SI52142 Datasheet, PDF (1/20 Pages) Silicon Laboratories – PCI-EXPRESS GEN 1, GEN 2 & GEN 3 CLOCK TWO OUTPUT GENERATOR WITH 25 MHZ REFERENCE CLOCK

Si52142
PCI-EXPRESS GEN 1, GEN 2 & GEN 3 CLOCK TWO
OUTPUT GENERATOR WITH 25 MHZ REFERENCE CLOCK
Features
 PCI-Express Gen 1, Gen 2 &
Gen 3 compliant
 25 MHz crystal input or clock
input
 Low power push-pull type
differential output buffers
 I²C support with readback
capabilities
 Integrated resistors on differential _{ Triangular spread spectrum}
clocks
profile for maximum
 Dedicated output enable
electromagnetic interference
hardware pin for each clock
(EMI) reduction
 Hardware selectable spread
control
 Two PCI-Express clocks
 25 MHz reference clock
 Industrial temperature
–40 to 85 ^oC
 3.3 V power supply
 24-pin QFN package
Ordering Information:
See page 18
Applications
 Network attached storage
 Multi-function printer
 Wireless access point
 Routers
Description
The Si52142 is a spread-controlled PCIe clock generator that can source
two PCIe clocks and a 25 MHz reference clock. The device has three
hardware output enable control inputs for enabling the respective outputs
on the fly while powered on along with the hardware input for spread
spectrum and frequency control on outputs. In addition to the hardware
control pins, I²C programmability is also available to promptly achieve
optimum clock signal integrity through skew and edge rate control on true,
compliment, or both differential outputs as well as amplitude control.
Pin Assignments
VDD_REF 1
REF 2
OE_REF¹ 3
VSS_REF 4
OE_DIFF0¹ 5
VDD_DIFF 6
24 23 22 21 20 19
18 OE_DIFF1¹
17 VDD_DIFF
25
GND
16 DIFF1
15 DIFF1
14 DIFF0
13 DIFF0
7 8 9 10 11 12
Notes:
1. Internal 100 kohm pull-up.
2. Internal 100 kohm pull-down.
Functional Block Diagram
Patents pending
XIN/CLKIN
XOUT
SCLK
SDATA
OE_REF
OE [1:0]
SS [1:0]
PLL1
(SSC)
Control & Memory
Control RAM
Divider
REF
DIFF0
DIFF1
Preliminary 0.1 12/11
Copyright © 2011 by Silicon Laboratories
Si52142
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.