GS66508B

Bottom-side cooled 650 V E-mode GaN transistor

Datasheet

Rev 200402

© 2009-2020 GaN Systems Inc.

12

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On-state condition (VGS = +6 V): The reverse conduction characteristics of a GaN Systems enhancement mode

HEMT in the on-state is similar to that of a silicon MOSFET, with the I-V curve symmetrical about the origin and it

exhibits a channel resistance, RDS(on), similar to forward conduction operation.

Off-state condition (VGS ≤ 0 V): The reverse characteristics in the off-state are different from silicon MOSFETs as

the GaN device has no body diode. In the reverse direction, the device starts to conduct when the gate voltage,

with respect to the drain, VGD, exceeds the gate threshold voltage. At this point the device exhibits a channel

resistance. This condition can be modeled as a “body diode” with slightly higher VF and no reverse recovery

charge.

If negative gate voltage is used in the off-state, the source-drain voltage must be higher than VGS(th)+VGS(off) in

order to turn the device on. Therefore, a negative gate voltage will add to the reverse voltage drop “VF” and

hence increase the reverse conduction loss.

Blocking Voltage

The blocking voltage rating, V(BL)DSS, is defined by the drain leakage current. The hard (unrecoverable) breakdown

voltage is approximately 30 % higher than the rated V(BL)DSS. As a general practice, the maximum drain voltage

should be de-rated in a similar manner as IGBTs or silicon MOSFETs. All GaN E-HEMTs do not avalanche and thus

do not have an avalanche breakdown rating. The maximum drain-to-source rating is 650 V and does not change

with negative gate voltage. GaN Systems tests devices in production with a 750V Drain-to-source voltage

pulse to insure blocking voltage margin.

Packaging and Soldering

The package material is high temperature epoxy-based PCB material which is similar to FR4 but has a higher

temperature rating, thus allowing the device to be specified to 150 °C. The device can handle at least 3 reflow

cycles.

It is recommended to use the reflow profile in IPC/JEDEC J-STD-020 REV D.1 (March 2008)

The basic temperature profiles for Pb-free (Sn-Ag-Cu) assembly are:

•

Preheat/Soak: 60 - 120 seconds. Tmin = 150 °C, Tmax = 200 °C.

•

Reflow: Ramp up rate 3 °C/sec, max. Peak temperature is 260 °C and time within 5 °C of peak

temperature is 30 seconds.

•

Cool down: Ramp down rate 6 °C/sec max.

Using “No-Clean” soldering paste and operating at high temperatures may cause a reactivation of the “No-

Clean” flux residues. In extreme conditions, unwanted conduction paths may be created. Therefore, when the

product operates at greater than 100

°C it is recommended to also clean the “No-Clean” paste residues.