MAX17521
22Pages

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter General Description The MAX17521 dual-output, high-efficiency, high-voltage, synchronous step-down DC-DC converter with integrated MOSFETs operates over a 4.5V to 60V input. The converter can deliver up to 1A at each output. Each output is programmable from 0.9V to 92%VIN. The feedback voltage regulation accuracy over -40°C to +125°C is ±1.7%. ●● Reduces External Components and Total Cost • No Schottky—Synchronous Operation • All-Ceramic Capacitors, Compact Layout ●● Reduces Number of DC-DC Regulators to Stock • Wide 4.5V to 60V Input • Each Output Adjustable From 0.9V to 92%VIN • Pin-Selectable 560kHz or 300kHz Switching Frequency • Independent Input Voltage Pin for Each Output The MAX17521 uses peak-current-mode control. Each output can be operated in the pulse-width modulation (PWM) or pulse-frequency modulation (PFM) control schemes. ●● Reduces Power Dissipation • Peak Efficiency > 90% • PFM Mode Enables Enhanced Light-Load Efficiency • 1μA Shutdown Current The MAX17521 is available in a 24-pin (4mm x 5mm) TQFN package. Simulation models are available. Industrial Control Power Supplies CPU, DSP, or FPGA Power Distributed Supply Regulation General-Purpose Point of Load ●● Operates Reliably in Adverse Industrial Environments • Hiccup Mode Overload Protection • Adjustable Soft-Start Pin for Each Output • Built-In Output Voltage Monitoring with RESET for Each Output • Adjustable EN/UVLO Threshold for Each Output • Monotonic Startup Into Prebiased Load • Overtemperature Protection • High Industrial -40°C to +125°C Ambient Operating Temperature Range/-40°C to +150°C Junction Temperature Range Ordering Information appears at end of data sheet. Typical Application Circuit

Note 1: Junction temperature greater than +125°C degrades operating lifetimes. 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. Maxim Integrated

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Electrical Characteristics (continued) (VIN_ = +24V, VSGND_ = VpGND_ = Vfsel = 0V, C|N = 2.2jF, CvCC_ = 1jF, VEN/UvLo_ = 1.5V, Css_ = 0.01jF, FB_ = 0.98 x Vfb-REG, COMP_ = unconnected, LX_ = unconnected, RESET_ = unconnected. Ta = -40°C to +125°C, unless otherwise noted. Typical values are at Ta = +25°C. All voltages are referenced to SGND_, unless otherwise noted.) (Note 2)

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Electrical Characteristics (continued) (VIN_ = +24V, VSGND_ = VpGND_ = Vfsel = 0V, C|N = 2.2jF, CvCC_ = 1jF, VEN/UvLo_ = 1.5V, Css_ = 0.01jF, FB_ = 0.98 x Vfb-REG, COMP_ = unconnected, LX_ = unconnected, RESET_ = unconnected. Ta = -40°C to +125°C, unless otherwise noted. Typical values are at Ta = +25°C. All voltages are referenced to SGND_, unless otherwise noted.) (Note 2)

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Electrical Characteristics (continued) (VIN_ = +24V, VSGND_ = VpGND_ = Vfsel = 0V, C|N = 2.2jF, CvCC_ = 1jF, VEN/UvLo_ = 1.5V, Css_ = 0.01jF, FB_ = 0.98 x Vfb-REG, COMP_ = unconnected, LX_ = unconnected, RESET_ = unconnected. Ta = -40°C to +125°C, unless otherwise noted. Typical values are at Ta = +25°C. All voltages are referenced to SGND_, unless otherwise noted.) (Note 2) Note 2: Limits are 100% tested at Ta = +25°C. Limits over the operating temperature range and relevant supply voltage range are guaranteed by...

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC ConverterTypical Operating Characteristics All lata measured on the Typical Application Circuit.

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Typical Operating Characteristics (continued) All data measured on the Typical Application Circuit. STARTUP FROM EN/UVLO, 5V OUTPUT, 1A LOAD CURRENT TOC08 STARTUP FROM EN/UVLO, 3.3V OUTPUT, 1A LOAD CURRENT STARTUP FROM VIN, 5V OUTPUT, 1A LOAD CURRENT STARTUP FROM VIN, 3.3V OUTPUT, 1A LOAD CURRENT STARTUP WITH 2.5V PREBIAS, 5V OUTPUT, NO LOAD STARTUP WITH 2V PREBIAS, 3.3V OUTPUT, NO LOAD STARTUP IN RATIOMETRIC TRACKING MODE, 1A LOAD ON BOTH OUTPUTS TOC14 Maxim Integrated

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Typical Operating Characteristics (continued) All data measured on the Typical Application Circuit. 5V OUTPUT,PWM MODE, (LOAD CURRENT STEPPED FROM 0.5A—1A) STARTUP IN SEQUENTIAL TRACKING MODE, 1A LOAD ON BOTH OUTPUTS TOC16 STARTUP IN COINCIDENT TRACKING MODE, 1A LOAD ON BOTH OUTPUTS TOC15 5V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0 TO 0.5A) 5V OUTPUT, PFM MODE, (LOAD CURRENT STEPPED FROM 5mA—500mA) TOC19 3.3V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0—0.5A) 3.3V OUTPUT,PWM MODE, (LOAD CURRENT STEPPED FROM...

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Typical Operating Characteristics (continued) All data measured on the Typical Application Circuit. 3.3V OUTPUT, PFM MODE, (LOAD CURRENT STEPPED FROM 5mA—0.5A) STEADY-STATE SWITCHING WAVEFORMS, 5V OUTPUT, NO LOAD, PWM MODE STEADY-STATE SWITCHING WAVEFORMS, 5V OUTPUT, 1A LOAD TOC23 STEADY-STATE SWITCHING WAVEFORMS, 5V OUTPUT, 5mA LOAD, PFM MODE STEADY-STATE SWITCHING WAVEFORMS, 3.3V OUTPUT, 1A LOAD TOC26 STEADY-STATE SWITCHING WAVEFORMS, 3.3V OUTPUT, NO LOAD, PWM MODE STEADY-STATE SWITCHING WAVEFORMS, 3.3V OUTPUT,...

60V, 1A, Dual-Output, High-Efficiency, Synchronous Step-Down DC-DC Converter Typical Operating Characteristics (continued) All data measured on the Typical Application Circuit. OUTPUT SHORT-CIRCUIT PROTECTION, 5V OUTPUT TOC29 OUTPUT SHORT-CIRCUIT PROTECTION, 3.3V OUTPUT TOC30 5V OUTPUT, 1A LOAD, BODE PLOT 3.3V OUTPUT, 1A LOAD, BODE PLOT VOUT = 5V FCR = 51kHz, Phase Margin = 62.3° FCR = 51K, Phase Margin = 62.3° GAIN FREQUENCY(Hz)