MAX16975 28V, 1.2A Automotive Step-Down Converter with Low Operating Current General Description Features The MAX16975 is a 1.2A current-mode step-down con- S Wide 3.5V to 28V Input Voltage Range verter with an integrated high-side switch. The device S 42V Input Transient Tolerance operates with input voltages from 3.5V to 28V while using S 5V Fixed or 1V to 10V Adjustable Output Voltage only 45FA quiescent current at no load. The switching S Integrated 1.2A High-Side Switch frequency is adjustable from 220kHz to 1.0MHz by using an external resistor, and can be synchronized to an exter- S 220kHz to 1.0MHz Adjustable Switching Frequency nal clock. The devices output voltage is pin-selectable to S Frequency Synchronization Input a fixed 5V or adjustable from 1V to 10V using external S Internal Boost Diode resistors. The wide input voltage range makes the device ideal for automotive and industrial applications. S 45A Skip-Mode Operating Current The device operates in skip mode for reduced current S Less than 10A Shutdown Current consumption in light-load conditions. An adjustable S Adjustable Power-Good Output Level and Timing reset threshold helps keep microcontrollers alive down S 3.3V Logic Level to 42V Compatible Enable Input to the lowest specified input voltage. Protection features include cycle-by-cycle current limit, soft-start, overvolt- S Current-Limit, Thermal Shutdown, and age, and thermal shutdown with automatic recovery. Overvoltage Protection The device also features a power-good monitor to ease S -40C to +125C Automotive Temperature Range power-supply sequencing. Applications The device is available in 16-pin QSOP and thermally enhanced QSOP-EP packages. It operates over the Automotive -40C to +125C automotive temperature range. Industrial Ordering Information appears at end of data sheet. Typical Application Circuit 3.5V TO 28V C C C IN1 IN2 IN3 C BST 47F 4.7F 0.1F 0.1F SUP SUPSW L1 V = 1.25V AT OUT EN BST 10H 1.2A AT 400kHz LX FSYNC V OUT R FB1 C C OUT1 OUT2 COMP D1 C 25kI 47F 47F COMP1 OUT 5600pF CCOMP2 MAX16975 R RESETI FOSC R OPEN COMP 61.9kI V BIAS 12kI FOSC R FB2 FB R RES 100kI 10kI BIAS RES C BIAS CRES 1F GND C PLACE C (0.1F) RIGHT NEXT TO SUP. CRES IN3 1nF For related parts and recommended products to use with this part, refer to: www.maximintegrated.com/MAX16975.related For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-5673 Rev 1 10/13MAX16975 28V, 1.2A Automotive Step-Down Converter with Low Operating Current ABSOLUTE MAXIMUM RATINGS SUP, SUPSW, LX, EN to GND ...............................-0.3V to +45V Continuous Power Dissipation (T = +70NC) A BST to GND ..........................................................-0.3V to +47V QSOP (derate 9.6mW/NC above +70NC) ..................771.5mW BST to LX ...............................................................-0.3V to +6V QSOP-EP (derate 22.7mW/NC above +70NC) ......1818.20mW OUT to GND ..........................................................-0.3V to +12V Operating Temperature Range ........................ -40NC to +125NC SUP to SUPSW .....................................................-0.3V to +0.3V Junction Temperature .....................................................+150NC RESETI, FOSC, COMP, BIAS, Storage Temperature Range ............................ -65NC to +150NC FSYNC, CRES, RES, FB to GND .........................-0.3V to +6V Lead Temperature (soldering, 10s) ................................+300NC Output Short-Circuit Duration ....................................Continuous Soldering Temperature (reflow) ......................................+260NC 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) QSOP QSOP-EP Junction-to-Ambient Thermal Resistance (q ) .....103.7C/W Junction-to-Ambient Thermal Resistance (q ) ..........44C/W JA JA Junction-to-Case Thermal Resistance (q ) ...............37C/W Junction-to-Case Thermal Resistance (q ) .................6C/W JC 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. ELECTRICAL CHARACTERISTICS (V = V = 14V, V = 14V, L1 = 22FH, C = 4.7FF, C = 100FF, C = 1FF, C = 0.1FF, C = 1nF, R = SUP SUPSW EN IN OUT BIAS BST CRES FOSC 61.9kI, T = T = -40NC to +125NC, unless otherwise noted. Typical values are at T = +25NC.) A J A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS V , SUP Supply Voltage Normal operation 3.5 28 V V SUPSW Normal operation, no switching 2.9 mA Supply Current I SUP Skip mode, no load, V = 5V 45 FA OUT Shutdown Supply Current V = 0V 9 FA EN V = V = 6V to 42V, V < 3V or SUP SUPSW OUT BIAS Regulator Voltage V 4.7 5.0 5.3 V BIAS V > 5.5V, I = 0A (Note 2) OUT LOAD BIAS Undervoltage Lockout V V rising 2.95 3.15 3.35 V UVBIAS BIAS BIAS Undervoltage Hysteresis 550 mV Thermal-Shutdown Threshold +175 NC Thermal-Shutdown Threshold +15 NC Hysteresis OUTPUT VOLTAGE (OUT) Normal operation, V = V , I = 1A, FB BIAS LOAD 4.95 5 5.05 T = +25C A Output Voltage V V OUT Normal operation, V = V , I = 1A, FB BIAS LOAD 4.9 5 5.1 -40C P T P +125C A Skip-Mode Output Voltage V No load, V = V (Note 3) 4.9 5.05 5.2 V OUT SKIP FB BIAS Load Regulation V = 5V, V = V 30mA < I < 1A 0.3 % OUT FB BIAS, LOAD Line Regulation 6V < V < 28V 0.02 %/V SUP Maxim Integrated 2 *The parametric values (min, typ, max limits) shown in the Electrical Characteristics table supersede values quoted elsewhere in this data sheet.