CY29949 Datasheet, PDF (1/7 Pages) Cypress Semiconductor – 2.5V or 3.3V 200-MHz 1:15 Clock Distribution Buffer

CY29949
2.5V or 3.3V 200-MHz 1:15 Clock Distribution Buffer
Features
• 2.5V or 3.3V operation
• 200-MHz clock support
• LVPECL or LVCMOS/LVTTL clock input
• LVCMOS-/LVTTL-compatible outputs
• 15 clock outputs: drive up to 30 clock lines
• 1X and 1/2X configurable outputs
• Output three-state control
• 350 ps max. output-to-output skew
• Pin compatible with MPC949, MPC9449
• Available in Commercial and Industrial temp. range
• 52-pin TQFP package
Description
The CY29949 is a low-voltage 200-MHz clock distribution
buffer with the capability to select either a differential LVPECL
or 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 15 outputs are LVCMOS or
LVTTL compatible and can drive 50Ω series or parallel termi-
nated transmission lines. For series terminated transmission
lines, each output can drive one or two traces giving the device
an effective fanout of 1:30.
The CY29949 is capable of generating 1X and 1/2X signals
from a 1X source. These signals are generated and retimed
internally to ensure minimal skew between the 1X and 1/2X
signals. SEL(A:D) inputs allow flexibility in selecting the ratio
of 1X to1/2X outputs.
The CY29949 outputs can also be three-stated via the
MR/OE# input. When MR/OE# is set HIGH, it resets the
internal flip-flops and three-states the outputs.
Block Diagram
Pin Configuration
TCLK_SEL
0
1
0
PECL_CLK
1
PECL_CLK#
PECL_SEL
DSELA
DSELB
DSELC
DSELD
MR/OE#
1
R2
0
1
1
0
R2
1
1
0
R2
1
1
0
R2
1
2 _QA(0:1)
3 _QB(0:2)
MR/OE#
TCLK_SEL
VDD
TCLK0
TCLK1
52 51 50 49 48 47 46 45 44 43 42 41 40
1
39
2
38
3
37
4
36
5
35
NC
VSS
QC0
VDDC
QC1
PECL_CLK 6
PECL_CLK# 7
4 _QC(0:3)
PCLK_SEL 8
DSELA 9
CY29949
34 VSS
33 QC2
32 VDDC
31 QC3
DSELB 10
30 VSS
DSELC 11
29 VSS
6
QD(0:5)
DSELD 12
28 QD5
VSS 13
27 NC
14 15 16 17 18 19 20 21 22 23 24 25 26
Cypress Semiconductor Corporation • 3901 North First Street • San Jose, CA 95134 • 408-943-2600
Document #: 38-07289 Rev. *D
Revised November 6, 2003