Overview
The SM74611KTTR, produced by Texas Instruments, is a smart bypass diode designed specifically for photovoltaic applications. This device serves as an alternate path for string current when parts of the solar panel are shaded, preventing hot spots caused by excessive power dissipation in reverse-biased cells. It is an advanced solution compared to traditional P-N junction or Schottky diodes, offering lower forward voltage drop and reduced power dissipation, which enhances the overall efficiency and reliability of solar panels.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Maximum Reverse Voltage (VR) | - | - | 30 | V |
| Operating Forward Current (IF) | - | - | 15 | A |
| Average Forward Voltage (VF) at 8 A | - | 26 mV | - | mV |
| Power Dissipation at 8 A | - | 208 mW | - | mW |
| Junction Temperature Range (TJ) | -40 | - | 125 | °C |
| Package Type | - | - | TO-263 (KTT) | - |
| Pins | - | - | 3 | - |
Key Features
- Maximum Reverse Voltage (VR) of 30 V
- Operating Forward Current (IF) of up to 15 A
- Low Average Forward Voltage (26 mV at 8 A)
- Less Power Dissipation than Schottky Diode
- Lower Leakage Current than Schottky Diode
- Footprint and Pin-Compatible With Conventional D2PAK Schottky Diode
- Operating Range (TJ) of –40°C to 125°C
Applications
The SM74611KTTR is primarily used in photovoltaic applications, particularly in solar junction boxes and power optimizers. It serves as a bypass diode to provide an alternate path for string current when parts of the solar panel are shaded, thus preventing hot spots and reducing power dissipation. This device is also suitable for microinverter applications.
In solar junction boxes, the SM74611KTTR is often connected in series across substrings of solar cells to ensure efficient operation and compliance with standards such as IEC61215, IEC61646, EN 50548, IEC62790, and UL3730.
Q & A
- What is the primary function of the SM74611KTTR?
The SM74611KTTR serves as a smart bypass diode to provide an alternate path for string current when parts of the solar panel are shaded, preventing hot spots and reducing power dissipation.
- What is the maximum reverse voltage of the SM74611KTTR?
The maximum reverse voltage (VR) of the SM74611KTTR is 30 V.
- What is the operating forward current of the SM74611KTTR?
The operating forward current (IF) of the SM74611KTTR is up to 15 A.
- How does the SM74611KTTR reduce power dissipation compared to traditional diodes?
The SM74611KTTR has a lower average forward voltage drop (26 mV at 8 A) compared to traditional P-N junction or Schottky diodes, resulting in significantly less power dissipation.
- Is the SM74611KTTR compatible with conventional D2PAK Schottky diodes?
- What is the operating temperature range of the SM74611KTTR?
The operating temperature range (TJ) of the SM74611KTTR is –40°C to 125°C.
- How is the SM74611KTTR typically used in solar junction boxes?
The SM74611KTTR is connected in series across substrings of solar cells in solar junction boxes to provide bypass paths and ensure efficient operation.
- What standards does the SM74611KTTR comply with?
The SM74611KTTR complies with standards such as IEC61215, IEC61646, EN 50548, IEC62790, and UL3730.
- Why can't a normal diode tester be used to test the SM74611KTTR?
A normal diode tester cannot be used because the SM74611KTTR cycles the FET ON and OFF to recharge the charge pump, causing the body diode to conduct occasionally instead of the FET.
- How should the SM74611KTTR be tested in a junction box application?
The SM74611KTTR should be tested using a specific setup that accounts for its switching behavior, as described in the datasheet.
