Pin Description

Pin No.

Pin Name

I/O

Description

1

OSC1

I

System clock input

2, 4

VSS

¾

Negative power supply, ground

3

VDD

¾

Positive power supply

5, 6

IO0~IO1

O

Customer defined optional output lines

39, 40, 7~12

C0~C7

I

Keyboard matrix scanning input pins

16~23, 28,

29, 13~15

24, 26, 27

33, 35

R0~R18

O

Keyboard matrix scanning output pins

25, 34

NC

¾

No connection

30

SCRL

O

LED pin

31

NUM

O

LED pin

32

CAP

O

LED pin

37

CLOCK

I/O

Synchronous clock signal. Used to clock the transmission data

38

DATA

I/O

Bidirectional data transmission line

Absolute Maximum Ratings

Supply Voltage .......................................4.75V to 5.25V

Storage Temperature ............................

-55°Cto125°C

Operating Temperature...............................0

°Cto70°C

Note: These are stress ratings only. Stresses exceeding the range specified under

²Absolute Maximum Ratings² may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those

listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-

ity.

Electrical Characteristics

Ta=25

°C

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Operating Voltage

¾

4.75

5

5.25

V

Operating Current

¾¾

25

mA

Input Low Voltage (C0~C7)

¾

0

¾

0.6

V

Input Low Voltage (DATA, CLOCK)

¾

0

¾

0.6

V

Input High Voltage

¾

3.5

¾

V

Output Low Voltage (R0~R18)

¾¾

0.5

V

Output Low Voltage (DATA, CLOCK)

¾¾

0.5

V

Internal Pull-high Resistance (C0~C7)

¾

510

20

k

W

Internal Pull-high Resistance (CLOCK, DATA)

¾

25

15

k

W

System Clock

R=120k

W¾

4

¾

MHz

HT82K28A

Rev. 1.30

2

June 27, 2002