2.5 / 3.3V PHASE-LOCK LOOP CLOCK DRIVER
2.5V / 3.3V PHASE-LOCK
LOOP CLOCK DRIVER
ZERO DELAY BUFFER
• Operates at 3.3V VDD/AVDD and 2.5V/3.3V VDDQ
• 1:10 fanout
• 3-level inputs for output control
• External feedback (FBIN) pin is used to synchronize the
outputs to the clock input signal
• No external RC network required for PLL loop stability
• Configurable 2.5V or 3.3V LVTTL outputs
• tPD Phase Error at 100MHz to 166MHz: ±150ps
• Jitter (peak-to-peak) at 133MHz and 166MHz: ±75ps
• Spread spectrum compatible
• Operating Frequency:
− Std: 25MHz to 140MHz
− A: 25MHz to 167MHz
• Available in TSSOP package
The IDT5V2528 is a high performance, low-skew, low-jitter, phase-lock
loop (PLL) clock driver. It uses a PLL to precisely align, in both frequency
and phase, the feedback (FBOUT) output to the clock (CLK) input signal.
FUNCTIONAL BLOCK DIAGRAM
The IDT5V2528 inputs, PLL core, Y0, Y1, and FBOUT buffers operate from
the 3.3V VDD and AVDD power supply pins.
One bank of ten outputs provide low-skew, low-jitter copies of CLK. Of
the ten outputs, up to seven may be configured for 2.5V or 3.3V LVTTL
outputs. The number of 2.5V outputs is controlled by 3-level input signals
G_Ctrl and T_Ctrl, and by connecting the appropriate VDDQ pins to 2.5V or
3.3V. The 3-level input signals may be hard-wired to high-mid-low levels.
Output signal duty cycles are adjusted to 50 percent, independent of the duty
cycle at CLK. The outputs can be enabled or disabled via the G_Ctrl input.
When the G_Ctrl input is mid or high, the outputs switch in phase and
frequency with CLK; when the G_Ctrl is low, all outputs (except FBOUT) are
disabled to the logic-low state.
Unlike many products containing PLLs, the IDT5V2528 does not require
external RC networks. The loop filter for the PLL is included on-chip,
minimizing component count, board space, and cost.
Because it is based on PLL circuitry, the IDT5V2528 requires a
stabilization time to achieve phase lock of the feedback signal to the
reference signal. This stabilization time is required, following power up and
application of a fixed-frequency, fixed-phase signal at CLK, as well as
following any changes to the PLL reference or feedback signals. The PLL
can be bypassed for test purposes by strapping AVDD to ground.
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
INDUSTRIAL TEMPERATURE RANGE
c 2002 Integrated Device Technology, Inc.
TY0, VDDQ pin 4
TY1, VDDQ pin 25
TY2, VDDQ pin 25
TY3, VDDQ pin 15
TY4, VDDQ pin 15
TY5, VDDQ pin 11
TY6, VDDQ pin 11
TY7, VDDQ pin 11
Y0, VDD pin 21
Y1, VDD pin 21
FBOUT, VDD pin 21