MP2491CGQB-Z

MP2491C 32V, 6A, Step-Down Converter with Programmable Current Limit and Output Voltage Scaling Control DESCRIPTION FEATURES The MP2491C is a fully integrated, high-voltage, step-down converter. The MP2491C can achieve 6A of continuous output current with excellent load and line regulation over a wide input supply range.            Constant-on-time (COT) control operation provides very fast transient response, easy loop design, and very tight output regulation. Full protection features include over-current protection (OCP), hiccup current limiting, output over-voltage protection (OVP), and thermal shutdown.    The MP2491C requires a minimal number of readily available, standard, external components and is available in a QFN-13 (2.5mmx3mm) package.    Wide 4.0V to 32V Operating Input Range 0.5V to 30V Output Voltage Range 6A Output Current Constant-on-Time (COT) Control Two Dedicate Voltage Scaling Control Pins Slew Rate Control during DVS Low Dropout Mode Operation 33mΩ/22mΩ Internal MOSFET Switches 450µA IQ Fixed 490kHz Switching Frequency Output Line Drop Compensation when VFB = 0.5V EN Shutdown Discharge Output Over-Voltage Protection (OVP) Adjustable Auto-PFM/PWM Mode or Forced PWM Mode Adjustable Current Limit Power Good (PG) Indication Available in a QFN-13 (2.5mmx3mm) Package APPLICATIONS     TVs, Monitors MFP Power Supplies USB Power Supplies with PD Automotive Cigarette Lighter Adapters All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS”, the MPS logo, and “Simple, Easy Solutions” are trademarks of Monolithic Power Systems, Inc. or its subsidiaries. TYPICAL APPLICATION Efficiency vs. Load Current VIN 24V VIN=24V U1 L1 4.7μH IN R6 300kΩ SW BST EN C3 2.2μF C4 1μF MP2491C VCC FB VSEL1 VSEL2 MODE PG R5 51kΩ ILIM AGND PGND R1 100kΩ R2 11kΩ 100 VOUT 5V C2 88μF 95 EFFICIENCY (%) C1 30μF 90 85 80 VOUT=5V VOUT=9V VOUT=12V 75 70 0.01 0.1 1 LOAD CURRENT (A) MP2491C Rev. 1.0 www.MonolithicPower.com 11/14/2018 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 10 1 MP2491C – 32V, 6A, STEP-DOWN CONVERTER ORDERING INFORMATION Part Number* MP2491CGQB Package QFN-13 (2.5mmx3mm) Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MP2491CGQB–Z). TOP MARKING BAX: Product code of MP2491CGQB Y: Year code WW: Week code LLL: Lot number PACKAGE REFERENCE TOP VIEW IN PGND PG ILIM EN 13 12 11 MODE 10 1 2 3 VCC 4 5 VSEL1 VSEL2 9 BST 8 SW 7 AGND 6 FB QFN-13 (2.5mmx3mm) MP2491C Rev. 1.0 www.MonolithicPower.com 11/14/2018 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 2 MP2491C – 32V, 6A, STEP-DOWN CONVERTER PIN FUNCTIONS QFN-13 Pin # Name 1 IN 2 PGND 3 VCC 4 VSEL1 5 VSEL2 6 FB 7 8 AGND SW 9 BST 10 MODE 11 EN 12 ILIM 13 PG Description Supply voltage. IN is the drain of the internal power device and power supply for the entire chip. The MP2491C operates from a 4V to 32V unregulated input. Place a capacitor (CIN) as close to the IC as possible to prevent large voltage spikes from appearing at the input. Power ground. Place the PGND node outside of the CIN ground path to prevent switching current spikes from inducing voltage noise into the part. Internal 5V LDO regulator output. Decouple VCC with a 2.2µF capacitor. The VCC LDO is active even if EN is pulled low. Select the FB reference voltage 1. Connect VSEL1 to VCC, AGND, or a 1/2 VCC divider. VSEL1 cannot be left floating. Select the FB reference voltage 2. Connect VSEL2 to VCC or AGND. VSEL2 cannot be left floating. Feedback. Connect FB to the tap of an external resistor divider from the output to GND to set the output voltage. Analog ground. Connect AGND to PGND. Switch output. SW is the source of the high-side power device. Bootstrap. A BST capacitor is needed to drive the power switch’s gate above the supply voltage. Connect this capacitor between SW and BST to form a floating supply across the power switch driver. An on-chip regulator is used to charge up the external bootstrap capacitor. Buck operation mode set. Connect MODE to VCC or AGND to set auto-PFM/PWM mode or forced PWM mode. MODE cannot be left floating. Enable control. Drive EN high to enable the MP2491C. EN has a 2MΩ pull-down resistor to GND. Buck current limit set. Connect a resistor from ILIM to ground to program the output current limit. ILIM cannot be left floating. Power good output. PG is an open drain and indicates both output UV and OV. PG does not respond for BST low or UV conditions. When the VSEL1/VSEL2 voltage changes, PG switches low. After the output voltage settles, PG goes high again. MP2491C Rev. 1.0 www.MonolithicPower.com 11/14/2018 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 3 MP2491C – 32V, 6A, STEP-DOWN CONVERTER θJA θJC ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Supply voltage (VIN) ..................................... 34V VSW ............... -0.3V (-7V for