EVALUATION KIT AVAILABLE Click here for production status of specific part numbers. MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency, Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current General Description The MAX17552/MAX17552A high-efficiency, high-voltage, synchronous step-down DC-DC converters with integrated MOSFETs operate over a 4V to 60V input voltage range. The converters can deliver output current up to 100mA at output voltages of 0.8V to 0.9 x VIN. The output voltage is accurate to within 1.75% over the -40C to +125C temperature range. The devices employ a peak-current-mode control architecture with a MODE pin that can be used to operate the device in pulse-width modulation (PWM) or pulsefrequency modulation (PFM) control schemes. PWM operation provides constant frequency operation at all loads and is useful in applications sensitive to variable switching frequency. PFM operation disables negative inductor current and additionally skips pulses at light loads for high efficiency. The converters consume only 22A of no-load supply current in PFM mode. The lowresistance, on-chip MOSFETs ensure high efficiency at full load and simplify PCB layout. Benefits and Features Eliminates External Components and Reduces Total Cost * No Schottky--Synchronous Operation for High Efficiency and Reduced Cost * Internal Compensation * Fixed Internal 5.1ms or Programmable Soft-Start * All-Ceramic Capacitors, Ultra-Compact Layout Reduces Number of DC-DC Regulators to Stock * Wide 4V to 60V Input Voltage Range * Adjustable 0.8V to 0.9 x VIN Output Voltages * Delivers Up to 100mA Load Current * 100kHz to 2.2MHz Adjustable Switching Frequency Range with External Synchronization * Configurable Between PFM and Forced-PWM Modes Reduces Power Dissipation * 22A No Load Supply Current * Peak Efficiency > 90% * PFM Feature for High Light-Load Efficiency * 1.2A (typ) Shutdown Current The devices offer programmable switching frequency to optimize solution size and efficiency. Programmable softstart allows the user to reduce the inrush currents. During overload, the MAX17552 implements a hysteretic cycleby-cycle peak-current-limit protection scheme, while the MAX17552A implements a HICCUP-type overload protection scheme to protect the inductor and the internal FETs. An EN/UVLO pin allows the user to turn on/off the device at the desired input-voltage level. An open-drain RESET pin allows output-voltage monitoring. The devices operate over the -40C to +125C industrial temperature range and is available in a compact 10-pin (3mm x 2mm) TDFN and 10-pin (3mm x 3mm) MAX(R) packages. Simulation models are available. Operates Reliably in Adverse Industrial Environments * Peak Current-Limit Protection Applications Ordering Information appears at end of data sheet. Industrial Sensors and Process Control 4mA-20mA Current-Loop Powered Sensors High-Voltage LDO Replacement Battery-Powered Equipment HVAC and Building Control General-Purpose Point of Load MAX is a registered trademark of Maxim Integrated Products, Inc. 19-6903; Rev 5; 8/18 Built-In Output-Voltage Monitoring with Open-Drain RESET Pin * Programmable EN/UVLO Threshold * Monotonic Startup into Prebiased Output * Overtemperature Protection * High Industrial -40C to +125C Ambient Operating Temperature Range / -40C to +150C Junction Temperature Range MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Application Circuit--High-Efficiency 5V, 100mA Regulator VIN 6V TO 60V IN MAX17552/ LX L1 220H MAX17552A CIN 1F EN/UVLO GND SS VOUT MODE COUT 10F R4 22.1 C1 0.22F FB RT/SYNC R3 191k VOUT 5V, 100mA R1 261k R2 49.9k RESET SWITCHING FREQUENCY = 220kHz L1 COILCRAFT LPS5030-224M COUT MURATA 10F/X7R/6.3V/1206 (GRM31CR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) www.maximintegrated.com Maxim Integrated 2 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Absolute Maximum Ratings (Note 1) IN, EN/UVLO, VOUT, RESET to GND...................-0.3V to +70V LX to GND........................................................ -0.3V to IN +0.3V RT/SYNC, SS, FB, MODE to GND..........................-0.3V to +6V LX Total RMS Current.........................................................1.6A Output Short-Circuit Duration.....................................Continuous Junction Temperature.......................................................+150C Storage Temperature Range............................. -65C to +150C Lead Temperature (soldering, 10s).................................. +300C Soldering Temperature (reflow)........................................+260C 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. Note 1: Junction temperature greater than +125C degrades operating lifetimes. Package Information PACKAGE TYPE: 10 TDFN Package Code T1032N+1 Outline Number 21-0429 Land Pattern Number 90-0082 THERMAL RESISTANCE, FOUR-LAYER BOARD Continuous Power Dissipation (TA = +70C) (derate 14.9mW/C above +70C) 1188.7mW Junction to Ambient (JA) 67.3C/W Junction to Case (JC) 18.2C/W PACKAGE TYPE: 10 MAX Package Code U10+5 Outline Number 21-0061 Land Pattern Number 90-0330 THERMAL RESISTANCE, FOUR-LAYER BOARD Continuous Power Dissipation (TA = +70C) (derate 8.8mW/C above +70C) 707.3mW Junction to Ambient (JA) 113.1C/W Junction to Case (JC) 42C/W For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 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. www.maximintegrated.com Maxim Integrated 3 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Electrical Characteristics (VIN = 24V, VGND = 0V, VVOUT = 3.3V, VFB = 0.85V, VEN/UVLO = 1.5V, RT/SYNC = 191k, LX = SS = MODE = RESET = unconnected; TA = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. All voltages are referenced to GND, unless otherwise noted) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 60 V INPUT SUPPLY (IN) Input Voltage Range Input Shutdown Current Input Supply Current VIN 4 IIN-SH VEN/UVLO = 0V, TA = +25C IQ-PFM VMODE = unconnected (Note 3) IQ-PWM Normal switching mode, VIN = 24V 0.67 1.2 2.25 18 32 245 525 760 2.96 3.05 3.12 A EXTERNAL BIAS (VOUT) VOUT Switchover Threshold V ENABLE/UVLO (EN/UVLO) EN/UVLO Threshold VENR VEN/UVLO rising 1.2 1.25 1.3 VENF VEN/UVLO falling 1.1 1.15 1.2 V +100 nA VEN-TRUESD EN/UVLO Leakage Current IEN VEN/UVLO falling, true shutdown VEN/UVLO = 1.3V, TA = +25C 0.7 -100 POWER MOSFETs High-Side pMOS On-Resistance RDS-ONH ILX = 0.1A (sourcing) 1.5 2.7 5.1 Low-Side nMOS On-Resistance RDS-ONL ILX = 0.1A (sinking) 0.8 1.4 2.6 VEN = 0V, TA = +25C, VLX = (VGND + 1V) to (VIN - 1V) -1 +1 A SS = unconnected 4.4 5.1 5.8 ms 4.7 5 5.3 A MODE = GND 0.786 0.8 0.814 MODE = unconnected 0.786 0.812 0.826 VFB = 1V, TA = 25C -100 LX Leakage Current ILX-LKG SOFT-START (SS) Soft-Start Time tSS SS Charging Current ISS FEEDBACK (FB) FB Regulation Voltage FB Input Leakage Current VFB-REG IFB V +100 nA 210 235 mA 105 130 CURRENT LIMIT Peak Current-Limit Threshold IPEAK-LIMIT Negative Current-Limit Threshold ISINK-LIMIT PFM Current Level IPFM 185 VMODE = GND 79 VMODE = unconnected VMODE = unconnected 0.01 50 72 90 RRT = 422k 90 100 111 RRT = 191k 205 220 235 RRT = 130k 295 319 340 RRT = 69.8k 540 592 638 RRT = 45.3k 813 900 973 RRT = 19.1k 1.86 2.08 2.3 mA mA OSCILLATOR (RT/SYNC) Switching Frequency www.maximintegrated.com fSW kHz MHz Maxim Integrated 4 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Electrical Characteristics (continued) (VIN = 24V, VGND = 0V, VVOUT = 3.3V, VFB = 0.85V, VEN/UVLO = 1.5V, RT/SYNC = 191k, LX = SS = MODE = RESET = unconnected; TA = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. All voltages are referenced to GND, unless otherwise noted) (Note 2) PARAMETER SYMBOL Switching Frequency Adjustable Range CONDITIONS See the Switching Frequency (RT/ SYNC) section for details SYNC Input Frequency SYNC Pulse Minimum Off-Time SYNC Rising Threshold Hysteresis MIN TYP MAX UNITS 100 2200 kHz 1.1 x fSW 2200 kHz 40 ns VSYNC-H 1 1.22 1.44 VSYNC-HYS 0.115 0.18 0.265 Number of SYNC Pulses to Enable Synchronization 1 V Cycles TIMING Minimum On-Time Maximum Duty Cycle tON-MIN DMAX Hiccup Timeout 46 82 128 fSW 600kHz, VFB = 0.98 x VFB-REG 90 94 98 fSW > 600kHz, VFB = 0.98 x VFB-REG 87 92 % MAX17552A RESET ns 51 ms FB Threshold for RESET Rising VFB-OKR VFB rising 93 95 97 % FB Threshold for RESET Falling VFB-OKF VFB falling 90 92 94 % RESET Delay after FB Reaches 95% Regulation RESET Output Level Low IRESET = 1mA RESET Output Leakage Current VFB = 1.01 x VFB-REG, TA = +25C 2.1 ms 0.23 V 1 A 1.44 V MODE MODE PFM Threshold VMODE-PFM MODE Hysteresis VMODE-HYS MODE Internal Pullup Resistor 1 1.22 0.19 VMODE = unconnected (MAX17552) VMODE = unconnected (MAX17552A) V 235 123 k VMODE = GND 1390 Temperature rising 160 C 20 C THERMAL SHUTDOWN Thermal-Shutdown Threshold Thermal-Shutdown Hysteresis Note 2: Limits are 100% tested at TA = +25C. Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization. Note 3: Actual IQ-PFM in the application circuit is higher due to additional current in the output voltage feedback resistor divider. For example, IQ-PFM (MODE = unconnected) = 26A for Figure 6, 22A for Figure 7, and 78A for Figure 11. www.maximintegrated.com Maxim Integrated 5 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) EFFICIENCY vs. LOAD CURRENT (MAX17552) 100 EFFICIENCY vs. LOAD CURRENT (MAX17552A) toc2 toc1 VIN = 12V VIN = 24V VIN = 36V 50 40 30 FIGURE 6 APPLICATION CIRCUIT, PFM MODE VOUT = 5V fSW = 220kHz (RRT = 191k) 20 10 1 10 60 VIN = 36V VIN = 48V VIN = 24V 50 40 10 0 1 EFFICIENCY vs. LOAD CURRENT (MAX17552A) VIN = 48V VIN = 60V 30 FIGURE 7 APPLICATION CIRCUIT, PFM MODE VOUT = 3.3V FSW = 220kHz(RRT = 191k) 20 10 1 10 VIN = 60V 50 VIN = 36V 40 VIN = 12V toc7 60 VIN = 36V 50 VIN = 48V 40 VIN = 60V 30 20 FIGURE 6 APPLICATION CIRCUIT, PWM MODE, VOUT = 5V FSW = 220kHz (RRT = 191k) 10 0 20 40 60 LOAD CURRENT (mA) www.maximintegrated.com 60 50 40 VIN = 12V 10 FIGURE 7 APPLICATION CIRCUIT, PFM MODE, VOUT = 3.3V FSW = 600kHz (RRT = 69.8k) 20 10 0 100 1 10 80 100 90 80 80 VIN = 12V VIN = 24V 50 VIN = 36V 40 VIN = 48V 30 VIN = 60V 20 10 0 0 20 70 VIN = 24V 60 toc9 VIN = 12V VIN = 36V 50 40 VIN = 48V 30 FIGURE 6 APPLICATION CIRCUIT, PWM MODE, VOUT = 5V FSW = 220kHz (R RT = 191k) 40 EFFICIENCY VS. LOAD CURRENT (MAX17552) 100 90 70 100 LOAD CURRENT (mA) EFFICIENCY vs. LOAD CURRENT (MAX17552A) toc8 60 VIN = 36V VIN = 24V 30 1 100 VIN = 12V toc6 70 LOAD CURRENT (mA) EFFICIENCY (%) VIN = 24V 70 EFFICIENCY vs. LOAD CURRENT (MAX17552A) 100 FIGURE 6 APPLICATION CIRCUIT, PFM MODE, VOUT = 5V FSW = 600kHz (RRT = 69.8k) 10 90 80 VIN = 48V VIN = 24V 30 0 100 80 60 20 100 EFFICIENCY vs. LOAD CURRENT (MAX17552) 100 10 90 LOAD CURRENT (mA) EFFICIENCY (%) toc5 EFFICIENCY (%) VIN = 12V 1 LOAD CURRENT (mA) EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) VIN = 24V 40 0 0 70 50 VIN = 36V FIGURE 7 APPLICATION CIRCUIT, PFM MODE VOUT = 3.3V fSW = 220kHz (RRT = 191k) 10 80 VIN = 36V VIN = 24V 40 100 EFFICIENCY vs LOAD CURRENT (MAX17552A) toc4 80 60 VIN = 12V 50 20 90 70 60 LOAD CURRENT (mA) 90 0 10 70 30 FIGURE 6 APPLICATION CIRCUIT, PFM MODE VOUT = 5V fSW = 220kHz (RRT = 191k) 20 LOAD CURRENT (mA) 100 VIN = 60V VIN = 12V 30 100 EFFICIENCY (%) 60 EFFICIENCY (%) EFFICIENCY (%) 80 70 70 toc3 90 80 80 0 100 90 90 EFFICIENCY vs. LOAD CURRENT (MAX17552) 60 LOAD CURRENT (mA) 80 100 VIN = 60V FIGURE 7 APPLICATION CIRCUIT, PWM MODE, VOUT = 3 3V . FSW = 220kHz (RRT = 191k) 20 10 0 0 20 40 60 80 100 LOAD CURRENT (mA) Maxim Integrated 6 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (continued) (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) 90 70 VIN = 12V 60 VIN = 24V 50 VIN = 36V 40 VIN = 48V 30 20 0 20 90 80 80 70 VIN = 12V 60 VIN = 24V 50 VIN = 36V 40 VIN = 48V 40 60 80 10 0 100 0 20 40 EFFICIENCY VS. LOAD CURRENT (MAX17552) 80 70 70 EFFICIENCY (%) VIN = 12V VIN = 36V 40 20 0 20 40 60 60 50 VIN = 36V 80 0 100 0 20 40 VIN = 12V,24V 3.32 FIGURE 7 APPLICATION CIRCUIT, PFM MODE 20 40 60 LOAD CURRENT (mA) www.maximintegrated.com 80 5.04 100 VIN = 12V 4.941 VIN = 36V V = 48V IN VIN = 24V VIN = 60V 4.939 4.937 100 VIN = 48V VIN = 60V VIN = 12V 4.98 VIN = 24V 0 20 40 60 80 100 LOAD CURRENT (mA) FIGURE6 APPLICATION CIRCUIT, PWM MODE 4.943 80 VIN = 36V 5.01 4.92 100 OUTPUT VOLTAGE vs. LOAD CURRENT 3.330 FIGURE 7 APPLICATION CIRCUIT, PWM MODE 3.328 4.945 VIN = 60V 0 80 OUTPUT VOLTAGE vs. LOAD CURRENT 4.947 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 3.36 VIN = 48V 60 60 toc18 VIN = 36V 40 FIGURE 6 APPLICATION CIRCUIT, PFM MODE 4.95 toc17 3.38 3.28 VIN = 24V VIN = 12V LOAD CURRENT (mA) toc16 3.40 3.30 20 OUTPUT VOLTAGE vs. LOAD CURRENT 5.10 toc14 FIGURE 7 APPLICATION CIRCUIT, PWM MODE, VOUT = 3.3V FSW = 600kHz (RRT = 69.8k) 10 OUTPUT VOLTAGE vs. LOAD CURRENT 3.34 0 LOAD CURRENT (mA) 40 LOAD CURRENT (mA) 3.42 0 100 5.07 20 FIGURE 7 APPLICATION CIRCUIT, PWM MODE, VOUT = 3.3V FSW = 600kHz (RRT = 69.8k) 10 VIN = 48V VIN = 60V FIGURE 6 APPLICATION CIRCUIT, PWM MODE, VOUT = 5V FSW = 600kHz (RRT = 69.8k) 10 30 30 0 80 VIN = 12V VIN = 36V 40 20 OUTPUT VOLTAGE (V) EFFICIENCY (%) 80 50 60 EFFICIENCY VS. LOAD CURRENT (MAX17552A) 100 90 VIN = 24V VIN = 24V 50 toc12 toc15 toc13 90 60 60 LOAD CURRENT (mA) LOAD CURRENT (mA) 100 70 30 VIN = 60V FIGURE 6 APPLICATION CIRCUIT, PWM MODE, VOUT = 5V FSW = 600kHz (RRT = 69.8k) 20 EFFICIENCY vs. LOAD CURRENT (MAX17552A) 100 90 30 FIGURE 7 APPLICATION CIRCUIT, PWM MODE, VOUT = 3.3V FSW = 220kHz (RRT = 191k) VIN = 60V 10 0 EFFICIENCY (%) EFFICIENCY (%) 80 toc11 OUTPUT VOLTAGE (V) 100 EFFICIENCY vs. LOAD CURRENT (MAX17552) 100 toc10 EFFICIENCY (%) EFFICIENCY VS. LOAD CURRENT (MAX17552A) 3.326 3.324 VIN = 12V 3.322 VIN = 24V VIN = 36V VIN = 48V VIN = 60V 3.320 3.318 0 20 40 60 LOAD CURRENT (mA) 80 100 3.316 0 20 40 60 80 100 LOAD CURRENT (mA) Maxim Integrated 7 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (continued) (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) OUTPUT VOLTAGE vs. LOAD CURRENT VVININ=24V = 24V VVININ=36V = 36V 4.94 4.90 VIN = 48V VIN = 60V 0 20 40 4.958 3.36 VIN = 12V 3.32 VIN = 24V 3.24 60 80 100 FIGURE 9 APPLICATION CIRCUIT, PFM MODE 0 20 40 LOAD CURRENT (mA) 60 80 3.323 60 80 toc23 0.79 0.78 100 toc25 -40 -20 0 5 15 25 35 45 INPUT VOLTAGE (V) www.maximintegrated.com 0 20 55 40 60 80 100 NO LOAD SUPPLY CURRENT vs. INPUT VOLTAGE toc24 100 40 60 80 80 60 40 20 0 100 120 1.4 1.1 0.8 -40 -20 0 20 40 60 TEMPERATURE (C) 15 25 35 45 55 80 100 120 SWITCH CURRENT LIMIT vs. INPUT VOLTAGE 250 toc26 1.7 0.5 5 INPUT VOLTAGE (V) SWITCH CURRENT LIMIT (mA) SHUTDOWN CURRENT (A) SHUTDOWN CURRENT (A) -0.5 -2.0 20 SHUTDOWN CURRENT vs. TEMPERATURE 2.0 4.0 1.0 VIN = 60V 4.951 TEMPERATURE (C) 2.5 VIN = 48V LOAD CURRENT (mA) 0.80 LOAD CURRENT (mA) SHUTDOWN CURRENT vs. INPUT VOLTAGE VIN = 36V 4.952 4.949 NO LOAD SUPPLY CURRENT (A) VIN = 12V VIN = 24V VIN = 36V 40 4.953 PFM MODE FEEDBACK VOLTAGE (V) OUTPUT VOLTAGE (V) 3.325 20 VIN = 12V 4.954 4.950 100 0.81 0 4.955 toc22 FIGURE 9 APPLICATION CIRCUIT, PWM MODE FEEDBACK VOLTAGE VS. TEMPERATURE 0.82 3.327 3.321 4.956 LOAD CURRENT (mA) OUTPUT VOLTAGE vs. LOAD CURRENT 3.329 VIN = 36V 3.28 3.20 VIN = 24V 4.957 3.40 OUTPUT VOLTAGE (V) 4.98 FIGURE 8 APPLICATION CIRCUIT, PWM MODE 4.959 3.44 OUTPUT VOLTAGE (V) VVININ=12V = 12V OUTPUT VOLTAGE vs. LOAD CURRENT 4.960 toc20 5.06 5.02 3.48 toc19 5.10 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE vs. LOAD CURRENT FIGURE 8 APPLICATION FIGURE8 APPLICATION CIRCUIT, PFMPFM MODE CIRCUIT, MODE toc21 5.14 200 toc27 SWITCH PEAK CURRENT LIMIT 150 100 SWITCH NEGATIVE CURRENT LIMIT 50 0 5 15 25 35 45 55 INPUT VOLTAGE (V) Maxim Integrated 8 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (continued) (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) 200 SWITCH PEAK CURRENT LIMIT 150 100 SWITCH NEGATIVE CURRENT LIMIT 50 0 EN/UVLO THRESHOLD VOLTAGE vs. TEMPERATURE 1.30 toc29 RISING 1.26 1.22 1.18 1.14 SWITCHING FREQUENCY vs. TEMPERATURE 1000 SWITCHING FREQUENCY (KHz) SWITCH CURRENT LIMIT (mA) 250 toc28 EN/UVLO THRESHOLD VOLTAGE (V) SWITCH CURRENT LIMIT vs. TEMPERATURE 800 RT = 69.8k 600 400 RT = 191k 200 RT = 422k FALLING 1.10 -40 -20 0 20 40 60 80 100 120 96 -20 0 20 40 60 80 100 120 0 LOAD TRANSIENT RESPONSE, PFM MODE (LOAD CURRENT STEPPED FROM 5mA to 50mA) toc32 toc31 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) TEMPERATURE (C) TEMPERATURE (C) RESET THRESHOLD vs. TEMPERATURE -40 toc30 RT = 45.3k LOAD TRANSIENT RESPONSE PFM MODE (LOAD CURRENT STEPPED FROM 5mA to 50mA) toc33 RISING RESET THRESHOLD (%) 95 VOUT (AC) 94 FIGURE6 APPLICATION FIGURE 6 CIRCUIT APPLICATIONVOUT CIRCUIT =5V VOUT = 5V 93 92 FALLING 91 90 -40 -20 0 20 40 60 IOUT 80 100 120 VOUT (AC) LOAD TRANSIENT RESPONSE PFM OR PWM MODE (LOAD CURRENT STEPPED FROM 50mA TO 100mA) toc34 50mA/div IOUT LOAD TRANSIENT RESPONSE PWM MODE (LOAD CURRENT STEPPED FROM NO-LOAD TO 50mA) toc36 toc35 VOUT (AC) 50mA/div 200s/div LOAD TRANSIENT RESPONSE PFM OR PWM MODE (LOAD CURRENT STEPPED FROM 50mA TO 100mA) 100mV/div 100mV/div FIGURE7 FIGURE 7APPLICATION APPLICATION CIRCUIT VOUT = 3.3V VOUT=3.3V 200s/div TEMPERATURE (C) VOUT (AC) 100mV/div 100mV/div VOUT (AC) 100mV/div FIGURE 6 APPLICATION CIRCUIT VOUT = 5V 50mA/div IOUT FIGURE 6 APPLICATION CIRCUIT VOUT = 5V 100s/div www.maximintegrated.com IOUT FIGURE 7 APPLICATION CIRCUIT VOUT = 3.3V 100s/div 50mA/div IOUT 50mA/div 100s/div Maxim Integrated 9 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (continued) (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) LOAD TRANSIENT RESPONSE PWM MODE (LOAD CURRENT STEPPED FROM NO-LOAD TO 50mA) toc37 SWITCHING WAVEFORMS (PFM MODE) toc38 FULL LOAD-SWITCHING WAVEFORMS (PWM OR PFM MODE) toc39 FIGURE 6 APPLICATION CIRCUIT VOUT = 5V,LOAD = 20mA 100mV/ div VOUT (AC) FIGURE 7 APPLICATION CIRCUIT VOUT = 3.3V 50mA/div IOUT VOUT (AC) 100mV/div LX 10V/div ILX 100mA/div 20mV/div VOUT (AC) LX 10V/div ILX 100mA/div 4s/div 10s/div 100s/div NO LOAD SWITCHING WAVEFORMS (PWM MODE) toc40 VOUT (AC) FIGURE 6 APPLICATION CIRCUIT VOUT = 5V, LOAD = 100mA SOFT START FIGURE 6 APPLICATION CIRCUIT VOUT = 5V 20mV/div SOFT START toc41 5V/div 5V/div VEN/UVLO 2V/div toc42 VEN/UVLO 1V/div VOUT LX 10V/div IOUT 100mA/div ILX VRESET toc43 SOFT START WITH 3V PREBIAS 1V/div 2ms/div www.maximintegrated.com VLX FIGURE 6 APPLICATION CIRCUIT NO LOAD PWM MODE 50mA/div 5V/div EXTERNAL SYNCHRONIZATION WITH 300kHz CLOCK FREQUENCY toc44 5V/div VOUT 5V/div VRESET 2V/div toc45 2V/div VRESET VRESET 50mA/div 1ms/div VEN/UVLO FIGURE 6 APPLICATION CIRCUIT VOUT = 5V IOUT FIGURE 7 APPLICATION CIRCUIT VOUT = 3.3V IOUT 5V/div 5V/div VEN/UVLO VOUT VOUT 1ms/div 4s/div SHUTDOWN WITH ENABLE 50mA/div FIGURE 6 APPLICATION CIRCUIT VOUT = 5V 1ms/div VRT/SYNC 10V/div FIGURE 6 APPLICATION CIRCUIT 100mA LOAD PWM MODE 2V/div 4s/div Maxim Integrated 10 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Operating Characteristics (continued) (VIN = 24V, VGND = 0V, VOUT = 3.3V, VEN/UVLO = 1.5V, RT/SYNC = 191k, CIN = 1F, TA = +25C unless otherwise noted.) OVERLOAD PROTECTION (MAX17552) VOUT OVERLOAD PROTECTION (MAX17552A) toc46 FIGURE 6 APPLICATION CIRCUIT VOUT = 5V toc47 5V/div ILX I LX 100mA/div 100mA/div 20ms/div 1ms/div BODE PLOT toc48 BODE PLOT 180 50 40 144 40 144 30 108 30 108 20 72 20 36 10 0 0 PHASE 10 0 -10 FCR = 8.5KHz, PHASE MARGIN = 64 -20 -30 -50 GAIN -36 -10 -72 -20 -108 -30 FIGURE 6 APPLICATION CIRCUIT -144 VOUT = 5V -40 1k 10k -180 100k 1k AVERAGE LIMIT 40 30 PEAK EMISSIONS 20 10 0.15 www.maximintegrated.com AVERAGE EMISSIONS 1 10 FREQUENCY (MHz) 30 AMPLITUDE (dBuV/m) 50 -72 10k 100k RADIATED EMI CURVE (5V OUTPUT, 100mA LOAD CURRENT) 70 60 QUASI-PEAK LIMIT -36 GAIN -108 FIGURE 7 APPLICATION CIRCUIT -144 VOUT = 3.3V -180 -50 70 60 36 0 FCR = 10.5KHz, PHASE MARGIN = 61 -40 toc50 80 72 PHASE CONDUCTED EMI CURVE (5V OUTPUT, 100mA LOAD CURRENT) CONDUCTED EMI (dBV) toc49 180 50 toc51 Class B limit CLASS B LIMIT Horizontal limit HORIZONTAL VERTICAL Vertical EMISSION limit 50 40 30 20 10 0 -10 30 100 FREQUENCY (MHz) 500 1000 Maxim Integrated 11 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Pin Configuration TOP VIEW LX 10 GND MODE RESET VOUT 9 8 7 6 MAX17552/ MAX17552A + 1 IN 2 3 4 5 EN/ RT/ SS UVLO SYNC FB IN 1 EN/UVLO 2 RT/SYNC 3 SS 4 FB 5 + MAX17552/ MAX17552A 10 LX 9 GND 8 MODE 7 RESET 6 VOUT MAX 3mm x 3mm TDFN 3mm x 2mm Pin Description PIN NAME 1 IN Switching Regulator Input. Connect a X7R 1F ceramic capacitor from IN to GND for bypassing. 2 EN/UVLO Active-High, Enable/Undervoltage-Detection Input. Pull EN/UVLO to GND to disable the regulator output. Connect EN/UVLO to IN for always-on operation. Connect a resistor-divider between IN, EN/UVLO, and GND to program the input voltage at which the device is enabled and turns on. 3 RT/SYNC Oscillator Timing Resistor Input. Connect a resistor from RT/SYNC to GND to program the switching frequency from 100kHz to 2.2MHz. See the Switching Frequency (RT/SYNC) section for details. An external pulse can be applied to RT/SYNC through a coupling capacitor to synchronize the internal clock to the external pulse frequency. See the External Synchronization section for details. 4 SS Soft-Start Capacitor Input. Connect a capacitor from SS to GND to set the soft-start time. Leave SS unconnected for default 5.1ms internal soft-start. 5 FB Output Feedback Connection. Connect FB to a resistor-divider between VOUT and GND to set the output voltage. See the Adjusting the Output Voltage section for details. 6 VOUT External Bias Input for Internal Control Circuitry. Decouple to GND with a 0.22F capacitor and connect to output capacitor positive terminal with a 22.1 resistor for applications with an output voltage from 3.3V to 5V. Connect to GND for output voltages < 3.3V and > 5V. See the External Bias section for details. 7 RESET Open-Drain Reset Output. Pull up RESET to an external power supply with an external resistor. RESET pulls low if FB voltage drops below 92% of its set value. RESET goes high impedance 2ms after FB voltage rises above 95% of its set value. 8 MODE PFM/PWM Mode-Selection Input. Connect MODE to GND to enable the fixed-frequency PWM operation. Leave MODE unconnected for light-load PFM operation. 9 GND 10 LX Inductor Connection. Connect LX to the switching side of the inductor. LX is high impedance when the device is in shutdown. -- EP Exposed Pad (TDFN Only). Connect to the GND pin to the IC. www.maximintegrated.com FUNCTION Ground. Connect GND to the power ground plane. Connect all the circuit ground connections together at a single point. See the PCB Layout Guidelines section. Maxim Integrated 12 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Block Diagram IN INTERNAL LDO REGULATOR VOUT POK VCC_INT PEAK-LIMIT EN/UVLO CURRENTSENSE LOGIC CHIPEN 1.25V PFM THERMAL SHUTDOWN CLK RT/SYNC PFM/PWM CONTROL LOGIC OSCILLATOR SLOPE VCC_INT SLOPE SS CS INTERNAL OR EXTERNAL SOFT-START CONTROL DH LX LOW-SIDE DRIVER MODE SELECT 1.22V FB CURRENTSENSE AMPLIFIER HIGH-SIDE DRIVER DL MODE CS SINK-LIMIT CURRENT SENSE AMPLIFIER PWM ERROR AMPLIFIER NEGATIVE CURRENT REF GND RESET 0.76V FB CLK 2ms DELAY MAX17552/MAX17552A www.maximintegrated.com Maxim Integrated 13 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Detailed Description The MAX17552/MAX17552A high-efficiency, high-voltage, synchronous step-down DC-DC converters with integrated MOSFETs operate over a 4V to 60V input voltage range. The converter can deliver output current up to 100mA at output voltages of 0.8V to 0.9 x VIN. The output voltage is accurate to within 1.75% over -40C to +125C. The converter consumes only 22A of supply current in PFM mode while regulating the output voltage at no load. The devices use an internally compensated, peakcurrent-mode control architecture (see the Block Diagram). On the rising edge of the internal clock, the high-side pMOSFET turns on. An internal error amplifier compares the feedback voltage to a fixed internal reference voltage and generates an error voltage. The error voltage is compared to a sum of the current-sense voltage and a slope-compensation voltage by a PWM comparator to set the "on-time." During the on-time of the pMOSFET, the inductor current ramps up. For the remainder of the switching period (off-time), the pMOSFET is kept off and the low-side nMOSFET turns on. During the off-time, the inductor releases the stored energy as the inductor current ramps down, providing current to the output. Under overload conditions, cycle-by-cycle current-limit feature limits inductor peak current by turning off the highside pMOSFET and turning on the low-side nMOSFET. Mode Selection (MODE) The devices feature a MODE pin for selecting either forced-PWM or PFM mode of operation. If the MODE pin is left unconnected, the devices operate in PFM mode at light loads. If the MODE pin is grounded, the devices operate in a constant-frequency forced-PWM mode at all loads. Mode of operation can be changed on-the-fly during normal operation of the device. In PWM mode, the inductor current is allowed to go negative. PWM operation is useful in frequency-sensitive applications and provides fixed switching frequency at all loads. However, the PWM mode of operation gives lower efficiency at light loads compared to PFM mode of operation. PFM mode disables negative inductor current and additionally skips pulses at light loads for high efficiency. In PFM mode, the inductor current is forced to a fixed peak of 72mA (typ) (IPFM) every clock cycle until the output rises to 102% (typ) of the nominal voltage. Once the output reaches 102% (typ) of the nominal voltage, both high-side and low-side FETs are turned off and the device www.maximintegrated.com enters hibernate operation until the load discharges the output to 101% (typ) of the nominal voltage. Most of the internal blocks are turned off in hibernate operation to save quiescent current. After the output falls below 101% (typ) of the nominal voltage, the devices come out of hibernate operation, turns on all internal blocks, and again commences the process of delivering pulses of energy to the output until it reaches 102% (typ) of the nominal output voltage. The devices naturally exit PFM mode when the load current increases to a magnitude of approximately: IPFM - (I/2) where I is the peak-peak ripple current in the output inductor. The part enters PFM mode again if the load current reduces to approximately (I/2). See the Inductor Selection section for details. The advantage of the PFM mode is higher efficiency at light loads because of lower current drawn from the supply. Enable Input (EN/UVLO) and Soft-Start (SS) When EN/UVLO voltage increases above 1.25V (typ), the devices initiate a soft-start sequence and the duration of the soft-start depends on the status of the SS pin voltage at the time of power-up. If the SS pin is not connected, the devices use a fixed 5ms internal soft-start to ramp up the internal error-amplifier reference. If a capacitor is connected from SS to GND, a 5A current source charges the capacitor and ramps up the SS pin voltage. The SS pin voltage is used as reference for the internal error amplifier. Such a reference ramp up allows the output voltage to increase monotonically from zero to the final set value independent of the load current. EN/UVLO can be used as an input voltage UVLOadjustment input. An external voltage-divider between IN and EN/UVLO to GND adjusts the input voltage at which the device turns on or turns off. See the Setting the Input Undervoltage-Lockout Level section for details. If input UVLO programming is not desired, connect EN/ UVLO to IN (see the Electrical Characteristics table for EN/UVLO rising and falling-threshold voltages). Driving EN/UVLO low disables both power MOSFETs, as well as other internal circuitry, and reduces IN quiescent current to below 1.2A. The SS capacitor is discharged with an internal pulldown resistor when EN/UVLO is low. If the EN/UVLO pin is driven from an external signal source, a series resistance of minimum 1kW is recommended to be placed between the signal source output and the EN/ UVLO pin, to reduce voltage ringing on the line. Maxim Integrated 14 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Switching Frequency (RT/SYNC) Switching frequency of the devices can be programmed from 100kHz to 2.2MHz by using a resistor connected from RT/SYNC to GND. The switching frequency (fSW) is related to the resistor connected at the RT/SYNC pin (RT) by the following equation, where RT is in k and fSW is in kHz: RT = 42000 f SW The switching frequency in ranges of 130kHz to 160kHz and 230kHz to 280kHz are not allowed for user programming to ensure proper configuration of the internal adaptive-loop compensation scheme. External Synchronization The RT/SYNC pin can be used to synchronize the device's internal oscillator to an external system clock. The external clock should be coupled to the RT/SYNC pin through a 47pF capacitor, as shown in Figure 1. The external clock logic high level should be higher than 3V, logic low level lower than 0.5V and the duty cycle of the external clock should be in the range of 10% to 70%. External clock synchronization is allowed only in PWM mode of operation (MODE pin connected to GND). The RT resistor should be selected to set the switching frequency 10% lower than the external clock frequency. The external clock should be applied at least 500s after enabling the device, for proper configuration of the internal loop compensation. MAX17552/ MAX17552A 47pF RT/SYNC CLOCK SOURCE RT VLOGIC-HIGH VLOGIC-LOW DUTY Figure 1. Synchronization to an External Clock www.maximintegrated.com External Bias (VOUT) The devices provide a VOUT pin to power the internal blocks from a low-voltage supply. When the VOUT pin voltage exceeds 3.1V, the devices draw switching and quiescent current from this pin to improve the converter's efficiency. In applications with an output voltage setting from 3.3V to 5V, VOUT should be decoupled to GND with a ceramic capacitor, and should be connected to the positive terminal of the output capacitor with a resistor (R4, C1) as shown in the typical application circuits. In the absence of R4 and C1, the absolute maximum rating of VOUT (-0.3V) can be exceeded under short-circuit conditions, due to oscillations between the ceramic output capacitor and the inductance of the short-circuit path. In general, parasitic board or wiring inductance should be minimized and the output voltage waveform under short circuit operation should be verified to ensure that the absolute maximum rating of VOUT is not exceeded. For applications with an output voltage setting less than 3.3V or greater than 5V, VOUT should be connected to GND. Reset Output (RESET) The devices include an open-drain RESET output to monitor output voltage. RESET should be pulled up with an external resistor to the desired external power supply. RESET goes high impedance 2ms after the output rises above 95% of its nominal set value and pulls low when the output voltage falls below 92% of the set nominal output voltage. Startup Into a Prebiased Output The devices support monotonic startup into a prebiased output. When the device starts into a prebiased output, both the high-side and low-side switches are turned off so that the converter does not sink current from the output. High-side and low-side switches do not start switching until the PWM comparator commands the first PWM pulse, at which point switching commences. The output voltage is then smoothly ramped up to the target value in alignment with the internal reference. Such a feature is useful in applications where digital integrated circuits with multiple rails are powered. Operating Input Voltage Range The maximum operating input voltage is determined by the minimum controllable on-time, and the minimum operating input voltage is determined by the maximum duty cycle and circuit voltage drops. The minimum and maximum operating input voltages for a given output voltage should be calculated as follows: Maxim Integrated 15 MAX17552/MAX17552A VINMIN 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current VOUT + (I OUT x (R DCR + 2.6)) + (I OUT x 2.5) D MAX VOUT VINMAX = t ONMIN x f SW where VOUT is the steady-state output voltage, IOUT is the maximum load current, RDCR is the DC resistance of the inductor, fSW is the switching frequency (max), DMAX is the maximum duty cycle (0.9), and tONMIN is the worstcase minimum controllable switch on-time (128ns) Overcurrent Protection The MAX17552 implements a hysteretic cycle-by-cycle peak-current limit protection scheme to protect the inductor and internal FETs under output short circuit conditions. When the inductor peak current exceeds 0.21A (typ), high side switch is turned off and low side switch is turned on to discharge the inductor current. Subsequent clock pulses do not turn on the high-side switch until inductor current discharges to 0.15A (typ). This operation continues until overload/short circuit is removed on the output. Since the inductor current is bounded between two limits, inductor current runaway never happens in this scheme. Additionally, hysteretic negative peak current limit controls the low-side switch negative current when it exceeds 0.1A (typ). The MAX17552A implements a HICCUP-type overload protection scheme to protect the inductor and internal FETs under output short-circuit conditions. When the inductor peak current exceeds 0.21A (typ) 16 consecutive times, the part enters HICCUP mode. In this mode, the part is initially operated with hysteretic cycle-by-cycle peak-current limit that continues for a time period equal to twice the soft-start time. The part is then turned off for a fixed 51ms hiccup timeout period. This sequence of hysteretic inductor current waveforms, followed by a hiccup timeout period, continues until the short/overload on the output is removed. Since the inductor current is bound between two limits, inductor current runway never happens. Thermal-Overload Protection Thermal-overload protection limits the total power dissipation in the IC. When the junction temperature exceeds +160C, an on-chip thermal sensor shuts down the device, turns off the internal power MOSFETs, allowing the device to cool down. The device turns on after the junction temperature cools by 20C. www.maximintegrated.com Applications Information Inductor Selection A low-loss inductor having the lowest possible DC resistance that fits in the allotted dimensions should be selected. Calculate the required inductance from the equation: L= 10000 x VOUT f SW where L is inductance in H, VOUT is output voltage and fSW is the switching frequency in kHz. Calculate the peak-peak ripple current (I) in the output inductor from the equation: V 1000 x VOUT x 1 - OUT V IN I = f SW x L where L is inductance in H, VOUT is output voltage, VIN is input voltage and fSW is the switching frequency in kHz. The saturation current rating of the inductor must exceed the maximum current-limit value (IPEAK-LIMIT). The saturation current rating should be the maximum of either 0.235A or the value from the equation: I= SAT 0.15 + VINMAX x t ON-MIN L where L is inductance in H, VINMAX is maximum input voltage and tON-MIN is worst case minimum on time (128ns). Once the L value is known, the next step is to select the right core material. Ferrite and powdered iron are commonly available core materials. Ferrite cores have low core losses and are preferred for high-efficiency designs. Powdered iron cores have more core losses and are relatively cheaper than ferrite cores. Input Capacitor Selection Small ceramic input capacitors are recommended for the IC. The input capacitor reduces peak current drawn from the power source and reduces noise and voltage ripple on the input caused by the switching circuitry. A minimum of 1F, X7R-grade capacitor in a package larger than 0805 is recommended for the input capacitor of the IC to keep the input-voltage ripple under 2% of the minimum input voltage, and to meet the maximum ripple-current requirements. Maxim Integrated 16 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Output Capacitor Selection Small ceramic X7R-grade output capacitors are recommended for the devices. The output capacitor has two functions. It stores sufficient energy to support the output voltage under load transient conditions and stabilizes the device's internal control loop. Usually the output capacitor is sized to support a step load of 50% of the maximum output current in the application, such that the outputvoltage deviation is less than 3%. Calculate the minimum required output capacitance from the following equations: Frequency Range (kHz) Minimum Output Capacitance (F) 50 100 to 130 VOUT 160 to 230 25 VOUT 280 to 2200 17 VOUT It should be noted that dielectric materials used in ceramic capacitors exhibit capacitance loss due to DC bias levels and should be appropriately derated to ensure the required output capacitance is obtained in the application. Soft-Start Capacitor Selection The devices offer a 5.1ms internal soft-start when the SS pin is left unconnected. When adjustable soft-start time is required, connect a capacitor from SS to GND to program the soft-start time. The minimum soft-start time is related to the output capacitance (COUT) and the output voltage(VOUT) by the following equation. tSS > 0.05 x COUT x VOUT where tSS is in milliseconds and COUT is in F. Soft-start time (tSS) is related to the capacitor connected at SS (CSS) by the following equation: C= SS 6.25 x t SS where tSS is in milliseconds and CSS is in nanofarads. Setting the Input Undervoltage-Lockout Level The devices offer an adjustable input undervoltagelockout level. Set the voltage at which the device turns on with a resistive voltage-divider connected from IN to GND (see Figure 2). Connect the center node of the divider to EN/UVLO. Choose R1 to be 3.3M max and then calculate R2 as follows: R2 = R1x 1.25 (VINU - 1.25) where VINU is the voltage at which the device is required to turn on. If the EN/UVLO pin is driven from an external signal source, a series resistance of minimum 1k is recommended to be placed between the signal source output and the EN/UVLO pin to reduce voltage ringing on the line. VOUT VIN IN R1 MAX17552/ MAX17552A EN/UVLO MAX17552/ MAX17552A R1 FB R2 R2 GND Figure 2. Adjustable EN/UVLO Network www.maximintegrated.com Figure 3. Setting the Output Voltage Maxim Integrated 17 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current 1 2 PLOSS = POUT x - 1 - (I OUT x R DCR ) 4.7 P= OUT VOUT x I OUT IN CIN 1F MAX17552/ MAX17552A GND The junction temperature (TJ) of the device can be estimated at any ambient temperature (TA) from the following equation: Figure 4. Transient Protection TJ= T A + ( JA x PLOSS ) Adjusting the Output Voltage The output voltage can be programmed from 0.8V to 0.9V x VIN. Set the output voltage by connecting a resistordivider from output to FB to GND (see Figure 3). Choose R2 in the range of 25k to 100k and calculate R1 with the following equation: = R1 V R2 x OUT 0.8 where POUT is the output power, is the efficiency of power conversion, and RDCR is the DC resistance of the output inductor. See the Typical Operating Characteristics for the power-conversion efficiency or measure the efficiency to determine the total power dissipation. - 1 Transient Protection In applications where fast line transients or oscillations with a slew rate in excess of 15V/s are expected during power-up or steady-state operation, the MAX17552/ MAX17552A should be protected with a series resistor that forms a lowpass filter with the input ceramic capacitor (Figure 4). These transients can occur in conditions such as hot-plugging from a low-impedance source or due to inductive load switching and surges on the supply lines. where JA is the junction-to-ambient thermal impedance of the package. Junction temperature greater than +125C degrades operating lifetimes. PCB Layout Guidelines Careful PCB layout (Figure 5) is critical to achieve clean and stable operation. The switching power stage requires particular attention. Follow these guidelines for good PCB layout: Place the input ceramic capacitor as close as possible to VIN and GND pins Minimize the area formed by the LX pin and inductor connection to reduce the radiated EMI Ensure that all feedback connections are short and direct Route high-speed switching node (LX) away from the signal pins Power Dissipation For a sample PCB layout that ensures the first-pass success, refer to the MAX17552/MAX17552A evaluation kit data sheet. www.maximintegrated.com Maxim Integrated 18 At a particular operating condition, the power losses that lead to temperature rise of the device are estimated as follows: MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current VIN IN MAX17552/ MAX17552A R1 CIN CSS VOUT COUT GND EN/UVLO R2 L1 LX SS VOUT CF R7 MODE FB RT/SYNC R4 R5 R3 R6 VOUT RESET GND PLANE CIN VIN PLANE R3 VOUT PLANE U1 R1 R2 L1 LX IN EN/UVLO GND RT/SYNC MODE RESET SS FB CSS COUT R6 R4 VOUT R7 R5 GND PLANE CF Vias to Bottom-Side Ground Plane Vias to VOUT Vias to RESET Figure 5. Layout Guidelines www.maximintegrated.com Maxim Integrated 19 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Application Circuits VIN 6V TO 60V CIN 1F L1 220H IN MAX17552/ LX MAX17552A EN/UVLO COUT 10F GND MODE C1 0.22F RT/SYNC MAX17552/ LX MAX17552A EN/UVLO SS GND VOUT MODE R1 261k FB R3 191k IN CIN 1F R4 22.1 SS VOUT VIN 4V TO 60V VOUT 5V, 100mA RT/SYNC R2 49.9k L1 150H VOUT 3.3V, 100mA COUT 10F R4 22.1 C1 0.22F R1 158k FB R2 49.9k R3 191k RESET RESET SWITCHING FREQUENCY = 220kHz L1 COILCRAFT LPS5030-224M COUT MURATA 10F/X7R/6.3V/1206 (GRM31CR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) SWITCHING FREQUENCY = 220kHz L1 COILCRAFT LPS5030-154M COUT MURATA 10F/X7R/6.3V/1206 (GRM31CR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) Figure 7. High-Efficiency 3.3V, 100mA Regulator Figure 6. High-Efficiency 5V, 100mA Regulator VIN 6V TO 60V IN MAX17552/ LX L1 100H MAX17552A CIN 1F EN/UVLO SS MODE R4 22.1 C1 0.22F R1 261k FB R2 49.9k RT/SYNC R3 69.8k COUT 10F GND VOUT VOUT 5V, 100mA RESET SWITCHING FREQUENCY = 600kHz L1 COILCRAFT LPS3015-104M COUT MURATA 10F/X7R/6.3V/0805 (GRM21BR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) Figure 8. Small Footprint 5V, 100mA Regulator www.maximintegrated.com Maxim Integrated 20 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Typical Application Circuits (continued) VIN 4V TO 45V IN MAX17552/ LX L1 68H EN/UVLO SS MODE GND VOUT IN MAX17552/ LX MAX17552A CIN 1F R4 22.1 EN/UVLO SS C1 0.22F R1 158k FB MODE R2 49.9k RT/SYNC R3 69.8k VIN 4V TO 24V COUT 10F MAX17552A CIN 1F VOUT 3.3V, 100mA R3 69.8k Figure 9. Small Footprint 3.3V, 100mA Regulator VOUT R1 127k FB R2 100k RESET Figure 10. Small Footprint 1.8V, 100mA Regulator IN MAX17552/ LX MAX17552A CIN 1F COUT 10F SWITCHING FREQUENCY = 600kHz L1 COILCRAFT LPS3015-333M COUT MURATA 10F/X7R/6.3V/1206 (GRM31CR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) SWITCHING FREQUENCY = 600kHz L1 COILCRAFT LPS3015-683M COUT MURATA 10F/X7R/6.3V/0805 (GRM21BR70J106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) VIN 15V TO 60V VOUT 1.8V, 100mA GND RT/SYNC RESET L1 33H EN/UVLO SS MODE VOUT 12V, 100mA COUT 10F GND VOUT R1 348k FB R2 24.9k RT/SYNC R3 69.8k L1 220H RESET SWITCHING FREQUENCY = 600kHz L1 COILCRAFT LPS5030-224M COUT MURATA 10F/X7R/16V/1206 (GRM31CR71C106K) CIN MURATA 1F/X7R/100V/1206 (GRM31CR72A105K) Figure 11. Small Footprint 12V, 100mA Step-Down Regulator www.maximintegrated.com Maxim Integrated 21 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Ordering Information PART TEMP RANGE PIN-PACKAGE MAX17552ATB+ -40C to +125C 10 TDFN-EP* MAX17552AUB+ -40C to +125C 10 MAX MAX17552AATB+ -40C to +125C 10 TDFN-EP* MAX17552AAUB+ -40C to +125C 10 MAX +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Chip Information PROCESS: BiCMOS www.maximintegrated.com Maxim Integrated 22 MAX17552/MAX17552A 60V, 100mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converter with 22A No-Load Supply Current Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 2/14 Initial release -- 1 6/14 Added statement regarding EN/UVLO connection 11 2 2/15 Updating to include MAX17552A 3 6/15 Included small solution-size TOCs in Typical Operating Characteristics section and updated Typical Application Circuit diagrams 2, 6-10, 19, 20 4 9/17 Updated Features and Benefits, Mode Selection (MODE), Setting the Input Undervoltage-Lockout Level, and Power Dissipation sections. Updated the Electrical Characteristics table global characteristics. Inserted new Note 1 and updated Absolute Maximum Ratings, and added TOC50 and TOC51. 1, 3-5, 11, 14, 17-18 5 8/18 Updated the Mode Selection (MODE) section. DESCRIPTION 1-20 14 For pricing, delivery, and ordering information, please visit Maxim Integrated's online storefront at https://www.maximintegrated.com/en/storefront/storefront.html. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2018 Maxim Integrated Products, Inc. 23 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX17552ATB+T MAX17552AUB+T MAX17552AUB+