Datasheet LTC4360-1, LTC4360-2 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | Overvoltage Protection Controller |
| Pages / Page | 14 / 10 — APPLICATIONS INFORMATION. Figure 6. 50V Hot-Plug into the LTC4360. … |
| Revision | B |
| File Format / Size | PDF / 547 Kb |
| Document Language | English |
APPLICATIONS INFORMATION. Figure 6. 50V Hot-Plug into the LTC4360. Figure 7. Input Transient After Overvoltage
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APPLICATIONS INFORMATION
As the IN pin can withstand up to 80V, a high voltage This is well below the 85V absolute maximum voltage N-channel MOSFET can be used to protect the system rating of the LTC4360. The single, nonrepetitive, pulse of against rugged abuse from high transient or DC voltages energy (EAS) absorbed by the MOSFET during this ava- up to the BVDSS of the MOSFET. Figure 6 shows a 50V lanche breakdown with a peak current IAS is approximated input plugged into the LTC4360 controlling a 60V rated by the formula: MOSFET. E 2 AS = 0.5 • LIN • IAS Input transients also occur when the current through the For L cable inductance changes abruptly. This can happen when IN = 2µH and IAS = 4A, then EAS = 16µJ. This is within the I the LTC4360 turns off the N-channel MOSFET rapidly in an AS and EAS capabilities of most MOSFET’s including the Si1470DH. So in most instances, the LTC4360 can overvoltage event. Figure 7 shows the effects of a voltage ride through such transients without a bypass capacitor, transient at the wall adaptor output VADAPTOR. The cur- transient voltage suppressor or other external compo- rent in LIN will cause VIN to overshoot and avalanche the nents at IN. N-channel MOSFET to COUT . Typically, IN will be clamped to a voltage of VOUT + 1.3•(BVDSS of Si1470DH) = 45V. Figure 8 shows a particularly severe situation which can occur in a mobile device with dual power inputs. A 20V VIN 20V/DIV V V ADAPTOR IN 20V/DIV VADAPTOR/VOUT VOUT 5V/DIV VOUT 1V/DIV ICABLE 5A/DIV ICABLE 5A/DIV 5µs/DIV 436012 F05 2µs/DIV 436012 F06 FDC5612 FIGURE 5 CIRCUIT RIN = 150mΩ, LIN = 0.7µH RIN = 150µΩ, LIN = 2µH LOAD = 10Ω, COUT = 10µF LOAD = 10Ω, COUT = 10µF
Figure 6. 50V Hot-Plug into the LTC4360 Figure 7. Input Transient After Overvoltage
RIN LIN 20V + ICABLE M1 WALL IN Si1470DH OUT ADAPTER – D1 COUT B160 GATE IN OUT LOAD + LTC4360 5V R1 USB 100k GND – 436012 F07
Figure 8. Set-Up for Testing 20V Plugged into 5V System
Rev B 10 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts
APPLICATIONS INFORMATION
As the IN pin can withstand up to 80V, a high voltage This is well below the 85V absolute maximum voltage N-channel MOSFET can be used to protect the system rating of the LTC4360. The single, nonrepetitive, pulse of against rugged abuse from high transient or DC voltages energy (EAS) absorbed by the MOSFET during this ava- up to the BVDSS of the MOSFET. Figure 6 shows a 50V lanche breakdown with a peak current IAS is approximated input plugged into the LTC4360 controlling a 60V rated by the formula: MOSFET. E 2 AS = 0.5 • LIN • IAS Input transients also occur when the current through the For L cable inductance changes abruptly. This can happen when IN = 2µH and IAS = 4A, then EAS = 16µJ. This is within the I the LTC4360 turns off the N-channel MOSFET rapidly in an AS and EAS capabilities of most MOSFET’s including the Si1470DH. So in most instances, the LTC4360 can overvoltage event. Figure 7 shows the effects of a voltage ride through such transients without a bypass capacitor, transient at the wall adaptor output VADAPTOR. The cur- transient voltage suppressor or other external compo- rent in LIN will cause VIN to overshoot and avalanche the nents at IN. N-channel MOSFET to COUT . Typically, IN will be clamped to a voltage of VOUT + 1.3•(BVDSS of Si1470DH) = 45V. Figure 8 shows a particularly severe situation which can occur in a mobile device with dual power inputs. A 20V VIN 20V/DIV V V ADAPTOR IN 20V/DIV VADAPTOR/VOUT VOUT 5V/DIV VOUT 1V/DIV ICABLE 5A/DIV ICABLE 5A/DIV 5µs/DIV 436012 F05 2µs/DIV 436012 F06 FDC5612 FIGURE 5 CIRCUIT RIN = 150mΩ, LIN = 0.7µH RIN = 150µΩ, LIN = 2µH LOAD = 10Ω, COUT = 10µF LOAD = 10Ω, COUT = 10µF
Figure 6. 50V Hot-Plug into the LTC4360 Figure 7. Input Transient After Overvoltage
RIN LIN 20V + ICABLE M1 WALL IN Si1470DH OUT ADAPTER – D1 COUT B160 GATE IN OUT LOAD + LTC4360 5V R1 USB 100k GND – 436012 F07
Figure 8. Set-Up for Testing 20V Plugged into 5V System
Rev B 10 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts
