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LTC4364-1/LTC4364-2

436412f

TYPICAL APPLICATION

FEATURES DESCRIPTION

Surge Stopper

with Ideal Diode

The LTC

4364 surge stopper with ideal diode controller

protects loads from high voltage transients. It limits and

regulates the output during an overvoltage event, such

as load dump in automobiles, by controlling the voltage

drop across an external N-channel MOSFET pass device.

The LTC4364 also includes a timed, current limited circuit

breaker. In a fault condition, an adjustable fault timer must

expire before the pass device is turned off. The LTC4364-1

latches off the pass device while the LTC4364-2 automati-

cally restarts after a delay. The LTC4364 precisely monitors

the input supply for overvoltage (OV) and undervoltage

(UV) conditions. The external MOSFET is held off in un-

dervoltage and auto-retry is disabled in overvoltage.

An integrated ideal diode controller drives a second MOS-

FET to replace a Schottky diode for reverse input protec-

tion and output voltage holdup. The LTC4364 controls the

forward voltage drop across the MOSFET and minimizes

reverse current transients upon power source failure,

brownout or input short.

Overvoltage Protector Regulates

Output at 27V During Input Transient

Ideal Diode Holds Up Output

During Input Short

4A, 12V Overvoltage Output Regulator with Ideal Diode

Withstands 200V 1ms Transient at V

APPLICATIONS

Wide Operating Voltage Range: 4V to 80V

Withstands Surges Over 80V with V

Clamp

Adjustable Output Clamp Voltage

Ideal Diode Controller Holds Up Output Voltage

During Input Brownouts

Reverse Input Protection to –40V

Reverse Output Protection to –20V

Overcurrent Protection

Low 10μA Shutdown Current at 12V

Adjustable Fault Timer

0.1% Retry Duty Cycle During Faults (LTC4364-2)

Available in 4mm × 3mm 14-Lead DFN, 16-Lead MSOP,

and 16-Lead SO Packages

Automotive/Avionic Surge Protection

Hot Swap/Live Insertion

Redundant Supply ORing

Output Port Protection

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

OUTSENSEDGATESOURCEHGATE

TMRGND

0.22µF

60V

ENOUT

ENABLE

FAULT

436412 TA01a

F LT

SHDN FB

10Ω

2.2k

383k

12V

90.9k

10k

102k

22µF

OUT

CLAMPED

AT 27V

4.99k

CMZ5945B

68V

FDB33N25 FDB3682

10mΩ

6.8nF

LTC4364

50ms/DIV

TMR

= 6.8µF

LOAD

= 0.5A

20V/DIV

12V

OUT

20V/DIV

92V INPUT SURGE

27V CLAMP (ADJUSTABLE)

4364 TA01b

1ms/DIV

LOAD

= 6300µF

LOAD

= 0.5A

10V/DIV

12V

OUT

10V/DIV

4364 TA01c

INPUT SHORTED

TO GND

OUTPUT HELD UP

Summary of content (24 pages)

PAGE 1
LTC4364-1/LTC4364-2 Surge Stopper with Ideal Diode FEATURES n n n n n n n n n n n DESCRIPTION Wide Operating Voltage Range: 4V to 80V Withstands Surges Over 80V with VCC Clamp Adjustable Output Clamp Voltage Ideal Diode Controller Holds Up Output Voltage During Input Brownouts Reverse Input Protection to –40V Reverse Output Protection to –20V Overcurrent Protection Low 10μA Shutdown Current at 12V Adjustable Fault Timer 0.
PAGE 2
LTC4364-1/LTC4364-2 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Supply Voltage: VCC .................................. –40V to 100V SOURCE, OV, UV, SHDN Voltages.............. –40V to 100V DGATE, HGATE Voltages (Note 3)...................... SOURCE – 0.3V to SOURCE + 10V ENOUT, FLT Voltages................................. –0.3V to 100V OUT, SENSE Voltages.................................–20V to 100V Voltage Difference (SENSE to OUT)............. –30V to 30V Voltage Difference (OUT to VCC)...............
PAGE 3
LTC4364-1/LTC4364-2 ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4364CS-1#PBF LTC4364CS-1#TRPBF LTC4364S-1 16-Lead Plastic SO 0°C to 70°C LTC4364IS-1#PBF LTC4364IS-1#TRPBF LTC4364S-1 16-Lead Plastic SO –40°C to 85°C LTC4364HS-1#PBF LTC4364HS-1#TRPBF LTC4364S-1 16-Lead Plastic SO –40°C to 125°C LTC4364CS-2#PBF LTC4364CS-2#TRPBF LTC4364S-2 16-Lead Plastic SO 0°C to 70°C LTC4364IS-2#PBF LTC4364IS-2#TRPBF LTC4364S-2 16-Lead P
PAGE 4
LTC4364-1/LTC4364-2 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 12V. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VTMR(R) TMR Retry Threshold HGATE Rising (After 32 Cycles), VCC = 4V to 80V l 0.125 0.15 0.175 V ∆VTMR Early Warning Timer Window VTMR(G) – VTMR(F), VCC = 4V to 80V l 75 100 125 UV Falling, VCC = 4V to 80V l 1.22 1.25 1.
PAGE 5
LTC4364-1/LTC4364-2 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs VCC VCC = SOURCE = SENSE = OUT 400 300 250 200 ISNS + IOUT 150 SHDN = 0 12 OUT = 0 40 30 20 OUT = VCC 10 50 0 10 20 40 30 50 60 70 0 80 20 10 0 30 40 50 VCC (V) 60 OUT = 0 8 OUT = 12V 6 ISNS + IOUT in Shutdown vs VCC 100 70 0 –50 –25 80 –24 SOURCE = VCC HGATE = DGATE = SOURCE = VCC ∆VSD = 100mV 20 12 ∆VHGATE (V) IGATE(UP) (µA) 40 DGATE –8 –4 20 30 40 50 60 70 0 80 4 8 6 10 VCC (V)
PAGE 6
LTC4364-1/LTC4364-2 TYPICAL PERFORMANCE CHARACTERISTICS HGATE Pull-Down Current vs Temperature 175 150 125 100 75 150 125 50 25 75 0 TEMPERATURE (°C) 100 50 25 75 0 TEMPERATURE (°C) 100 10 125 –60 –200 –150 –100 –50 20 30 40 50 VCC – VOUT (V) 60 70 0 80 0 10 20 30 40 50 VCC – VOUT (V) 60 70 0 10 20 30 40 50 VCC – VOUT (V) 60 70 80 VCC = 4V 50 35 ∆VSD (mV) ∆VSD (mV) VOL (V) 0.2 60 40 1.00 30 25 20 0 OVERCURRENT CONDITION OUT = 0V 0.
PAGE 7
LTC4364-1/LTC4364-2 PIN FUNCTIONS DGATE: Diode Controller Gate Drive Output. When the load current creates more than 30mV of drop across the MOSFET, the DGATE pin is pulled high by an internal charge pump current source and clamped to 12V above the SOURCE pin. When the load current is small, the DGATE pin is actively driven to maintain 30mV across the MOSFET. If reverse current develops, a 130mA fast pull-down circuit quickly connects the DGATE pin to the SOURCE pin, turning off the MOSFET.
PAGE 8
LTC4364-1/LTC4364-2 PIN FUNCTIONS TMR: Fault Timer Input. Connect a capacitor between this pin and ground to set the times for fault warning, fault turn-off, and cool down periods. Either voltage regulation or current regulation starts pulling up the TMR pin. The current charging up this pin during the fault conditions increases with the voltage difference between VCC and OUT pins (see Applications Information). When TMR reaches 1.25V, the FLT pin pulls low to indicate the detection of a fault condition.
PAGE 9
LTC4364-1/LTC4364-2 BLOCK DIAGRAM VCC SOURCE HGATE HGATE OFF 10µA CHARGE PUMP f = 620kHz DGATE 12V 12V SENSE DGATE OFF 20µA FD – VA – IA + – 1.25V + – + + – DA + + – + – 30mV 30mV 50mV/ 25mV OUT FB SHDN – OC ENOUT SET OV ENOUT RESET SHDN + UVIN RETRY OV – 1.35V + 0.15V VCC – CONTROL CIRCUITRY VCC – 0.7V + 1.25V + – UV – + 2.2V FLT + 32x ENOUT – + 2µA 1.
PAGE 10
LTC4364-1/LTC4364-2 OPERATION The LTC4364 is designed to suppress high voltage surges and limit the output voltage to protect load circuitry and ensure normal operation in high availability power systems. It features an overvoltage protection regulator that drives an external N-channel MOSFET (M1) as the pass device and an ideal diode controller that drives a second external N-channel MOSFET (M2) for reverse input protection and output voltage holdup.
PAGE 11
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION Some power systems must cope with high voltage surges of short duration such as those in automobiles. Load circuitry must be protected from these transients, yet critical systems may need to continue operating during these events. If the voltage regulation loop is engaged for longer than the timeout period, set by the timer capacitor, an overvoltage fault is detected. The HGATE pin is pulled down to the SOURCE pin by a 130mA current, turning M1 off.
PAGE 12
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION An overcurrent fault occurs when the current limit circuitry has been engaged for longer than the timeout delay set by the timer capacitor. The HGATE pin is then immediately pulled low by 130mA to the SOURCE pin, turning off the MOSFET M1. After the fault condition has disappeared and a cool down period has transpired, the HGATE pin is allowed to pull back up and turn on the pass device (LTC4364-2).
PAGE 13
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION since it would lengthen the overall fault timer period and cause more stress on the power transistor during an overcurrent event. VTMR (V) ITMR = 5µA 1.35 ITMR = 5µA 1.
PAGE 14
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION period. If the UV reset pulse is asserted during the cool down period, the TMR pulses are unaffected and the part restarts after the cool down period ends. If OV is higher than 1.25V while UV reset pulse is applied, the part will not restart until OV drops below 1.25V even if the cool down period ends. reverse input protection with minimum voltage drop in normal operation.
PAGE 15
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION gate and source of each MOSFET for extra protection (Figures 8 to 10). Transient Stress in the MOSFET The SOA of the MOSFET must encompass all fault conditions. In normal operation the pass devices are fully on, dissipating very little power. But during either overvoltage or overcurrent faults, the HGATE pin is controlled to regulate either the output voltage or the current through MOSFET M1.
PAGE 16
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION Then:  1 ( b − a )3 1  b  P 2 t =ILOAD2  tr + τ  2a 2In + 3a 2 + b2 – 4ab   2  a b  3  Typically VREG ≈ VIN and τ >> tr simplifying the above to: 1 2 P 2 t = ILOAD2 ( VPK − VREG ) τ 2 For the transient conditions of VPK = 80V, VIN = 12V, VREG = 16V, tr = 10μs and τ = 1ms, and a load current of 3A, P2t is 18.4W2s—easily handled by a MOSFET in a D-pak package.
PAGE 17
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION Another way to limit supply transients above 100V at the VCC pin is to use a Zener diode and a resistor, D1 and R4, as shown in Figure 1. D1 clamps voltage spikes at the VCC pin while R4 limits the current through D1 to a safe level during the surge. In the negative direction, D1 along with R4 clamps the VCC pin near GND.
PAGE 18
LTC4364-1/LTC4364-2 APPLICATIONS INFORMATION Choosing 250μA for the resistive divider: R8 = 1.25V = 5k 250µA P= Select 4.99k for R8. R7 = (27V – 1.25V ) •R8 = 102.8k 1.25V The closest standard value for R7 is 102k. Now, calculate the sense resistor, RSNS, value: RSNS = ∆VSNS(MIN) ILIM = 45mV = 11mΩ 4A Choose 10mΩ for RSNS. 1ms• 5µA CTMR = = 50nF 100mV The closest standard value for CTMR is 47nF. Finally, calculate R1, R2 and R3 for 6V low battery detection and 60V input overvoltage level: 1.
PAGE 19
LTC4364-1/LTC4364-2 TYPICAL APPLICATIONS + OV 36V HGATE VCC SHDN R1 118k SOURCE DGATE SENSE UV R2 44.2k VOUT 2A OUT FB LTC4364 ENOUT OV R3 5.9k CLOAD 100µF R5 10Ω D6 DDZ9702T CHG 47nF D1 SMAT70A UV 4.2V RSNS 20mΩ M1 SUD50N03-9 VIN 5V TO 28V GND FLT TMR 436412 F08 CTMR 0.22µF Figure 8. 2A Wide Range Hot Swap Controller with Circuit Breaker M1 FDB3632 VIN 18V TO 33V OV 45V VOUT 2.5A CLAMPED CLOAD AT 36V 100µF + CHG 47nF UV 15V RSNS 15mΩ M2 FDMS86101 R1 100k R2 6.04k R3 3.
PAGE 20
LTC4364-1/LTC4364-2 TYPICAL APPLICATIONS M1A FDD16AN08A0 VINA 12V M2A FDD16AN08A0 RSNSA 10mΩ + CHGA 6.8nF HGATE SOURCE DGATE SENSE VCC SHDN UV R8A 4.99k ENOUT TMR FLT GND M1B FDD16AN08A0 VINB 12V VCC M2B FDD16AN08A0 RSNSB 10mΩ + CHGB 6.8nF COUTB 22µF R5B 10Ω HGATE SOURCE DGATE SENSE SHDN UV OUT FB LTC4364 OV R7B 59k R8B 4.99k ENOUT TMR CTMRB 0.22µF R7A 59k OUT FB LTC4364 OV CTMRA 0.22µF COUTA 22µF R5A 10Ω VOUT CLAMPED AT 16V FLT GND 436412 F11 Figure 11.
PAGE 21
LTC4364-1/LTC4364-2 TYPICAL APPLICATIONS R9 1k, 1W M1 FDD16AN08A0 VIN 12V UV 6V OV 30V VCC SHDN R1 191k + R4 2.2k CHG 6.8nF D1 CMZ5945B 68V R5 10Ω HGATE SOURCE DGATE SENSE UV R2 40.2k RSNS M2 FDD16AN08A0 10mΩ VOUT 4A CLAMPED D8 1N4746A AT 16V 18V, 1W COUT 22µF R7 287k OUT FB R8 24.9k LTC4364 ENOUT OV R3 10k GND FLT TMR 436412 F13 CTMR 0.1µF Figure 13. Overvoltage Regulator with Output Keep Alive During Shutdown PACKAGE DESCRIPTION Please refer to http://www.linear.
PAGE 22
LTC4364-1/LTC4364-2 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MS Package 16-Lead Plastic MSOP (Reference LTC DWG # 05-08-1669 Rev Ø) 0.889 ± 0.127 (.035 ± .005) 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 4.039 ± 0.102 (.159 ± .004) (NOTE 3) 0.50 (.0197) BSC 0.305 ± 0.038 (.0120 ± .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) DETAIL “A” 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .
PAGE 23
LTC4364-1/LTC4364-2 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S Package 16-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) .386 – .394 (9.804 – 10.008) NOTE 3 .045 ±.005 .050 BSC 16 N 14 13 12 11 10 9 N .245 MIN .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) 1 .030 ±.005 TYP 15 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.
PAGE 24
LTC4364-1/LTC4364-2 TYPICAL APPLICATION M1 FDB3632 VIN 12V CIN 10µF UV 6V OV 60V R1 383k 1% R2 90.9k 1% R3 10k 1% CHG 6.8nF VCC SHDN M2 FDMS86101 RSNS 0.2Ω R7 49.9k 1% R5 10Ω HGATE SOURCE DGATE SENSE UV OUT FB LTC4364 R9 16.9k 1% 10µF 50V CER D2 DDZ9702T 15V 10µF 50V CER VOUT* CLAMPED AT 18V RESR 100mΩ R8 4.99k 1% ENOUT OV GND FLT TMR 0.1µF 436412 F14 *PROTECTED AGAINST BACKFEEDING OR FORWARD CONDUCTING FROM –20V TO 50V Figure 14. 0.