The 40 V MOSFET is an essential building block in many automotive applications such as motor control for power steering, transmission control, ABS, ESC, fan speed control, and reverse battery protection, among others.
Looking to help automotive designers save board area and power, Diodes Incorporated recently released its newest product: a dual 40 V MOSFET package. The DMT47M2LDVQ can replace two discrete MOSFETs to reduce the board space while also offering what the company claims are the lowest industry RDS(on) for its configuration.
In this article, we’ll stack this device up against some competitors, namely Nexperia’s BUK9J0R9-40H and Toshiba’s TPWR7940PB.
Diode’s Incorporated’s DMT47MLDVQ
When looking at conduction losses at a maximum operating VGS of 10 V and a drain current of 30.2 A, Diodes Incorporated’s DMT47MLDVQ offers an RDS(on) as low as 10.8 mΩ. Under a 4.5V VGS and a drain current of 25.6 A, the device sees a high RDS(on) reaching up to 15 mΩ.
The DMT47MLDVQ MOSFETs. Image used courtesy of Diodes Incorporated
Switching loss is directly related to the amount of time required to switch the MOSFET, which in turn is directly related to the charge on the gate. With respect to this, the device claims a typical gate charge of 14.0 nC at a VGS of 10 V and an ID of 20 A.
The device also fits two MOSFETs into a 3.3 mm x 3.3 mm package, aiming to decrease board space and save area and cost for designers.
A counterpart to the new Diodes Incorporated’s 40 V MOSFET is Nexperia’s BUK9J0R9-40H—a single MOSFET featuring some impressive specs. The device comes in a 4.58 mm x 5.13 mm package, making it larger than Diode’s product.
RDS(on) vs. VGS for BUK9J0R9-40H. Image used courtesy of Nexperia
The device has an extremely low RDS(on) of 0.94 mΩ at a VGS of 10 V and drain current of 25 A. While it is only a single MOSFET, if we wanted to compare it to Diode Incorporated’s new product (which is a dual MOSFET), we can create a worst-case scenario calculation.
If we assume two of these devices in series, we can add their RDS(on) values and see a worse case 1.88 mΩ RDS(on)—still significantly less than the DMT47MLDVQ and at a lower current value.
With respect to switching loss, this device from Nexperia has a typical gate charge of 12.7 nC at VGS of 4.5 V and an ID of 20 A. This is less efficient than the comparable RDS(on) spec because it is at a considerably lower gate-to-source voltage, but a marginally smaller gate charge.
Toshiba’s device, the TPWR7940PB, is also a single AEC-Q101 qualified MOSFET. It comes in a 5 mm x 6 mm package, larger than both Diode Incorporated’s and Nexperia’s offerings.
RDS(ON) and ID of Toshiba’s TPW1R104PB. Image used courtesy of Toshiba (downloads as PDF)
At a VGS of 10 V and an ID of 60 A, this device offers an RDS(on) of .95 mΩ. This is a similar value to Nexperia’s device but at a significantly higher current. Furthermore, at a VGS of 10 V and a drain current of 120 A, we see a gate charge of 55 nC. This is significantly higher than both other devices, implying larger switching losses.
After comparing these three devices, we see that while the DMT47MLDVQ MOSFETs may not have the lowest conduction losses (RDS(on)) or switching losses (gate charge), it still offers some significant benefits.
For starters, this device has a smaller package than both other competitors we looked at—and it incorporates two MOSFETs within that area. With this in mind, we see it is easily the most space-efficient of the three devices. It is yet to be seen if there are other dual-channel devices as small as Diodes Incorporated’s product that also offer lower RDS(on).
Depending on your application needs, especially when area is a primary concern, this new device could be a useful option when selecting 40 V MOSFETs.
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