Datasheet LT4356-1, LT4356-2 (Analog Devices) - 8
| Fabricante | Analog Devices |
| Descripción | Surge Stopper |
| Páginas / Página | 26 / 8 — PIN FUNCTIONS. AOUT (DFN and SO Packages Only):. SHDN. EN:. Exposed Pad … |
| Revisión | C |
| Formato / tamaño de archivo | PDF / 480 Kb |
| Idioma del documento | Inglés |
PIN FUNCTIONS. AOUT (DFN and SO Packages Only):. SHDN. EN:. Exposed Pad (DFN Package Only):. FB:. SNS:. FLT:. TMR:. GATE:. GND:
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- LT4356CDE-1#PBF LT4356CDE-1#TRPBF LT4356CDE-2#PBF LT4356CDE-2#TRPBF LT4356CMS-1#PBF LT4356CMS-1#TRPBF LT4356CS-1#PBF LT4356CS-1#TRPBF LT4356CS-2#PBF LT4356CS-2#TRPBF LT4356HDE-1#PBF LT4356HDE-1#TRPBF LT4356HDE-2#PBF LT4356HDE-2#TRPBF LT4356HMS-1#PBF LT4356HMS-1#TRPBF LT4356HS-1#PBF LT4356HS-1#TRPBF LT4356HS-2#PBF LT4356HS-2#TRPBF LT4356IDE-1#PBF LT4356IDE-1#TRPBF LT4356IDE-2#PBF LT4356IDE-2#TRPBF LT4356IMS-1#PBF LT4356IMS-1#TRPBF LT4356IS-1#PBF LT4356IS-1#TRPBF LT4356IS-2#PBF LT4356IS-2#TRPBF
Versión de texto del documento
LT4356-1/LT4356-2
PIN FUNCTIONS AOUT (DFN and SO Packages Only):
Amplifier Output.
SHDN
: Shutdown Control Input. Pulling the SHDN pin low Open collector output of the auxiliary amplifier. It is capable shuts the part down to a low current mode. All functions of sinking up to 2mA from 80V. The negative input of the are turned off for the LT4356-1 while the internal reference amplifier is internally connected to a 1.25V reference. and the auxiliary amplifier stay active for the LT4356-2.
EN:
Open-Collector Enable Output. The EN pin goes high The SHDN input threshold is similar to a TTL input. If the impedance when the voltage at the OUT pin is above (V SHDN voltage goes below 2.1V, the voltage must go below CC – 0.7V), indicating the external MOSFET is fully on. The 0.4V for 100μs to properly shut down the part. To turn state of the pin is latched until the OUT pin voltage resets the part back on, the SHDN voltage must transition from at below 0.5V and goes back up above 2V. The internal below 0.4V to greater than 2.1V with a slew rate faster NPN is capable of sinking up to 3mA of current from 80V than 10V/ms. An internal, 4μA current source is provided to drive an LED or opto-coupler. to pull the SHDN pin up. An external pull-up device should be used if the leakage current to ground might exceed 1μA.
Exposed Pad (DFN Package Only):
Exposed pad may be The SHDN pin can be pulled up to 100V or below GND by left open or connected to device ground (GND). 60V without damage.
FB:
Voltage Regulator Feedback Input. Connect this pin
SNS:
Current Sense Input. Connect this pin to the output of to the center tap of the output resistive divider connected the current sense resistor. The current limit circuit controls between the OUT pin and ground. During an overvoltage the GATE pin to limit the sense voltage between VCC and condition, the GATE pin is servoed to maintain a 1.25V SNS pins to 50mV. At the same time the sense amplifier threshold at the FB pin. This pin is clamped internally to also starts a current source to charge up the TMR pin. 7V. Tie to GND to disable the OV clamp. This pin can be pulled below GND by up to 60V, though
FLT:
Open-Collector Fault Output. This pin pulls low after the the voltage difference with the VCC pin must be limited to voltage at the TMR pin has reached the fault threshold of 1.25V. less than 30V. Connect to VCC if unused. It indicates the pass transistor is about to turn off because
TMR:
Fault Timer Input. Connect a capacitor between this either the supply voltage has stayed at an elevated level for an pin and ground to set the times for early warning, fault extended period of time (voltage fault) or the device is in an and cool down periods. The current charging up this pin overcurrent condition (current fault). The internal NPN is capa- during fault conditions depends on the voltage difference ble of sinking up to 3mA of current from 80V to drive an LED or between the VCC and OUT pins. When VTMR reaches 1.25V, opto-coupler. the FLT pin pulls low to indicate the detection of a fault
GATE:
N-Channel MOSFET Gate Drive Output. The GATE condition. If the condition persists, the pass transistor turns pin is pulled up by an internal charge pump current source off when VTMR reaches the threshold of 1.35V. As soon as and clamped to 14V above the OUT pin. Both voltage and the fault condition disappears, the pull up current stops current amplifiers control the GATE pin to regulate the and a 2µA current starts to pull the TMR pin down. When output voltage and limit the current through the MOSFET. VTMR reaches the retry threshold of 0.5V, the GATE pin pulls high turning back on the pass transistor. A minimum of
GND:
Device Ground. 10nF capacitor is needed to compensate the loop. A 10V
IN+ (DFN and SO Packages Only):
Positive Input of the rated X7R capacitor is recommended for CTMR. Auxiliary Amplifier. This amplifier can be used as a level
VCC:
Positive Supply Voltage Input. The positive supply detection comparator with external hysteresis or linear input ranges from 4V to 80V for normal operation. It regulator controlling an external PNP transistor. This pin can also be pulled below ground potential by up to 60V is clamped internally to 7V. Connect to ground if unused. during a reverse battery condition, without damaging the
OUT:
Output Voltage Sense Input. This pin senses the part. The supply current is reduced to 7µA with all the voltage at the source of the N-channel MOSFET and sets functional blocks off. the fault timer current. When the OUT pin voltage reaches 0.7V away from VCC, the EN pin goes high impedance. Rev. C 8 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 Typical Applications Package Description Revision History Typical Application Related Parts
PIN FUNCTIONS AOUT (DFN and SO Packages Only):
Amplifier Output.
SHDN
: Shutdown Control Input. Pulling the SHDN pin low Open collector output of the auxiliary amplifier. It is capable shuts the part down to a low current mode. All functions of sinking up to 2mA from 80V. The negative input of the are turned off for the LT4356-1 while the internal reference amplifier is internally connected to a 1.25V reference. and the auxiliary amplifier stay active for the LT4356-2.
EN:
Open-Collector Enable Output. The EN pin goes high The SHDN input threshold is similar to a TTL input. If the impedance when the voltage at the OUT pin is above (V SHDN voltage goes below 2.1V, the voltage must go below CC – 0.7V), indicating the external MOSFET is fully on. The 0.4V for 100μs to properly shut down the part. To turn state of the pin is latched until the OUT pin voltage resets the part back on, the SHDN voltage must transition from at below 0.5V and goes back up above 2V. The internal below 0.4V to greater than 2.1V with a slew rate faster NPN is capable of sinking up to 3mA of current from 80V than 10V/ms. An internal, 4μA current source is provided to drive an LED or opto-coupler. to pull the SHDN pin up. An external pull-up device should be used if the leakage current to ground might exceed 1μA.
Exposed Pad (DFN Package Only):
Exposed pad may be The SHDN pin can be pulled up to 100V or below GND by left open or connected to device ground (GND). 60V without damage.
FB:
Voltage Regulator Feedback Input. Connect this pin
SNS:
Current Sense Input. Connect this pin to the output of to the center tap of the output resistive divider connected the current sense resistor. The current limit circuit controls between the OUT pin and ground. During an overvoltage the GATE pin to limit the sense voltage between VCC and condition, the GATE pin is servoed to maintain a 1.25V SNS pins to 50mV. At the same time the sense amplifier threshold at the FB pin. This pin is clamped internally to also starts a current source to charge up the TMR pin. 7V. Tie to GND to disable the OV clamp. This pin can be pulled below GND by up to 60V, though
FLT:
Open-Collector Fault Output. This pin pulls low after the the voltage difference with the VCC pin must be limited to voltage at the TMR pin has reached the fault threshold of 1.25V. less than 30V. Connect to VCC if unused. It indicates the pass transistor is about to turn off because
TMR:
Fault Timer Input. Connect a capacitor between this either the supply voltage has stayed at an elevated level for an pin and ground to set the times for early warning, fault extended period of time (voltage fault) or the device is in an and cool down periods. The current charging up this pin overcurrent condition (current fault). The internal NPN is capa- during fault conditions depends on the voltage difference ble of sinking up to 3mA of current from 80V to drive an LED or between the VCC and OUT pins. When VTMR reaches 1.25V, opto-coupler. the FLT pin pulls low to indicate the detection of a fault
GATE:
N-Channel MOSFET Gate Drive Output. The GATE condition. If the condition persists, the pass transistor turns pin is pulled up by an internal charge pump current source off when VTMR reaches the threshold of 1.35V. As soon as and clamped to 14V above the OUT pin. Both voltage and the fault condition disappears, the pull up current stops current amplifiers control the GATE pin to regulate the and a 2µA current starts to pull the TMR pin down. When output voltage and limit the current through the MOSFET. VTMR reaches the retry threshold of 0.5V, the GATE pin pulls high turning back on the pass transistor. A minimum of
GND:
Device Ground. 10nF capacitor is needed to compensate the loop. A 10V
IN+ (DFN and SO Packages Only):
Positive Input of the rated X7R capacitor is recommended for CTMR. Auxiliary Amplifier. This amplifier can be used as a level
VCC:
Positive Supply Voltage Input. The positive supply detection comparator with external hysteresis or linear input ranges from 4V to 80V for normal operation. It regulator controlling an external PNP transistor. This pin can also be pulled below ground potential by up to 60V is clamped internally to 7V. Connect to ground if unused. during a reverse battery condition, without damaging the
OUT:
Output Voltage Sense Input. This pin senses the part. The supply current is reduced to 7µA with all the voltage at the source of the N-channel MOSFET and sets functional blocks off. the fault timer current. When the OUT pin voltage reaches 0.7V away from VCC, the EN pin goes high impedance. Rev. C 8 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 Typical Applications Package Description Revision History Typical Application Related Parts