ICS840271I Datasheet, PDF (1/13 Pages) Integrated Device Technology – SYNCHRONOUS ETHERNET FREQUENCY TRANSLATOR

SYNCHRONOUS ETHERNET FREQUENCY TRANSLATOR
ICS840271I
General Description
The ICS840271I is a PLL-based Frequency
ICS
Translator intended for use in telecommunication
HiPerClockS™ _{applications such as Synchronous Ethernet. The}
internal PLL translates Ethernet clock frequencies
such as 125MHz (1Gb Ethernet), 156.25MHz
(10GbE XAUI) and 161.1328MHz (10Gb Ethernet) to an output
frequency of 25MHz. The PLL does not any require external
components. The input frequency is selectable by a 2-pin
interface. The ICS840271I is optimized for low cycle-to-cycle jitter
on the 25MHz output signal. The input of the device accepts
differential (LVPECL, LVDS, LVHSTL, SSTL, HCSL) or
single-ended (LVCMOS) signals. The extended temperature range
supports telecommunication and networking equipment
requirements. The ICS840271I uses a small RoHS 6, 8-pin
TSSOP package and is an effective solution for space-constrained
applications.
Features
• Clock frequency translator for Synchronous Ethernet
applications
• One single-ended output (LVCMOS or LVTTL levels),
16Ω output impedance
• Differential input pair (CLK, nCLK) accepts LVPECL, LVDS,
LVHSTL, SSTL, HCSL input levels
• Supports input clock frequencies of: 125MHz, 156.25MHz or
161.1328MHz
• Generates a 25MHz output clock signal
• Internal resistor bias on nCLK pin allows the user to drive CLK
input with external single-ended (LVCMOS/LVTTL) input levels
• Internal PLL is optimized for low cycle-to-cycle jitter at the
output
• Full 3.3V or 2.5V supply voltage
• -40°C to 85°C ambient operating temperature
• Available in lead-free (RoHS 6) package
Block Diagram
CLK
Pre-
PLL
nCLK
divider
Feedback
divider
SEL(1:0)
Input Control Logic
00 = PLL Bypass
01 = 161.1328125 MHz
10 = 156.2500000 MHz
11 = 125.0000000 MHz
Output
Q
divider
25 MHz
Pin Assignment
V_DDA
1
SEL0 2
CLK ³
nCLK ⁴
8 V_DD
7Q
6 GND
5 SEL1
ICS840271I
8 Lead TSSOP
4.40mm x 3.0mm x 0.925mm
package body
G Package
Top View
IDT™ / ICS™ SYNCHRONOUS ETHERNET FREQUENCY TRANSLATOR
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ICS840271BGI REV. A APRIL 23, 2009