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Rev. BFor more information www.analog.com TYPICAL APPLICATION FEATURES DESCRIPTION 100V UV/OV and Reverse Protection Controller with Bidirectional Circuit Breaker
APPLICATIONS
n Wide Operating Voltage Range: 2.5V to 60V n Overvoltage Protection to 100V n Reverse Supply Protection to –40V n Bidirectional Electronic Circuit Breaker: n +50mV Forward Sense Threshold n –50mV Reverse (LTC4368-1) n –3mV Reverse (LTC4368-2) n Adjustable ±1.5% Undervoltage and Overvoltage Thresholds n Low Operating Current: 80µA n Low Shutdown Current: 5µA n Controls Back-to-Back N-Channel MOSFETs n Blocks 50Hz and 60Hz AC Power n Hot Swappable Supply Input n Pin-Selectable Overcurrent Auto-Retry Timer or Latchoff n 10-Pin MSOP and 3mm × 3mm DFN Packages n AEC-Q100 Qualified for Automotive Applications n Reverse Battery Protection n Portable Instrumentation n Automotive and Industrial Surge Protection n Energy Storage Systems Load Protected from Reverse and Overvoltage at VIN The LT C®4368 protects applications from power supply voltages that may be too high, too low, or even negative and from overcurrent faults in both forward and reverse directions. The LTC4368 controls the gate voltage of a pair of external N-channel MOSFETs to ensure that the load is connected to the input supply only when there are no voltage or current faults. T wo comparator inputs allow configuration of the over- voltage (OV) and undervoltage (UV) set points using an external resistive divider . A current sense resistor sets the forward and reverse circuit breaker current thresholds. After a forward current fault, the LTC4368 will either latch- off power , or retry after a user adjustable delay. After a reverse current fault, the LTC4368 waits for the output to fall 100mV below the input to reconnect power to the load. The LTC4368 has a 32ms turn-on delay that debounces live supply input connections and blocks 50Hz and 60Hz AC power . UV/OV faults also trigger the 32ms recovery delay before the external MOSFETs are turned back on. VALID WINDOW V IN V IN V OUT V OUT OV = 36V UV = 7V 200ms/DIV –40V 20V/DIV GND
4368 TA01b
+70V 20V/DIV +50mV –3mV VIN UV OV RETRY SHDN
4368 TA01a
100µF VOUT 7V TO 36VSiR870 SiR870 GND LTC4368-2 464k 1500k 121k 29.4k 3.3nF 1200ms COOLDOWN AFTER FORWARD OC FAULT 0.005/uni03A9–40V TO 100V INRUSH CONTROL 22k 0.22µF OV = 36V UV = 7V I OUT –0.6A TO 10A VOUTSENSE Document Feedback All registered trademarks and trademarks are the property of their respective owners.
Rev. B For more information www.analog.com LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4368CDD-1#PBF LTC4368CDD-1#TRPBF LGTH 10-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C LTC4368CDD-2#PBF LTC4368CDD-2#TRPBF LGTK 10-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C LTC4368IDD-1#PBF LTC4368IDD-1#TRPBF LGTH 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C LTC4368IDD-2#PBF LTC4368IDD-2#TRPBF LGTK 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C LTC4368HDD-1#PBF LTC4368HDD-1#TRPBF LGTH 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C LTC4368HDD-2#PBF LTC4368HDD-2#TRPBF LGTK 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C LTC4368CMS-1#PBF LTC4368CMS-1#TRPBF L TGTG 10-Lead Plastic MSOP 0°C to 70°C LTC4368CMS-2#PBF LTC4368CMS-2#TRPBF L TGTJ 10-Lead Plastic MSOP 0°C to 70°C LTC4368IMS-1#PBF LTC4368IMS-1#TRPBF L TGTG 10-Lead Plastic MSOP –40°C to 85°C LTC4368IMS-2#PBF LTC4368IMS-2#TRPBF L TGTJ 10-Lead Plastic MSOP –40°C to 85°C LTC4368HMS-1#PBF LTC4368HMS-1#TRPBF L TGTG 10-Lead Plastic MSOP –40°C to 125°C LTC4368HMS-2#PBF LTC4368HMS-2#TRPBF L TGTJ 10-Lead Plastic MSOP –40°C to 125°C PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS Supply Voltage Input Voltages UV, SHDN (Note 3) O V (Note 3) R ETRY (Note 3) 3V to 5V TOP VIEW DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN
1 GATE
EXPOSED PAD (PIN 11) PCB GROUND CONNECTION OPTIONAL TJMAX = 150°C, θJA = 43°C/W V IN UV OV RETRY GND GATE SENSE VOUT FAULT SHDN TOP VIEW MS10 PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 160°C/W ORDER INFORMATION Output Voltages F AULT (Note 3) Input Currents R A Operating Ambient Temperature Range LTC 4368C LTC 4368I LTC 4368H Storage Temperature Range Lead Temperature (Soldering, 10 sec) (Note 1, Note 2)
Rev. BFor more information www.analog.com ORDER INFORMATION SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN, VOUT, SENSE VIN Input Voltage: Operating Range Protection Range l l 2.5 –40 100 V V VIN(UVLO) Input Supply Undervoltage Lockout V IN Rising l 1.8 2.2 2.4 V IVIN Input Supply Current: On Off SHDN = 2.5V, SENSE = VOUT = VIN SHDN = 0V, SENSE = VOUT = VIN l l 100 µA µA IVIN(R) Reverse Input Supply Current VIN = –40V, SENSE = VOUT = 0V l –1.5 –2.5 mA VOUT(UVLO) VOUT Undervoltage Lockout VOUT Rising, VOUT – SENSE = 100mV, VIN = 12V l 1.8 2.2 2.4 V tVOUT(UVLO) VOUT Undervoltage Lockout Delay V IN = 12V, VOUT:0V→12V, VOUT – SENSE = 100mV l 40 120 280 µs IVOUT VOUT Input Current: On Off Reverse SHDN = 2.5V, SENSE = VOUT = VIN SHDN = 0V, SENSE = VOUT = VIN VIN = –40V, SENSE = VOUT = 0V l l l 125 µA µA µA Current Sense I SENSE SENSE Input Current: On Off Reverse SHDN = 2.5V, SENSE = VOUT = VIN SHDN = 0V, SENSE = VOUT = VIN VIN = –40V, SENSE = VOUT = 0V l l l 1.2 0.1 µA µA µA ΔV SENSE,F Overcurrent Fault Threshold, Forward (SENSE – V OUT) VOUT = VIN VIN = 12V, VOUT = 0.5V VIN = 12V, VOUT = 0V l l l mV mV mV ΔV SENSE,R Overcurrent Fault Threshold, Reverse (SENSE – V OUT) LTC4368-1 VOUT = VIN LTC4368-2 VOUT = VIN l l –42 mV mV ΔVRR Reverse Overcurrent Re-Enable Turn-On Threshold (VIN – VOUT) VIN = SENSE = 6V to 60V VIN = SENSE = 2.5V to <6V l l 100 125 125 mV mV GA TE ΔVGATE Gate Drive (GATE – VOUT) VIN = 2.5V, IGATE = 0µA, –1µA VIN = 5V, IGATE = 0µA, –1µA VIN = 12V to 60V, IGATE = 0µA, –1µA l l l 7.2 8.7 5.5 10.8 13.1 V V V ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 2.5V to 60V, unless otherwise noted (Note 2). UV = 2.5V, OV = 0V, SHDN = 2.5V, SENSE = VOUT = VIN unless otherwise specified. AUTOMOTIVE PRODUCTS** LTC4368IMS-1#WPBF LTC4368IMS-1#WTRPBF L TGTG 10-Lead Plastic MSOP –40°C to 85°C LTC4368IMS-2#WPBF LTC4368IMS-2#WTRPBF L TGTJ 10-Lead Plastic MSOP –40°C to 85°C LTC4368HMS-1#WPBF LTC4368HMS-1#WTRPBF L TGTG 10-Lead Plastic MSOP –40°C to 125°C LTC4368HMS-2#WPBF LTC4368HMS-2#WTRPBF L TGTJ 10-Lead Plastic MSOP –40°C to 125°C *Temperature grades are identified by a label on the shipping container . Consult ADI Marketing for parts specified with wider operating temperature ranges. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. **Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a #W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models.
Rev. B For more information www.analog.com Note 1. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2. All currents into pins are positive; all voltages are referenced to GND unless otherwise noted. Note 3. These pins can be tied to voltages below –0.3V through a resistor that limits the current below 1mA. The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 2.5V to 60V, unless otherwise noted (Note 2). UV = 2.5V, OV = 0V, SHDN = 2.5V, SENSE = VOUT = VIN unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IGATE(UP) Gate Pull Up Current GATE = 15V, VIN = 12V l –20 –35 –60 µA IGATE(SLOW) Gate Slow Pull Down Current GATE = 20V, VIN = 12V l 40 90 160 µA IGATE(FAST) Gate Fast Pull Down Current GATE = 20V, SENSE = VIN = 12V l 30 60 90 mA tD(FAST) Gate Fast Turn Off Delay CGATE = 2.2nF: UV , OV Fault l 2 6 µs tD(SLOW) Gate Slow Turn Off Delay CGATE = 2.2nF, SHDN Falling, VIN = 12V l 150 275 575 µs tD(ON) Gate Turn-On Delay Time VIN = 12V, Power Good to ΔVGATE > 0V l 22 32 45 ms tp(GATE) Overcurrent Fault Propagation Delay C GATE = 2.2nF, Overcurrent Fault to ΔVGATE = 0V SENSE – VOUT: 0 to +100mV, or SENSE – VOUT: 0 to –100mV (LTC4368-1) SENSE – VOUT: 0 to –10mV (LTC4368-2) l 3 8 18 µs UV , OV VUV UV Input Threshold Voltage UV Falling l 492.5 500 507.5 mV VOV OV Input Threshold Voltage OV Rising l 492.5 500 507.5 mV VUVHYST UV Input Hysteresis l 20 25 32 mV VOVHYST OV Input Hysteresis l 20 25 32 mV ILEAK UV , OV Leakage Current V = 0.5V, VIN = 60V l ±10 nA tFAUL T UV , OV Fault Propagation Delay Overdrive = 50mV, V IN = 12V l 1 2 µs SHDN VSHDN SHDN Input Threshold SHDN Falling l 0.4 0.75 1.2 V ISHDN SHDN Input Current SHDN = 10V, VIN = 60V l ±15 nA tSTART Delay Coming Out of Shutdown Mode SHDN Rising to FAULT, VIN = 12V l 400 800 1400 µs tSHDN(F) SHDN To FAULT Asserted VIN = 12V l 1.5 3 µs tLOWPWR Delay From Turn Off to Low Power Operation VIN = 12V l 20 32 48 ms FAULT VOL FAULT Output Voltage Low IFAUL T = 500µA, VIN = 12V l 0.15 0.4 V IFAUL T FAULT Leakage Current FAULT = 5V, VIN = 60V l ±20 nA RETRY V RETRY Configuration Threshold for GATE Latch-Off RETRY Falling to ΔIRETRY > 2µA VIN = 12V l 0.5 1 1.5 V IRETRY Output Current for RETRY Timer RETRY = 2V, V IN = 12V RETRY = 0V, VIN = 12V l l 2.5 –10 3.5 –17 4.5 –25 µA µA tCLEAR Minimum SHDN Pulse to Clear Forward Overcurrent RETRY Latch RETRY = 0V, VIN = 12V l 15 µs tRETRY Forward Overcurrent Cool-Down Delay FAULT Asserted to FAULT Released, CRETRY = 22nF SENSE = VOUT = VIN = 12V l 80 120 150 ms
ELECTRICAL CHARACTERISTICS
Rev. BFor more information www.analog.com VOUT Operating Current vs Temperature VOUT Shutdown Current vs Temperature VOUT Current vs Reverse VIN GATE Drive vs GATE CurrentGATE Drive vs VIN Supply Voltage V OUT = 12V V OUT = 2.5V V OUT = 60V TEMPERATURE (°C) –50 –25 100 125 I VOUT (µA)
4368 G04
= 2.5V V IN = V OUT V OUT = 12V V OUT = 2.5V V OUT = 60V TEMPERATURE (°C) –50 –25 100 125 I VOUT (µA)
4368 G05
SHDN = 0V VIN = VOUT 25°C 125°C –45°C V OUT = 0V V IN (V) –10 –20 –30 –40 I VOUT (µA)
4368 G06
V OUT = V IN V OUT = 0V V IN (V) GATE (V)
4368 G07
TA = 25°C IGATE = –1µA V IN = V OUT = 12V IGATE(UP) (µA) –10 –20 –30 –40 –50 –60 ∆VGATE (V)
4368 G08
TA = 125°C TA = 25°C TA = –45°C TYPICAL PERFORMANCE CHARACTERISTICS VIN Operating Current vs Temperature VIN Shutdown Current vs Voltage VIN Supply Current vs Voltage (–40V to 100V) V IN = 12V V IN = 2.5V V IN = 60V SHDN = 2.5V V IN = V OUT TEMPERATURE (°C) –50 –25 100 125 I VIN (µA)
4368 G01
V IN (V) I VIN (µA)
4368 G02
TA = 125°C TA = 70°C TA = 25°C TA = –45°C SHDN = 0V V IN = VOUT UV = SHDN = 0V V OUT = 0V V IN (V) –50 –25 100 –2000 –1500 –1000 –500 500 I VIN (µA)
4368 G03
TA = 125°C TA = 25°C TA = –45°C
Rev. B For more information www.analog.com FAULT Output Current vs Voltage UV/OV Propagation Delay vs Overdrive GATE Turn-On Delay Time vs VIN ∆VRR Threshold vs VOUT FAULT Leakage vs Temperature UV , OV Thresholds vs Temperature TYPICAL PERFORMANCE CHARACTERISTICS V IN = V OUT = 12V TEMPERATURE (°C) –50 –25 100 125 492 496 500 504 508 V UV (mV)
4368 G09
125°C 25°C –45°C V IN = 12V V OUT (V) 102 120 RR (mV)
4368 G10
TEMPERATURE (°C) –50 –25 100 125 I FAUL T (nA)
4368 G11
VIN = 12V FAULT = 5V 125°C 25°C –45°C VIN = 12V UV = SHDN = 0V V OL (V) I FAUL T (mA)
4368 G12
VIN = VOUT = 12V TA = 25°C OVERDRIVE (mV) 100 tFAUL T (µs)
4368 G13
TA = 125°C TA = 25°C TA = –45°C V IN (V)
4368 G14
tD(ON) (ms) V OUT V IN GATE DUAL Si7942 1k, 10µF LOAD ON VOUT 5ms/DIV 20V/DIV 1V/DIV
4368 G15
V OUT SHDN 400µs/DIV 3V/DIV GND 5V/DIV
4368 G16
VIN = 12V DUAL Si7942 MOSFET 100µF , 12Ω LOAD SHDN GATE V OUT DUAL Si7942 MOSFET 100µF , 12Ω LOAD VIN = 12V 400µs/DIV 5V/DIV GND 3V/DIV
4368 G17
AC Blocking Turn-On Timing Turn-Off Timing
Rev. BFor more information www.analog.com PIN FUNCTIONS Exposed Pad: The exposed pad may be left open or con- nected to device ground. FAULT: Fault Indication Output. Connect to a pull-up resis- tor . This high voltage open drain output is pulled low if there is a voltage or current fault, if SHDN is low, or if VIN has not risen above VIN(UVLO). Leave unconnected if unused. GATE: Gate Drive Output for External N-channel MOSFETs. An internal charge pump provides 35µA of pull-up current and up to 13.1V of enhancement to the gate of an external MOSFET . When turned off, GATE is pulled just below the lower of V IN or V OUT. When V IN goes negative, GATE is automatically connected to VIN. GND: Device Ground. OV: Overvoltage Comparator Input. Connect this pin to an external resistive divider to set the desired V IN overvolt- age fault threshold. This input connects an accurate, fast 1µs) comparator with a 0.5V rising threshold and 25mV of hysteresis. When OV rises above its threshold, a 60mA current sink pulls down on the GATE output. When OV falls back below 0.475V, and after a 32ms GATE turn-on delay waiting period, the GATE charge pump is enabled. The low leakage current on this input allows the use of large valued resistors for the external resistive divider . Connect to GND if unused. RETRY: Retry or Latch-Off Selection Input. Connect to ground to latch off the MOSFETs after a forward over - current fault. To turn the external MOSFETs back on, the SHDN pin must be toggled low then high. Connect RETRY to an external capacitor to configure a 5.5ms/nF delay before the MOSFETs automatically turn on again. Leave unconnected if unused. SENSE: Overcurrent Sense Input. Connect a current sense resistor between SENSE and V OUT. This input detects overcurrent faults in both directions: forward at ΔVSENSE = 50mV, and reverse at ΔVSENSE = – 50mV (LTC4368-1 option) or ΔVSENSE = –3mV ( LTC4368-2 option). When an overcurrent fault is detected, a 60mA current sink pulls down on the GATE output, thus quickly disconnecting the load from the input. After a reverse cur- rent fault, when VOUT falls 100mV below VIN, the LTC4368 automatically turns on the external MOSFETs. A forward overcurrent fault uses the RETRY pin to set the conditions for reconnecting power to the load. Connect to V OUT if unused. SHDN: Shutdown Control Input. Assuming no voltage or current faults, SHDN high enables the GATE charge pump which in turn enhances the gate of the external N-channel MOSFETs. A low on SHDN generates a pull down on the GATE output with a 90µA current sink and places the LTC4368 in low current mode (5µA). If a forward overcur- rent condition latches off the external MOSFETs (RETRY grounded), the SHDN pin must be toggled low then high to re-enable the charge pump that enhances the external MOSFETs. If V IN goes above 80V, the SHDN pin voltage must be kept below 80V. UV: Undervoltage Comparator Input. Connect this pin to an external resistive divider to set the desired VIN under- voltage fault threshold. This input connects to an accu - rate, fast (1µs) comparator with a 0.5V falling threshold and 25mV of hysteresis. When UV falls below its thresh- old, a 60mA current sink pulls down on the GATE output. When UV rises back above 0.525V, and after a 32ms GATE turn-on delay waiting period, the GATE charge pump is enabled. The low leakage current on this input allows the use of large valued resistors for the external resistive divider . If unused and VIN is less than 80V, connect to VIN with a 510k resistor . VIN: Power Supply Input. Maximum protection range: –40V to 100V. Operating range: 2.5V to 60V. This pin can be hot swapped and has a 2.2V UVLO. VOUT: Output Voltage Sense Input. Connect a current sense resistor between V OUT and SENSE. The GATE charge pump voltage is referenced to VOUT. It is used as the charge pump input when VOUT is greater than approxi- mately 5V. The reverse current fault comparators require that V OUT rise above its 2.2V UVLO. V OUT cannot be hot swapped with supplies above 24V. Place at least 1µF from VOUT to GND.
Rev. B For more information www.analog.com BLOCK DIAGRAM 4368 BD VIN 2.2V UVLO 0.5V 0.5V 25mV HYSTERESIS UV OV SHDN VIN –40V TO 100V LDO IGATE 35µA REVERSE PROTECTION CLOSES SWITCH WHEN VIN IS NEGATIVE ENABLE VOUT GATE CHARGE PUMP f = 400kHz GATE SLOW OFF FAST OFF FWD_RESET REV_RESET OC_REV OC_FWD START TIMER GATE PULLDOWN FORWARD OVERCURRENT TIMER OVERCURRENT COMPARATORS 90µA 60mA – + DELAY TIMERS LOGIC FAULT RETRY + – 50mV (4368-1) 3mV (4368-2) 100mV 50mV GND 17µA 3.5µA
31 CYCLES
- The load or the input is shorted to ground or to another supply Excessive current flows from the supply to the load or from the load to the supply These conditions, if unchecked, can damage electronic systems and their connectors. Damage can take the form
Figure 1. Polarity Protection for DC Barrel Connectors degrade from repeated overstress. load by turning off the external back-to-back MOSFETs. RSENSE) or reverse (–50mV or –3mV/R SENSE) direction. 10-lead 3mm × 3mm DFN and MSOP packages.
4368 F01
4365 F03
connecting the load at VOUT to the supply at VIN. is enough gate drive to support the load.
4368 F02
Figure 2. LTC4368-2 Protects Load from Voltage (–40V to 100V) and Current (–0.75A to 12.5A) Faults Figure 3. Gate Drive (GATE – VOUT) vs VOUT
Figure 5 shows the timing associated with the UV pin. Figure 6 shows the timing associated with the OV pin.
4368 F04
Figure 4. UV , OV Comparators Monitor 12V Supply gate drive begins to increase up to a maximum of 13.1V. IN would be slightly higher . with a correspondingly lower threshold voltage. application for an input supply of 12V.
4368 F05
Figure 5. UV Timing (OV < (VOV – VOVHYST), SHDN > 1.2V)
4368 F06
Figure 6. OV Timing (UV > (VUV + VUVHYST), SHDN > 1.2V)
Rev. B For more information www.analog.com APPLICATIONS INFORMATION The example of Figure 4 uses standard 1% resistor values. The following parameters were selected: VOS(UV) = 3mV IUV = 10nA UVTH = 3.5V OVTH = 18V The resistor values can then be solved: 1. R1 + R2 = 3mV 10nA = 300k 2. R3 = 2 • 3mV 10nA The closest 1% value: R3 = 1.82M 3. R1 = 300k + 1.82M 2 • 18V = 58.9k The closest 1% value: R1 = 59K = 300K – 59K = 241K The closest 1% value: R2 = 243K Therefore: OV = 17.93V, UV = 3.51V. Limiting Inrush Current During Turn On Charging large capacitors on VOUT can lead to excessive inrush currents when LTC4368 turns on the external N-channel MOSFET . The maximum slew rate at the GATE pin can be reduced by adding a capacitor on the GATE pin: Slew Rate = IGATE(UP) CGATE When both the UV and OV faults are removed, the exter- nal MOSFETs are not immediately turned on. The input supply must remain within the user selected power good window for typically 32ms (tD(ON)) before the load is again connected to the supply. This recovery timeout period filters noise (including line noise) at the input supply and prevents chattering of power at the load. Procedure for Selecting UV/OV External Resistor Values The following 3-step procedure helps select the resistor values for the resistive divider of Figure 4. This procedure minimizes UV and OV offset errors caused by leakage currents at the respective pins. 1. Choose maximum tolerable offset at the UV pin, VOS(UV). Divide by the worst case leakage current at the UV pin, IUV (10nA). Set the sum of R1 + R2 equal to VOS(UV) divided by 10nA. Note that due to the pres- ence of R3, the actual offset at UV will be slightly lower . R1 + R2 = VOS(UV) IUV 2. Select the desired VIN UV trip threshold, UV TH. Find the value of R3: R3 = VOS(UV) IUV UV TH – 0.5V 0.5V 3. Select the desired VIN OV trip threshold, OV TH. Find the values of R1 and R2: R1 = VOS(UV) IUV ⎟⎟ + R3 OV TH
- 0.5V R2 = VOS(UV) IUV – R1
- IGATE(UP) For example, a 1A inrush current into a 100µF output capacitance requires a GATE capacitance of (using IGATE(UP) = 35µA): CGATE = 35µA • COUT IINRUSH CGATE = 35µA • 100µF = 3.5nF The 3.3nF C GATE capacitor in the application circuit of Figure 7 limits the inrush current to just over 1A. R GATE prevents CGATE from slowing down the reverse polarity protection circuits. It also stabilizes the fast pull-down circuits and prevents chatter during fault conditions. Set R GATE to 22k for most applications. Forward Overcurrent Fault Forward overcurrent protection prevents large currents from flowing from VIN to VOUT. This threshold current is determined by the external sense resistor (RSENSE) and an internal comparator (Figure 7, U1) with a 50mV threshold: IOC,FWD = 50mV RSENSE For the example of Figure 7, if 2.5A flows to the output across the 20mΩ sense resistor , the external MOSFETs (M1, M2) are immediately (8µs) turned off. This discon- nects the load from the input supply. Note that during initial startup, the output capacitance (COUT) charges from ground to V IN. To prevent this capacitive inrush current (I INRUSH) from falsely trigger - ing the forward overcurrent comparator , place an inrush limiting capacitor (C GATE) on the GATE pin (see Limiting Inrush Current During Turn On). This inrush current plus the output current must be less than the desired forward overcurrent threshold: IOC,FWD > IINRUSH + IOUT For the example of Figure 7, the 3.3nF GATE capacitor and the 100µF output capacitor limit the inrush current (IINRUSH) to approximately 1A. This means that the output current (IOUT) must be less than 1.5A during turn on in order to avoid a forward overcurrent fault during turn on. Once V OUT has ramped to its final value, the output cur - rent is limited to 2.5A. Once a for ward overcurrent fault is triggered, there are two application choices for turning the external MOSFETs back on: Automatically restart by placing an external capaci - tor on the RETRY pin. An internal cool-down timer will charge/discharge this capacitor 31 times with a 5.5ms/nF total delay. At the end of this delay, the external MOSFETs are turned back on, thus reconnect- ing the load to the input supply. The 0.22µF capaci - tor (CRETRY) in the application of Figure 7 yields a 1200ms cool-down timer delay. Note that the adjust- able cool-down period provides the user with a means of keeping the external MOSFETs within the rated SOA (safe operating area). See Figure 8 timing diagram.
Figure 7. Overcurrent Comparators Monitor 2.5A/–0.15A
4368 F07
- Latch off the MOSFET s by grounding the RETRY pin
toggled low then high (tCLEAR pulse width < tLOWPWR). See Figure 9 timing diagram.
4368 F08
Figure 8. Forward Overcurrent Fault with 0.22µF RETRY Capacitor Figure 9. Forward Overcurrent Fault with RETRY Pin Grounded
4368 F10
Figure 10. Reverse Overcurrent Fault: SENSE – VOUT < –3mV
Figure 11. Reverse VIN Protection Circuits
4368 F11
negative voltage from passing to the output load. M2 must withstand the reverse voltage excursion at VIN. out additional overshoot mitigation techniques in place. indistinguishable on the scale shown. gate and source terminals of the back-to-back MOSFETs. Figure 12. Hot Swapping VIN to –20V
pin is pulled all the way to ground. MOSFETs, and a 2A load with 100µF output capacitor .
4368 F13
Figure 13. Hot Swapping VIN to +48V
4368 F15
Figure 15. Slow Shutdown: GATE T racks VOUT as VOUT Decays
4368 F14
Figure 14. Recovery Timing During Power-On has a reverse breakdown of at least 40V. UV/OV power good window. See Figure 14.
4368 F16
Figure 16. Slow Shutdown Timing
and 16 show the FAULT output timing. Figure 17 shows two LTC4368-2 connected in parallel. always fully enhances the MOSFETs, even at light loads. VOUT to be larger than VIN while in the off condition. low on duty cycle for the MOSFET . See Figure 18.
4368 F17
Figure 17. Alternative to Ideal Diode
4368 F18
Figure 18. Single MOSFET High Power Application
commonly encountered during an overvoltage condition. of the wire along with the capacitance at the V IN node. solely to the sense resistor . TE pin should also be minimized. of trace volume connected to the drain and source pins. Figure 19. OV Fault with Large VIN Inductance
4368 F19
Figure 20. T ransients During 0V Fault when
4368 F20
Rev. BFor more information www.analog.com PACKAGE DESCRIPTION MSOP (MS) 0213 REV F 0.53 ±0.152 (.021 ±.006) SEATING PLANE 0.18 (.007) 1.10 (.043) MAX 0.17 –/uni00A00.27 (.007 – .011) TYP 0.86 (.034) REF 0.50 (.0197) BSC 1 2 3 4 5 4.90 ±0.152 (.193 ±.006) 0.497 ±0.076 (.0196 ±.003) REF8 9 107 6 3.00 ±0.102 (.118 ±.004) (NOTE 3) 3.00 ±0.102 (.118 ±.004) (NOTE 4) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 0.254 (.010) 0° – 6° TYP DETAIL “A” DETAIL “A” GAUGE PLANE 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 0.889 ±0.127 (.035 ±.005) RECOMMENDED SOLDER PAD LAYOUT 0.305 ±0.038 (.0120 ±.0015) TYP 0.50 (.0197) BSC 0.1016 ±0.0508 (.004 ±.002) 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1661 Rev F)
Rev. B For more information www.analog.com PACKAGE DESCRIPTION 3.00 ±0.10 (4 SIDES) NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 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 0.15mm ON ANY SIDE 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 0.40 ±0.10 BOTTOM VIEW—EXPOSED PAD 1.65 ±0.10 (2 SIDES) 0.75 ±0.05 R = 0.125 TYP 2.38 ±0.10 (2 SIDES) 106 PIN 1 TOP MARK (SEE NOTE 6)
0.200 REF
0.00 – 0.05 (DD) DFN REV C 0310 0.25 ±0.05 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.65 ±0.05 (2 SIDES)2.15 ±0.05 0.50 BSC 0.70 ±0.05 3.55 ±0.05 PACKAGE OUTLINE 0.25 ±0.05
0.50 BSC
10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699 Rev C) PIN 1 NOTCH R = 0.20 OR 0.35 × 45° CHAMFER
Rev. BFor more information www.analog.com Information furnished by Analog Devices is believed to be accurate and reliable. However , no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER A 06/18 Attached Note 3 to OV and FAULT Absolute Maximum Ratings 2 B 06/19 Added AEC-Q100 qualification and “W” part numbers 1,3
Rev. B For more information www.analog.com ANALOG DEVICES, INC. 2017-2019 D17021-0-6/18(B) www.analog.com RELATED PARTS TYPICAL APPLICATION LTC2966 Extends UV/OV Hysteresis Window PART NUMBER DESCRIPTION COMMENTS LTC4365 Overvoltage, Undervoltage and Reverse Supply Protection Controller Wide Operating Range: 2.5V to 34V, Protection Range: –40V to 60V, No TVS Required for Most Applications LT C4367 100V Overvoltage, Undervoltage and Reverse Supply Protection Controller Wide Operating Range: 2.5V to 60V, Protection Range: –40V to 100V, No TVS Required for Most Applications LT4363 High V oltage Surge Stopper with Current Limit Wide Operating Range: 4V to 80V, Reverse Protection to –60V, Adjustable Output Clamp Voltage LTC4380 8µA IQ Surge Stopper 4V to 72V Operation, Pin Selectable Clamp Voltage LTC4364 Surge Stopper with Ideal Diode 4V to 80V Operation, –40V Reverse Input, –20V Reverse Output LTC4366 High Voltage Surge Stopper 9V to >500V Operation, 8-Pin TSOT and 3mm × 2mm DFN Packages LTC4361 Overvoltage/Overcurrent Protection Controllers 5.8V Overvoltage Threshold, 85V Absolute Maximum LTC2909 T riple/Dual Inputs UV/OV Negative Monitor Pin Selectable Input Polarity Allows Negative and OV Monitoring LTC2912/LTC2913 Single/Dual UV/OV Voltage Monitor Adjustable UV and OV T rip Values, ±1.5% Threshold Accuracy LTC2914 Quad UV/OV Monitor For Positive and Negative Supplies LTC2955 Pushbutton On/Off Controller Automatic Turn-On, 1.5V to 36V Input, ±36V PB Input LT4256 Positive 48V Hot Swap Controller with Open-Circuit Detect Foldback Current Limiting, Open-Cir cuit and Overcurrent Fault Output, Up to 80V Supply LT C4260 Positive High Voltage Hot Swap Controller with ADC and I2C Wide Operating Range 8.5V to 80V LTC4352 Ideal Diode Controller External N-Channel MOSFETs Replace ORing Diodes, 0V to 18V Operation LTC4371 Dual Negative Voltage Ideal Diode-OR Controller External N-Channel MOSFETs, –4.5V to > –100V Operation LTC4355 Dual Positive Voltage Ideal Diode-OR Controller External N-Channel MOSFETs, 0.4µs Turn-Off, 80V Operation LT1913 Step-Down Switching Regulator 3.6V to 25V Input, 3.5A Maximum Current, 200kHz to 2.4MHz
4368 TA02
1.96k 301k 698k 1nF 301k 150k 750k INHA INLA L TC2966 INHB INLB V INA VINB OUTA OUTB PSA RS1A RS2A PSB RS1B RS2B GND 100k 100k VIN 12V Si7942DP 100µF 510k RETRY VOUT FAULT LTC4368-2 SENSEVIN UV OV SHDN GATE GND VOUT 0.02/uni03A9 3.3nF 22k 100k UV: OFF AT 7V ON AT 10V OV: OFF AT 18V ON AT 15V 0.22µF