ICS98UAE877A Datasheet, PDF (1/18 Pages) Integrated Device Technology – 1.5V LOW-POWER WIDE-RANGE FREQUENCY CLOCK DRIVER

DATASHEET
1.5V LOW-POWER WIDE-RANGE FREQUENCY CLOCK DRIVER
ICS98UAE877A
Description
The PLL clock buffer, ICS98UAE877A, is designed for a
VDDQ of 1.5V, an AVDD of 1.5V and differential data input
and output levels.
ICS98UAE877A is a zero delay buffer that distributes a
differential clock input pair (CLK_INT, CLK_INC) to ten
differential pair of clock outputs (CLKT[0:9], CLKC[0:9]) and
one differential pair feedback clock outputs (FB_OUTT,
FBOUTC). The clock outputs are controlled by the input
clocks (CLK_INT, CLK_INC), the feedback clocks (FB_INT,
FB_INC), the LVCMOS program pins (OE, OS) and the
Analog Power input (AVDD). When OE is low, the outputs
(except FB_OUTT/FB_OUTC) are disabled while the
internal PLL continues to maintain its locked-in frequency.
OS (Output Select) is a program pin that must be tied to
GND or VDDQ. When OS is high, OE will function as
described above. When OS is low, OE has no effect on
CLKT7/CLKC7 (they are free running in addition to
FB_OUTT/FB_OUTC). When AVDD is grounded, the PLL is
turned off and bypassed for test purposes.
When both clock signals (CLK_INT, CLK_INC) are logic
low, the device will enter a low power mode. An input logic
detection circuit on the differential inputs, independent from
the input buffers, will detect the logic low level and perform
a low power state where all outputs, the feedback and the
PLL are OFF. When the inputs transition from both being
logic low to being differential signals, the PLL will be turned
back on, the inputs and outputs will be enabled and the PLL
will obtain phase lock between the feedback clock pair
(FB_INT, FB_INC) and the input clock pair (CLK_INT,
CLK_INC) within the specified stabilization time tSTAB.
The PLL in ICS98UAE877A clock driver uses the input
clocks (CLK_INT, CLK_INC) and the feedback clocks
(FB_INT, FB_INC) to provide high-performance, low-skew,
low-jitter output differential clocks (CLKT[0:9], CLKC[0:9]).
ICS98UAE877A is also able to track Spread Spectrum
Clocking (SSC) for reduced EMI.
ICS98UAE877A is available in Commercial Temperature
Range (0°C to 70°C) and Industrial Temperature Range
(-40°C to +85°C). See Ordering Information for details
Features
• Low skew, low jitter PLL clock driver
• 1 to 10 differential clock distribution
• Feedback pins for input to output synchronization
• Spread Spectrum tolerant inputs
• Auto PD when input signal is at a certain logic state
• Available in 52-ball VFBGA and a 40-pin MLF
Applications
• DDR2 Memory Modules / Zero Delay Board Fan Out
• Provides complete DDR DIMM solution with
IDT74SSTUAE32xxx family
Switching Characteristics
• Period jitter:
40ps (DDR2-400/533)
30ps (DDR2-667)
• Half-period jitter:
60ps (DDR2-400/533)
50ps (DDR2-667)
• Output-Output Skew 40ps (DDR2-400/533)
30ps (DDR2-667)
• Cycle-Cycle Jitter
40ps
1.5V LOW-POWER WIDE-RANGE FREQUENCY CLOCK DRIVER
1
ICS98UAE877A
7181/2