STSJ100NHS3LL
New STripFET technology with built-in schottky diode

STSJ100NHS3LL Product Page The ever increasing demand for greater power from the latest CPU generations has given VRD/VRM designers a new challenge. The highest system efficiency can be achieved not only by selecting a proper circuit topology, but also with a good choice of IC driver and Power MOSFETs. To meet these requirements, ST has developed a new Power MOSFET family by using the third generation of STripFET technology with a monolithic Schottky diode.

The widely used buck converter (shown below) is essentially two MOSFETs, one called the control FET (or high side FET), and the second is the synchronous FET (or low side FET), respectively. These Power MOSFETs are properly designed to fit the application requirements:
The high side FET must have low input capacitance, low gate resistance, and a total gate charge to minimize the switching losses.
The low side FET is required to have low ON resistance (R_DS(on)) to reduce conduction losses.

The buck converter is not enough when very
high efficiency is a must. In fact, besides the switching and conduction losses, other factors should be taken into account, such as intrinsic power loss because of the low side FET’s integrated diode during the dead time.


Synchronous buck converter circuit with integrated Schottky diode
By placing a Schottky diode in parallel, two key parameters such as the forward voltage (Vf) and reverse recovery gate charge (Q_RR) are optimized. Moreover, no parasitic stray inductances are introduced because of the monolithic approach.

In order to demonstrate this new technology, a test was performed on a VRD customer board, assuming the following conditions:
V_IN = 12V,
V_OUT = 1.4V, and
3 phases with 250kHz of switching frequency.

The Power MOSFETs are ST’s STSJ50NH3LL and STSJ100NHS3LL, and the competitor’s devices are designed with Trench technology.
The test showed that ST's solution provides better efficiency, resulting in a lower operating temperature and in turn, higher reliability than the competition.


ST's STripFET versus competition

The two products, available in both the SO-8 and PowerSO-8 packages, represent the best choice for notebook and server applications. The present product range will soon expand with other package options.

Part number	RDS(on) @ 10V(max) [Ω]	RDS(on) @ 4.5V(max) [Ω]	Vf (typ) [V]
STS20NHS3LL*	0.004	0.0055	0.5
STSJ100NHS3LL**	0.004	0.0055	0.5