POWER LOSS (W) LTC7820 Fixed Ratio High Power Inductorless (Charge Pump) DC/DC Controller FEATURES DESCRIPTION n Low Profile, High Power Density, Capable of 500W+ The LTC 7820 is a fixed ratio high voltage high power n switched capacitor/charge pump controller. The device Soft Switching: 99% Peak Efficiency and Low EMI n includes four N-channel MOSFET gate drivers to drive V Max for Voltage Divider (2:1): 72V IN n external power MOSFETs in voltage divider, doubler or V Max for Voltage Doubler (1:2)/Inverter (1:1): 36V IN n inverter configurations. The device achieves a 2:1 step- Wide Bias V Range: 6V to 72V CC down ratio from an input voltage as high as 72V, a 1:2 n Soft Startup into Steady State Operation step-up ratio from an input voltage as high as 36V, or a n 6.5V to 40V EXTV Input for Improved Efficiency CC 1:1 inverting ratio from an input voltage up to 36V. Each n Input Current Sensing and Overcurrent Protection power MOSFET is switched with 50% duty cycle at a n Wide Operating Frequency Range: 100kHz to 1MHz constant pre-programmed switching frequency. System n Output Short-Circuit/OV/UV Protections with efficiency can be optimized to over 99%. The LTC7820 Programmable Timer and Retry provides a small and cost effective solution for high n Thermally Enhanced 28-Pin 4mm 5mm QFN Package power, non-isolated intermediate bus applications with fault protection. APPLICATIONS The LTC7820 switching frequency can be linearly n Bus Converters programmed from 100kHz to 1MHz. The device is available n High Power Distributed Power Systems in a thermally enhanced 28-lead QFN package with some n Communications Systems no-connect pins for high voltage compatible pin spacing. n Industrial Applications All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 9484799. TYPICAL APPLICATION Very High Efficiency 5A Voltage Divider Efficiency and Power Loss 10 V vs Load Current IN 48V/24V R SENSE 0.1F 100 2.0 V V 0.005 HIGH SENSE CC V = 48V IN 100 EFFICIENCY G1 V = 24V OUT I SENSE 0.1F 1.6 99 0.1F BOOST1 + I SENSE LTC7820 98 1.2 SW1 TIMER 10F G2 f = 100kHz s 1F 0.1F 6 97 0.8 RUN BOOST2 V OUT V = 24V IN 24V/12V 12V EXTV V = 12V CC OUT V 10 5A* LOW INTV CC 10F 96 0.4 V LOW SENSE G3 0.1F 10k 1F POWER LOSS UV 95 0 10k BOOST3 0 1 2 3 4 5 HYS PRGM LOAD CURRENT (A) 10k SW3 7820 TA01b * LOAD CURRENT APPLIED PGOOD AFTER STARTUP G4 FREQ INTV INTV CC CC 10k 40k 4.7F GND FAULT 7820 TA01a 7820fc 1 For more information www.linear.com/LTC7820 EFFICIENCY (%)LTC7820 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 3) TOP VIEW V , V ....................................... 0.3V to 80V CC HIGH SENSE BOOST1 ..................................................... 0.3V to 86V BOOST2, BOOST3 .......................................0.3V to 51V 28 27 26 25 24 23 SW1 .............................................................. 5V to 80V V 1 22 BOOST2 HIGH SENSE SW3 .............................................................. 5V to 45V NC 2 21 G2 HYS PRGM 3 20 V V , V ..................................... 0.3V to 45V LOW LOW LOW SENSE + TIMER 4 19 V 29 LOW SENSE I , I .......................................... 0.3V to 80V SENSE SENSE GND FREQ 5 18 BOOST3 (BOOST1 - SW1), (BOOST2 - V ) ............ 0.3V to 6V LOW RUN 6 17 G3 (BOOST3 - SW3) .......................................... 0.3V to 6V PGOOD 7 16 SW3 INTV , RUN ................................................ 0.3V to 6V CC UV 8 15 G4 EXTV , PGOOD ........................................ 0.3V to 45V 9 10 11 12 13 14 CC HYS PRGM, FREQ, TIMER, UV ............0.3V to INTV CC FAULT ......................................................... 0.3V to 80V INTV Peak Current (Note 10) ............................150mA UFD PACKAGE CC 28-LEAD (4mm 5mm) PLASTIC QFN Operating Junction Temperature T = 125C, = 43C/W , = 3.4C/W JMAX JA JC(bottom) EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Range (Notes 2, 11) ............................... 40C to 125C Storage Temperature Range .................. 65C to 150C