EVALUATION KIT AVAILABLE MAX17497A/MAX17497B AC-DC and DC-DC Peak Current-Mode Converters with Integrated Step-Down Regulator General Description Benefits and Features The MAX17497A/MAX17497B include both a current- S Reduced Component Count and Board Space mode fixed-frequency flyback converter and a synchro- Flyback/Boost with Integrated Internally nous step-down regulator. They contain all the control Compensated Step-Down Regulator circuitry required to design wide input-voltage noniso- No Current-Sense Resistor lated power supplies to supply multiple output rails for Space-Saving 16-Pin (3mm x 3mm) TQFN smart meters, industrial control, and other similar applica- Package tions. The MAX17497A has its rising/falling undervoltage S Minimal Radio Interference lockout (UVLO) thresholds optimized for universal offline 250kHz Switching in Offline Version (85V AC to 265V AC) applications, while the MAX17497B Minimizes Interference with Radio Receivers supports undervoltage lockout (UVLO) thresholds suit- in Smart Meter Applications able to low-voltage DC-DC applications. Both devices S Reduced Inrush Current also include a 3.3V fixed-output synchronous step-down Programmable Flyback/Boost Soft-Start regulator that delivers up to 600mA load current. Internal Digital Soft-Start for Step-Down The switching frequency of the MAX17497A flyback Regulator converter is 250kHz, while the MAX17497B flyback/ S Reduced Power Dissipation Under Fault boost converter is 500kHz. The internally compensated Hiccup Mode Overcurrent Protection synchronous step-down regulator switches at 1MHz on Thermal Shutdown with Hysteresis both versions. These frequencies allow the use of tiny magnetic and filter components resulting in compact, S Robust Protection Features cost-effective power supplies. An EN/UVLO input allows Flyback/Boost Programmable Current Limit the user to start the power supply precisely at the desired Input Overvoltage Protection input voltage, while also functioning as an on/off pin. The S Optimized Loop Performance OVI pin enables implementation of an input overvoltage- Programmable Slope Compensation for protection scheme that ensures the converter shuts Flyback/Boost Maximizes Obtainable Phase down when the DC input voltage exceeds the desired Margin maximum value. S High Efficiency Programmable current limit allows proper sizing and Low R , 150mI, 65V-Rated Internal DSON protection of the primary switching FET. The devices nMOSFET support a maximum duty cycle greater than 92% and 3.3V Step-Down Regulator Efficiency Greater provides programmable slope compensation to allow Than 90% optimization of control-loop performance. The devices S Optional Spread Spectrum provide an open-drain RESETN pin that serves as a power-good indicator and enters the high-impedance Applications state to indicate that the flyback/boost converter and 3.3V step-down regulator outputs are in regulation. An AC-DC Power Supplies for Smart Meter SSF pin allows programmable soft-start time for the fly- Applications back/boost converter, while an internal digital soft-start is Universal-Input Offline AC-DC Power Supplies employed for the 3.3V step-down regulator to limit inrush Wide-Range DC Input Flyback/Boost Industrial current. Hiccup mode overcurrent protection and thermal Power Supplies shutdown are provided to minimize dissipation under overcurrent and overtemperature fault conditions. The devices are available in a space-saving 16-pin (3mm x 3mm) TQFN package with 0.5mm lead spacing. Ordering Information appears at end of data sheet. For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX17497A.related. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-5981 Rev 3 4/13MAX17497A/MAX17497B AC-DC and DC-DC Peak Current-Mode Converters with Integrated Step-Down Regulator ABSOLUTE MAXIMUM RATINGS IN to SGND ............................................................-0.3V to +40V RESETN to SGND ....................................................-0.3V to +6V EN/UVLO to SGND ....................................... -0.3V to V + 0.3V PGNDF, PGNDB to SGND ...................................-0.3V to +0.3V IN OVI to SGND ...............................................-0.3V to V + 0.3V Continuous Power Dissipation (Single-Layer Board) CC V to SGND ..........................................................-0.3V to +6V TQFN (derate 20.8mW/NC above +70NC)..................1700mW CC SSF, RLIMF, EAFN, COMPF, SCOMPF Operating Temperature Range ........................ -40NC to +125NC to SGND ............................................... -0.3V to (V + 0.3V) Storage Temperature Range ............................ -65NC to +160NC CC LXF to SGND .........................................................-0.3V to +70V Junction Temperature (continuous) ................................+150NC INB to SGND .........................................................-0.3V to +26V Lead Temperature (soldering, 10s) ................................+300NC LXB to SGND .............................................. -0.3V to V + 0.3V Soldering Temperature (reflow) ......................................+260NC INB OUTB to SGND .......................................................-0.3V to +6V 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 = +15V, V = +2V, COMPF = open, C = 1FF, C = 1FF, T = T = -40NC to +125NC, unless otherwise noted. Typical IN EN/UVLO IN VCC A J values are at T = +25NC.) (Note 1) A PARAMETER CONDITIONS MIN TYP MAX UNITS INPUT SUPPLY (V ) IN MAX17497A 4.5 29 IN Voltage Range (V ) V IN MAX17497B 4.5 36 IN Supply Startup Current Under I , V < UVLO or EN/UVLO = SGND 22 36 FA INSTARTUP IN UVLO IN Supply Current (I ) Switching, f = 250kHz 2.75 4.5 mA IN SW MAX17497A 19 20.5 22 IN Boostrap UVLO Rising V Threshold MAX17497B 3.85 4.15 4.4 IN Bootstrap UVLO Falling 3.65 3.95 4.25 V Rising 1.18 1.23 1.28 EN/UVLO Threshold V Falling 1.11 1.17 1.21 EN/UVLO Input Leakage Current 0V < V < 1.5V, T = +25NC -100 0 +100 nA EN/UVLO A LDO V Output Voltage Range 6V < V < 29V, 0mA < I < 50mA 4.8 5 5.2 V CC IN VCC V Dropout Voltage V = 4.5V, I = 20mA 160 300 mV CC IN VCC V Current Limit V = 0V, V = 6V 50 100 mA CC CC IN OVERVOLTAGE PROTECTION Rising 1.18 1.23 1.28 OVI Threshold V Falling 1.11 1.17 1.21 OVI Masking Delay 2 Fs OVI Input Leakage Current 0V < V < 1.5V, T = +25NC -100 0 +100 nA OVI A Maxim Integrated 2