Overview
The LTC4353IMS#PBF, produced by Analog Devices Inc., is a Dual Low Voltage Ideal Diode Controller designed to control external N-channel MOSFETs to implement an ideal diode function. This controller replaces two high power Schottky diodes and their associated heat sinks, thereby saving power and board area. It is particularly useful in low loss power supply ORing and supply holdup applications, ensuring smooth current transfer and minimizing reverse-current transients in case of input supply failures or short-circuits.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| VIN Operating Range | With External VCC Supply | 2.9 | - | 18 | V |
| VCC External Supply Operating Range | VIN1, VIN2 ≤ VCC | 2.9 | - | 6 | V |
| VCC Regulated Voltage | - | 4.5 | 5 | 5.5 | V |
| Input Current (IIN) | Enabled, Higher Supply Enabled, Lower Supply Pull-Up Disabled | - | - | 10 | mA |
| Gate Fast Pull-Up Current | VCPO = VIN = 2.9V | -60 | - | -90 | µA |
Key Features
- Controls external N-channel MOSFETs to implement an ideal diode function, replacing two high power Schottky diodes and their heat sinks.
- Operates with supplies from 2.9V to 18V; requires an external supply at the VCC pin if both supplies are below 2.9V.
- Regulates the forward-voltage drop across the MOSFET to ensure smooth current transfer in diode-OR applications.
- Fast turn-on reduces load voltage droop during supply switchover, and fast turn-off minimizes reverse-current transients in case of input supply failures or short-circuits.
- Enable inputs to turn off the MOSFET and put the controller in a low current state.
- Status outputs indicate whether the MOSFETs are on or off.
Applications
- Low loss power supply ORing and supply holdup applications.
- High availability systems with parallel connected power supplies or battery feeds for redundancy and enhanced system reliability.
- Hot swap controllers and power supply configurations where smooth current transfer and minimal reverse-current transients are critical.
- Systems requiring low voltage drop from the supply to the load, such as in power distribution units (PDUs) and data center power supplies.
Q & A
- What is the primary function of the LTC4353IMS#PBF?
The LTC4353IMS#PBF controls external N-channel MOSFETs to implement an ideal diode function, replacing high power Schottky diodes and their associated heat sinks.
- What is the operating voltage range for the LTC4353IMS#PBF?
The controller operates with supplies from 2.9V to 18V.
- What happens if both input supplies are below 2.9V?
If both supplies are below 2.9V, an external supply is needed at the VCC pin.
- How does the LTC4353IMS#PBF handle input supply failures or short-circuits?
In case of an input supply failure or short-circuit, the controller rapidly turns off the MOSFET to minimize reverse-current transients.
- What are the key benefits of using the LTC4353IMS#PBF in power supply ORing applications?
The key benefits include low loss power supply ORing, smooth current transfer, and minimal reverse-current transients during supply switchover.
- How does the LTC4353IMS#PBF regulate the forward-voltage drop across the MOSFET?
The controller regulates the forward-voltage drop across the MOSFET to ensure it is equal to a predefined value (VFR), enhancing the MOSFET if the load current causes the drop to exceed VFR.
- What are the enable and status features of the LTC4353IMS#PBF?
The controller has enable inputs to turn off the MOSFET and put the controller in a low current state, and status outputs to indicate whether the MOSFETs are on or off.
- What type of MOSFETs does the LTC4353IMS#PBF drive?
The controller drives N-channel MOSFETs, with important features including maximum drain-source voltage (BVDSS), maximum gate-source voltage (VGS(MAX)), and on-resistance (RDS(ON)).
- In what applications is the LTC4353IMS#PBF particularly useful?
The controller is particularly useful in high availability systems, hot swap controllers, and power supply configurations requiring low voltage drop and smooth current transfer.
- How does the LTC4353IMS#PBF handle inrush current during power-up?
The controller ensures fast turn-on and minimal load voltage droop during supply switchover, managing inrush current effectively.
