EVALUATION KIT AVAILABLE MAX16840 LED Driver with Integrated MOSFET for MR16 and Other 12V AC Input Lamps General Description Benefits and Features The MAX16840 is an LED driver IC for lighting applica- Cost-Effective Solution for MR16 and Other SSL tions. It includes all the necessary features to design low- Applications component-count LED drivers for 12V AC and 24V AC Proprietary Input Current-Control Scheme to input (e.g., MR16) light bulbs. A proprietary input-current Achieve Electronic Transformer Compatibility control scheme allows LED lamps based on this device and Dimmability to be compatible with electronic transformers, and dim- Buck, Boost, SEPIC, and Buck-Boost mable with standard trailing-edge dimmers (where elec- Topologies tronic transformers are present). Analog Dimming The IC can be used in buck, boost, and buck-boost Minimal Component Count Saves Cost and Space topologies and features. It has an integrated 0.2I (max), Integrated 0.2 (max) 48V Switching MOSFET 48V switching MOSFET. Protection Features and Wide Operating Temperature The IC uses constant-frequency average current-mode Range Improves Reliability control. It senses the input current through the voltage Thermal-Fold back Protection at the FB pin, and regulates its average. An input pin Output Overvoltage Protection (REFI) allows the setting of the input-current level. When Internal Overtemperature Protection the voltage at this pin is set below a certain threshold, the Available in a 10-Pin Thermally Enhanced TDFN input current is proportional to this voltage, while when Package that voltage is beyond the threshold, the input current is Operation Over -40C to +125C Temperature set at a fixed, predefined level. This nonlinear behavior of Range REFI allows its use to achieve thermal foldback, by con- necting it to an NTC resistor. Ordering Information PART TEMP RANGE PIN-PACKAGE The IC also features an internal overvoltage protection on the IN pin to protect the internal switching MOSFET from MAX16840ATB+ -40NC to +125NC 10 TDFN-EP* damage if the LED string is open or if the voltage on the +Denotes a lead(Pb)-free/RoHS-compliant package. LED string is too high. *EP = Exposed pad. 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 low- Typical Operating Circuit input voltages for proper operation with electronic trans- formers. EXT drives an external npn transistor. Once the UVLO threshold of 5.5V is crossed on IN, EXT is pulled LED- to ground and the external npn transistor is turned off. C2 L2 D1 LED+ The IC is available in a 3mm x 3mm, 10-pin TDFN power R3 package, and is rated over the -40NC to +125NC operat- DRAIN L1 BD1 REFI IN ing temperature range. MAX16840 12V AC C1 EXT Applications COMP SOURCE MR16 and Other 12V AC or DC Input LED C4 FB Lighting Applications GND R1 R2 19-5671 Rev 4 1/15MAX16840 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.maximintegrated.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 opera- tion 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 Maxim Integrated 2 www.maximintegrated.com