EVALUATION KIT AVAILABLE MAX16840 LED Driver with Integrated MOSFET for MR16 and Other 12V AC Input Lamps General Description Features The MAX16840 is an LED driver IC for lighting applica- S Control of the Average Input Current to Achieve tions. It includes all the necessary features to design Operation with Electronic Transformers and low-component-count LED drivers for 12V AC and 24V Dimmability AC input (e.g., MR16) light bulbs. A proprietary input- S Buck, Boost, SEPIC, and Buck-Boost Topologies current control scheme allows LED lamps based on this S Integrated 0.2I (max) 48V Switching MOSFET device to be compatible with electronic transformers, S Analog Dimming and Thermal Foldback and dimmable with standard trailing-edge dimmers (where electronic transformers are present). S Output Overvoltage Protection The IC can be used in buck, boost, and buck-boost S Internal Overtemperature Protection topologies and features. It has an integrated 0.2I (max), S -40C to +125C Operating Temperature Range 48V switching MOSFET. S 3mm x 3mm, 10-Pin TDFN Package The IC uses constant-frequency average current-mode control. It senses the input current through the voltage at the FB pin, and regulates its average. An input pin Ordering Information (REFI) allows the setting of the input-current level. When the voltage at this pin is set below a certain threshold, the PART TEMP RANGE PIN-PACKAGE input current is proportional to this voltage, while when MAX16840ATB+ -40NC to +125NC 10 TDFN-EP* that voltage is beyond the threshold, the input current is +Denotes a lead(Pb)-free/RoHS-compliant package. set at a fixed, predefined level. This nonlinear behavior *EP = Exposed pad. of REFI allows its use to achieve thermal foldback, by connecting it to an NTC resistor. The IC also features an internal overvoltage protection on Typical Operating Circuit the IN pin to protect the internal switching MOSFET from damage if the LED string is open or if the voltage on the LED- LED string is too high. C2 L2 D1 LED+ The IC has a separate EXT pin that can be used to guar- antee that there is a kick-start of current at turn-on for Functional Diagrams R3 DRAIN low-input voltages for proper operation with electronic L1 BD1 REFI IN transformers. EXT drives an external npn transistor. 12V AC C1 EXT Once the UVLO threshold of 5.5V is crossed on IN, EXT MAX16840 is pulled to ground and the external npn transistor is COMP SOURCE turned off. C4 FB GND R1 The IC is available in a 3mm x 3mm, 10-pin TDFN power R2 package, and is rated over the -40NC to +125NC operat- ing temperature range. Applications MR16 and Other 12V AC or DC Input LED Lighting Applications Pin Configurations appear at end of data sheet. Functional Diagrams continued at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim integrated.com. 19-5671 Rev 3 8/11 AVAILABLEMAX16840 LED Driver with Integrated MOSFET for MR16 and Other 12V AC Input Lamps ABSOLUTE MAXIMUM RATINGS IN, DRAIN to GND ....................................................-0.3V, +52V Any Pin to Any Pin ESD Rating ............................... 2kV (HBM) EXT, COMP, REFI to GND .......................................-0.3V, +6.0V Operating Temperature Range ........................ -40NC to +125NC FB, SOURCE to GND ..............................................-0.3V, +1.5V Maximum Junction Temperature .....................................+150NC Maximum RMS Current, FB, SOURCE to GND ....................0.8A Storage Temperature Range ............................ -65NC to +150NC Maximum RMS Current Through DRAIN and SOURCE ......Q2A Lead Temperature (soldering, 10s) ................................+300NC Continuous Power Dissipation (T = +70NC) Soldering Temperature (reflow) ......................................+260NC A TDFN (derate 24.4mW/NC above +70NC) ..................1951mW PACKAGE THERMAL CHARACTERISTICS (Note 1) TDFN Junction-to-Ambient Thermal Resistance (B ) ......... 41NC/W JA Junction-to-Case Thermal Resistance (B ) ................ 9NC/W 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.maxim-ic.com/thermal-tutorial . 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 (V = 12V V = V = V = V = 0V COMP, REFI, and DRAIN = open T = T = -40NC to +125NC, unless otherwise IN EXT SOURCE FB GND A J noted. Typical values are at T = +25NC.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Operating Voltage Range V 6.5 48 V IN When MOSFET fully on 1 2 IN Supply Current I mA IN When MOSFET switching, V = 2V, COMP 1.5 3 drain to 5V through 50I Undervoltage Lockout UVLO IN rising 5 5.6 6.1 V IN UVLO Hysteresis 200 mV Overvoltage Protection on IN V IN rising 43.6 46 48 V OVP OVP Hysteresis 1.2 V Switching Frequency 270 300 330 kHz Ramp P-P Voltage 2 V T = +25NC 196 200 204 A FB Average Voltage mV 190 210 -40C P T P +125NC A Transconductance g 550 FS m No-Load Gain A 75 dB COMP Sink Current I V = 2V, V = 0.65V 150 250 350 FA SINK COMP FB COMP Source Current I V = 2V, V = 0V 70 115 160 FA SOURCE COMP FB Power Switch On-Resistance R I = 1A 0.1 0.2 I DSON DS Switch Leakage Current I V = 48V, V = 0V 25 FA LEAK DRAIN COMP DRAIN Rise Time t I = 1A 10 ns RDRAIN DS DRAIN Fall Time t I = 1A 10 ns FDRAIN DS SOURCE Limit Threshold V SOURCE connected to FB 0.66 0.72 0.78 V SOURCETH 2 Maxim Integrated