ZHCSNL2A February 2022 – May 2022 LM74502-Q1 , LM74502H-Q1
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Parameter Measurement Information
- 9 Detailed Description
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10Application and Implementation
- 10.1 Application Information
- 10.2 Typical Application
- 10.3 Surge Stopper Using LM74502-Q1, LM74502H-Q1
- 10.4 Fast Turn-On and Turn-Off High Side Switch Driver Using LM74502H-Q1
- 11Power Supply Recommendations
- 12Layout
- 13Device and Documentation Support
- 14Mechanical, Packaging, and Orderable Information
10.3.3 MOSFET Selection
The VDS rating of the MOSFET Q1 must be minimum VIN(max) for designs with output overvoltage cutoff where output can reach 0 V with higher loads. For designs with output overvoltage clamp, MOSFET VDS rating must be (VIN(max) – VOUT_CLAMP). The VGS rating is based on GATE-SRC maximum voltage of 15 V. TI recommends a 20-V VGS rated MOSFET. Power dissipation on MOSFET Q1 on a design where output is clamped is critical and SOA characteristics of the MOSFET must be considered with sufficient design margin for reliable operation. An additional Zener diode from GATE to SRC can be needed to protect the external FET in case output is expected to drop to the level where it can exceed external FET VGS(max) rating.
Figure 10-12 200-V Surge Stopper with Overvoltage Cutoff Using LM74502-Q1