1

PS7038B

09/08/97

Pin Name Pin # I/O Description

S0

6

I

Select 0, internal pull-up

S1

7

I

Select 1, internal pull-up

X1

2

C

Crystal or clock input, 8 to 23 MHz

X2

3

C

Crystal connection or no connect

CLK

5

O

Clock output

OE

1

I

OE = 1 Enable CLK output

OE = 0 Disable CLK output

3.3V Precision Clock Generator

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PI6C918/919

Features

• No external capacitors (919 only)

• Excellent signal quality

• Very low jitter

• Precise frequencies

• Minimal undershoot, ringback or overshoot

• Nearly perfect 50% duty cycle

• Four selectable clock frequencies

• Operates at Vcc = 3.3V

• Output may be disabled to save power

• Small 150-mil wide SOIC -8 (W8) package

saves board area

Pin Configuration

Pin Description

Product Speed Grades

Max CLK

Max VCO

Part No.

Output Freq.

Frequency

PI6C918/919

80 MHz

160 MHz

PI6C918A/919A

100 MHz

200 MHz

PI6C918B/919B

120 MHz

240 MHz

Output CLK Frequency Selection

Vcc

1

OE

8

S1

2

X1

7

S0

3

X2

6

CLK

4

GND

5

8-PIN

W8

Note:

1. I = Input, O = Output, C = Crystal

Description

The PI6C918 and PI6C919 are high-precision, low-voltage

general-purpose clock generators that reach a maximum output

frequency of 120 MHz. These devices use an external low-cost

crystal to generate very accurate and stable system clocks.

These frequency synthesizers include a crystal oscillator, a

programmable PLL and an output buffer. Any one of four

different output frequencies can be selected via two select pins

(S0, S1). The frequency multipliers are: 2, 4, 5, and 7.

The PI6C919 has on-chip capacitors, eliminating the need for

external capacitors at the X1, X2 pins. This reduces overall parts

count and board area, and increases reliability.

The OE (output enable) pin may be pulled down to disable the

output buffer and save system power.

The small surface-mount SOIC-8 package is ideal for compact

portable equipment applications.

Notes:

1. Indicates popular target frequencies.

2. The ratio of N/M may be changed by mask option.

n

o

i

t

c

e

l

e

S

0

S

,

1

SM

/

N

)

2

(

k

c

o

l

C

0

1

g

n

i

s

u

(

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l

a

t

X

z

H

M

k

c

o

l

C

6

.

6

1

g

n

i

s

u

(

)

l

a

t

X

z

H

M

k

c

o

l

C

0

2

g

n

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u

(

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t

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z

H

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k

c

o

l

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1

.

2

2

g

n

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u

(

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M

0

02

–

3

.

3

3

)

1

(

0

42

.

4

4

1

04

0

4

)

1

(

6

.

6

6

)

1

(

0

8

)

1

(

4

.

8

8

0

15

0

5

)

1

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3

80

0

1

)

1

(

5

.

0

1

1

1

170

7

)

1

(

6

1

1

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