IRF7807 datasheet(4/8 Pages) IRF

4 / 8 page

www.irf.com

IRF7807/IRF7807A

5V Supply : Q1=Q2=IRF7807

11.5

22.5

33.5

44.5

Load Current (A)

Vin = 10V

Vin = 14V

Vin=24V

Typical Mobile PC Application

The performance of these new devices has been tested

in circuit and correlates well with performance predic-

tions generated by the system models. An advantage

of this new technology platform is that the MOSFETs

it produces are suitable for both control FET and syn-

chronous FET applications. This has been demon-

strated with the 3.3V and 5V converters. (Fig 3 and

Fig 4). In these applications the same MOSFET IRF7807

was used for both the control FET (Q1) and the syn-

chronous FET (Q2). This provides a highly effective

cost/performance solution.

3.3V Supply : Q1=Q2=IRF7807

11.522.5

33.5

44.5

Load Current (A)

Vin = 10V

Vin = 14V

Vin = 24V

Figure 3

Figure 4

Figure 2: Q

oss Characteristic

For the synchronous MOSFET Q2, R

ds(on) is an im-

portant characteristic; however, once again the impor-

tance of gate charge must not be overlooked since it

impacts three critical areas. Under light load the

MOSFET must still be turned on and off by the con-

trol IC so the gate drive losses become much more

significant. Secondly, the output charge Q

oss and re-

verse recovery charge Q

rr both generate losses that

are transfered to Q1 and increase the dissipation in

that device. Thirdly, gate charge will impact the

MOSFETs’ susceptibility to Cdv/dt turn on.

The drain of Q2 is connected to the switching node

of the converter and therefore sees transitions be-

tween ground and V

in. As Q1 turns on and off there is

a rate of change of drain voltage dV/dt which is ca-

pacitively coupled to the gate of Q2 and can induce

a voltage spike on the gate that is sufficient to turn

the MOSFET on, resulting in shoot-through current .

The ratio of Q

gd/Qgs1 must be minimized to reduce the

potential for Cdv/dt turn on.

Spice model for IRF7807 can be downloaded in ma-

chine readable format at www.irf.com.

IRF7807 Datasheet(PDF) 4 Page - International Rectifier

IRF7807 Datasheet(HTML) 4 Page - International Rectifier

Html Pages

1 2 3 4 5 6 7 8

Datasheet Download

Link URL