Low Skew, 1-to-18 LVPECL-to-
LVCMOS/LVTTL Fanout Buffer
PRODUCT DISCONTINUATION NOTICE - LAST TIME BUY EXPIRES JANUARY 27, 2015
ICS83940
GENERAL DESCRIPTION
The ICS83940 is a low skew, 1-to-18 LVPECL-to-LVCMOS/
LVTTL Fanout Buffer. The ICS83940 has twoselectable
clock inputs. The PCLK, nPCLK pair can accept LVPECL,
CML, or SSTL input levels. The LVCMOS_CLK can accept
LVCMOS or LVTTL input levels. The low impedance
LVCMOS/LVTTL outputs are designed to drive 50Ω series
or parallel terminated transmission lines.
The ICS83940 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
applications demanding well defined performance and
repeatability.
FEATURES
• Eighteen LVCMOS/LVTTL outputs, 16Ω typical output
impedance
• Selectable LVCMOS_CLK or LVPECL clock inputs
• PCLK, nPCLK supports the following input types:
LVPECL, CML, SSTL
• LVCMOS_CLK accepts the following input levels:
LVCMOS or LVTTL
• Maximum output frequency: 250MHz
• Output skew: 150ps (maximum)
• Part to part skew: 750ps (maximum)
• Full 3.3V or 2.5V supply modes
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
• Lead-Free package fully RoHS compliant
• For New Designs Use: 83940DYLF or 83940DYILF
BLOCK DIAGRAM
PIN ASSIGNMENT
CLK_SEL
PCLK
nPCLK
0
LVCMOS_CLK
1
18
Q0:Q17
GND
GND
LVCMOS_CLK
CLK_SEL
PCLK
nPCLK
VDD
VDDO
32 31 30 29 28 27 26 25
1
24
2
23
3
22
4
ICS83940 21
5
20
6
19
7
18
8
17
9 10 11 12 13 14 15 16
Q6
Q7
Q8
VDD
Q9
Q10
Q11
GND
32-Lead LQFP
7mm x 7mm x 1.4mm package body
Y Pacakge
Top View
83940BY
www.idt.com
1
REV. B JANUARY 31, 2014