LTM4655 EN55022B Compliant 40V, Dual 4A or Single 8A StepDown or 50W Inverting Module Regulator FEATURES DESCRIPTION n Dual 4A/Single 8A Low EMI Switch Mode Power Supply The LTM 4655 is an ultralow noise 40V, dual 4A or single n EN55022 Class B Compliant 8A DC/DC Module regulator designed to meet the radi- n Two Fully Independent Channels, Each ated emissions requirements of EN55022. Its channels Configurable for Positive or Negative Output are fully independent, parallelable and capable of deliver- Voltage Polarity ing positive or negative output polarity. Conducted emis- + n Output Voltage Range: 0.5V V V 26.5V sion requirements can be met by adding standard filter OUTn OUTn n Wide Input Voltage Range: Up to 40V components. Included in the package are the switching n 3.1V or 3.6V Start-Up, Configuration-Dependent controllers, power MOSFETs, inductors, filters and sup- n 1.67% Total DC Output Voltage Error Over Line, port components. A 5V, 25mA LDO and clock generator Load and Temperature enable phase interleaving of the power switching stages, n Analog Output Current Indicator (Positive-V Only) for improved EMC performance. OUT n LDO : 5V Fixed, 25mA Capable LDO OUT + The LTM4655 can regulate positive V voltages OUTn n Parallelable with LTM4651/LTM4653 between 0.5V and 26.5V from a 3.1V to 40V input. The n Constant-Frequency Current Mode Control LTM4655 can regulate negative V voltages between OUTn n Power Good Indicators and Programmable Soft-Start 0.5V and 26.5V from a maximum input range of 3.6V to n Overcurrent and Overtemperature Protection 40V, with the span from V to V not to exceed 40V. A INn OUTn n 16mm 16mm 5.01mm BGA Package switching frequency range of 250kHz to 3MHz issupported. The LTM4655 is offered in a 16mm 16mm 5.01mm APPLICATIONS BGA package with SnPb or RoHS compliant terminal finish. n Automated Test and Measurement All registered trademarks and trademarks are the property of their respective owners. Protected n Avionics and Industrial Control Systems by U.S. Patents, including 5481178, 5705919, 5847554, 6580258. n Video, Imaging and Instrumentation TYPICAL APPLICATION Concurrent, 12V Output DC/DC Module Regulator* I OUT1 V IN 12V + OUT V V IN1 OUT1 13V TO 28V UP TO 4A 4.7F + SV V IN1 OSNS1 22F V D1 SV LOAD1 OUT1 2 Output Voltage 4.7F V OUT1 Start-Up Waveforms f SET1 124k IMON1a CHANNEL 1 ANALOG OUTPUT RUN1,2 CURRENT INDICATOR 5V/DIV IMON1b V IN2 V = 0.25 I IMON1 OUT1 4.7F + SV IN2 LDO OUT 5V V OUT OUT1 LTM4655 UP TO 25mA 5V/DIV V D2 4.7F + V V OUT2 124k OUT2 5V/DIV f SET2 + V OSNS2 47F 240k LOAD2 2 PGOOD1,2 ISET2a 5V/DIV V 12V OUT2 OUT 4655 TA01b ISET2b UP TO 2.9A** 2ms/DIV I OUT2 SV OUT2 ISET1a 240k ISET1b GND 4655 TA01a * FOR COMPLETE CIRCUIT, SEE FIGURE 50. ** FOR CHANNELS CONFIGURED TO REGULATE NEGATIVE V : CURRENT LIMIT FREQUENCY-FOLDBACK INCEPTION IS OUT n A FUNCTION OF V , V -, AND f . CONTINUOUS OUTPUT CURRENT CAPABILITY IS SUBJECT TO DETAILS OF INn OUTn SWn APPLICATION IMPLEMENTATION. SEE NOTES 2 AND 3 AND THE APPLICATIONS INFORMATION SECTION, FOR DETAILS. Rev. A 1 Document Feedback For more information www.analog.comLTM4655 TABLE OF CONTENTS Features ..................................................... 1 Loop Compensation ................................................29 Applications ................................................ 1 Hot Plugging Safely ................................................30 Typical Application ........................................ 1 Input Disconnect/Input Short Considerations .........30 Description.................................................. 1 INTV and EXTV Connection .........................30 CCn CCn Absolute Maximum Ratings .............................. 3 Multiphase Operation ..............................................31 Pin Configuration .......................................... 3 Negative Output Current Capability Varies as a Order Information .......................................... 4 Function of V to V Conversion Ratios, INn OUTn Electrical Characteristics ................................. 4 Negative-V Operation .......................................32 OUT Typical Performance Characteristics .................. 10 Input Capacitors, Negative-V Operation ...........33 OUT Pin Functions .............................................. 14 Output Capacitors, Negative-V Operation ........34 OUT Simplified Block Diagram ............................... 21 Optional Diodes to Guard Against Overstress, Test Circuit ................................................. 22 Negative-V Operation .......................................34 OUT Decoupling Requirements ............................... 24 Frequency Adjustment, Negative-V OUT Operation................................................... 25 Operation ................................................................35 Power Module Overview .........................................25 Radiated EMI Noise ................................................36 V to V Conversion Ratios ................................26 Thermal Considerations and Output IN OUT Input Capacitors, Positive-V Operation .............26 Current Derating .....................................................36 OUT Output Capacitors, Positive-V Operation ...........27 Safety Considerations ............................................. 47 OUT Forced Continuous Operation .................................27 Layout Checklist/Example ...................................... 47 Output Voltage Programming, Tracking Typical Applications ...................................... 48 and Soft-Start .........................................................27 Package Description ..................................... 53 Frequency Adjustment ............................................28 Revision History .......................................... 55 Applications Information ................................ 29 Package Photograph ..................................... 56 Power Module Protection .......................................29 Design Resources ........................................ 56 RUN Pin Enable .......................................................29 Related Parts .............................................. 56 Rev. A 2 For more information www.analog.com