SM8721AB Datasheet, PDF (2/8 Pages) Nippon Precision Circuits Inc – 3-PLL Multi-Output Clock Generator

BLOCK DIAGRAM
SM8721AB
XTI
XTO
Oscillator
CLK2ON
FS1
FS2
FS3
XTAL_SEL
TEST1
TEST2
Control
Logic
Reference
Divider 1
Phase
Detector 1
Charge
Pump 1
LPF 1
VCO 1
(PLL1)
Loop
Divider 1
Reference
Divider 2
Phase
Detector 2
Charge
Pump 2
LPF 2
VCO 2
(PLL2)
Loop
Divider 2
Reference
Divider 3
Phase
Detector 3
Charge
Pump 3
LPF 3
VCO 3
(PLL3)
Loop
Divider 3
CLK1
CLK2
REF_CLK
PIN DESCRIPTION
Number
Name
I/O
1
VDD3
–
2
VDD3
–
3
VSS3
–
4
XTI
I
5
XTO
O
6
TEST1
I
7
XTAL_SEL
I
8
FS3
I
9
FS2
I
10
FS1
I
11
CLK1
O
12
CLK2ON
I
13
VSS1
–
14
VDD1
–
15
VDD1
–
16
CLK2
O
17
VSS2
–
18
VDD2
–
19
REF_CLK
O
20
TEST2
I
Description
Analog supply voltage 3
Analog supply voltage 3
Analog supply ground 3
Crystal oscillator element connection pin (14.318182/28.636363MHz)
Crystal oscillator element connection pin
Test pin 1. Built-in pull-down resistance (leave open circuit or connect to VSS)
Crystal oscillator element selection pin. Built-in pull-up resistance
(HIGH = 28.636MHz, LOW = 14.318MHz)
CLK1, CLK2 output select 3. Built-in pull-up resistance
CLK1, CLK2 output select 2. Built-in pull-up resistance
REF_CLK output select 1. Built-in pull-up resistance
Clock output (71/90/96/114MHz switchable output)
CLK2 output enable. Built-in pull-up resistance (HIGH = enable, LOW = disable)
Digital supply ground 1
Digital supply voltage 1
Digital supply voltage 1
Clock output (48/96MHz switchable output)
Digital supply ground 2
Digital supply voltage 2
Clock output (14.318/17.734MHz switchable output)
Test pin 2. Built-in pull-down resistance (leave open circuit or connect to VSS)
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