83940AY-02 www.icst.com/products/hiperclocks.html REV. A JULY 30, 2007
1
ICS83940-02
LOW SKEW, 1-TO-18
DIFFERENTIAL-TO-LVCMOS/LVTTL FANOUT BUFFER
GENERAL DESCRIPTION
The ICS83940-02 is a low skew, 1-to-18 Fanout
Buffer and a member of the HiPerClockS™
family of High Performance Clock Solutions from
ICS. The 83940-02 has two selectable clock in-
puts. The CLK0, nCLK0 pair can accept most
standard differential input levels. The single ended clock in-
put accepts LVCMOS or LVTTL input levels.The low imped-
ance LVCMOS/LVTTL outputs are designed to drive 50Ω
series or parallel terminated transmission lines. The effective
fanout can be increased from 18 to 36 by utilizing the ability
of the outputs to drive two series terminated lines.
The ICS83940-02 is characterized at full 3.3V, full 2.5V and
mixed 3.3V input and 2.5V output operating supply modes.
Guaranteed output and part-to-part skew characteristics
make the ICS83940 ideal for those clock distribution applica-
tions demanding well defined performance and repeatability.
BLOCK DIAGRAM PIN ASSIGNMENT
FEATURES
• 18 LVCMOS/LVTTL outputs, 7Ω typical output impedance
• Selectable LVCMOS_Clock or CLK0, nCLK0 input pair
• LVCMOS_CLK supports the following input types:
LVCMOS or LVTTL
• CLK0, nCLK0 pair can accept the following differential
input levels: LVPECL, LVDS, LVHSTL, SSTL, HCSL
• Maximum output frequency: 200MHz
• Output skew: 120ps (maximum)
• Part-to-part skew: 850ps (maximum)
• Output supply modes:
Core/Output
3.3V/3.3V
3.3V/2.5V
2.5V/2.5V
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
• Pin compatible with the MPC940L in single supply
applications
HiPerClockS™
ICS
32-Lead LQFP
Y Pacakge
7mm x 7mm x 1.4mm package body
Top View
Q0:Q17
CLK_SEL
CLK0
nCLK0
LVCMOS_CLK
0
1
32 31 30 29 28 27 26 25
9 10 11 12 13 14 15 16
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
Q6
Q7
Q8
V
DDO
Q9
Q10
Q11
GND
GND
GND
LVCMOS_CLK
CLK_SEL
CLK
nCLK
V
DD
VDDO
VDDO
Q12
Q13
Q14
GND
Q15
Q16
Q17
GND
Q5
Q4
Q3
V
DDO
Q2
Q1
Q0
ICS83940-02
