XRP7708EVB Exar Corporation, XRP7708EVB Datasheet - Page 25

• Manufacturer Part Number: XRP7708EVB
• Description: EVAL BOARD FOR XRP7708
• Manufacturer: Exar Corporation
• Type: PMIC Solutionsr

Specifications of XRP7708EVB

• Main Purpose: DC/DC, Step Down
• Outputs And Type: *
• Voltage - Output: *
• Current - Output: *
• Voltage - Input: *
• Regulator Topology: Buck
• Frequency - Switching: *
• Board Type: Fully Populated
• Utilized Ic / Part: XRP7708
• Board Size: 6 mm x 6 mm x 0.8 mm
• Interface Type: I2C
• Maximum Operating Temperature: + 125 C
• Operating Supply Voltage: 6.5 V to 20 V
• Product: Power Management Development Tools
• Sense Voltage (max): 5 mV
• Dimensions: 6 mm x 6 mm x 0.8 mm
• Silicon Manufacturer: Exar
• Silicon Core Number: XRP7708
• Kit Application Type: Power Management - Voltage Regulator
• Application Sub Type: Step Down DC/DC Controller
• For Use With/related Products: XRP7708
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 1016-1346

Selecting MOSFETs with lower Rdson reduces conduction losses at the expense of increased
switching losses. A simplified expression for conduction losses is given by:
MOSFET’s junction temperature can be estimated from:
This assumes that the switching loss is the same as the conduction loss.
thermal resistance from junction to ambient.
© 2010 Exar Corporation
Power MOSFETs Selection
Q
Q
u
u
a
a
P
T
Δ
d
d
cond
j
V
= 2
C
C
Tot
=
h
h
P
=
a
I
cond
a
out
Δ
25/27
n
n
V
2
R
n
n
Cin
⋅
thja
e
e
R
l
l
+
dson
+
D
D
Δ
T
V
ambient
i
i
⋅
g
g
V
ESR
V
i
out
i
in
t
t
a
a
l
l
P
P
W
W
M
M
S
S
t
t
e
e
R
p
p
thja
D
D
is the total MOSFET
o
o
w
w
n
n
X
X
C
C
R
R
o
o
n
P
n
P
Rev. 1.0.3
t
t
7
7
r
r
o
7
o
7
l
l
0
0
l
l
e
e
8
8
r
r