XR79120 22V, 20A Synchronous Step Down COT Power Module FEATURES General Description Controller, drivers, bootstrap diode and capaci- tor, MOSFETs, Inductor, CIN and COUT integrated The XR79120 is a 20A synchronous step-down Power Module for point-of in one package load supplies. A wide 4.5V to 22V input voltage range allows for single 20A Step Down Module supply operation from industry standard 5V, 12V, and 19.6V rails. Wide 4.5V to 22V Input Voltage Range With a proprietary emulated current mode Constant On-Time (COT) con- >0.6V Adjustable Output Voltage trol scheme, the XR79120 provides extremely fast line and load transient Proprietary Constant On-Time Control response using ceramic output capacitors. It requires no loop compensa- No Loop Compensation Required tion hence simplifying circuit implementation and reducing overall compo- Stable Ceramic Output Capacitor Operation nent count. The control loop also provides 0.12% load and 0.17% line Programmable 200ns to 2s On-Time regulation and maintains constant operating frequency. A selectable Constant 400kHz to 600kHz Frequency power saving mode allows the user to operate in discontinuous mode Selectable CCM or CCM/DCM (DCM) at light current loads thereby significantly increasing the converter CCM/DCM for high efficiency at light-load efficiency. With a 93% peak efficiency and 84% for loads as low as CCM for constant frequency at light-load 100mA, the XR79120 is suitable for applications where low power losses Programmable Hiccup Current Limit with Ther- are important. mal Compensation A host of protection features, including over-current, over-temperature, Precision Enable and Power Good flag short-circuit and UVLO, help achieve safe operation under abnormal Programmable Soft-start operating conditions. 74-pin 12x14x4mm QFN package The XR79120 is available in a RoHS compliant, green/halogen free APPLICATIONS space-saving 74-pin 12x14x4mm QFN package. With integrated control- Networking and Communications ler, drivers, bootstrap diode and capacitor, MOSFETs, inductor, CIN and Fast Transient Point-of-Loads COUT, this solution allows the smallest possible 20A POL design. Industrial and Medical Equipment Embedded High Power FPGA Ordering Information back page Typical Application Line Regulation V 1.820 IN VIN PVIN 1.815 Enable/Mode EN/MODE 1.810 V OUT Power Good PGOOD VOUT 1.805 C IN R VCC XR79120 SW 1.800 R LIM C FF R1 SS ILIM 1.795 C OUT TON FB 1.790 C C R VCC SS ON R2 1.785 AGND PGND 1.780 4 6 8 10 12 14 16 18 20 22 V (V) IN 2014 Exar Corporation 1 / 19 exar.com/XR79120 Rev 1A V (V) OUTXR79120 Absolute Maximum Ratings Operating Conditions PV ...............................................................................3V to 22V Stresses beyond the limits listed below may cause perma- IN nent damage to the device. Exposure to any Absolute Max- V ..............................................................................4.5V to 22V IN imum Rating condition for extended periods may affect device reliability and lifetime. V ............................................................................4.5V to 5.5V CC PV , V ...................................................................-0.3V to 25V 1 IN IN SW, ILIM.....................................................................-1V to 22V V ...........................................................................-0.3V to 6.0V CC PGOOD, V , T , SS, EN, FB...............................-0.3V to 5.5V CC ON 1 3 BST..........................................................................-0.3V to 31V Switching Frequency......................................400kHz to 600kHz BST-SW.......................................................................-0.3V to 6V Junction Temperature Range..............................-40C to +125C 1, 2 SW, ILIM...................................................................-1V to 25V JEDEC51 Package Thermal Resistance, ................14.5C/W JA ALL other pins.................................................-0.3V to VCC+0.3V Package Power Dissipation at 25C......................................6.9W Storage Temperature...........................................-65C to +150C Junction Temperature..........................................................150C Note 1: No external voltage applied. Power Dissipation...............................................Internally Limited Note 2: SW pins minimum DC range is -1V, transient is -5V for less than 50ns. Lead Temperature (Soldering, 10 sec)......................260C MSL3 Note 3: Recommended frequency for optimum performance ESD Rating (HBM - Human Body Model)...............................2kV Electrical Characteristics Unless otherwise noted: T = 25C, V =12V, BST=V , SW=AGND=PGND=0V, C =4.7uF. Limits applying over the full J IN CC VCC operating temperature range are denoted by a Symbol Parameter Conditions Min Typ Max Units Power Supply Characteristics VCC regulating 522 V Input Voltage Range V IN VCC tied to VIN 4.5 5.5 I VIN Input Supply Current Not switching, V = 12V, V = 0.7V 0.7 1.5 mA VIN IN FB I VCC Quiescent Current Not switching, V =V = 5V, V = 0.7V 0.7 1.5 mA VCC CC IN FB I VIN Input Supply Current f=500kHz, R =61.9k, VFB=0.58V 21 mA VIN ON I Shutdown Current Enable = 0V, V = 12V 1 A OFF IN Enable and Under-Voltage Lock-Out UVLO V EN Pin Rising Threshold 1.8 1.9 2.0 V IH EN V EN Pin Hysteresis 50 mV EN HYS V EN Pin Rising Threshold for DCM/ 2.8 3.0 3.1 V IH EN CCM operation V EN Pin Hysteresis 100 mV EN HYS 2014 Exar Corporation 2 / 19 exar.com/XR79120 Rev 1A