|
|
PDF XRK49911 Data sheet ( Hoja de datos )
| Número de pieza | XRK49911 | |
| Descripción | SKEW CLOCK BUFFER | |
| Fabricantes | Exar Corporation | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de XRK49911 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
|
No Preview Available !
xrwww.DataSheet4U.com
XRK49911
3.3V HIGH-SPEED (110 MHZ) PROGRAMMABLE SKEW CLOCK BUFFER
OCTOBER 2005
FUNCTIONAL DESCRIPTION
FEATURES
REV. 1.0.1
The XRK49911 is a 3.3V High-Speed Low-Voltage
Programmable Skew Clock Buffer. It is intended for
high-performance computer systems and offers user
selectable control over system clock functions to
optimize timing. Eight outputs, arranged in four
banks, can each drive 50Ω terminated transmission
lines while delivering minimal and specified output
skews and full-swing Low Voltage TTL logic levels.
Each bank (two outputs per bank) can be individually
selected for one of nine delay or function
configurations through two dedicated tri-level inputs.
These outputs are able to lead or lag the CLKIN input
reference clock by up to 6 time units from their
nominal “zero” skew position. The integrated PLL
allows external load and transmission line delay
effects to be canceled achieving zero delay capability.
Combining the zero delay capability with the
selectable output skew functions, output-to-output
delays of up to ±12 time units can be created.
The XRK49911’s divide functions (divide-by-two and
divide-by-four) allow distribution of a low-frequency
clock that can be multiplied by two or four at the clock
destination. This feature facilitates clock distribution
while allowing maximum system clock flexibility.
• 3.75- to 110-MHz output operation
• All output pair skew <100 ps typical
• Three skew grades
-2 : tSKEW0<250ps
-5 : tSKEW0<500ps
-7 : tSKEW0<700ps
• Selectable output functions
Skew adjustments of +/- 6tU (up to 18 ns)
Inverted and non-inverted
Operation at 1/2 and 1/4 input frequency
Operation at 2x and 4x input frequency
• Cycle-Cycle Jitter
< 25 ps (rms)
< 200 ps (pk-pk)
• Zero input-to-output delay
• 50% duty-cycle outputs
• LVTTL outputs drive 50Ω terminated lines
• Operates from a single 3.3V supply
• 32-pin PLCC package
• Green packaging
• Lead free lead frame available
FIGURE 1. BLOCK DIAGRAM OF THE XRK49911
CLKIN
FB_IN
Ref
PLL
Feedback
FSEL*
PLL_BYPASS*
SELA[1:0]*
SELB[1:0]*
SELC[1:0]*
SELD[1:0]*
* Tri-Level inputs
2
2
2
2
H
M
L
Bank “SKEW”
Control
QA0
QA1
QB0
QB1
QC0
QC1
QD0
QD1
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com
1 page  
xr
REV. 1.0.1
XRK49911
3.3V HIGH-SPEED (110 MHZ) PROGRAMMABLE SKEW CLOCK BUFFER
FIGURE 3. TYPICAL OUTPUTS WITH FB_IN CONNECTED TO A ZERO-SKEW OUTPUT
SELA[1:0]
SELB[1:0]
(N/A)
LL
LM
LH
ML
MM
MH
HL
HM
HH
(N/A)
(N/A)
(N/A)
FB_IN
SELC[1:0] CLKIN
SELD[1:0]
LM
LH
(N/A)
ML
(N/A)
MM
(N/A)
MH
(N/A)
HL
HM
LL/HH
-6tU
-4tU
-3tU
-2tU
-1tU
0tU
+1tU
+2tU
+3tU
+4tU
+6tU
DIVIDED
HH(D) INVERT
PLL_BYPASS
The PLL_BYPASS input is a tri-level input. In normal system operation, this pin is connected to ground.
In normal operation (tied LOW) all outputs will function based only on the connection of their own function
select inputs (SELx[1:0]) and the waveform characteristics of the PLL.
If the PLL_BYPASS input is forced to its MID or HIGH state the device will operate in PLL bypass mode, with
the phase locked loop disconnected, and CLKIN waveforms will directly control all outputs. Relative output to
output timing is controlled by the SELx[1:0], the same as in normal mode.
5
5 Page 
xr
REV. 1.0.1
XRK49911
3.3V HIGH-SPEED (110 MHZ) PROGRAMMABLE SKEW CLOCK BUFFER
PACKAGE DIMENSIONS
32 LEAD PLASTIC LEADED CHIP CARRIER
(PLCC)
Rev. 1.00
D
D1
2 1 32
45° x H2
30° x H1
A1
A2
Corner Chamfer
E3
E1 E
B1
B D2
7°±2 deg typ.
e
C
R
D3
A SEATING PLANE
INCHES
MILLIMETERS
SYMBOL MIN MAX MIN MAX
A
0.120
0.140
3.05
3.56
A1
0.075
0.095
1.91
2.41
A2 0.020
---
0.51
---
B
0.013
0.021
0.33
0.53
B1
0.026
0.032
0.66
0.81
C
0.008
0.013
0.19
0.32
D
0.485
0.495
12.33
12.58
D1
0.448
0.454
11.39
11.54
D2
0.400
0.440
10.17
11.18
D3 0.300 typ.
7.62 typ.
E
0.585
0.595
14.87
15.11
E1
0.545
0.557
13.85
14.15
E2
0.500
0.540
12.71
13.72
E3 0.400 typ.
10.16 typ.
e 0.050 BSC
1.27 BSC
H1
0.023
0.029
0.58
0.74
H2
0.042
0.048
1.07
1.22
R
0.025
0.045
0.64
1.14
Note: The control dimension is in inches.
11
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet XRK49911.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| XRK4991 | SKEW CLOCK BUFFER | Exar Corporation |
| XRK49911 | SKEW CLOCK BUFFER | Exar Corporation |
| XRK4991A | SKEW CLOCK BUFFER | Exar Corporation |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |