Overview
The LM74502H, produced by Texas Instruments, is a low IQ high side switch controller designed for industrial applications requiring reverse polarity protection and load disconnect features. This controller operates in conjunction with external back-to-back connected N-channel MOSFETs to provide an efficient and fast reverse polarity protection circuit. It also supports driving high side MOSFETs as load switches with overvoltage protection. The device is characterized by its wide input supply range of 3.2 V to 65 V, making it suitable for various DC bus voltages such as 12-V, 24-V, and 48-V systems. It can withstand negative supply voltages down to –65 V, ensuring robust protection for the loads.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Input Voltage Range | 3.2 | - | 65 | V |
| Input Reverse Voltage Rating | -65 | - | -65 | V |
| Peak Gate Drive Source Current (LM74502H) | 3 | 11 | - | mA |
| Peak Gate Sink Current | - | - | 2.3 | A |
| Operating Quiescent Current (EN/UVLO = High) | - | 45 | - | µA |
| Shutdown Current (EN/UVLO = Low) | - | 1 | - | µA |
| Ambient Operating Temperature Range | -40 | - | 125 | °C |
| Package Type | - | - | 8-pin SOT-23 | - |
Key Features
- Integrated charge pump to drive external back-to-back connected N-channel MOSFETs and high side switch MOSFETs.
- Gate drive variants: LM74502H with 11-mA peak gate drive source capacity for fast turn-on and turn-off, and LM74502 with 60-µA peak gate drive source capacity for smooth start-up with inherent inrush current control.
- Enable pin feature allowing for low IQ shutdown mode with approximately 1 µA current draw.
- Adjustable overvoltage and undervoltage protection using the OV pin.
- Wide input supply range of 3.2 V to 65 V, suitable for various DC bus voltages.
- Capable of withstanding negative supply voltages down to –65 V.
- Operating ambient temperature range of –40°C to +125°C.
Applications
- Factory automation and control, particularly in PLC digital output modules.
- Industrial motor drives.
- Industrial transport systems.
- Power supply reverse polarity protection.
- Load switch applications requiring fast turn-on and turn-off.
Q & A
- What is the input voltage range of the LM74502H? The input voltage range is from 3.2 V to 65 V with a start-up voltage of 3.9 V.
- How does the LM74502H protect against reverse polarity? It operates with external back-to-back connected N-channel MOSFETs to provide reverse polarity protection and can withstand negative supply voltages down to –65 V.
- What are the gate drive variants of the LM74502H? The LM74502H has a peak gate drive source capacity of 11 mA, while the LM74502 has a peak gate drive source capacity of 60 µA.
- What is the typical operating quiescent current of the LM74502H? The typical operating quiescent current is 45 µA when the EN/UVLO pin is high.
- How does the enable pin function? The enable pin allows the device to enter a low IQ shutdown mode with approximately 1 µA current draw when the pin is pulled low.
- What is the ambient operating temperature range of the LM74502H? The ambient operating temperature range is from –40°C to +125°C.
- What type of package is the LM74502H available in? The LM74502H is available in an 8-pin SOT-23 package.
- Can the LM74502H be used for overvoltage protection? Yes, it provides adjustable overvoltage protection using the OV pin.
- What are some common applications of the LM74502H? Common applications include factory automation, industrial motor drives, industrial transport, and power supply reverse polarity protection.
- How does the charge pump function in the LM74502H? The integrated charge pump supplies the voltage necessary to drive the external N-channel MOSFETs.
