FAGD16556ECLBA Intel, FAGD16556ECLBA Datasheet - Page 10

• Manufacturer Part Number: FAGD16556ECLBA
• Manufacturer: Intel

Specifications of FAGD16556ECLBA

• Operating Supply Voltage (typ): 3.3V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 100
• Lead Free Status / RoHS Status: Not Compliant

Figure 16.GD16557/GD16578 DC-connection
Figure 17.GD16557/GD16578 AC-connection
High-speed Clock and Data
Outputs
The high-speed clock output (CKO,
CKON) and the serial data output (DO,
DON) are CML (with internal 50 W collec-
tor impendance) type outputs. They
should be connected as shown on
18.
The high-speed outputs of the GD16557
are suited to drive the GIGA GD16578
high-current laser driver. Connection
schemes are shown on
Figure 17.
Figure 18.GD16557 and GD16557/ECL
Data Sheet Rev.: 23
VDD
20mA
50W
2 x
CML output driver.
+3.3V Supply
+3.3V Supply
VDD
VDD
GD16557
GD16557
20mA
50 Line
20mA
50W
2 x
W
50W
2 x
Figure 16
DO
DON
DO
DON
VDD
100nF
50W
2 x
and
Figure
CML
50 Line
50 Line
GND
GND
W
W
100nF
100nF
Double PLL for Jitter
Clean-up
The device implements a double PLL for
high performance jitter-transfer charac-
teristics. It integrates:
u
u
u
To complete the PLLs it is only neces-
sary to add loop-filter components and a
low-noise crystal oscillator (VCXO) at the
board.
Loop Filters
The recommended loop filters are simple
first-order RC-filters as shown on
19.
is terminated to the positive VCO power
supply VDDA.
DINQ
DINQ
DINT
DINT
DIN
DIN
a low-noise LC-type Voltage Con-
trolled Oscillator (VCO)
two digital Phase Frequency Detec-
tors (PFDs)
two tristate-type Charge Pumps
(CHAPs)
Note that the on-chip VCO loop-filter
GD16578
GD16578
GD16556/GD16557*
-5.2V Supply
+5V Supply
50W
2 x
50W
2 x
Figure
Figure 19.GD16557 - Loop filters
Note:
Charge Pump Polarity
The pin VCOCHAP will sink current (de-
crease the voltage on the loop-filter ca-
pacitor) when the on-chip VCO is to
increase the frequency. When the on-
chip VCO is to decrease the frequency
the pin VCOCHAP will source current.
This corresponds to a negative VCO tun-
ing constant.
The VCXO control pin VCXOCHAP will
source a current when the VCXO is to in-
crease the frequency and sink a current
when the VCXO is to decrease its fre-
quency. If neither is to happen the pin
VCXOCHAP tristates. This corresponds
to a positive VCO tuning constant.
2.4kW
1 F
m
VDDA
VCXO
Values for “R1” and “C1” de-
pend on the specific VCXO.
“V” must be connected to the
same power supply reference
point as the VCXO.
R1
C1
VCXOCHAP
VCOCHAP
V
VCTL
XCK1
XCK1N
CHAP
CHAP
VCO
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