1.8V PLL DIFFERENTIAL 1:10 SDRAM CLOCK DRIVER
1.8V PHASE LOCKED LOOP
DIFFERENTIAL 1:10 SDRAM
• 1 to 10 differential clock distribution
• Optimized for clock distribution in DDR2 (Double Data Rate)
• Operating frequency: 125MHz to 340MHz
• Very low skew: ≤40ps
• Very low jitter: ≤40ps
• 1.8V AVDD and 1.8V VDDQ
• CMOS control signal input
• Test mode enables buffers while disabling PLL
• Low current power-down mode
• Tolerant of Spread Spectrum input clock
• Available in 52-Ball VFBGA and 40-pin MLF packages
• Meets or exceeds JEDEC standard 82.8 for registered DDR2
• Along with SSTU32864/65/66, DDR2 register, provides complete
solution for DDR2 DIMMs
The CSPU877D is a PLL based clock driver that acts as a zero delay buffer
to distribute one differential clock input pair(CLK, CLK ) to 10 differential
output pairs (Y [0:9], Y [0:9]) and one differential pair of feedback clock output
(FBOUT, FBOUT). External feedback pins (FBIN, FBIN) for synchronization
of the outputs to the input reference is provided. OE, OS, and AVDD control the
power-down and test mode logic. When AVDD is grounded, the PLL is turned
off and bypassed for test mode purposes. When the differential clock inputs
(CLK, CLK) are both at logic low, this device will enter a low power-down mode.
In this mode, the receivers are disabled, the PLL is turned off, and the output
clock drivers are disabled, resulting in a current consumption device of less than
The CSPU877D requires no external components and has been optimised
for very low phase error, skew, and jitter, while maintaining frequency and duty
cycle over the operating voltage and temperature range. The CSPU877D,
designed for use in both module assemblies and system motherboard based
solutions, provides an optimum high-performance clock source.
The CSPU877D is available in Commercial Temperature Range (0°C to
+70°C). See Ordering Information for details.
FUNCTIONAL BLOCK DIAGRAM
LD or OE
LD, OS, or OE
10KΩ - 100KΩ
The Logic Detect (LD) powers down the device when a logic LOW is applied to both CLK and CLK.
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
c 2004 Integrated Device Technology, Inc.