LT3468 Ver la hoja de datos (PDF) - Linear Technology

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componentes Descripción

Fabricante

LT3468

Photoflash Capacitor Chargers in ThinSOT™

Linear Technology 

LT3468/LT3468-1/LT3468-2

APPLICATIO S I FOR ATIO

Table 2. Pre-Designed Transformers - Typical Specifications Unless Otherwise Noted.

SIZE

LPRI LPRI-LEAKAGE

RPRI

RSEC

FOR USE WITH TRANSFORMER NAME (W × L × H) mm (µH)

(nH)

N (mΩ) (Ω)

LT3468/LT3468-2

LT3468-1

SBL-5.6-1

SBL-5.6S-1

5.6 × 8.5 × 4.0 10 200 Max 10.2 103

26

5.6 × 8.5 × 3.0 24 400 Max 10.2 305

55

LT3468

LT3468-1

LT3468-2

LDT565630T-001

LDT565630T-002

LDT565630T-003

LT3468/LT3468-1

LT3468-1

T-15-089

T-15-083

5.8 × 5.8 × 3.0 6

5.8 × 5.8 × 3.0 14.5

5.8 × 5.8 × 3.0 10.5

200 Max

500 Max

550 Max

10.4 100 Max 10 Max

10.2 240 Max 16.5 Max

10.2 210 Max 14 Max

6.4 × 7.7 × 4.0 12

8.0 × 8.9 × 2.0 20

400 Max 10.2 211 Max 27 Max

500 Max 10.2 675 Max 35 Max

VENDOR

Kijima Musen

Hong Kong Office

852-2489-8266 (ph)

kijimahk@netvigator.com (email)

TDK

Chicago Sales Office

(847) 803-6100 (ph)

www.components.tdk.com

Tokyo Coil Engineering

Japan Office

0426-56-6262 (ph)

www.tokyo-coil.co.jp

Capacitor Selection

For the input bypass capacitor, a high quality X5R or X7R

type 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:

( ) VPK−R = VOUT + N • VIN

The peak current of the diode is simply:

IPK−SEC

=

1.4

N

(LT3468)

IPK−SEC

=

1.0

N

(LT3468-2)

IPK−SEC

=

0.7

N

(LT3468-1)

For the circuit of Figure 6 with VIN of 5V, VPK-R is 371V and

IPK-SEC is 137mA. The GSD2004S dual silicon diode is

recommended for most LT3468/LT3468-1/LT3468-2

applications. Another option is to use the BAV23S dual

silicon diodes. Toshiba makes a dual diode named 1SS306

which also meets all the requirements. The CRF02 is a

single diode with an 800V reverse voltage rating which is

also suitable. Table 3 shows the various diodes and

relevant specifications. Use the appropriate number of

diodes to achieve the necessary reverse breakdown volt-

age.

SW Pin Clamp Diode Selection

The diode D2 in Figure 6 is needed to clamp the SW node.

Due to the new control scheme of the LT3468/LT3468-1/

LT3468-2, the SW node may go below ground during a

switch cycle. The clamp diode prevents the SW node from

Table 3. Recommended Output Diodes

PART

MAX REVERSE VOLTAGE MAX FORWARD CONTINUOUS CURRENT

(V)

(mA)

GSD2004S

2x300

225

(Dual Diode)

BAV23S

2x250

225

(Dual Diode)

1SS306

2x250

100

(Dual Diode)

CRF02

1x800

500

CAPACITANCE

(pF)

5

5

3

Not Specified

VENDOR

Vishay

(402) 563-6866

www.vishay.com

Philips Semiconductor

(800) 234-7381

www.philips.com

Toshiba

(949) 455-2000

www.semicon.toshiba.co.jp

346812f

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