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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
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.
1
2
3
4
8
Pin Configuration
OE
X1
X2
GND
Vcc
S1
S0
CLK
Pin Description
Pin Name Pin # I/O
S0
6
I
S1
7
I
X1
2
C
X2
3
C
CLK
5 O
OE
1
I
Clock
(using 22.1
MHz Xtal)
44.2
88.4
110.5
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8-PIN
W8
7
6
5
Output CLK Frequency Selection
Selection
S 1, S 0
00
01
10
11
Clock
Clock
Clock
(using10 (using 16.6 (using 20
MHz Xtal) MHz Xtal) MHz Xtal)
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40
(1)
50
(1)
Description
Select 0, internal pull-up
Select 1, internal pull-up
Crystal or clock input, 8 to 23 MHz
Crystal connection or no connect
Clock output
OE = 1 Enable CLK output
OE = 0 Disable CLK output
Note:
1. I = Input, O = Output, C = Crystal
N/M
(2)
2
4
5
7
Product Speed Grades
Part No.
PI6C918/919
PI6C918A/919A
PI6C918B/919B
Max CLK
Output Freq.
80 MHz
100 MHz
120 MHz
Max VCO
Frequency
160 MHz
200 MHz
240 MHz
33.3
(1)
40
80
(1)
100
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(1)
66.6
(1)
83
116
70
(1)
Notes:
1. Indicates popular target frequencies.
2. The ratio of N/M may be changed by mask option.
1
PS7038B
09/08/97
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2
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