LTC2928 Linear Technology, LTC2928 Datasheet
LTC2928
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LTC2928 Summary of contents
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... Individual channel controls are available to independently exercise enable outputs and supervisory functions. A high voltage input allows the LTC2928 to be powered from voltages as high as 16.5V. A buffered reference output permits single negative power supply sequencing and monitoring operations. ...
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... IV .................................................................±10mA CC IHV ...............................................................±20mA CC I ..................................................................±10mA REF Operating Ambient Temperature Range LTC2928C ................................................ 0°C to 70°C + 0.3V LTC2928I ............................................. –40°C to 85° 0.3V Storage Temperature Range CC SSOP Package ................................... –65°C to 150°C QFN Package ...................................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) SSOP Package .................................................. 300°C ...
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... MON MON(TH) V above Overvoltage Threshold by MON –1μA EN Enable Pin On, V ≤ 4V 2.5mA 2.5mA CMP I = –1μA CMP 1.1V HZ LTC2928 www.DataSheet4U.com MIN TYP MAX UNITS 2.9 6 ● 1 2.5 mA ● 2.75 2.8 2.85 ● 50 100 150 mV ● 7.2 12 16.5 ● 3.2 3.3 3.4 ● –10 mA ● ...
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... D O N E Voltage Output Low DONE(OL) I D O N E Pull-Down Current DONE(DN) R Required Pull-Up Resistance on “Last” DONE LTC2928 V Voltage Output High when Configured DONE(LAST) as “Last” Reset Pin: R S R S T Voltage Output Low ...
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... Note 6: The D O N E pull-down current is present when D O N high to facilitate cascading multiple LTC2928s. Note 7: The R S T and O V outputs have an internal pullup to V –10μA. However, external pull-up resistors may be used when faster rise ...
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... LTC2928 TYPICAL PERFORMANCE CHARACTERISTICS VCC GND CC 85°C 4 25°C 3 –40° 2.5 3 3.5 4 4.5 5 5.5 V (V) CC 2928 G08 Regulated 3 REG 3.35 3.3 3.25 3 (V) CC 2928 G11 Enable Output Voltage vs Enable Output Current and ...
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... Three State Selection Pin Current vs Pin Voltage (SQT1, SQT2, MS1, MS2, RDIS –5 –10 –15 –20 0.3 0.6 0.9 1.2 1 THREE STATE PIN VOLTAGE (V) LTC2928 www.DataSheet4U.com Comparator Over-Voltage Glitch Immunity 1k OV OCCURS ABOVE CURVE 100 COMPARATOR IGNORES GLITCH 10 100 0 COMPARATOR OVERDRIVE (% OF OV THRESHOLD) 2928 G15 ...
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... LTC2928 TYPICAL PERFOR A CE CHARACTERISTICS Temperature CAS(UP) (device configured as MASTER) – GND CAS –69 –63 –57 –51 –45 –50 – TEMPERATURE (°C) 2928 G22 Voltage Output Low (CMP, CAS, F L D O N R S O ...
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... See Applications Information for the fault reporting details. Leave the CMP outputs open if unused. D O N Sequence Done Output. The last (or only) LTC2928 must have D O N E pulled high with an external resistor to V (3.3k 5% recommended). The LTC2928 fl ...
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... LTC2928 PI FU CTIO OVA: Over Voltage Adjust Input. After configuring the undervoltage thresholds, bias this input to set the overvoltage threshold for all positive supplies. Leave the pin floating to set an overvoltage threshold approximately 32% above the undervoltage threshold. Tie OVA move the overvoltage threshold above 1V ...
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... DECODERS SEQUENCING LOGIC V CC TIME OUTPUT 4 POSITION CONTROL 6 DECODERS V CC 100µ 50µA + – 100µ 20µA LTC2928 www.DataSheet4U.com GND REF V CP 10µA 4 EN1 EN2 EN3 EN4 2µA 2uA 2uA RTMR PTMR STMR 22µA 22uA 22uA 10µA 10uA 10uA ...
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... While V CC mode and pulls down its CAS pin. When V the LTC2928 is configured for operation and releases its CAS pin. Multiple LTC2928s with common CAS connec- tions will therefore synchronize with each other. The ON input is used to start the sequence-up and sequence- down process ...
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... R S T line pulls low. The reset timer starts once all inputs return above threshold. The LTC2928 can be configured to issue a fault if R S T pulls low due to an undervoltage event (see master/slave configuration table in Applications Information). Upon a ...
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... Applications Information and discussion on system faults later in this document. After the system has clocked through “time position 1”, the last LTC2928 (defined by a 2.4k to 5.1k pull-up resistor on D O N releases the pull down on D O N E and D O N E pulls high. ...
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... An external fault is generated by pulling the F L T pin low. Tie the O V pin to F L generate overvoltage faults. In applications using multiple LTC2928s, tie all the F L T pins together to ensure proper re-sequencing. Upon detecting an external fault, all enable outputs are pulled low. ...
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... CAS pins between master and slave devices are tied together (Figure 1). To achieve time extension, the D O N E pin of the preceding LTC2928 is connected to the ON pin of the subsequent LTC2928 (Figure 2). Both con- nections are allowed to exist within one system (Figure 4). ...
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... The second device then releases its D O N E pin, which pulls Time extension can cascade to more than two devices as shown in Figure simple matter of adding more LTC2928s in the middle of the cascade, with a master/not- first designation. (MASTER/FIRST) LTC2928 ...
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... Another interesting application combines the usage of both the CAS pin connection and the D O N E —ON communica- tions link. Figure 4 shows a two dimensional configura- tion of four LTC2928s that allows for 16 supplies to be sequenced time positions. 16 SUPPLIES, 16 TIME POSITIONS ...
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... This may cause the module to shutdown. The LTC2928 is easily configured to enable a sense tran- sistor after a power supply has been sequenced on and inrush currents have diminished (Figure 7). The sense transistor feeds the sequenced supply voltage back to the sense line of the power module ...
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... U U 12V V IN 1N4148 1 F 97.6k 10k Figure 10. Supply Sequencing with Stabilized Power Module Outputs DC/DC 3. OUT SHDN 100 DC/DC 2. OUT SHDN 100 LTC2928 EN1 V1 EN2 V2 EN3 V3 EN4 MS1 470 F MS2 VSEL CC 1.5k RT1 GND 3.4k RT2 RTMR 95.3k RT3 PTMR 95 ...
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... Any channel that is asynchronously OFF is removed from participation in the sequencing and supply monitoring processes, allowing the LTC2928 to operate normally on the remaining operating channels. When experiencing a fault in the “No Shutdown Debug Mode”, the asynchronous OFF feature may be used to conveniently pull down the enable outputs ...
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... RT1 EN1 RT2 EN2 RT3 EN3 RT4 EN4 3.3k ON DONE DONE EN1-4 SEQUENCING SEQUENCING SEQUENCING UP DOWN LTC2928 RT1 V1 RT2 V2 RT3 V3 RT4 100k ON FLT 1N4148 ON V1-4 SEQUENCING UP SHUTDOWN RESTART FLT Figure 13. Automatic Restart After Fault www.DataSheet4U.com SUPPLY BANK ...
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... RT3 EN3 RT4 EN4 V CC CONTROLLER ON FLT 1N4148 ON FLT EN1-4 SEQUENCING UP SHUTDOWN LTC3704 –5. –4.67V) MON(TH) RUN 43.2k LTC2928 10k V1 11k V MON(TH) REF EN1 SEL 2928 F12a Figure 15. Negative Supply Monitoring LTC2928 www.DataSheet4U.com V CC 3.3k 2928 F11a = –V (43.2k/11k) REF 2928f 23 ...
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... The application monitors four positive voltages. Connect the voltage selection input (VSEL) to ground (Table 1). c. Device designations The application requires only one LTC2928, and it is con- sidered the MASTER device. By definition also the FIRST and LAST device. Configure the MASTER/FIRST designation with the three-state MS1 and MS2 inputs connected to ground (Table 2) ...
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... The application requires a fast shutdown upon overvoltage. To generate a fault upon an overvoltage condition, tie O F L The fault condition shuts down all controlled supplies. LTC2928 www.DataSheet4U.com 400 µ ...
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... F L T pulls low. All enable outputs pull low and the pass transis- tors shut off. Because of the fault condition, the LTC2928 is prevented from re-sequencing until all supplies drop below their sequence-down threshold, and the ON input is below 0 ...
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... U t STMR ON DONE CAS 1 EN3 V3 EN4 V4 EN1, EN2 V1 V2 CMP3, CMP4, CMP1 CMP2 RST PTMR RTMR Figure 18. Design Example Timing Diagram, Sequencing- 0.67V MON(TH) 0.67V MON(TH) LTC2928 www.DataSheet4U.com 0.67V MON(TH) V MON(TH) 0.67V MON(TH) t RTMR 2928 TA02 2928f 27 ...
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... LTC2928 APPLICATIO S I FOR ATIO STMR ON DONE CAS 8 EN1, EN2 V1, V2 EN4 V4 EN3 V3 CMP1, CMP2 CMP3, CMP4 RST PTMR Figure 19. Design Example Timing Diagram, Sequencing-Down 0.67V MON(TH) 0.67V www.DataSheet4U.com MON(TH) 0.67V MON(TH) 2928 TA03 2928f ...
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... BSC * DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED .152mm (.006") PER SIDE ** DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE LTC2928 www.DataSheet4U.com 12.50 – 13.10* (.492 – .516 ...
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... LTC2928 5.00 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 7.00 ± 0.10 (2 SIDES) 0.75 ± 0.05 NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE M0-220 VARIATION WHKD 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE 5 ...
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... PTMR CMP3 PTMR C 3300pF STMR CMP4 STMR V REF CC SQT2 OVA SQT1 RST CAS OV RDIS FLT ON DONE 3.32k 10k 10k V CC Figure 20. LTC2928 Design Example LTC2928 www.DataSheet4U.com RP1 10k 1.5V CORE FPGA 2.5V I/O RST 1.8V CORE DSP 3.3V I/O RST R2B SD1 18.2k R1B 36.5k BAT85 R1A 10k R2A ...
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... LTC2928 RELATED PARTS PART NUMBER DESCRIPTION LTC2920-1 Single/Dual Power Supply LTC2920-2 Margining Controller LTC2921/LTC2922 Power Supply Tracker with Input Monitor LTC2923 Power Supply Tracking Controller LTC2924 Quad Power Supply Sequencer LTC2925 Multiple Power Supply Tracking Controller with Power Good Timeout LTC2926 ...