On-resistance in AW2K21 is typically 2mΩ and comes in a 2 x 2mm WLCSP.
It “adopts a proprietary structure that enhances cell density while minimising the on-resistance per unit chip area – even compared to similarly sized GaN hemts, on-resistance is decreased by up to 50%”, said Rohm. “The structure places the drain terminal on the top surface, unlike on the backside in standard vertical trench MOS structures. This enables the use of a WLCSP, which achieves a larger chip-to-package area ratio that further reduces on-resistance per unit area.”
Current rating is ±20A continuous and ±40A pulsed. Both of these are 25°C figures, where max power dissipation is 1.6W on a 40 x 40 x 0.8mm copper board.
2mΩ is the typical figure with 5V on the gate – where the maximum is 4mΩ. Increasing gate drive to 10V drops these figures to 1.5mΩ typ and 3mΩ max – all at 20A.
This is not a device for driving just with a single Li-ion cell as, looking at the data sheet, 3V gate drive would be marginal for any significant through current, and even 4V might not be enough at high temperature.
For driving the gate with a charge-pump, a source connection is provided as a counter terminal. Internally, this source connection includes a 100Ω typ parasitic resistance.
In use, the company recommends ≥4.7uF on both drains, and a transient voltage suppressor on the charger side.
As well as a bidirectional switch, the company suggests that it is so small that it can compete as a uni-directional protection mosfet in load switches – an even smaller (1.2 x 1.2mm) version is under development.
Use is foreseen in phones with large capacity batteries, as well as VR headsets, tablets, portable gaming consoles and drones.
DigiKey, Mouser and Farnell are carrying the device. “The product will be offered at other on-line distributors as it becomes available,” said Rohm.
Find the AW2K21 on this Rohm web page
A couple of years ago, Toshiba took the common drain approach for a 13.6mΩ 30V mosfet aimed at similar applications
