Overview
The LT4356IDE-2#TRPBF, produced by Analog Devices Inc., is a surge stopper designed to protect loads from high voltage transients. This device regulates the output during overvoltage events, such as load dumps in automotive systems, by controlling the gate of an external N-channel MOSFET. It ensures the output voltage remains within a safe range, allowing the loads to continue functioning. The LT4356 also monitors voltage drops to protect against overcurrent faults and includes an internal amplifier to limit the current sense voltage to 50mV.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| VCC Operating Voltage Range | 4 | 80 | V | ||
| ICC VCC Supply Current (LT4356-2) | VSHDN = 0V, IN+ = 1.3V | 60 | 100 | µA | |
| IGATE(UP) GATE Pin Pull-Up Current | VGATE = 12V, VCC = 12V | -4 | -4.5 | µA | |
| IGATE(DN) GATE Pin Pull-Down Current | Overvoltage, VFB = 1.4V, VGATE = 12V | 75 | 150 | mA | |
| VFB FB Pin Servo Voltage | VGATE = 12V, VOUT = 12V | 1.4 | 1.5 | V | |
| VSHDN SHDN Pin Threshold | VCC = 12V to 48V | 0.6 | 1.7 | V | |
| Temperature Range | -40 | 85 | °C |
Key Features
- Protects loads from high voltage transients and overvoltage events such as load dumps in automotive systems.
- Regulates output voltage by controlling the gate of an external N-channel MOSFET.
- Monitors voltage drops to protect against overcurrent faults with an internal amplifier limiting the current sense voltage to 50mV.
- Includes an adjustable fault timer that starts when a fault condition is detected, and the MOSFET is turned off if the timer expires.
- Auxiliary amplifier that can be configured as a linear regulator controller or a comparator to monitor voltages.
- Shutdown pin to turn off the pass transistor and reduce supply current to less than 7µA for LT4356-1 and 60µA for LT4356-2.
- Output pull-down device capable of sinking up to 2mA of current to drive an LED or opto-coupler.
Applications
- Automotive systems to protect against load dump and other high voltage transients.
- Industrial power systems requiring overvoltage and overcurrent protection.
- Power supply systems in harsh environments where transient protection is crucial.
- Cable drop compensation and current limit switches in various power management systems.
Q & A
- What is the primary function of the LT4356IDE-2#TRPBF?
The primary function is to protect loads from high voltage transients and overvoltage events by regulating the output voltage and controlling an external N-channel MOSFET.
- What types of faults does the LT4356 monitor?
The LT4356 monitors both overvoltage and overcurrent faults.
- How does the LT4356 handle overcurrent faults?
The LT4356 monitors the voltage drop between the VCC and SNS pins and limits the current sense voltage to 50mV using an internal amplifier.
- What is the purpose of the fault timer in the LT4356?
The fault timer is adjustable and starts when a fault condition is detected. If the timer expires, the MOSFET is turned off to protect the system.
- How does the shutdown pin function in the LT4356?
The shutdown pin turns off the pass transistor and reduces the supply current to less than 7µA for LT4356-1 and 60µA for LT4356-2.
- What is the temperature range for the LT4356IDE-2#TRPBF?
The temperature range is -40°C to 85°C.
- Can the auxiliary amplifier be used for other functions?
Yes, the auxiliary amplifier can be configured as a linear regulator controller or a comparator to monitor voltages.
- What is the maximum current the output pull-down device can sink?
The output pull-down device can sink up to 2mA of current.
- In what types of systems is the LT4356 commonly used?
The LT4356 is commonly used in automotive systems, industrial power systems, and other power supply systems requiring transient protection.
- How is the fault timer period set in the LT4356?
The fault timer period is set by connecting a capacitor from the TMR pin to ground.
