1
All trademarks are property of their respective owners. www.diodes.com 07/31/17
Block Diagram
Phase
Lock
Loop
Crystal
Driver
VDD
GND
X1/CLK
X2
25 MHz
crystal or clock
Control
Logic
SS1:SS0
2
S1:S0
2
CLK0
CLK0
R
R
CLK1
CLK1
2
2
OE
Pulling
Capacitors
Pin Configuration (16-Pin TSSOP)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VDDX
CLK0
CLK0
GNDA
VDDA
CLK1
CLK1
IREF
S0
S1
SS0
X1/CLK
X2
OE
GNDX
SS1
Description
e PI6C557-03A is a spread spectrum clock generator compliant to
PCI Express® 2.0 and Ethernet requirements. e device is used
for PC or embedded systems to substantially reduce Electro-
magnetic Interference (EMI).
e PI6C557-03A provides two dierential (HCSL) or LVDS
spread spectrum outputs. e PI6C557-03A is congured to
select spread and clock selection. Using Pericom's patented
Phase-Locked Loop (PLL) techniques, the device takes a 25MHz
crystal input and produces two pairs of dierential outputs (HCSL)
at 25MHz, 100MHz, 125MHz and 200MHz clock frequencies.
It also provides spread selection of -0.5%, -0.75%, and no spread.
Features
PCIe® 2.0 compliant
Phase jitter - 2.1ps RMS (typ)
LVDS compatible outputs
Supply voltage of 3.3V ±10%
25MHz crystal or clock input frequency
HCSL outputs, 0.8V Current mode dierential pair
Jitter 35ps cycle-to-cycle (typ)
Spread of -0.5%, -0.75%, and no spread
Industrial temperature range
Spread Bypass option available
Spread and frequency selection via external pins
Packaging: (Pb-free and Green)
16-pin TSSOP (L16)
16-pin QSOP (Q16)
A product Line of
Diodes Incorporated
PI6C557-03A
PCIe 2.0 Clock Generator with 2 HCSL Outputs
13-0052
