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| 844003 Datasheet, PDF (1/18 Pages) Integrated Device Technology – FemtoClock Crystal-to-3.3V LVDS Frequency Synthesizer | |||
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FemtoClock® Crystal-to-3.3V LVDSï
Frequency Synthesizer
844003
Datasheet
General Description
The 844003 is a three differential output LVDS Synthesizer designed
to generate Ethernet reference clock frequencies. Using a 31.25MHz
or 26.041666MHz, 18pF parallel resonant crystal, the following
frequencies can be generated based on the settings of four
frequency select pins (DIV_SEL[A1:A0], DIV_SEL[B1:B0]): 625MHz,
312.5MHz, 156.25MHz, and 125MHz. The 844003 has two output
banks, Bank A with one differential LVDS output pair and ï
Bank B with two differential LVDS output pairs.
The two banks have their own dedicated frequency select pins and
can be independently set for the frequencies mentioned above. The
844003 uses IDTâs 3rd generation low phase noise VCO technology
and can achieve 1ps or lower typical rms phase jitter, easily meeting
Ethernet jitter requirements. The 844003 is packaged in a small
24-pin TSSOP package.
Features
⢠Three LVDS outputs on two banks, A Bank with one LVDS pair
and B Bank with two LVDS output pairs
⢠Using a 31.25MHz or 26.041666MHz crystal, the two output
banks can be independently set for 625MHz, 312.5MHz,
156.25MHz or 125MHz
⢠Selectable crystal oscillator interface or LVCMOS/LVTTL
single-ended input
⢠VCO range: 560MHz to 700MHz
⢠RMS phase jitter @ 156.25MHz (1.875MHz - 20MHz): 0.63ps (typical)
⢠3.3V output supply mode
⢠0°C to 70°C ambient operating temperature
⢠Available in lead-free (RoHS 6) packaging
Pin Assignment
Block Diagram
OEA
DIV_SELA[1:0]
VCO_SEL
TEST_CLK
Pullup
Pulldown:Pullup
Pullup
Pulldown
0
XTAL_IN
OSC 1
XTAL_OUT
XTAL_SEL
Pullup
FB_DIV
DIV_SELB[1:0]
MR
OEB
Pulldown
Pullup:Pulldown
Pulldown
Pullup
Phase
Detector
VCO
FB_DIV
0 = ÷20 (default)
1 = ÷24
0 0 ÷1
0 1 ÷2 (default)
0
1 0 ÷4
1 1 ÷5
1
0 0 ÷1
0 1 ÷2
1 0 ÷4 (default)
1 1 ÷5
QA0
nQA0
DIV_SELB0 1
VCO_SEL 2
MR 3
VDDO_A 4
QA0 5
nQA0 6
OEB 7
OEA 8
FB_DIV 9
VDDA 10
VDD 11
DIV_SELA0 12
24 DIV_SELB1
23 VDDO_B
22 QB0
21 nQB0
20 QB1
19 nQB1
18 XTAL_SEL
17 TEST_CLK
16 XTAL_IN
15 XTAL_OUT
14 GND
13 DIV_SELA1
844003
24-Lead TSSOP
4.40mm x 7.8mm x 0.92mm
package body
G Package
Top View
QB0
nQB0
QB1
nQB1
©2016 Integrated Device Technology, Inc.
1
January 29, 2016
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