOUT Serial data output pin. RSET LED current set pin VDD Positive supply Voltage Pin Function GND is the ground reference pin for the device. This pin must be connected to the ground plane on the PCB. SIN is the serial data input. Data is loaded into the internal register on each rising edge of CLK. CLK is the serial clock input. On each rising CLK edge, data is transferred from SIN to the internal 8−bit serial shift register. LATCH is the latch data input. On the rising edge of LATCH, data is loaded from the 8−bit serial shift register into the output register latch. On the falling edge, this data is latched in the output register and isolated from the state of the serial shift register. LED1 – LED8 are the LED current sink channels. These pins are connected to the LED cathodes. The current sinks drive the LEDs with a current equal to about 51 times RSET pin current. For the LED sink to operate correctly, the voltage on the LED pin must be above 0.4 V. BLANK is the LED channel enable and disable input pin. When low, LEDs are enabled according to the output latch register content. When high, all LEDs are off, while preserving the data in the output latch register. SOUT is the serial data output of the 8−bit serial shift register. This pin is used to cascade several devices on the serial bus. The SOUT pin is then connected to the SIN input of the next device on the serial bus to cascade. RSET is the LED current setting pin. A resistor is connected between this pin and ground. Each LED channel current is set to about 51 times the current pulled out of the pin. The RSET pin voltage is regulated to 1.2 V. VDD is the positive supply pin voltage for the entire device. A small 1 mF ceramic is recommended close to pin. Current Setting Resistor Table 6 lists standard resistor values for various LED current settings. Table 6. LED CURRENT AND RSET RESISTOR VALUES LED Current [mA] RSET [kW] 10 6.19 20 3.09 30 2.05 40 1.54 60 1.02 80 0.768 www.onsemi.com 8 CAT4008 Block Diagram LED1 LED2 LED3 LED8 VDD + VIN + CURRENT SINKS Current Setting BLANK RSET 1.2 V Ref GND LATCH SIN LATCHES L1 L2 L3 L8 SHIFT REGISTER S1 S2 S3 S8 SOUT CLK Figure 17. CAT4008 Functional Block Diagram Basic Operation The CAT4008 uses 8 tightly matched current sinks to accurately regulate the LED current in each channel. The external resistor, RSET, is used to set the LED channel current to about 51 times the current in RSET. LED current ^ 51 Pull−up and pull−down resistors are internally provided to set the state of the BLANK and LATCH pins to the off−state when not externally driven. Serial Interface 1.2 R SET A high−speed serial 4−wire interface is provided to program the state of each LED on or off. The interface contains an 8−bit serial to parallel shift register (S1−S8) and an 8−bit latch (L1−L8). Programming the serial to parallel register is accomplished via SIN and CLK input pins. On each rising edge of the CLK signal, the data from SIN is moved through the shift register serially. Data is also moved out of SOUT which can be connected to a next device if programming more than one device on the same interface. On the rising edge of LATCH, the data contents of the serial to parallel shift register is reflected in the latches. On the falling edge of LATCH, the state of the serial to parallel register at that particular time is saved in the latches and does not change irrespective of the contents of the serial to parallel register. BLANK is used to disable all LEDs (turn off) simultaneously while maintaining the same data in the latch register. When low, the LED outputs reflect the data in the latches. When high, all outputs are high impedance (zero current). Tight current regulation for all channels is possible over a wide range of input and LED voltages due to independent current sensing circuitry on each channel. The LED channels have a maximum dropout of 0.4 V for most current and supply voltage conditions. This helps improve the heat dissipation and efficiency of the LED driver. Upon power−up, an under−voltage lockout circuit clears all latches and shift registers and sets all outputs to off. Once the under−voltage lockout threshold has been reached the device can be programmed. The driver delays the activation of each consecutive LED output channel by 17 ns (typical). Relative to LED1, LED2 is delayed by 17 ns, LED3 by 34 ns and LED8 by 120 ns typical. The delay is introduced when LATCH is activated. The delay minimizes the inrush current on the LED supply by staggering the turn on and off current spikes over a period of time and therefore allowing usage of smaller bypass capacitors. www.onsemi.com 9 CAT4008 PACKAGE DIMENSIONS TSSOP16, 4.4x5 CASE 948AN ISSUE O b SYMBOL MIN NOM 1.10 A E1 E MAX A1 0.05 0.15 A2 0.85 0.95 b 0.19 0.30 c 0.13 0.20 D 4.90 5.10 E 6.30 6.50 E1 4.30 4.50 0.65 BSC e L 1.00 REF L1 0.45 0.75 θ 0º 8º e PIN#1 IDENTIFICATION TOP VIEW D A2 A c θ1 A1 L1 SIDE VIEW END VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-153. www.onsemi.com 10 L CAT4008 Table 7. ORDERING INFORMATION Part Number Marking Package Shipping† CAT4008Y-T2 CAT4008Y TSSOP16 (Pb−Free) 2,000 / Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. ON Semiconductor and the are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. 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