LTC2925 Multiple Power Supply Tracking Controller with Power Good Timeout Fea T Descrip T n Flexible Power Supply Tracking Up and Down The LTC 2925 provides a simple solution to power supply n Power Supply Sequencing tracking and sequencing requirements. By selecting a few n Supply Stability Is Not Affected resistors, the supplies can be configured to ramp-up and n Controls Three Supplies Without Series FETs ramp-down together or with voltage offsets, time delays n Controls an Optional Fourth Supply with a or different ramp rates. Series FET The LTC2925 controls the outputs of three independent n Electronic Circuit Breaker supplies without inserting any pass element losses. For n Remote Sense Switch Compensates for Voltage systems that require a fourth supply, or when a supply Drop Across a Series FET does not allow direct access to its feedback resistors, one n Supply Shutdown Outputs supply can be controlled with a series FET. When the FET n FAULT Output is used, an internal remote sense switch compensates for n Adjustable Power Good Timeout the voltage drop across the FET and current sense resistor, n Available in Narrow 24-Lead SSOP and Tiny 24-Lead and an electronic circuit breaker provides protection from QFN Packages short-circuit conditions. The LTC2925 also includes a power good timeout feature a T that turns off the supplies if an external supply monitor n V and V Supply Tracking CORE I/O fails to indicate that the supplies have entered regulation n Microprocessor, DSP and FPGA Supplies within an adjustable timeout period. n Servers L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Communication Systems Technology Corporation. All other trademarks are the property of their respective owners. Typical a T 0.015 Si4412ADY 3.3V V IN MASTER 0.1F 0.1F 10 SUPPLY 3.3V MONITOR 138k 2.5V V SENSEP SENSEN GATE RAMP CC RST 1V/DIV 1.8V ON 3.3V PGI 1.5V 100k SD1 RUN/SS IN DC/DC REMOTE FB1 FB = 1.235V OUT 1.8V V IN SLAVE1 10k 2925 TA02a 16.5k 10ms/DIV 35.7k STATUS 3.3V V IN LTC2925 SD2 RUN/SS IN 10k DC/DC FB2 FB = 0.8V OUT 2.5V FAULT SLAVE2 RAMPBUF 3.3V 1.65k 88.7k 41.2k 2.5V TRACK1 1V/DIV 3.3V 1.8V 88.7k 1.5V 13k SD3 RUN/SS IN TRACK2 DC/DC 86.6k 41.2k FB3 FB = 0.8V OUT 1.5V TRACK3 SLAVE3 GND SCTMR SDTMR PGTMR 100k 86.6k 2925 TA02b 100k 10ms/DIV 0.47F 0.082F 0.82F 2925 TA01 2925fd 1 For more information www.linear.com/LTC2925 ion pplica ions pplica ion uresLTC2925 a Te Maxi Mu M r a T (Notes 1, 2) Supply Voltage (V ) ................................. 0.3V to 10V GATE (Note 3) ......................................0.3V to 11.5V CC Input Voltages Average Current ON, PGI, SENSEP, SENSEN ................... 0.3V to 10V TRACK1, TRACK2, TRACK3 .................................5mA TRACK1, TRACK2, TRACK3 .........0.3V to V + 0.3V FB1, FB2, FB3.......................................................5mA CC SCTMR, SDTMR, PGTMR ............0.3V to V + 0.3V Operating Temperature Range CC Output Voltages LTC2925C ................................................ 0C to 70C FAULT, SD1, SD2, SD3, LTC2925I .............................................40C to 85C FB1, FB2, FB3, STATUS .......................... 0.3V to 10V Storage Temperature Range .................. 65C to 150C RAMPBUF, REMOTE ....................0.3V to V + 0.3V Lead Temperature (Soldering, 10 sec) CC RAMP .............................................0.3V to V + 1V MS Package ......................................................300C CC p in c F T TOP VIEW TOP VIEW 1 SCTMR V 24 CC 2 PGTMR SENSEP 23 24 23 22 21 20 19 3 PGI SENSEN 22 ON 1 18 STATUS 4 STATUS ON 21 SDTMR 2 17 FAULT 5 FAULT SDTMR 20 SD1 3 16 GATE 6 GATE 25 SD1 19 SD2 4 15 RAMP 7 RAMP SD2 18 SD3 5 14 REMOTE 8 REMOTE SD3 17 RAMPBUF 6 13 FB1 9 FB1 RAMPBUF 16 7 8 9 10 11 12 10 TRACK1 GND 15 11 TRACK2 FB3 14 12 FB2 TRACK3 13 UF PACKAGE 24-LEAD (4mm 4mm) PLASTIC QFN GN PACKAGE EXPOSED PAD (PIN 25) 24-LEAD PLASTIC SSOP PCB GND CONNECTION OPTIONAL T = 125C, = 85C/W JMAX JA T = 125C, = 37C/W JMAX JA Der in F Ma T