ZHCSI81L February 2009 – May 2018 LM26420
PRODUCTION DATA.
- 1 特性
- 2 應(yīng)用
- 3 說(shuō)明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1 LM26420X 2.2-MHz, 0.8-V Typical High-Efficiency Application Circuit
- 8.2.2 LM26420X 2.2-MHz, 1.8-V Typical High-Efficiency Application Circuit
- 8.2.3 LM26420X 2.2-MHz, 2.5-V Typical High-Efficiency Application Circuit
- 8.2.4 LM26420Y 550 kHz, 0.8-V Typical High-Efficiency Application Circuit
- 8.2.5 LM26420Y 550-kHz, 1.8-V Typical High-Efficiency Application Circuit
- 8.2.6 LM26420Y 550-kHz, 2.5-V Typical High-Efficiency Application Circuit
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機(jī)械、封裝和可訂購(gòu)信息
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購(gòu)信息
10.3.1 Method 1: Silicon Junction Temperature Determination
To accurately measure the silicon temperature for a given application, two methods can be used. The first method requires the user to know the thermal impedance of the silicon junction to top case temperature.
Some clarification needs to be made before we go any further.
RθJC is the thermal impedance from silicon junction to the exposed pad.
RθJT is the thermal impedance from top case to the silicon junction.
In this data sheet RθJT is used so that it allows the user to measure top case temperature with a small thermocouple attached to the top case.
RθJT is approximately 20°C/W for the 16-pin WQFN package with the exposed pad. Knowing the internal dissipation from the efficiency calculation given previously, and the case temperature, which can be empirically measured on the bench we have:
Therefore:
From the previous example: