CY29946
2.5V or 3.3V, 200-MHz, 1:10 Clock Distribution Buffer
Features
鈥?2.5V or 3.3V operation
鈥?200-MHz clock support
鈥?Two LVCMOS-/LVTTL-compatible inputs
鈥?Ten clock outputs: drive up to 20 clock lines
鈥?1脳 or 1/2脳 configurable outputs
鈥?Output three-state control
鈥?250-ps max. output-to-output skew
鈥?Pin-compatible with MPC946, MPC9446
鈥?Available in commercial and industrial temperature
range
鈥?32-pin TQFP package
Description
The CY29946 is a low-voltage 200-MHz clock distribution
buffer with the capability to select one of two LVCMOS/LVTTL
compatible input clocks. These clock sources can be used to
provide for test clocks as well as the primary system clocks.
All other control inputs are LVCMOS/LVTTL compatible. The
10 outputs are LVCMOS or 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 1:20.
The CY29946 is capable of generating 1脳 and 1/2脳 signals
from a 1脳 source. These signals are generated and retimed
internally to ensure minimal skew between the 1脳 and 1/2脳
signals. SEL(A:C) inputs allow flexibility in selecting the ratio
of 1脳 to1/2脳 outputs.
The CY29946 outputs can also be three-stated via MR/OE#
input. When MR/OE# is set HIGH, it resets the internal
flip-flops and three-states the outputs.
Block Diagram
TCLK_SEL
TCLK0
TCLK1
DSELA
/1
R
/1
Pin Configuration
0
3
/2
QA0:2
1
0
3
QB0:2
1
R /2
DSELB
/1
0
4
QC0:3
1
TCLK_SEL
VDD
TCLK0
TCLK1
DSELA
DSELB
DSELC
VSS
1
2
3
4
5
6
7
8
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
MR/OE#
VSS
QA0
VDDC
QA1
VSS
QA2
VDDC
CY29946
VSS
QB0
VDDC
QB1
VSS
QB2
VDDC
VDDC
R
/2
DSELC
MR/OE#
Cypress Semiconductor Corporation
Document #: 38-07286 Rev. *E
鈥?/div>
3901 North First Street
鈥?/div>
San Jose
,
CA 95134
鈥?/div>
408-943-2600
Revised April 22, 2004
VDDC
QC0
VSS
QC1
VDDC
QC2
VSS
QC3
9
10
11
12
13
14
15
16
next