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200-MHz clock support
LVPECL or LVCMOS/LVTTL clock input
LVCMOS/LVTTL-compatible inputs
18 clock outputs: drive up to 36 clock lines
150 ps max. output-to-output skew
23鈩?output impedance
Dual or single supply operation:
鈥?3.3V core and 3.3V outputs
鈥?3.3V core and 2.5V outputs
鈥?2.5V core and 2.5V outputs
鈥?Pin-compatible with MPC940L, MPC9109
鈥?Available in commercial and industrial temperature
ranges
鈥?32-pin TQFP package
Description
The CY29940-1 is a low-voltage 200-MHz clock distribution
buffer with the capability to select either a differential LVPECL-
or a LVCMOS/LVTTL-compatible input clock. The two clock
sources can be used to provide for a test clock as well as the
primary system clock. All other control inputs are
LVCMOS/LVTTL-compatible. The eighteen outputs are 2.5V
or 3.3V LVCMOS/LVTTL-compatible and can drive 50鈩?series
or parallel terminated transmission lines. For series terminated
transmission lines, each output can drive one or two traces
giving the device an effective fanout of 1:36. Low
output-to-output skews make the CY29940-1 an ideal clock
distribution buffer for nested clock trees in the most
demanding of synchronous systems.
Block Diagram
Pin Configuration
VDDC
VDD
PECL_CLK
PECL_CLK#
TCLK
TCLK_SEL
0
1
VDDC
VSS
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
32 31 30 29 28 27 26 25
24
23
22
Q6
Q7
Q8
VDD
Q9
Q10
Q11
VSS
18
VSS
Q0-Q17
TCLK
TCLK_SEL
PECL_CLK
PECL_CLK#
VDD
VDDC
CY29940-1
VSS
21
20
19
18
17
VDDC
Q0
Q1
Q2
Q3
Q4
Q13
Q17
Q16
Q15
Q14
Cypress Semiconductor Corporation
Document #: 38-07487 Rev. **
鈥?/div>
3901 North First Street
鈥?/div>
San Jose
,
CA 95134
鈥?/div>
408-943-2600
Revised January 28, 2003
VSS
Q12
Q5
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