840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
1
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
GENERAL DESCRIPTION
The ICS840-125 is a Gigabit Ethernet Oscillator
Replacement and a member of the
HiPerClocksTM family of high performance
devices from ICS. The ICS840-125 uses a
25MHz crystal to synthesize 125MHz. The
ICS840-125 has excellent jitter performance. The
ICS840-125 is packaged in a small 8-pin TSSOP, making
it ideal for use in systems with limited board space.
FEATURES
•One LVCMOS/LVTTL output, 15Ω output impedance
•Crystal oscillator interface designed for 25MHz,
18pF parallel resonant crystal
•Output frequency: 125MHz
•Random jitter: 3.7ps (typical)
•Deterministic jitter: 0.1ps (typical)
•3.3V operating supply
•0°C to 70°C ambient operating temperature
•Available in both standard and lead-free RoHS-compliant
packages
HiPerClockS™
ICS
BLOCK DIAGRAM PIN ASSIGNMENT
Clock
Synthesizer
XTAL_IN
XTAL_OUT
OE
Q
Pullup
25MHz
125MHz ICS840-125
8-Lead TSSOP
4.40mm x 3.0mm x 0.925mm package body
G Package
Top View
ICS840-125
8-Lead SOIC
3.90mm x 4.92mm x 1.37mm body package
M Package
Top View
1
2
3
4
8
7
6
5
VDD
XTAL_OUT
XTAL_IN
OE
nc
Q
VDDO
GND
840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
2
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
TABLE 1. PIN DESCRIPTIONS
TABLE 2. PIN CHARACTERISTICS
TABLE 3. CONROL FUNCTION TABLE
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TUO
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840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
3
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
TABLE 5. CRYSTAL CHARACTERISTICS
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
DD 4.6V
Inputs, VI-0.5V to VDD + 0.5 V
Outputs, VO-0.5V to VDDO + 0.5V
Package Thermal Impedance, θJA
8 Lead TSSOP 101.7°C/W (0 mps)
8 Lead SOIC 112.7°C/W (0 lfpm)
Storage Temperature, T
STG -65°C to 150°C
NOTE: Stresses beyond those listed under Absolute
Maximum Ratings may cause permanent damage to the
device. These ratings are stress specifications only. Func-
tional operation of product at these conditions or any condi-
tions beyond those listed in the
DC Characteristics
or
AC
Characteristics
is not implied. Exposure to absolute maxi-
mum rating conditions for extended periods may affect prod-
uct reliability.
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDO = 3.3V±0.3V, TA = 0°C TO 70°C
TABLE 4B. LVCMOS/LVTTL DC CHARACTERISTICS, VDD = VDDO = 3.3V±0.3V, TA = 0°C TO 70°C
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840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
4
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
TABLE 6. AC CHARACTERISTICS, VDD = VDDO = 3.3V±0.3V, TA = 0°C TO 70°C
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840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
5
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
PARAMETER MEASUREMENT INFORMATION
OUTPUT RISE/FALL TIME
3.3V OUTPUT LOAD AC TEST CIRCUIT
SCOPE
Qx
LVCMOS
1.65V ± 0.15V
-1.65V ± 0.15V
Clock
Outputs
20%
80% 80%
20%
t
R
t
F
tPERIOD
tPW
tPERIOD
odc =
V
DDO
2
x 100%
tPW
Q
GND
VDD,
VDDO
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
6
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
APPLICATION INFORMATION
Figure 1. CRYSTAL INPUt INTERFACE
CRYSTAL INPUT INTERFACE
The ICS840-125 has been characterized with 18pF parallel
resonant crystals. The capacitor values, C1 and C2, shown in
Figure 1
below were determined using a 25MHz, 18pF paral-
lel resonant crystal and were chosen to minimize the ppm
error. The optimum C1 and C2 values can be slightly adjusted
for different board layouts.
X1
18pF Parallel Cry stal
C1
12p
XTA L_ OU T
XTA L_I N
C2
12p
840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
7
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
RELIABILITY INFORMATION
TRANSISTOR COUNT
The transistor count for ICS840-125 is: 2423
TABLE 7A. θJAVS. AIR FLOW T ABLE FOR 8 LEAD TSSOP
θθ
θθ
θJA by Velocity (Meters per Second)
0 1 2.5
Multi-Layer PCB, JEDEC Standard Test Boards 101.7°C/W 90.5°C/W 89.8°C/W
TABLE 7B. θJAVS. AIR FLOW T ABLE 8 LEAD SOIC
θθ
θθ
θJA by Velocity (Linear Feet per Minute)
0 200 500
Single-Layer PCB, JEDEC Standard Test Boards 153.3°C/W 128.5°C/W 115.5°C/W
Multi-Layer PCB, JEDEC Standard Test Boards 112.7°C/W 103.3°C/W 97.1°C/W
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
8
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
PACKAGE OUTLINE - G SUFFIX FOR 8 LEAD TSSOP
TABLE 8A. PACKAGE DIMENSIONS
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muminiMmumixaM
N8
A--02.1
1A50.051.0
2A08.050.1
b91.003.0
c90.002.0
D09.201.3
ECISAB04.6
1E03.405.4
eCISAB56.0
L54.057.0
α°0°8
aaa--01.0
PACKAGE OUTLINE - M SUFFIX FOR 8 LEAD SOIC
TABLE 8B. PACKAGE DIMENSIONS
Reference Document: JEDEC Publication 95, MS-012
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MUMINIMMUMIXAM
N8
A53.157.1
1A01.052.0
B33.015.0
C91.052.0
D08.400.5
E08.300.4
eCISAB72.1
H08.502.6
h52.005.0
L04.072.1
α°0°8
840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
9
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
TABLE 9. ORDERING INFORMATION
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (ICS) assumes no responsibility for either its use
or for infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use
in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are
not recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS
product for use in life support devices or critical medical instruments.
The aforementioned trademark, HiPerClockS is a trademark of Integrated Circuit Systems, Inc. or its subsidiaries in the United States and/or other countries.
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840AG-125 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
10
ICS840-125
125MHZ, LVCMOS/LVTTL
OSCILLATOR REPLACEMENT
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