DN86

Issue 1 - October 2007

3

www.zetex.com

© Zetex Semiconductors plc 2007

Referring to circuit schematic in Figure 2; the jumper connection could be used utilizing a zero

ohm resistor, in order to enable the pure DC operations.

Care has to be taken in this case, since the system is not reverse polarity protected.

In Figure 3 the circuit layout is shown, highlighting its space saving features and compactness.

Both bottom layer and top layer are shown to display effective devices arrangement.

TOP COPPER AND SILKSCREEN

BOTTOM COPPER AND SILK SCREEN

Figure 3 Circuit layout

The main layout design suggestions are:

•

All thin devices on one side

•

Employ a star connection for ground tracks

•

Use a ground ring protecting ADJ pin

•

Check that:

•

Tracks connecting R1 to ZXLD1350 are as short as possible (being sense tracks)

•

•

The freewheeling current path is as short as possible to ensure system precision and efficiency

Quantity

Part reference

Value

Description

Source

1R1

0.33

Resistor, 1%, 0805

Various

2

C1, C2

150µF/20V

Type D SMD Tantalum Cap

Kemet

1

C3

0.1µF/25V

SMD 0805 X7R

NIC

Componenents

1

C4

1µF/25V

SMD 1210 X7R

NIC

Componenents

1

L1

100µH

MSS6132-104

Coilcraft

1

U1

ZXLD1350

LED driver IC

ZETEX

1

U2

ZXSBMR16PT8

Schottky bridge rectifier

and freewheeling diode

ZETEX

Table 1

Bill of Material