EVALUATION KIT AVAILABLE MAX16838 Integrated, 2-Channel, High-Brightness LED Driver with High-Voltage Boost and SEPIC Controller General Description Features S Integrated, 2-Channel, 20mA to 150mA Linear LED The MAX16838 is a dual-channel LED driver that inte- Current Sinks grates both the DC-DC switching boost regulator and S Boost or SEPIC Power Topologies for Maximum two 150mA current sinks. A current-mode switching Flexibility DC-DC controller provides the necessary voltage to S Adaptive Voltage Optimization to Minimize Power both strings of HB LEDs. The MAX16838 accepts a wide Dissipation in Linear Current Sinks 4.75V to 40V input voltage range and directly withstands S 4.75V to 40V or 5V 10% Input Operating Voltage automotive load-dump events. For a 5V Q10% input volt- Range age, connect V to V . The wide input range allows IN CC S 5000:1 PWM Dimming at 200Hz powering HB LEDs for small-to-medium-sized LCD dis- S Open-Drain Fault Indicator Output plays in automotive and display backlight applications. S LED Open/Short Detection and Protection An internal current-mode switching DC-DC controller S Output Overvoltage and Overtemperature supports the boost or SEPIC topologies and operates Protection in an adjustable frequency range between 200kHz and S Programmable LED Current Foldback at Lower Input Voltages 2MHz. The current-mode control provides fast response and simplifies loop compensation. The MAX16838 also S 200kHz to 2MHz Resistor Programmable Switching Frequency with External features an adaptive output-voltage adjustment scheme Synchronization that minimizes the power dissipation in the LED current S Current-Mode Control Switching Stage with sink paths. The MAX16838 can be combined with the Internal Slope Compensation MAX15054 to achieve a buck-boost LED driver with two S Enable Input integrated current sinks. S Thermally Enhanced, 20-Pin TQFN (4mm x 4mm) The channel current is adjustable from 20mA to 150mA and 20-Pin TSSOP Packages using an external resistor. The external resistor sets both Ordering Information channel currents to the same value. The device allows connecting both strings in parallel to achieve a maximum PART TEMP RANGE PIN-PACKAGE current of 300mA in a single channel. The MAX16838 MAX16838ATP+ -40NC to +125NC 20 TQFN-EP* also features pulsed dimming control with minimum MAX16838ATP/V+ -40NC to +125NC 20 TQFN-EP* pulse widths as low as 1Fs, on both channels through a MAX16838AUP+ -40NC to +125NC 20 TSSOP-EP* logic input (DIM). MAX16838AUP/V+ -40NC to +125NC 20 TSSOP-EP* The MAX16838 includes an output overvoltage protec- +Denotes a lead(Pb)-free/RoHS-compliant package. tion, open LED, shorted LED detection and overtempera- *EP = Exposed pad. ture protection. The device operates over the -40NC to /V denotes an automotive qualified part. +125NC automotive temperature range. The MAX16838 is available in the 20-pin TSSOP and 4mm x 4mm, 20-pin Simplified Schematic TQFN packages. 4.75V TO 40V LD Applications C IN COUT R2 OV Automotive Display Backlights LED LCD Display Backlights IN DRAIN OV STRINGS R1OV EN NDRV Automotive Lighting Applications CFB GATE VCC OUT1 DRV OUT2 R ISET MAX16838 ISET FLT DIM CS COMP RT C R COMP COMP SGND PGND LEDGND RRT RCS Typical Operating Circuit and Pin Configurations appear at end of data sheet. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-4972 Rev 4 3/16MAX16838 Integrated, 2-Channel, High-Brightness LED Driver with High-Voltage Boost and SEPIC Controller ABSOLUTE MAXIMUM RATINGS IN, OUT , DRAIN to SGND ...................................-0.3V to +45V OUT Continuous Current ................................................175mA EN to SGND ...............................................-0.3V to (V + 0.3V) V Short-Circuit Duration .....................................Continuous IN DRV PGND to SGND ....................................................-0.3V to +0.3V Continuous Power Dissipation (T = +70NC) A LEDGND to SGND ...............................................-0.3V to +0.3V 20-Pin TQFN (derate 25.6mW/NC above +70NC) ............2051mW DRV to PGND ..........-0.3V to the lower of (V + 0.3V) and +6V 20-Pin TSSOP (derate 26.5mW/NC above +70NC) ......2122mW IN GATE to PGND ........................................................-0.3V to +6V Operating Temperature Range ........................ -40NC to +125NC NDRV to PGND .......................................-0.3V to (V + 0.3V) Junction Temperature .....................................................+150NC DRV Storage Temperature Range ............................ -65NC to +150NC V , FLT, DIM, CS, OV, CFB, to SGND .................-0.3V to +6V CC Soldering Temperature (reflow) ......................................+260NC RT, COMP, ISET to SGND .........................-0.3V to (V + 0.3V) CC DRAIN and CS Continuous Current ..................................Q2.5A 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) 20 TQFN 20 TSSOP Juction-to-Ambient Thermal Resistance (B ) .......... +39NC/W Junction-to-Ambient Thermal Resistance (B ) ..... +37.7NC/W JA JA Junction-to-Case Thermal Resistance (B ) ............... +6NC/W Junction-to-Case Thermal Resistance (B ) ............... +2NC/W JC JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (V = V = 12V, R = 12.2kI, R = 15kI, C = 1FF, V = V = V DRAIN, COMP, OUT , FLT = unconnected, V IN EN RT ISET VCC CC DRV CFB, OV = V = V = V = V = V = 0V, V = V , T = T = -40NC to +125NC, unless otherwise noted. Typical CS LEDGND DIM PGND SGND GATE NDRV A J values are at T = 25NC.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage Range V Internal LDO on 4.75 40 V IN Input Voltage Range V V = V 4.55 5.5 V IN IN CC Quiescent Supply Current I V = 5V 3.1 5 mA Q DIM Standby Supply Current I V = SGND (Note 3) 15.5 40 FA SH EN Undervoltage Lockout UVLO V rising, V = 5V 4 4.3 4.55 V IN IN DIM Undervoltage Lockout Hysteresis 177 mV DRV REGULATOR 5.75V < V < 10V, 0.1mA < I < 30mA IN LOAD Output Voltage V 4.75 5 5.25 V DRV 6.5V < V < 40V, 0.1mA < I < 3mA IN LOAD V DO Dropout Voltage V = 4.75V, I = 30mA 0.11 0.5 V IN OUT (V - V ) IN DRV Short-Circuit Current Limit DRV shorted to GND 97 mA V Undervoltage Lockout CC UVLO V rising 3.4 4.0 4.4 V VCC CC Threshold V (UVLO) Hysteresis 123 mV CC 2 Maxim Integrated