AL8808WT-7 Diodes Inc., AL8808WT-7 Datasheet - Page 18

• Manufacturer Part Number: AL8808WT-7
• Description: LED Lighting Drivers LED MV Int Switch TS Switch TSOT25 T&R 3K
• Manufacturer: Diodes Inc.

Specifications of AL8808WT-7

• Rohs: yes
• Input Voltage: 6 V to 30 V
• Operating Frequency: 1 MHz
• Maximum Supply Current: 450 uA
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: TSOT-25
• Minimum Operating Temperature: - 40 C

Applicatio
Fault Conditio
The AL8808 has
V
If the LEDs shou
the expected cu
dramatically and
LEDs.
The on-time of t
inductor. The off
32) causing a m
High Tempera
The AL8808 is a
temperature in
temperatures an
AL8808 off. This
The OTP shutdo
never switch-off
junction tempera
AL8808
Document number
IN
and the SW
on Informat
a high efficiency
d the switching f
s will allow the ju
ature of the AL88
on Operation
s by default open
uld become shor
urrent - so no e
ature Operatio
nd hence junctio
r: DS35648 Rev. 2
the internal pow
f-time is significa
own junction tem
uch slower deca
pin will then fall
excess of 100°
with a junction t
excessive heat w
ay in inductor cur
antly increased b
on temperature t
on and Protec
mperature of the
rted together the
808.
tion
n LED protection
temperature belo
to GND. No exce
requency will mo
er MOSFET swi
switching LED d
nction temperatu
C given the co
- 2
Figure 45. Sw
(cont.)
orrect thermal im
witching Charac
e AL8808 is app
will be generated
n. If the LEDs sh
rrent.
ure of the AL880
then the Over-Te
ow +125°C allow
essive voltages w
ost likely decrea
itch is significant
ecause the reve
tion
river capable of
AL8808 will con
mpedance to fre
wing the designe
hould become op
cteristics (norma
ntinue to switch a
will be seen by th
d within the AL8
w
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tly reduced beca
emperature Prot
rse voltage acros
8 to cool down a
roximately +145
se. See Figure 4
operating junctio
18 of 20
ee air. If a fault
and potentially giv
pen circuit the AL
ause almost all o
on temperatures
he AL8808.
and the current t
8808. However,
45 for an examp
tection (OTP) of
ss the inductor is
al open to short
r to design the s
m
°C with a hyster
system thermally
ple of this behav
f the AL8808 wil
L8808 will stop o
of the input volta
s now just the Sc
t LED chain)
ving an opportun
resis of +10°C.
hrough the AL88
up to +125°C. T
the duty cycle
should occur t
oscillating; the SE
808’s internal sw
age is now deve
nity for the fault to
chottky diode vol
that leads to inc
ll cut in turning t
at which it oper
ior at 24V input
his allows it ope
This means that
to fully utilize th
witch will still be a
eloped across the
he wide operating
rates will change
ET pin will rise to
ltage (See Figure
o clear itself.
t the AL8808 wi
rate with ambien
creased ambien
the output of the
voltage driving 3
© Diodes Incorporate
AL8808
January 201
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