1©2016 Integrated Device Technology, Inc. Revision B, November 7, 2016
General Description
The 843252-45 is a 2 LVPECL output Synthesizer optimized to
generate Ethernet reference clock frequencies. Using a 25MHz,
18pF parallel resonant crystal, the following frequencies can be
generated: 156.25MHz and 125MHz. The 843252-45 uses IDT’s 3
rd
generation low phase noise VCO technology and can achieve 1ps
or lower typical rms phase jitter, easily meeting Ethernet jitter
requirements. The 843252-45 is packaged in a small 16-pin TSSOP
package.
Features
Two differential LVPECL output pairs
Crystal oscillator interface designed for a 25MHz, 18pF parallel
resonant crystal
A 25MHz crystal generates output frequencies of: 156.25MHz
and 125MHz
VCO frequency: 625MHz
RMS Phase Jitter @ 156.25MHz, (1.875MHz – 20MHz) using a
25MHz crystal: 0.54ps (typical)
Full 3.3V supply mode
0°C to 70°C ambient operating temperature
Available in lead-free (RoHS 6) package
For functional replacement part us 8T49N241
Block Diagram
OSC
Phase
Detector
VCO
625MHz
Feedback Divider
÷25
÷4
÷5
25MHz
QA
nQ
A
QB
nQ
B
C
LK_EN_A
XTAL_IN
X
TAL_OUT
C
LK_EN_B
Pullup
Pullup
125MHz
156.25MH
z
Pin Assignment
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
VCCA
nc
V
CCOA
nQA
QA
V
EE
CLK_EN_A
CLK_EN_B
V
EE
QB
nQB
V
CCOB
XTAL_IN
XTAL_OUT
V
EE
843252-45
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package
843252-45
Datasheet
FemtoClock
®
Crystal-to-3.3V LVPECL
Frequency Synthesizer
2©2016 Integrated Device Technology, Inc. Revision B, November 7, 2016
843252-45 Datasheet
Table 1. Pin Descriptions
NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Table 2. Pin Characteristics
Function Tables
Table 3A. CLK_EN_A Function Table Table 3B. CLK_EN_B Function Table
Number Name Type Description
1 CLK_EN_A Input Pullup Output enable pin. LVCMOS/LVTTL interface levels. See Table 3A.
2, 9, 15 V
EE
Power Negative supply pins.
3, 4 QA, nQA Output Differential output pair. LVPECL interface levels.
5V
CCOA
Power Output supply pin for QA/nQA outputs.
6 nc Unused No connect.
7V
CCA
Power Analog supply pin.
8V
CC
Power Power supply pin.
10
11
XTAL_OUT
XTAL_IN
Input Crystal oscillator interface XTAL_IN is the input, XTAL_OUT is the output.
12 V
CCOB
Power Output supply pin for QB/nQB outputs.
13, 14 nQB, QB Output Differential output pair. LVPECL interface levels.
16 CLK_EN_B Input Pullup Output enable pin. LVCMOS/LVTTL interface levels. See Table 3B.
Symbol Parameter Test Conditions Minimum Typical Maximum Units
C
IN
Input Capacitance 4 pF
R
PULLUP
Input Pullup Resistor 51 k
Input Outputs
CLK_EN_A QA nQA
0LOWHIGH
1 (default) Active Active
Input Outputs
CLK_EN_B QB nQB
0 LOW HIGH
1 (default) Active Active
3©2016 Integrated Device Technology, Inc. Revision B, November 7, 2016
843252-45 Datasheet
Absolute Maximum Ratings
NOTE: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.
These ratings are stress specifications only. Functional operation of product at these conditions or any conditions beyond
those listed in the DC Characteristics or AC Characteristics is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect product reliability.
DC Electrical Characteristics
Table 4A. Power Supply DC Characteristics, V
CC
= V
CCOA
= V
CCOB
= 3.3V ± 5%, T
A
= 0°C to 70°C
Table 4B. LVCMOS/LVTTL DC Characteristics,V
CC
= V
CCOA
= V
CCOB
= 3.3V ± 5%, T
A
= 0°C to 70°C
Table 4C. LVPECL DC Characteristics, V
CC
= V
CCOA
= V
CCOB
= 3.3V ± 5%, T
A
= 0°C to 70°C
NOTE 1: Output termination with 50 to V
CCOA,B
– 2V.
Item Rating
Supply Voltage, V
CC
4.6V
Inputs, V
I
-0.5V to V
CC
+ 0.5V
Outputs, I
O
Continuos Current
Surge Current
50mA
100mA
Package Thermal Impedance,
JA
92.4C/W (0 mps)
Storage Temperature, T
STG
-65C to 150C
Symbol Parameter Test Conditions Minimum Typical Maximum Units
V
CC
Power Supply Voltage 3.135 3.3 3.465 V
V
CCA
Analog Supply Voltage V
CC
– 0.15 3.3 V
CC
V
V
CCOA,
V
CCOB
Power Supply Voltage 3.135 3.3 3.465 V
I
CCA
Analog Supply Current 15 mA
I
EE
Power Supply Current 75 mA
Symbol Parameter Test Conditions Minimum Typical Maximum Units
V
IH
Input High Voltage 2 V
CC
+ 0.3 V
V
IL
Input Low Voltage -0.3 0.8 V
I
IH
Input High Current
CLK_EN_A,
CLK_EN_B
V
CC
= V
IN
= 3.465V 5 µA
I
IL
Input Low Current
CLK_EN_A,
CLK_EN_B
V
CC
= 3.465V, V
IN
= 0V -150 µA
Symbol Parameter Test Conditions Minimum Typical Maximum Units
V
OH
Output High Voltage; NOTE 1 V
CCO
– 1.4 V
CCO
– 0.9 V
V
OL
Output Low Voltage; NOTE 1 V
CCO
– 2.0 V
CCO
– 1.7 V
V
SWING
Peak-to-Peak Output Voltage Swing 0.6 1.0 V

843252AG-45LF

Mfr. #:
Manufacturer:
IDT
Description:
Clock Generators & Support Products XTAL TO LVPECL SYNTHESIZER
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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