# Current Context and Research Trends in Linear DC-DC Converters
## 5 Current LDO Application Trends and Their Market Share  
Due to the excessive nature of communication and signal processing happening inside industrial automation systems, it is mandatory for them to have a noise-free clean power supply, as well as to maintain very low EMI levels [33]. EMI issues can cause serious errors in sensor measurements and PLC processing [34]. Because of their very low EMI levels and the ability to filter the noise components, LDOs have become popular in industrial automation systems [33]. Furthermore, with the simple compact design of LDOs such as ADP166 [26], TPS720 [24], and TLV733P [25], LDOs are the perfect alternative to the SMPS.  
Today's technology trend is to use more artificial intelligence and machine learning concepts in portable devices such as mobile phones, laptops, tablets, etc. In addition, in the modern world, most consumer devices tend to be portable/wireless. This concept involves a higher level of signal processing requirement. According to [PERSON]'s law, the number of transistors on a microchip doubles every two years, but the cost of computers is halved [35]. This statement clearly indicates that usage of microprocessors and microcontrollers will be further increased in future electronic devices. Figure 6[36] shows the growth prediction for transistors until 2030.  
Figure 5: Basic quiescent current of typical LDOs [21].  
\begin{table}
\begin{tabular}{c c c} \hline
**LDO Specific Property** & **Industrial Application** &
\begin{tabular}{c} **Commercially Available** \\ **LDOs** \\ \end{tabular} \\ \hline \multirow{4}{*}{Reduce noise and PSR levels} & High-speed communications applications, video processing applications, and high-accuracy measurement applications. & TPS717 xx family [23] \\ \hline \multirow{4}{*}{Compactness} & Compact portable devices & TPS720 [24], TLV733P [25], ADP160 [26], ADP166 [26], ADM7160 [27] \\ \hline \multirow{4}{*}{Lower quiescent current} & Battery-powered applications & TPS7A19 [28], TPS7B69 [29], LT3009 [30], STLG50 [31], LDK715 [32] \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \cline{1-1} \cline{2-3}  & & \\ \hline \end{tabular}
\end{table}
Table 3: Commercially available LDOs for specific applications.  
For portable devices, battery life and compactness are the major criteria of design. With these requirements, there is a challenge to design highly efficient power supplies with very low levels of noise, no EMI issues, and better transient performance. Due to their unique properties, as described in the above sections, LDOs are widely used in industry and consumer devices. As shown in Figure 7[37], due to the high demand for consumer devices, the LDOs market is quickly growing. The price of the LDO is also comparatively cheap, which is another reason why the market for LDOs is growing. Major LDO producers are consistently trying to introduce more enhanced versions of LDOs to keep up with the competition. As an example, in 2019, Texas Instruments introduced an ultra-low-dropout regulator (TPS7A02 [38]) which has the smallest quiescent current of 25 nA in the industry [38].  
Figure 6: Semiconductor devices production [36].  
Figure 7: LDO market share [37].