LT3965/LT3965-1 8-Switch Matrix LED Dimmer FEATURES DESCRIPTION n Eight Independent 17V 330m NMOS Switches The LT 3965/LT3965-1 is an LED bypass switching device n Independent On/Off/Dimming Control of 1 to 4 LEDs for dimming individual LEDs in a string using a common for Each Switch current source. It features eight individually controlled 2 n I C Multidrop Serial Interface with Programmable floating source 17V/330m NMOS switches. The eight Open LED and Shorted LED Fault Reporting switches can be connected in parallel and/or in series to 2 n 16 Unique I C Addresses bypass current around one or more LEDs in a string. The n V Range: 2.7V to 5.5V and V Range: 8V to 60V LT3965 is initialized with all switches off (LEDs on), and DD IN n Digital Programmable 256:1 PWM Dimming the LT3965-1 is initialized with all switches on (LEDs off) n 2 Fade Transition Between PWM Dimming States The LT3965/LT3965-1 uses the I C serial interface to n Optional Internal Clock Generator or External Clock communicate with the microcontroller. Each of the eight Source for PWM Dimming channels can be independently programmed to bypass n Open LED Overvoltage Protection the LED string in constant on or off, or PWM dimming n Flicker Free PWM Dimming with or without fade transition. Using the fade option provides 11-bit resolution logarithmic transition between APPLICATIONS PWM dimming states. The LT3965/LT3965-1 provides n Automotive LED Headlight Clusters an internal clock generator and also supports external n Large LED Displays clock source for PWM dimming. The LT3965/LT3965-1 n Automated Camera Flash Equipment reports fault conditions for each channel such as open n RGBW Color Mixing Lighting LED and shorted LED. The four address select pins allow 2 L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog 16 LT3965/LT3965-1 devices to share the I C bus. The Devices, Inc. All other trademarks are the property of their respective owners. device is available in a 28-lead TSSOP package TYPICAL APPLICATION Matrix LED Dimmer Powered by a Buck Mode LED Driver BIAS UVLO DETECT 750 Q2 BIAS Q1 1k 49.9k M1 1k D4 + 1k LED BIAS 0.5 V + IN Q3 LED 40V 1F EN/UVLO 100V 9.09k D2 D3 V CC V V IN DRN8 DD 20k 5V V ISP ISN 0.1F IN SRC8 10k 10k 10k EN/UVLO INTV CC DRN7 0.1F SDA SDA SRC7 PWM PWMOUT 100V LT3965/ DRN6 SCL SCL 2.2nF 1F LT3965-1 SYNC SRC6 ALERT ALERT VMODE LT3955 DRN5 V FB REF 500mA SRC5 EN/UVLO EN/UVLO CTRL GND DRN4 V LED RTCLK 1F GNDK SRC4 26V 28k 50V DRN3 500Hz DIMMING FREQUENCY PGND SW SRC3 ADDR1 RT DIM/SS VC DRN2 ADDR2 28.7k L1: WURTH 744066330 0.1F 0.01F SRC2 375kHz D1: DFLS260 ADDR3 DRN1 L1 D2, D3: CMSD6263S 2 IN 1 PACKAGE D1 ADDR4 33H D4, D5: PMEG6010CEH M1: VISHAY Si7309DN SRC1 LEDREF GND IN4148 Q1, Q3: ZETEX FMMT593 28k LED D5 Q2: ZETEX FMMT493 3965 TA01 39651fa 1 For more information www.linear.com/LT3965LT3965/LT3965-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V ............................................................................60V IN 1 28 SRC8 DRN8 V -SRC 8:1 ..........................................................0.3V IN 2 27 DRN7 V IN DRN 8:1 ...................................................................60V 3 26 SRC7 EN/UVLO SRC 8:1 ....................................................................60V 4 25 DRN6 ALERT LEDREF .....................................................................60V 5 24 SRC6 SCL DRN 8:1 -SRC 8:1 (Each Channel) ................0.3V, 25V 6 23 DRN5 SDA EN/UVLO ...................................................................12V 7 22 SRC5 V DD 29 V .............................................................................6V DD GND 8 21 DRN4 RTCLK SDA, SCL, ALERT ............................ 0.3V to V + 0.3V DD 9 20 SRC4 ADDR1 RTCLK .........................................................................6V 10 19 DRN3 ADDR2 ADDR 4:1 ...................................................................6V 11 18 SRC3 ADDR3 Operating Junction Temperature Range (Note 2) 12 17 DRN2 ADDR4 LT3965E/LT3965E-1/LT3965I/LT3965I-1 40 to 125C 13 16 SRC2 LEDREF 14 15 DRN1 Storage Temperature Range .................. 65C to 150C SRC1 FE PACKAGE 28-LEAD PLASTIC TSSOP = 10C/W JC EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION