EFFICIENCY (%) LT8210 100V V and V Synchronous 4-Switch IN OUT Buck-Boost DC/DC Controller with Pass-Thru FEATURES DESCRIPTION n Pin-Selectable Pass-Thru or Fixed Output CCM, The LT 8210 is a 4-switch synchronous buck-boost DCM, Burst Mode Operation DC/DC controller that can operate in pass-thru, forced n Programmable Non-Switching Pass-Thru Window continuous, pulse-skipping and Burst Mode operation. n 18A Pass-Thru Mode I with 99.9% Efficiency Pass-Thru is a feature that passes the input directly to Q n V Range: 2.8V to 100V (4.5V for Start-Up) the output when the input is within a user programmable IN n V Range: 1V to 100V window. Pass-Thru mode eliminates switching losses and OUT n Reverse Input Protection to 40V EMI along with maximizing efficiency. For input voltages n 1.25% Output Voltage Accuracy (40C to 125C) above or below the pass-thru window, the buck or boost n 3% Accurate Current Monitoring regulation loops maintain the output at the set maximum n 5% Accurate Current Regulation or minimum values, respectively. n 10V Quad N-Channel MOSFET Gate Drivers The GATEV driver supply is regulated to 10.6V allow- CC n EXTV LDO Powers Drivers from V /External Rail CC OUT ing the use of standard-level MOSFETs and can be pow- n 20% Cycle-by-Cycle Inductor Current Limit ered through the EXTV pin for improved efficiency. The CC n No Top MOSFET Refresh Noise in Buck or Boost GATEV regulator is back-drive-protected to ride through CC n Fixed/Phase-Lockable Frequency: 80kHz to 400kHz input brownouts while maintaining regulation. Optional n Spread Spectrum Frequency Modulation for Low EMI reverse input protection down to 40V can be imple- n Power Good Output Voltage/Overcurrent Monitor mented with the addition of a single N-channel MOSFET. n Available in a 38-Lead TSSOP and 40-Lead (6mm x The LT8210 includes a precision current sense ampli- 6mm) QFN Packages fier that can accurately monitor and limit output or input averagecurrent. APPLICATIONS All registered trademarks and trademarks are the property of their respective owners. Protected n Automotive, Industrial, Telecom, Avionics Systems by U.S. patents, including 10135340. n Automotive Start-Stop, Emergency Call Applications n ISO 7637, ISO 16750, MIL-1275, DO-160 Applications TYPICAL APPLICATION A 4m 4.7H D 4m Pass-Thru Transfer Characteristic V IN V OUT REGULATES: 8V TO 16V (V = 8V, V = 16V) OUT(BOOST) OUT(BUCK) 4V TO 100V 5A B C Transfer Characteristic + + SURVIVES: 10F 22F 220F 220F 36 100 40V TO 0.1F 0.1F 2 2 100V 96 PASS TG1 BST1 SW1 BG1 SNSP1 SNSN1 PGND BG2 SW2 BST2 TG2 THRU 24 V SNSP2 INP REGION 92 DG SNSN2 V EXTV IN CC EN/UVLO V OUT 88 BST1 GATEV 100k CC LT8210 12 V DD FB1 BST2 84 MODE1 7.15k V IN MODE2 FB2 V OUT 100k EFFICIENCY PWGD V 7.15k DD SYNC/ 0 80 4.7F 2.2F V V IMON 4 8 12 16 20 24 SPRD RT SS GND C1 C2 8210 TA01a 38.3k 59k INPUT VOLTAGE (V) 71.5k 15nF 8210 TA01b 46.4k 1nF 330pF 4.7nF 100pF 2.2nF Rev. B 1 Document Feedback For more information www.analog.com VOLTAGE (V)LT8210 TABLE OF CONTENTS Features ..................................................... 1 Reverse Input Protection ........................................20 Applications ................................................ 1 Current Monitoring and Regulation ........................20 Typical Application ........................................ 1 Buck Foldback .........................................................21 Description.................................................. 1 Bootstrap Capacitor Voltage ...................................21 Table of Contents .......................................... 2 PWGD Pin ...............................................................22 Absolute Maximum Ratings .............................. 3 Applications Information ................................ 23 Pin Configuration .......................................... 3 Maximum Output Current and R Selection ....23 SENSE Order Information .......................................... 3 Inductor Selection................................................... 24 Electrical Characteristics ................................. 4 Switching Frequency Selection ...............................25 Typical Performance Characteristics ................... 7 RT Set Switching Frequency ...................................25 Pin Functions .............................................. 12 Frequency Synchronization .....................................26 Block Diagram ............................................. 14 Spread-Spectrum Frequency Modulation ................26 Operation................................................... 15 Power MOSFET Selection .......................................27 Overview ................................................................. 15 C and C Selection ...........................................28 IN OUT Continuous Conduction Mode (CCM) ..................... 15 Bootstrap Capacitors (C , C ) .....................29 BST1 BST2 Discontinuous Conduction Mode (DCM) ................ 15 Bootstrap Diodes (D , D ) ............................30 BST1 BST2 Burst Mode Operation ............................................. 15 EXTV , GATEV and V ...................................30 CC CC DD Pass-Thru Mode ..................................................... 15 Programming Output Voltage .................................31 Power Switch Control (CCM, DCM, Burst Programming Input or Output Current Limit ...........31 ModeOperation) ................................................. 16 Programming V UVLO .........................................33 IN Power Switch Control: Buck Region Soft-Start ................................................................33 (V >1.19V ) ............................................ 17 Loop Compensation ...............................................33 INP OUT Power Switch Control: Boost Region Optional DG MOSFET Selection ..............................34 (V <0.84V ) ........................................... 17 Component Optimization for Pass-Thru Operation .34 INP OUT Power Switch Control: Buck-Boost Region Efficiency Considerations ......................................35 (0.84V < V < 1.19 V ) ...................... 17 PC Board Layout Checklist ....................................36 OUT INP OUT Power Switch Control (Pass-Thru Mode) ................ 18 Typical Applications ...................................... 38 Transitioning Between Operating Modes ................ 18 Revision History .......................................... 45 Enable and Start-Up ................................................ 19 Typical Application ....................................... 46 EXTV /GATEV /V Power Supplies .................. 19 Related Parts .............................................. 46 CC CC DD Rev. B 2 For more information www.analog.com