App note: Using High-Side NMOS drivers
Here is an app note describing how and why to use NMOS transistors for high-side switching operations, and how to implement it using associated drivers.
This entry was posted in app notes and tagged app note, High side, Linear Technology, NMOS.At first glance, P-channel MOSFETs appear to be the natural choice for high side switching. Unfortunately, the RDS(ON) exhibited by most P-channels is prohibitively high.(Mother Nature has decreed that electron mobility shall exceed hole mobility in silicon by about 2.5 times, so that a P-channel MOSFET with the same RDS(ON) and voltage rating as its N-channel counterpart is roughly 2 to 3 times larger and more expensive.) Also, the gate drive for a P-channel switch is limited to the supply voltage which may not fully enhance the switch as the supply voltage drops.
Comments
The link is wrong, it is from the article “http://dangerousprototypes.com/2012/06/24/app-note-msp430-based-usb-li-ion-battery-charger-and-fuel-gauge/” and points to the TI page.
The correct link seems to be this one: http://cds.linear.com/docs/Application%20Note/an53.pdf
There is quite a lot of other useful information in this appnote. It was a good read.
sorry about that, it’s fixed now, thanks…