AL8807MP-7 Diodes Inc., AL8807MP-7 Datasheet - Page 14

• Manufacturer Part Number: AL8807MP-7
• Description: LED Lighting Drivers 36V High EFF Low EMI 1A Buck LED Driver
• Manufacturer: Diodes Inc.

Specifications of AL8807MP-7

• Product Category: LED Lighting Drivers
• Rohs: yes

Applicatio
EMI and Lay
The AL8807 is
taken with dec
emissions by c
right comprom
dominates the
tracks. After t
resonant loop
The tracks from
C1 should be
For PCB track
handling 1A in
inductance. T
capacitance of
than 5nH.
AL8807
Document number
ons Informa
mise between p
yout Conside
e radiated EMI
ks a figure of 0
s a switching re
coupling and la
controlling the
ncreasing the
r: DS35281 Rev. 4
m the SW pin t
f the Schottky d
the Schottky d
between the S
he resonant fre
as short as po
Schottky diode c
ayout of the PC
0.5nH per mm
erations
diode reverse r
ossible. There
egulator with fa
ation
equency of any
diode. An exam
power dissipat
switching spee
to the Anode o
thickness will
- 2
which is due
Place D1 a
Inductor as
minimize r
(cont.
CB.To help with
ast edges and m
eds of the inter
of the Schottky
y oscillation is d
anode , SW pin and
ringing
F
Fig. 37 Reco
tion due to sw
recovery time
capacitance an
mple of good la
s close as possible t
)
can be used to
to an interacti
have a minor
is an inductan
Fig. 36 PC
HIGH E
ww
witching losses
CB Loop Res
y diode, D1, an
rnal power MO
nd the track ind
r effect on the
h these effects
nce internally in
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ayout is shown
to
FFICIENCY
o estimate the
determined by
on between th
of around 5ns
mmended P
14 of 21
SW
VIN
GN
all differential vo
sonance
n in figure 37 - t
s and radiated
he Schottky dio
ductance, L
Y LOW EM
ND
n the AL8807
CB Layout
SFET. The ris
d then from D1
the combined
the AL8807 h
primary reson
has occurred
inductance a
SET
CTRL
TRA
MI 36V 1A B
se and fall time
nant frequency
oltages; as a re
ode (D1), Swit
the stray track
1’s cathode to
; the falling ed
CK
this can be as
nd length will
as been devel
inductance in
EMI. The tu
, See figure
BUCK LED
es are controlle
urn-on edge (fa
dge of the SW
esult of this car
tching MOSFE
oped to minim
sumed to be a
. If the track is
the track and t
inductance sho
36.
the decoupling
dominate the
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L8807
W pin sees a
ET and PCB
ed to get the
around 1nH.
s capable of
g capacitors
the effective
re has to be
alling edge)
ould be less
s Incorporated
ise radiated
June 2012
DRIVER
size of the