registered DIMM Specification Rev. 1.2鈥?/div>
Distributes One Clock Input to One Bank of Five
and One Bank of Four Outputs
No External RC Network Required
External Feedback (FBIN) Pin is Used to
Synchronize the Outputs to the Clock Input
Separate Output Enable for Each Output Bank
Operates at 3.3 V V
cc
125 MHz Maximum Frequency
On-chip Series Damping Resistors
Support Spread Spectrum Clock(SSC)
Synthesizers
ESD Protection Exceeds 3000 V per MIL-STD-
883, Method 3015 ; Exceeds 350 V Using
Machine
Model ( C = 200 pF, R = 0 )
Latch-Up Performance Exceeds 400 mA per
JESD 17
Packaged in Plastic 24-Pin Thin Shrink Small-
Outline Package
General Description
The HC2509C is a low-skew, low jitter, phase-locked
loop(PLL) clock driver, distributing high frequency
clock signals for SDRAM.
The HC2509C operates at 3.3V V
cc
and provides
integrated series-damping resistors that make it ideal
for driving point-to-point loads. The propagation delay
from the CLK input to any clock output is nearly zero.
One bank of five outputs and one bank of four outputs
provide nine low-skew and low-jitter clocks. Each
bank of outputs can be enabled or disabled
separately via the control inputs (1G and 2G). Output
signal duty cycles are adjusted to 50 percent,
independent of the duty cycle at CLK.
The HC2509C is specially designed to interface with
high speed SDRAM applications in the range of
25MHz to 125MHz and includes an internal RC
network which provides excellent jitter characteristics
and eliminates the needs for external components.
For the test purpose, the PLL can be bypassed by
strapping AV
cc
to ground.
The HC2509C is characterized for operation from 0擄C
to 85擄C.
l
l
Pin Configuration
TSSOP 24 PACKAGE
(TOP VIEW)
AGND
Vcc
1Y0
1Y1
1Y2
GND
GND
1Y3
1Y4
Vcc
1G
FBOUT
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
CLK
AVcc
Vcc
2Y0
2Y1
GND
Function Table
INPUTS
1G
2G
X
L
H
L
H
CLK
L
H
H
H
H
1Y
(0:4)
X
L
L
H
H
L
L
L
H
H
OUTPUTS
2Y
(0:3)
L
L
H
L
H
L
H
H
H
H
FBOUT
GND
2Y2
2Y3
Vcc
2G
FBIN
1
1
2
3
4
5
6
