Application Circuits

Note:

For single side PCB, the GND should be routed first. Avoid routing the GND line and VDD line with jumping

wires.

The GND and VDD lines should be as wide as possible, also it is recommended that the GND and VDD lines

are placed in an empty area, in order to increase their area. Wherever possible the GND plane should surround

pins such as OSCI, OSCO, VDD, V330, RESET etc and other related circuits to minimize the noise effects.

The GND/VDD loop area should be minimized. Try to keep GND and VDD lines parallel.

The external 22

W resistor and 0.01mF capacitor connected to the VDD pin should be placed as close as possi-

ble to the VDD pin.

Allow room in the layout for the 0.1

mF capacitor that is connected to the VDD pin. This capacitor should be con-

nected as close as possible to the VDD pin. The function of this capacitor is to filter out high frequency noise.

The lines connecting the OSCI and OSCO pins to the crystal must be kept as short as possible to minimize any

cross coupling of noise from these pins.

The 0.1

mF capacitor connected to the RESET pin should be placed as close as possible to the RESET pin. The

function of this capacitor is to filter out high frequency noise to minimize the possibility of a glitch on this line

causing a false reset.

The 0.1

mF capacitor connected to the V33O pin should be placed as close as possible to the V33O pin.

The USBD+ and USBD- lines to the USB connector should be kept as short as possible and should not be

placed close to the other lines to reduce the possibility of noise coupling into other lines. The externally con-

nected 1.5k

W resistor connected to the USBD- pin should be placed as close to as possible the USBD- pin.

The USB cable should preferably have proper shielding.

HT82K629A

Rev. 1.30

21

April 16, 2004

C 1 7

C 1 6

R 3

R 2

R 1

R 0

F n S e l e c t

N U M

C A P S

S C R O L L

C 1 2

C 1 3

C 1 4

C 1 5

V D D

V 3 3 O

U S B D + / C L K

U S B D - / D A T A

C 0

C 1

C 1 8

C 1 9

R 4

R 5

R 6

R 7

C 1 1

C 1 0

C 9

C 8

O S C I

O S C O

R E S E T

V S S

C 7

C 6

C 5

C 4

C 3

C 2

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

1 9

2 0

4 0

3 9

3 8

3 7

3 6

3 5

3 4

3 3

3 2

3 1

3 0

2 9

2 8

2 7

2 6

2 5

2 4

2 3

2 2

2 1

V D D

U S B -

U S B +

V S S

6 M H z

D 1

D 2

D 3

S c r o l l L o c k

N u m L o c k

C a p s L o c k

U S B C O N

0 . 1 m F

0 . 1 m F

3 3 p F

0 . 1 m F

0 . 1 m F

2 2 W

0 . 0 1 m F

1 0 m F

2 2 W

M C U V D D

1

2

3

4

H T 8 2 K 6 2 9 A

V D D

1 . 5 k W

M C U V D D

1 0 k W

1 0 0 k W

F n _ S e l = 1 o r f l o a t i n g : d i s a b l e s M i n i - k e y b o a r d f u n c t i o n

F n _ S e l = 0 : e n a b l e s M i n i - k e y b o a r d f u n c t i o n

2 2 W

3 3 p F