DESCRIPTIO APPLICATIO S TYPICAL APPLICATIO LTC1921 Dual 48V Supply and Fuse Monitor FEATURES

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1 LTC9 Dual Supply and Fuse Monitor FEATRES Withstands Transient Voltages p to V/V Requires No Precision External Components Independently Monitors Two Supplies for ndervoltage Faults:.V ±V MAX Overvoltage Faults: V ±.V MAX Accurately Detects ndervoltage Fault Recovery: V ±.V MAX Monitors Two External Fuses Operates from V to V Tolerates DC Faults to V Tolerates Accidental Supply Reversal to V Small Footprint: -Lead MSOP Package Specified from C to C APPLICATIO S Telecom Backplanes or Switch Cards Networking Backplanes or Switch Cards High Voltage Fuse Monitoring DESCRIPTIO The LTC 9 monitors two independent supplies, including their fuses, and drives up to three optoisolators to indicate status, in accordance with standard backplane specifications. Requiring only three noncritical resistors and optoisolators, the LTC9 replaces multiple voltage comparators, a voltage reference and several precision resistors. The monitor features dual supply overvoltage and undervoltage detection circuits. The preset trip thresholds include overvoltage, undervoltage and undervoltage recovery that are guaranteed over temperature and meet or exceed common backplane specifications. Additional built-in circuitry detects the condition of supply fuses. Overvoltage and undervoltage detectors ignore fast supply transients, eliminating false detection. The LTC9 operates from V to V with a typical power dissipation of less than mw. The LTC9 is available in -pin MSOP and SOIC packages., LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO RETRN R k R k FSE GOOD LOGIC SPPLY LOAD OT F LTC9 FSE A FSE B OT A SPPLY A GOOD SPPLY B GOOD SPERVISOR µp LOGIC COMMON SPPLY A SPPLY B F F OT B D MRS D MRS R /W 9 TA 9f

2 LTC9 ABSOLTE AXI RATI GS W W W (Note ) All voltages referred to Supply Voltage (,, FSE A, FSE B)... V to V Transient Voltage (,, FSE A, FSE B) (Note )... V to V Transient Voltage (,, FSE A, FSE B) (Note )... V to V OT A, OT B, OT F Pins....V to V Maximum Junction Temperature... C Operating Temperature Range (Note ) LTC9C/LTC9I... C to C Specified Temperature Range (Note ) LTC9C/LTC9I... C to C Storage Temperature Range... C to C Lead Temperature (Soldering, sec)... C PACKAGE/ORDER I FOR ATIO W FSE A OT F TOP VIEW FSE B OT B OT A MS PACKAGE -LEAD PLASTIC MSOP T JMAX = C, θ JA = C/W ORDER PART NMBER LTC9CMS LTC9IMS MS PART MARKING LTZV LTZ FSE A OT F TOP VIEW S PACKAGE -LEAD PLASTIC SO T JMAX = C, θ JA = 9 C/W FSE B OT B OT A ORDER PART NMBER LTC9CS LTC9IS S PART MARKING 9 9I Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at T A = C. (Note ) = V, =, =, FSE A =, FSE B =, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Power Supply Supply Voltage Range (, ) V Supply Current (I A I B ) µa µa Supply Monitor ndervoltage Threshold 9.. V ndervoltage Recovery Threshold.. V Overvoltage Threshold.. V Overvoltage Threshold Hysteresis. V Fuse Monitor Input Resistance, FSE A, FSE B MΩ Fuse Comparison Threshold V FSEA, V FSEB V LTC9C.9. V LTC9I.. V Output Propagation Delay C OT = pf, Overdrive = V µs Output Switch Resistance, OT F, OT A, OT B = = V, V FSEA = V FSEB = V Ω I OT = ma Ω 9f

3 ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at T A = C. (Note ) = V, =, =, FSE A =, FSE B =, unless otherwise noted. Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : Transient voltage for less than µs. This parameter is not % tested. Voltage should not exceed V between any two pins. Note : The LTC9C and LTC9I are guaranteed functional over the operating temperature range of C to C. LTC9 PARAMETER CONDITIONS MIN TYP MAX NITS Output Switch Off Leakage pa Output Switch Resistance in ndervoltage Lockout, = = V, I OT = ma Ω OT F, OT A, OT B = V, = V, I OT = ma Ω = V, = V, I OT = ma Ω Note : The LTC9C is guaranteed to meet specified performance from C to C. The LTC9C is designed, characterized and expected to meet specified performance from C to C but is not tested or QA sampled at these temperatures. The LTC9I is guaranteed to meet specified performance from t C. Note : All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to unless otherwise specified. TYPICAL PERFOR A CE CHARACTERISTICS SPPLY CRRENT (µa) W Supply Current vs Supply Voltage = = V FSEA = V FSEB 9 SPPLY VOLTAGE (V) SPPLY CRRENT (µa) Supply Current vs Temperature I A I B I A, I B = = V FSEA = V FSEB = TEMPERATRE ( C) 9 NDERVOLTAGE THRESHOLD (V) ndervoltage Threshold vs Temperature TEMPERATRE ( C) 9 G 9 G 9 G NDERVOLTAGE RECOVERY THRESHOLD (V) ndervoltage Recovery Threshold vs Temperature TEMPERATRE ( C) OVERVOLTAGE THRESHOLD (V) Overvoltage Threshold vs Temperature. 9 TEMPERATRE ( C) OVERVOLTAGE HYSTERESIS (V) Overvoltage Hysteresis vs Temperature TEMPERATRE ( C) 9 G 9 G 9 G 9f

4 LTC9 TYPICAL PERFOR A CE CHARACTERISTICS W Fuse Window Positive Threshold vs Temperature Fuse Window Negative Threshold vs Temperature Output R DS(ON) vs Temperature.. FSE POSITIVE THRESHOLD (V) TEMPERATRE ( C) FSE NEGATIVE THRESHOLD (V) TEMPERATRE ( C) OTPT RDS(ON) (Ω) OT A (OT F = V) OT F, OT B (OT A = V) = V = V I = ma 9 TEMPERATRE ( C) 9 G 9 G 9 G9 ndervoltage Response Time T A = C Overvoltage Response Time T A = C RESPONSE TIME (µs) RESPONSE TIME (µs) SPPLY STEP FROM NDERVOLTAGE RECOVERY THRESHOLD (V) 9 G SPPLY STEP FROM OVERVOLTAGE RECOVERY THRESHOLD (V) 9 G 9f

5 LTC9 PI F CTIO S (Pin ): Supply to be Monitored. The voltage at this pin is compared to the valid supply voltage window and the result is output at OT A (Pin ). Supply current is drawn from as well as from (Pin ). FSE A (Pin ): This pin monitors the state of a fuse by comparing the voltage at this pin to the voltage at (Pin ). The result is output at OT F (Pin ). (Pin ): Supply Return Reference. This pin must be at an equal or higher potential than the other pins and should be wired to the return. OT F (Pin ): This pin indicates the state of the external fuses by ORing the comparisons made to the FSE A and FSE B pins. If V FSEA (V FSEA is within the specified window around ) and V FSEB, then OT F will exhibit a high internal impedance to the pin. If V FSEA or V FSEB, then OT F is shorted internally to the pin and can shunt enough current to turn off an optoisolator or LED wired between these pins. OT F should be clamped externally so that it cannot be driven more than V below. This is done automatically by the optoisolator or LED diodes shown in the application circuits. OT A (Pin ): Indicates the state of. If is within the specified voltage window (neither undervoltage nor overvoltage), OT A will exhibit a high internal impedance to the OT F pin. If is outside the specified overvoltage or undervoltage limits, then OT A is shorted internally to the OT F pin and can shunt enough current to turn off an optoisolator or LED wired between these pins. OT A should be clamped externally so that it cannot be driven more than V below. This is done automatically by the optoisolator or LED diodes shown in the application circuits. OT B (Pin ): Indicates the state of. If is within the specified voltage window (neither undervoltage nor overvoltage), OT B will exhibit a high internal impedance to the OT A pin. If is outside the specified overvoltage or undervoltage limits, then OT B is shorted internally to the OT A pin and can shunt enough current to turn off an optoisolator or LED wired between these pins. OT B should be clamped externally so that it cannot be driven more than V below. This is done automatically by the optoisolator or LED diodes shown in the application circuits. FSE B (Pin ): This pin monitors the state of a fuse by comparing the voltage at this pin to the voltage at (Pin ). The result is output at OT F (Pin ). (Pin ): Supply to be Monitored. The voltage at this pin is compared to the valid supply voltage window and the result is output at OT B (Pin ). Supply current is drawn from as well as from (Pin ). 9f

6 LTC9 BLOCK DIAGRA W REGLATOR REF OT F OT A OT B FSE A FSE B 9 BD 9f

7 LTC9 APPLICATIO S I FOR ATIO W Supply Monitoring The LTC9 is designed to monitor dual power supplies. This is accomplished with precision window comparators and an accurate bandgap reference, as well as internal level shifting circuitry. The comparators are preset to standard voltage thresholds in order to accurately verify the status of each supply. These comparators also include precision hysteresis which allows accurate determination of voltage recovery. Status of the two supplies are indicated by the OT A and OT B pins. The supply window comparison works in a straightforward way (Figure ). As long as each supply magnitude remains in the valid supply window (.V to V), the outputs will indicate a valid supply condition by exhibiting a high internal impedance. If a supply magnitude falls below the undervoltage threshold (.V), then its respective output will short internally (OT A to OT F or OT B to OT A) until that supply reaches the undervoltage recovery threshold, which is preset to V. At this time, the output will return to a high impedance state. If a supply magnitude rises above the overvoltage threshold (V), then its respective output will short internally, just as with an undervoltage condition. The output will return to its nominal state when the supply overcomes the overvoltage hysteresis. Monitoring for each supply, and, is independent of the condition of the other supply. The LTC9 can be powered equally from either, or both supplies. This allows the LTC9 to provide correct information at its outputs as long as at least one supply is functional, whether or not the fuses are intact (see Figure ). ndervoltage Lockout If both supplies are active and their magnitude falls below V, or if only one supply is active and its magnitude falls below 9V, the LTC9 will lock all outputs into a fault condition by closing all three output switches. This state will be held until one supply magnitude is driven above 9V or both are driven above V. Fuse Monitoring In addition to monitoring two supplies, the LTC9 can monitor the condition of two supply fuses via the FSE A (Pin ) and FSE B (Pin ) inputs. Fuse monitoring is accomplished by comparing the potential at FSE A to the potential at supply and comparing the potential at FSE B to the potential at supply. If V FSEA is within the specified voltage window around and V FSEB is within the specified voltage window around, the OT F pin will indicate that the fuses are intact by exhibiting a high SPPLY VOLTAGE (V).. NOMINAL VOLTAGE NDERVOLTAGE RECOVERY TIME NDERVOLTAGE FALT OVERVOLTAGE FALT OVERVOLTAGE RECOVERY 9 F Figure. Supply Comparison 9f

8 LTC9 APPLICATIO S I FOR ATIO W internal impedance to the return () pin. The application must be designed so that an open fuse condition will force the fuse input (FSE A or FSE B) to be outside the specified window around the supply pins, such as with a weak pull-up resistor to, so that the LTC9 can properly indicate a fault at OT F. If supply diodes that exhibit high reverse leakage, such as Schottky diodes, are used, then the values of the pull-up resistors must be reduced accordingly. The FSE A and FSE B pins may also be used in conjunction with and for simple window comparison, provided that one of the circuit nodes to be compared can provide the small amount of supply current required to bias the IC. The LTC9 is ideally suited for comparison functions in a circuit where only high supply voltages are available. Output Pins The output pins in the LTC9 are designed to shunt external optoisolator diodes or LEDs during a supply or fuse fault condition. p to three diodes may be used in series, one for each output. In this configuration (Figure ), a diode connected between OT F and will indicate the condition of both fuses. A diode connected between OT A and OT F will indicate the condition of supply A ( ) and a diode connected between OT B and OT A will indicate the condition of supply B ( ). A resistor connected from OT B to the negative supply is required to bias the diodes. The LTC9 is designed to allow the current from this resistor to flow through the diodes during normal supply conditions and intact fuses, and will shunt this current away from the proper diodes during a fault condition. These diodes will further clamp the output pin potentials to in order to keep the outputs within rated voltages. If LEDs are used instead of optoisolators, they should be green since they will be lit when the supplies are within the proper voltage range. The LTC9 may be connected in such a way as to OR various outputs to allow the use of fewer optocouplers or LEDs (Figures a and b). One and two diode circuits are shown. RETRN V FSE SPPLY A SPPLY B F F R k R k FSE A FSE B OT F LTC9 D D OT A OT B 9 F R /W V SPPLY A V SPPLY B OT = LOGIC COMMON V OR OV V OR OV : WITHIN SPECIFICATION OV: OVERVOLTAGE V: NDERVOLTAGE V FSE A = = V OR OV V OR OV V FSE B = = SPPLY A FSE * : LED/PHOTODIODE ON : LED/PHOTODIODE OFF *IF BOTH FSES (F AND F) ARE OPEN, ALL OTPTS WILL BE HIGH SINCE R WILL NOT BE POWERED SPPLY B Figure. 9f

9 LTC9 APPLICATIO S I FOR ATIO W RETRN V FSE SPPLY A SPPLY B F F R k R k FSE A FSE B OT F LTC9 OT A OT B 9 Fa MOCD R /W = LOGIC COMMON V SPPLY OT V OR OV V OR OV V OR OV V OR OV : WITHIN SPECIFICATION OV: OVERVOLTAGE V: NDERVOLTAGE V FSE A = = V FSE B = = SPPLY FSE * : LED/PHOTODIODE ON : LED/PHOTODIODE OFF *IF BOTH FSES (F AND F) ARE OPEN, ALL OTPTS WILL BE HIGH SINCE R WILL NOT BE POWERED Figure a. Combined Supply Status RETRN V R k R k OT F LOGIC COMMON FSE A FSE B LTC9 OT A V FSE A = V FSE B = ALL OTHER CONDITIONS : WITHIN SPECIFICATION : LED/PHOTODIODE ON : LED/PHOTODIODE OFF SPPLY A SPPLY B OT B 9 Fb R /W OT Figure b. All Outputs Combined 9f 9

10 LTC9 TYPICAL APPLICATIO S R /W Complete Telecom Supply Monitor and Hot Swap TM Controller FSE C nf V R Ω R k % SPPLY A SPPLY B * R 9k % R.9k % R k % V EE V DD LTL PWRGD SENSE C nf V C nf V C.µF V C.µF V C µf V C.µF V C µf V V OV R.Ω % DRAIN GATE R k % R Ω % N V IN VIN V OT LCENT FLTRV CASE V OT * DIODES INC. SMATA Q IRF = DIODES INC. B LCENT JWA-E V V 9 IN OT SENSE ON/OFF TRIM V SENSE V VIN OT CASE 9 TA R k W R9 k W OT F LTC9 FSE A FSE B OT A OT B A A A B Hot Swap is a trademark of Linear Technology Corporation 9f

11 LTC9 PACKAGE DESCRIPTIO MS Package -Lead Plastic MSOP (Reference LTC DWG # --).9 ±. (. ±.). (.) MIN.. (..). ±. (. ±.) TYP GAGE PLANE. (.). (.) DETAIL A. (.) BSC RECOMMENDED SOLDER PAD LAYOT NOTE:. DIMENSIONS IN MILLIMETER/(INCH). DRAWING NOT TO SCALE TYP. ±. (. ±.) DETAIL A SEATING PLANE. ±. (. ±.) (NOTE ).9 ±. (.9 ±.). (.) MAX.. (.9.) TYP. (.) BSC. DIMENSION DOES NOT INCLDE MOLD FLASH, PROTRSIONS OR GATE BRRS. MOLD FLASH, PROTRSIONS OR GATE BRRS SHALL NOT EXCEED.mm (.") PER SIDE. DIMENSION DOES NOT INCLDE INTERLEAD FLASH OR PROTRSIONS. INTERLEAD FLASH OR PROTRSIONS SHALL NOT EXCEED.mm (.") PER SIDE. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE.mm (.") MAX. (.) REF. ±. (. ±.) NOTE. (.) REF. ±. (. ±.) MSOP (MS) N S Package -Lead Plastic Small Outline (Narrow. Inch) (Reference LTC DWG # --). BSC. ±..9.9 (..) NOTE. MIN N/. ±... (.9.9) N N/.. (..9) NOTE. ±. TYP RECOMMENDED SOLDER PAD LAYOT.. (..).. (..) TYP..9 (..).. (..) (..) (..) (.) NOTE: INCHES TYP BSC. DIMENSIONS IN (MILLIMETERS). DRAWING NOT TO SCALE. THESE DIMENSIONS DO NOT INCLDE MOLD FLASH OR PROTRSIONS. MOLD FLASH OR PROTRSIONS SHALL NOT EXCEED." (.mm) Information furnished by Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. SO 9f

12 LTC9 TYPICAL APPLICATIO S Single V Supply Monitor Single Supply Monitor V LOGIC V LOGIC V OT F SPPLY GOOD V OT F SPPLY GOOD LTC9 FSE A OT A FSE B OT B LOGIC COMMON LTC9 FSE A OT A FSE B OT B LOGIC COMMON /W 9 TA /W 9 TA Voltage and Fuse Monitor with LED Outputs RETRN R k R k D GREEN OT F FSE A LTC9 D GREEN FSE B OT A D GREEN SPPLY A F D OT B R.k W OT SPPLY B F D 9 TA RELATED PARTS PART NMBER DESCRIPTION COMMENTS LT Hot Swap Controller in SO- Package Active Current Limiting, Supplies from V to V LTC Hot Swap Controller in SOT- Package Fast Active Current Limiting, Supplies from V (Floating) LTC Hot Swap Controller in MSOP Package Fast Active Current Limiting, Floating Supply, PWRGD Output LTC Hot Swap Controller with Sequencer Similar to LTC, Sequences Three DC/DC Converters Linear Technology Corporation 9f LT/TP 9 K PRINTED IN SA McCarthy Blvd., Milpitas, CA 9- () -9 FAX: () - LINEAR TECHNOLOGY CORPORATION

VID Controlled High Current 4-Phase DC/DC Converter (Simplified Block Diagram) 4.5V TO 22V V OS TG1 INTV CC SW1 LTC1629 BG1 PGND SGND TG2 EAIN SW2

VID Controlled High Current 4-Phase DC/DC Converter (Simplified Block Diagram) 4.5V TO 22V V OS TG1 INTV CC SW1 LTC1629 BG1 PGND SGND TG2 EAIN SW2 FEATRES Fully Compliant with the Intel RM 8. ID Specification Programs Regulator Output oltage from.0 to.8 in m Steps Programs an Entire Family of Linear Technology DC/DC Converters with 0.8 References