IRLU3714ZPBF International Rectifier, IRLU3714ZPBF Datasheet - Page 8

• Manufacturer Part Number: IRLU3714ZPBF
• Description: MOSFET N-CH 20V 37A I-PAK
• Manufacturer: International Rectifier
• Series: HEXFET®r

Specifications of IRLU3714ZPBF

• Fet Type: MOSFET N-Channel, Metal Oxide
• Fet Feature: Logic Level Gate
• Rds On (max) @ Id, Vgs: 15 mOhm @ 15A, 10V
• Drain To Source Voltage (vdss): 20V
• Current - Continuous Drain (id) @ 25° C: 37A
• Vgs(th) (max) @ Id: 2.55V @ 250µA
• Gate Charge (qg) @ Vgs: 7.1nC @ 4.5V
• Input Capacitance (ciss) @ Vds: 560pF @ 10V
• Power - Max: 35W
• Mounting Type: Through Hole
• Package / Case: IPak, TO-251, DPak, VPak (3 straight leads + tab)
• Transistor Polarity: N Channel
• Continuous Drain Current Id: 37A
• Drain Source Voltage Vds: 20V
• On Resistance Rds(on): 15mohm
• Rds(on) Test Voltage Vgs: 10V
• Peak Reflow Compatible (260 C): Yes
• Rohs Compliant: Yes
• Resistance Drain-source Rds (on): 25 mOhms
• Drain-source Breakdown Voltage: 20 V
• Gate-source Breakdown Voltage: 20 V
• Continuous Drain Current: 37 A
• Power Dissipation: 35 W
• Mounting Style: SMD/SMT
• Gate Charge Qg: 4.7 nC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *IRLU3714ZPBF

Control FET
P
P
Power MOSFET Selection for Non-Isolated DC/DC Converters
loss
8
loss
This can be expanded and approximated by;
= I
+ I ×
+ Q
+
= P
(
⎛
⎜
⎝
(
⎛
⎝
Q
rms
conduction
g
2
oss
× V
2
Q
× R
i
× V
g
gd
g
× f
ds(on )
in
× V
+ P
× f
)
in
)
switching
× f
⎞
⎠
⎞
⎟ + I ×
⎠
+ P
⎛
⎜
⎝
drive
Q
+ P
i
gs 2
g
× V
output
in
× f
⎞
⎟
⎠
Synchronous FET
by;
*dissipated primarily in Q1.
portant characteristic; however, once again the im-
portance 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
verse recovery charge Q
are transfered to Q1 and increase the dissipation in
that device. Thirdly, gate charge will impact the
MOSFETs’ susceptibility to Cdv/dt turn on.
of the converter and therefore sees transitions be-
tween ground and V
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
potential for Cdv/dt turn on.
Figure A: Q
P
P
loss
loss
The power loss equation for Q2 is approximated
For the synchronous MOSFET Q2, R
The drain of Q2 is connected to the switching node
= P
= I
+ Q
+
(
(
⎛
⎜
⎝
conduction
rms
Q
oss
g
2
oss
2
Characteristic
× V
gd
× R
/Q
× V
g
gs1
+ P
ds(on)
× f
in
in
must be minimized to reduce the
. As Q1 turns on and off there is
drive
× f
)
)
rr
⎞
⎠
+ P
both generate losses that
+ Q
output
(
*
rr
× V
www.irf.com
in
ds(on)
× f
oss
is an im-
and re-
)