CY29948_11 Datasheet, PDF (1/10 Pages) Cypress Semiconductor – 2.5 V or 3.3 V, 200-MHz, 1:12 Clock Distribution Buffer LVCMOS-/LVTTL-compatible inputs

CY29948
2.5 V or 3.3 V, 200-MHz,
1:12 Clock Distribution Buffer
2.5 V or 3.3 V, 200-MHz, 1:12 Clock Distribution Buffer
Features
■ 2.5 V or 3.3 V operation
■ 200-MHz clock support
■ LVPECL or LVCMOS/LVTTL clock input
■ LVCMOS-/LVTTL-compatible inputs
■ 12 clock outputs: drive up to 24 clock lines
■ Synchronous Output Enable
■ Output three-state control
■ 150 ps typical output-to-output skew
■ Pin compatible with MPC948, MPC948L, MPC9448
■ Available in Commercial and Industrial temp. range
■ 32-pin TQFP package
Block Diagram
PECL_CLK
PECL_CLK#
TCLK
TCLK_SEL
SYNC_OE
TS#
VDD
0
1
Description
The CY29948 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 12 outputs are LVCMOS or LVTTL compatible
and can drive 50  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
1:24. The outputs can also be three-stated via the three-state
input TS#. Low output-to-output skews make the CY29948 an
ideal clock distribution buffer for nested clock trees in the most
demanding of synchronous systems.
The CY29948 also provides a synchronous output enable input
for enabling or disabling the output clocks. Since this input is
internally synchronized to the input clock, potential output
glitching or runt pulse generation is eliminated.
VDDC
12 _Q0-Q11
Pin Configuration
TCLK_SEL
TCLK
PECL_CLK
PECL_CLK#
SYNC_OE
TS#
VDD
VSS
1
24
2
23
3
22
4
5
CY29948
21
20
6
19
7
18
8
17
VSS
Q4
VDDC
Q5
VSS
Q6
VDDC
Q7
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 38-07288 Rev. *E
• San Jose, CA 95134-1709 • 408-943-2600
Revised May 2, 2011
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