LT3485EDD-1#TRPBF Linear Technology, LT3485EDD-1#TRPBF Datasheet - Page 11
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LT3485EDD-1#TRPBF
Manufacturer Part Number
LT3485EDD-1#TRPBF
Description
IC CHARGER PHOTOFLASH 10-DFN
Manufacturer
Linear Technology
Datasheet
1.LT3485EDD-3PBF.pdf
(20 pages)
Specifications of LT3485EDD-1#TRPBF
Applications
Photoflash Capacitor Charger, Xenon
Current - Supply
5mA
Voltage - Supply
1.7 V ~ 10 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
10-DFN
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
APPLICATIO S I FOR ATIO
Table 2. Pre-Designed Transformers – Typical Specifications Unless Otherwise Noted
FOR USE WITH
LT3485-0/LT3485-2
LT3485-1
LT3485-0
LT3485-1
LT3485-2
LT3485-3
LT3485-0/LT3485-1
LT3485-1
LT3485-3
Note that the absolute maximum rating of the SW pin is
not exceeded. Make sure to check the SW voltage wave-
form with V
worst case condition for SW voltage. Figure 4 shows the
various limits on the SW voltage during switch turn off.
It is important not to minimize the leakage inductance to
a very low level. Although this would result in a very low
leakage spike on the SW pin, the parasitic capacitance of
the transformer would become large. This will adversely
affect the charge time of the photoflash circuit.
Linear Technology has worked with several leading mag-
netic component manufacturers to produce pre-designed
flyback transformers for use with the LT3485-0/LT3485-
1/LT3485-2/LT3485-3. Table 2 shows the details of sev-
eral of these transformers.
10A/DIV
1A/DIV
V
I
PRI
SW
Figure 3. LT3485 SW Voltage Waveform
OUT
V
V
IN
OUT
2
near the target output voltage, as this is the
= 5V
= 320V
LDT565630T-001
LDT565630T-002
LDT565630T-003
LDT565630T-041
TRANSFORMER
U
SBL-5.6S-1
T-17-109A
SBL-5.6-1
T-15-089
T-15-083
NAME
100ns/DIV
U
(W × L × H) mm
W
5.6 × 8.5 × 4.0
5.6 × 8.5 × 3.0
5.8 × 5.8 × 3.0
5.8 × 5.8 × 3.0
5.8 × 5.8 × 3.0
5.8 × 5.8 × 3.0
6.4 × 7.7 × 4.0
8.0 × 8.9 × 2.0
6.5 × 7.9 × 4.0
3485 F03
SIZE
U
L
(µH)
14.5
10.5
4.7
5.9
10
24
12
20
PRI
6
LPRI-LEAKAGE
200 Max
400 Max
200 Max
500 Max
550 Max
150 Max
400 Max
500 Max
300 Max
(nH)
Capacitor Selection
For the input bypass capacitors, high quality X5R or X7R
types should be used. Make sure the voltage capability of
the part is adequate.
Output Diode Selection
The rectifying diode(s) should be low capacitance type
with sufficient reverse voltage and forward current rat-
ings. The peak reverse voltage that the diode(s) will see is
approximately:
V
PK R
Figure 4. New Transformer Design Check (Not to Scale)
V
−
SW
0V
10.2
10.2
10.4
10.2
10.2
10.4
10.2
10.2
10.2
N
=
V
100 Max 10 Max
240 Max 16.5 Max
210 Max 14 Max
211 Max 27 Max
675 Max 35 Max
“A”
90 Max
78 Max 18.61 Max
OUT
(mΩ)
R
103
305
PRI
LT3485-0/LT3485-1/
+ ( •
LT3485-2/LT3485-3
N V
6.4 Max
“B”
R
(Ω)
26
55
SEC
IN
)
kijimahk@netvigator.com (email)
www.components.tdk.com
Tokyo Coil Engineering
www.tokyo-coil.co.jp
(847) 803-6100 (ph)
852-2489-8266 (ph)
Chicago Sales Office
0426-56-6262 (ph)
Hong Kong Office
Kijima Musen
3485 F04
Japan Office
VENDOR
MUST BE
LESS THAN 50V
MUST BE
LESS THAN 40V
TDK
11
34850123fb