MAX6970 19-3890 Rev 0 10/05 8-Port, 36V Constant-Current LED Driver General Description Features The MAX6970 serial-interfaced LED driver provides 25Mbps Industry-Standard 4-Wire Serial Interface eight open-drain, constant-current-sinking LED driver at 5V outputs rated at 36V. The device operates from a 3V to 3V to 5.5V Logic Supply 5.5V supply. The MAX6970 supply and the LEDs sup- ply can power up in any order. The constant-current Eight Constant-Current LED Outputs Rated at 36V outputs are programmed together up to 55mA using a Up to 55mA Continuous Current per Output single external resistor. The MAX6970 operates with a 25Mbps, industry-standard, 4-wire serial interface. Output Current Programmed by Single Resistor The MAX6970 uses the industry-standard shift-register- 3% Current Matching Between Outputs plus-latch-type serial interface. The driver accepts data shifted into an 8-bit shift register using data input DIN 6% Current Matching Between ICs and clock input CLK. Input data appears at output -40C to +125C Temperature Range DOUT eight clock cycles later to allow cascading of multiple MAX6970s. The latch-enable input, LE, loads the 8 bits of shift register data into an 8-bit output latch to set which LEDs are on and which are off. The output- enable input, OE, gates all eight outputs on and off, and is fast enough to be used as a PWM input for LED Ordering Information intensity control. PIN- PKG For applications requiring LED fault detection, refer to PART TEMP RANGE PACKAGE CODE the MAX6981 data sheet that automatically detects MAX6970AUE -40C to +125C 16 TSSOP-EP* U16E-3 open-circuit LEDs. MAX6970AAE -40C to +125C 16 SSOP P16-1 For safety-related applications requiring a watchdog timer, refer to the MAX6980 data sheet, which includes *EP = Exposed pad. a fail-safe feature that blanks the display if the serial interface becomes inactive for more than 1s. The MAX6970 is one of a family of 10 shift-register-plus- latch-type LED drivers. The family includes 8-port and Typical Application Circuit and Selector Guide appear at 16-port types, with 5.5V- or 36V-rated LED outputs, with end of data sheet. and without open-circuit LED detection and watchdog. All versions operate from a 3V to 5.5V supply, and are Pin Configuration specified over the -40C to +125C temperature range. TOP VIEW Applications GND Variable Message Signs 1 16 V+ Marquee Displays DIN 2 15 SET CLK 3 14 DOUT Point-of-Order Signs LE 4 13 OE Traffic Signs MAX6970 OUT0 5 12 OUT7 Gaming Features OUT1 6 11 OUT6 Architectural Lighting OUT2 7 10 OUT5 OUT3 9 OUT4 8 TSSOP/SSOP Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE8-Port, 36V Constant-Current LED Driver ABSOLUTE MAXIMUM RATINGS (Voltage with respect to GND.) Continuous Power Dissipation (T = +70C) A V+ ............................................................................-0.3V to +6V 16-Pin TSSOP-EP OUT .....................................................................-0.3V to +40V (derate 21.3mW/C above +70C)..............................1702mW DIN, CLK, LE, OE, SET ................................-0.3V to (V+ + 0.3V) 16-Pin SSOP (derate 7.1mW/C above +70C) ............571mW DOUT Current ..................................................................10mA Operating Temperature Range .........................-40C to +125C OUT Sink Current .............................................................60mA Junction Temperature......................................................+150C Total GND Current ...........................................................480mA Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C 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 specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (Typical Operating Circuit, V+ = 3V to 5.5V, T = T to T , unless otherwise noted. Typical values are at V+ = 5V, T = +25C.) A MIN MAX A (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Operating Supply Voltage V+ 3.0 5.5 V Output Voltage V 36 V OUT Standby Current All logic inputs at V+ or GND, DOUT (Interface Idle, All Output Ports I+ 3.6 5.6 mA unloaded High Impedance, R = 360) SET Standby Current (Interface Running, All Output f = 5MHz, OE = V+, DIN and LE = V+ CLK I+ 3.8 6 mA Ports High Impedance, or GND, DOUT unloaded R = 360) SET Supply Current All logic inputs at V+ or GND, (Interface Idle, All Output Ports I+ 17 30 mA DOUT unloaded Active Low, R = 360) SET Input High Voltage V 0.7 x V+ V IH DIN, CLK, LE, OE Input Low Voltage V 0.3 x V+ V IL DIN, CLK, LE, OE Hysteresis Voltage V 0.8 V I DIN, CLK, LE, OE Input Leakage Current I , I -1 +1 A IH IL DIN, CLK, LE, OE Pullup Resistor to V+, OE R V+ = 5.5V 0.170 3 10.000 M OE Pullup Resistor to GND, LE R V+ = 5.5V 0.170 3 10.000 M LE Output High Voltage DOUT V I = 4mA V+ - 0.5V V OH SOURCE Output Low Voltage V I = 4mA 0.5 V OL SINK V+ = 3.0V to 5.5V, V = 0.8V to 2.5V, OUT Output Current OUT I 36 50 60 mA OUT R = 360 SET Output Leakage Current OUT I OE = V+ 1 A LEAK 2 MAX6970