A

1

2

B

TRIG 18

CLOCK/RC/XTLI 4

XTLO(LS7212)

5

5

RCS/CLKS(LS7211)

6

PSCLS

1M

1M

OSC

MUX

3-STATE

DECODER

CLOCK

LATCH

EDGE

DETECT

MODE

REG

CONTROL

LOGIC

LATCH/TIMER

PRESCALER

500K

8

BUF

9

10-17

OUT

WB7-WB0

FIGURE 2. LS7211/LS7212 BLOCK DIAGRAM

500K

500K

500K

500K (8)

3

8

+V

-V (Gnd)

+V

+V

+

V

7

RESET

500K

ELECTRICAL CHARACTERISTICS (Voltages referenced to Vss) (Con’t)

Characteristic

SYMBOL

Unit

Condition

Min

Max

Min

Max

Min

Max

Switching Characteristics (See Fig. 3)

4.0

-

1.3

-

1.0

-

0.76

MHz

RC Oscillator Frequency

10.0

-

4.0

-

3.0

-

2.3

MHz

-

18.0

-

6.0

-

4.5

-

3.4

MHz

4.0

-

2.3

-

1.8

-

1.3

MHz

For prescale

External Clock or

10.0

-

7.0

-

5.5

-

4.0

MHz

factor S = 1 or 3000

Crystal Oscillator

18.0

-

11.0

-

8.5

-

6.5

MHz

or 3600

Frequency

4.0

-

1.2

-

0.93

-

0.7

MHz

S = 32768

10.0

-

4.0

-

3.0

-

2.3

MHz

or

18.0

-

7.0

-

5.5

-

4.2

MHz

32768 X 60

TRIG Set-Up Time

-

23

-

30

-

40

-

ns

-

A, B Set-Up Time

-

0

-

0

-

0

-

ns

-

WB0 - WB7 Set-Up Time

-

0

-

0

-

0

-

ns

-

4.0

215

-

280

-

370

-

ns

Clock to Out Delay

10.0

80

-

105

-

140

-

ns

18.0

50

-

65

-

85

-

ns