LTC2925 Linear Technology, LTC2925 Datasheet
LTC2925
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LTC2925 Summary of contents
Page 1
... FET and current sense resistor, and an electronic circuit breaker provides protection from short-circuit conditions. The LTC2925 also includes a power good timeout feature that turns off the supplies if an external supply monitor fails to indicate that the supplies have entered regulation within an adjustable time-out period ...
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... U GATE (Note 3) ........................................ –0.3 to 11.5V Average Current TRACK1, TRACK2, TRACK3 .................................. 5mA FB1, FB2, FB3 ....................................................... 5mA + 0.3V CC Operating Temperature Range + 0.3V CC LTC2925C ............................................... LTC2925I ............................................. – Storage Temperature Range .................. – 150 C Lead Temperature (Soldering, 10 sec Package ..................................................... 300 ORDER PART ...
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... SCTMR SCTMR SDTMR PGI PGTMR Note 3: The GATE pin is internally limited to a minimum of 11.5V. Driving this pin to voltages beyond the clamp may damage the part. LTC2925 www.DataSheet4U.com MIN TYP MAX 25 5 5.5 6 –7 –10 – ...
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... SDx pins will be pulled low again when RAMP <100mV and ON <1.23V slave supply is capable of operating with an input supply that is lower than the LTC2925’s minimum operating voltage of 2.9V, the SDx pins can be used to hold off the slave supplies. Each SDx pin is capable of sinking greater than 1mA with supplies as low as 2 ...
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... Tracking is achieved by mirroring the current from TRACKx into FBx. If the appropriate resistive divider connects RAMPBUF and TRACKx, the FBx current will force OUTx to track RAMP. The LTC2925 is capable of controlling slave supplies with feedback voltages between 0V and 1.6V. To prevent damage to the slave supply, the FBx pin will not force the slave’ ...
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... LTC2925 CTIO S GN/UF Packages SCTMR (Pin 24/Pin 21): Circuit Breaker Timer. A capaci- tor from SCTMR to GND programs the maximum time that a short circuit can be sustained before GATE is pulled low. When (SENSEP – SENSEN) > 50mV, SCTMR will pull up with 50 A, otherwise it pulls down with 2 A. When the voltage at SCTMR exceeds 1 ...
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... The LTC2925 provides a simple solution to all of the power supply tracking and sequencing profiles shown in Figures single LTC2925 controls up to four supplies with three “slave” supplies that track a “master” signal. With just two resistors, a slave supply is configured to ramp function of the master signal ...
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... TRACK1 pin is zero. In this case, there is no current from the FB1 pin and the LTC2925 has no effect on the output voltage accu- racy, transient response or stability of the slave supply. When the ON pin falls below V cally 1 ...
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... PGTMR Figure 7. Typical Application With External FET Electronic Circuit Breaker The LTC2925 features an electronic circuit breaker func- tion that protects the optional series FET against short circuits. An external sense resistor is used to measure the current flowing in the FET. If the voltage across the sense ...
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... In some applications it might be necessary to control the shutdown or RUN/SS pins of the slave supplies. The , is determined from: LTC2925 may not be able to supply the rated 1mA of cur- rent from the FB1, FB2, and FB3 pins when V 2.9V. If the slave power supplies are capable of operating ...
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... FET’s GATE ramps up on each cycle. Note that tying FAULT to ON also causes the LTC2925 to retry on Power Good Timeout faults. In this mode, verify that the slave supplies’ current limits provide sufficient protection under short-circuit conditions. ...
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... SENSE GATE R ONB V SENSEP SENSEN GATE RAMP 154k ONA 100k REMOTE V IN 10k STATUS V IN LTC2925 10k FAULT RAMPBUF R TB1 TRACK1 R TB2 R TA1 TRACK2 R R TB3 TA2 TRACK3 GND SCTMR SDTMR PGTMR R TA3 Figure 10. Four Supply Application ...
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... Si4412ADY MASTER 0 GATE 10 0.1 F SUPPLY MONITOR V SENSEP SENSEN GATE RAMP CC RST ON PGI SD1 RUN/SS DC/DC REMOTE FB1 FB = 1.235V R R FA1 16.5k 35.7k STATUS LTC2925 SD2 RUN/SS DC/DC FB2 FB = 0.8V FAULT RAMPBUF R R FA2 41.2k 88.7k TRACK1 SD3 RUN/SS TRACK2 DC/DC FB3 FB = 0.8V TRACK3 GND SCTMR SDTMR PGTMR R R FA3 C ...
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... TA C GATE 0.1 F 0.1 F SUPPLY MONITOR V SENSEP SENSEN GATE RAMP CC RST ON PGI SD1 RUN/SS DC/DC REMOTE FB1 FB = 1.235V R R FA1 16.5k 35.7k STATUS LTC2925 SD2 RUN/SS DC/DC FB2 FB = 0.8V FAULT RAMPBUF R R FA2 41.2k 88.7k TRACK1 SD3 RUN/SS TRACK2 DC/DC FB3 FB = 0.8V TRACK3 GND SCTMR SDTMR PGTMR R R FA3 ...
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... Si4412ADY MASTER 0 GATE 10 0.1 F SUPPLY MONITOR V SENSEP SENSEN GATE RAMP CC RST ON PGI SD1 RUN/SS DC/DC REMOTE FB1 FB = 1.235V R R FA1 16.5k 35.7k STATUS LTC2925 SD2 RUN/SS DC/DC FB2 FB = 0.8V FAULT RAMPBUF R R FA2 41.2k 88.7k TRACK1 SD3 RUN/SS TRACK2 DC/DC FB3 FB = 0.8V TRACK3 GND SCTMR SDTMR PGTMR R R FA3 C ...
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... MASTER 0 GATE 0 SUPPLY MONITOR V SENSEP SENSEN GATE RAMP RST CC ON PGI SD1 RUN/SS DC/DC REMOTE FB1 FB = 1.235V R R FA1 16.5k 35.7k STATUS LTC2925 SD2 RUN/SS DC/DC FB2 FB = 0.8V FAULT RAMPBUF R R FA2 41.2k 88.7k TRACK1 SD3 RUN/SS TRACK2 DC/DC FB3 FB = 0.8V TRACK3 GND SCTMR SDTMR PGTMR R R FA3 ...
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... TB 2 Caution with Boost Regulators and Linear Regulators Note that the LTC2925’s tracking cell is not able to control the outputs of all types of power supplies necessary to control a supply, where the output is not controllable through its feedback node, the series FET can be used to control its output ...
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... Figure 21. Layout Considerations advantageous to add a resistor near the feedback node of the slave supply in series with the FBx pin of the LTC2925. This resistor must not exceed: R SERIES This resistor is most effective if there is already a capacitor at the feedback node of the slave supply (often a compen- sation component). Increasing the capacitance on a slave supply’ ...
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... DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE LTC2925 www.DataSheet4U.com .337 – .344* (8.560 – 8.738) .033 (0 ...
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... GATE RAMP RST CC ON 3.3V PGI SD1 RUN/SS IN DC/DC REMOTE FB1 FB = 1.235V OUT R R FB1 FA1 16.5k 35.7k STATUS 3.3V SD2 RUN/SS IN DC/DC FB2 FB = 0.8V OUT FAULT LTC2925 RAMPBUF R R FA2 FB2 41.2k 88.7k TRACK1 3.3V SD3 RUN/SS IN TRACK2 DC/DC FB3 FB = 0.8V OUT TRACK3 R R FB3 FA3 86.6k 100k SENSEP SENSEN GND SCTMR SDTMR ...