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3

EVALUATION KIT FOR

SA305EX

DB62

SPECIAL CONSIDERATIONS

a) 6 schottky diodes D1-D6 (2 for each output provided with

DB62) are recommended for use as external flyback diodes

becauseofsuperiorreverserecoverycharacteristics.Please

note that in the DB62, jumpers are needed in order to con-

nect the external schottky diodes (see EVAL49 layout).

b) External RC snubber circuits (R13 and C5, R16 and C8,

R19 and C10 in EVAL49 schematic) can provide noise

immunity especially in high load current scenarios. A 100

V 4.7nF capacitor in series with a 50 ohm 5W resistor

(provided with kit) is recommended for the snubber to be

connected between each output and PGND.

The power dissipated in the snubber components can be

estimated by;

P = V2 • C • FSW

Where

P is the power dissipated

V is the VS supply voltage

C is the snubber capacitor value (15nF)

FSW is the switching frequency.

GROUNDING CONSIDERATIONS

The EVAL49 has three separate ground paths for signal

ground (SGND), power ground (PGND) and digital ground

(DGND). SGND and PGND are the ground paths for the

SA305 while the DGND is for the MCU and related circuitry.

These grounds need to be connected on the board by putting

a jumper between SGND and DGND and another between

PGND and DGND. These jumpers are located in the center

of the board on the right of the SA305. Do not connect the

grounds at any other points to avoid ground loops and un-

wanted voltage drops.

PARTS LIST

Apex Part #

Description, Vendor

Qty

EVAL49

PC Board, Apex

1

OX7R105KWN

1µF Cap, Novacap

4

MS06

Pin Socket

1

MS11

Socket Strip

1 Bag

(Black) 151-203-RC

Test Point

3

Mouser

(White) 151-201-RC

Test Point

5

Mouser

110-13-328-41-001000

DIP28 Socket

1

Mill-Max

(White) 571-0600

4mm single PCB socket

16

Deltron

(Red) 571-0500

4mm single PCB socket

3

Deltron

(Black) 571-0100

4mm single PCB socket

3

Deltron

ECG-EVQPAC07K

Push Button Switch,

3

Panasonic

3352W-1-102

Potentiometer,

2

Bourns

50SQ100

Schottky Diodes,

6

International Rectifier

140-ESRL100V100

100uF cap,

2

Xicon

MCU-305

PIC18F2331-1/SP-ND

1

Microchip

CFRN60D1001FRE6

1K Ohm Resistor,

3

(R23,R24.R25)

5% 0.25W

RN60D4701FB14

4.7K Ohm Resistor,

4

(R1, R2, R3, R6)

5% 0.25W

CFI-4C1R0J

1 Ohm Resistor,

2

(R5, R10)

5% 0.25W

RN60D2000FB14

200 Ohm Resistor,

6

(R17, R18, R20,

R21, R22, R26)

5% 0.25W

WP63GD

Green LED's,

5

(D8-D12)

WP631D

Red LED, (D7)

1

(Optional Components: Refer to SA305U for details)

Apex Part #

Description, Vendor

Qty

HWRE06

Includes the following:

HS32

Heatsink,

1

Apex

CLAMP05

Clip,

1

Apex

TW12

Thermal Washer,

1 Box

Apex

C062K472K2X5CA

4.7 nF Capacitor,

3

Kemet

286-51-RC

50 ohm 5W resistor,

3

Xicon