CY29976AIT

CY29976
3.3V, 125-MHz, Multi-Output Zero Delay Buffer
Cypress Semiconductor Corporation 198 Champion Court San Jose, CA 95134-1709 408-943-2600
Document #: 38-07413 Rev. *B Revised September 09, 2008
Features
Output frequency up to 125 MHz
Supports PowerPC
®
, and Pentium
®
processors
12 clock outputs: frequency configurable
Configurable Output Disable
Two reference clock inputs for dynamic toggling
Oscillator or PECL reference input
Spread spectrum compatible
Glitch-free output clocks transitioning
3.3V power supply
Pin compatible with SC973X
Industrial temperature range: –40°C to +85°C
52-Pin TQFP package
Table 1. Frequency Table
[1]
VC0_SEL FB_SEL2 FB_SEL1 FB_SEL0 F
VCO
00008x
000112x
001016x
001120x
01008x
010112x
011016x
011120x
10004x
10016x
10108x
101110x
11004x
11016x
11108x
111110x
Note
1. x = the reference input frequency, 200MHz < F
VCO
< 480MHz.
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CY29976
Document #: 38-07413 Rev. *B Page 2 of 9
Pinouts
Logic Block Diagram
REF_SEL
0
1
0
1
Phase
Detector
VCO
LPF
Sync
Frz
D
Q
QA0
Sync
Frz
D
Q
Sync
Frz
D
Q
Sync
Frz
D
Q
Sync
Frz
D
Q
Sync
Frz
D
Q
P ow er-O n
Reset
Output Disable
Circuitry
D a ta G e n e ra to r
/2 , /6 , /4 , /1 2
/2 , /6 , /4 , /1 0
/8 , /2 , /6 , /4
/4 , /6 , /8 , /1 0
Sync Pulse
PECL_CLK
PECL_CLK#
TCLK0
TCLK1
TCLK_SEL
FB_IN
MR#/OE
SELA(0,1)
2
SELB(0,1)
2
SELC(0,1)
2
FB_SEL(0:2)
3
SCLK
SDATA
IN V _ C L K
QA1
QA2
QA3
QB0
QB1
QB2
QB3
QC0
QC1
QC2
QC3
FB_OUT
SYNC
12
VCO_SEL
PLL_EN
VSS
MR#/OE
SCLK
SDATA
FB_SEL2
PLL_EN
REF_SEL
TCLK_SEL
TCLK0
TCLK1
PECL_CLK
PECL_CLK#
VDD
FB_SEL1
SYNC
VSS
QC0
VDDC
QC1
SELC0
SELC1
QC2
VDDC
QC3
VSS
INV_CLK
SELB1
SELB0
SELA1
SELA0
QA3
VDDC
QA2
VSS
QA1
VDDC
QA0
VSS
VCO_SEL
VSS
QB0
VDDC
QB1
VSS
QB2
VDDC
QB3
FB_IN
VSS
FB_OUT
VDDC
FB_SEL0
1
2
3
4
5
6
7
8
9
10
11
12
13
39
38
37
36
35
34
33
32
31
30
29
28
27
14 15 16 17 18 19 20 21 22 23 24 25 26
52 51 50 49 48 47 46 45 44 43 42 41 40
CY29976
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CY29976
Document #: 38-07413 Rev. *B Page 3 of 9
Note
2. A bypass capacitor (0.1μF) must be placed as close as possible to each positive power (<0.2”). If these bypass capacitors are not close to the pins their high frequency
filtering characteristics are cancelled by the lead inductance of the traces.
Pin Definitions
[2]
Pin No. Pin Name PWR IO Type Description
11 PECL_CLK I PU PECL Clock Input.
12 PECL_CLK# I PD PECL Clock Input.
9 TCLK0 I PU External Reference/Test Clock Input.
10 TCLK1 I PU External Reference/Test Clock Input.
44, 46, 48, 50 QA(3:0) V
DDC
O Clock Outputs. See Table 2 on page 4 for frequency selections.
32, 34, 36, 38 QB(3:0) V
DDC
O Clock Outputs. See Table 2 on page 4 for frequency selections.
16, 18, 21, 23 QC(3:0) V
DDC
O Clock Outputs. See Table 2 on page 4 for frequency selections.
29 FB_OUT V
DDC
O
Feedback Clock Output. Connect to FB_IN for normal operation. The
divider ratio for this output is set by FB_SEL(0:2). See Table 1 on page
1. A bypass delay capacitor at this output controls Input Reference/
Output Banks phase relationships.
25 SYNC V
DDC
O
Synchronous Pulse Output. This output is used for system synchroni-
zation. The rising edge of the output pulse is in sync with both the rising
edges of QA (0:3) and QC(0:3) output clocks regardless of the divider
ratios selected.
42, 43 SELA(1,0) I PU
Frequency Select Inputs. These inputs select the divider ratio at
QA(0:3) outputs. See Table 2 on page 4.
40, 41 SELB(1,0) I PU
Frequency Select Inputs. These inputs select the divider ratio at
QB(0:3) outputs. See Table 2 on page 4.
19, 20 SELC(1,0) I PU
Frequency Select Inputs. These inputs select the divider ratio at
QC(0:3) outputs. See Table 2 on page 4.
5, 26, 27 FB_SEL(2:0) I PU
Feedback Select Inputs. These inputs select the divide ratio at FB_OUT
output. See Table 1 on page 1.
52 VCO_SEL I PU
VCO Divider Select Input. When set LOW, the VCO output is divided
by 2. When set HIGH, the divider is bypassed. See Table 1 on page 1.
31 FB_IN I PU Feedback Clock Input. Connect to FB_OUT for accessing the PLL.
6 PLL_EN I PU
PLL Enable Input. When asserted HIGH, PLL is enabled. When LOW,
PLL is bypassed.
7 REF_SEL I PU
Reference Select Input. When HIGH, the PECL clock is selected. When
LOW, TCLK (0,1) is the reference clock.
8 TCLK_SEL I PU
TCLK Select Input. When LOW, TCLK0 is selected and when HIGH
TCLK1 is selected.
2MR#/OE IPU
Master Reset/Output Enable Input. When asserted LOW, resets all of
the internal flip-flops and also disables all of the outputs. When pulled
HIGH, releases the internal flip-flops from reset and enables all of the
outputs.
14 INV_CLK I PU
Inverted Clock Input. When set HIGH, QC(2,3) outputs are inverted.
When set LOW, the inverter is bypassed.
3 SCLK I PU Serial Clock Input. Clocks data at SDATA into the internal register.
4SDATA IPU
Serial Data Input. Input data is clocked to the internal register to
enable/disable individual outputs. This provides flexibility in power
management.
17, 22, 28,
33,37, 45, 49
VDDC
3.3V Power Supply for Output Clock Buffers.
13 VDD 3.3V Supply for PLL
1, 15, 24, 30,
35, 39, 47, 51
VSS
Common Ground
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CY29976AIT

Mfr. #:
Manufacturer:
Cypress Semiconductor
Description:
Phase Locked Loops - PLL 3.3V,125MHz,LVPECL/ LVCMOS In,12 Out
Lifecycle:
New from this manufacturer.
Delivery:
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