MPC940L Datasheet, PDF (1/11 Pages) Motorola, Inc – LOW VOLTAGE 1:18 CLOCK DISTRIBUTION CHIP

LOW VOLTAGE 1:18 CLOCK DISTRIBUTION CHIP
MPC940L
The MPC940L is a 1:18 low voltage clock distribution chip with 2.5 V or 3.3 V LVCMOS
output capabilities. The device features the capability to select either a differential
LVPECL or an LVCMOS compatible input. The 18 outputs are 2.5 V or 3.3 V LVCMOS
compatible and feature the drive strength to drive 50 Ω series or parallel terminated
transmission lines. With output-to-output skews of 150 ps, the MPC940L is ideal as a
clock distribution chip for the most demanding of synchronous systems. The 2.5 V outputs
also make the device ideal for supplying clocks for a high performance microprocessor
based design. For a similar device at a lower price/performance point, the reader is
referred to the MPC9109.
• LVPECL or LVCMOS Clock Input
• 2.5 V LVCMOS Outputs for Pentium II Microprocessor Support
• 150 ps Maximum Output-to-Output Skew
• Maximum Output Frequency of 250 MHz
• 32-Lead LQFP Packaging
• 32-Lead Pb-Free Package Available
• Dual or Single Supply Device:
• Dual V_CC Supply Voltage, 3.3 V Core and 2.5 V Output
• Single 3.3 V V_CC Supply Voltage for 3.3 V Outputs
• Single 2.5 V V_CC Supply Voltage for 2.5 V I/O
MPC940L
LOW VOLTAGE
1:18 CLOCK
DISTRIBUTION CHIP
FA SUFFIX
32-LEAD LQFP PACKAGE
CASE 873A-04
With a low output impedance (≈20 Ω), in both the HIGH and LOW logic states, the
output buffers of the MPC940L are ideal for driving series terminated transmission lines.
With a 20 Ω output impedance the 940L has the capability of driving two series terminated
lines from each output. This gives the device an effective fanout of 1:36. If a lower output
impedance is desired please see the MPC942 data sheet.
AC SUFFIX
32-LEAD LQFP PACKAGE
Pb-FREE PACKAGE
CASE 873A-04
The differential LVPECL inputs of the MPC940L allow the device to interface directly
with a LVPECL fanout buffer like the MC100EP111 to build very wide clock fanout trees
or to couple to a high frequency clock source. The LVCMOS input provides a more standard interface for applications requiring only a
single clock distribution chip at relatively low frequencies. In addition, the two clock sources can be used to provide for a test clock
interface as well as the primary system clock. A logic HIGH on the LVCMOS_CLK_SEL pin will select the LVCMOS level clock input. All
inputs of the MPC940L have internal pullup/pulldown resistors so they can be left open if unused.
The MPC940L is a single or dual supply device. The device power supply offers a high degree of flexibility. The device can operate
with a 3.3 V core and 3.3 V output, a 3.3 V core and 2.5 V outputs as well as a 2.5 V core and 2.5 V outputs. The 32-lead LQFP package
was chosen to optimize performance, board space and cost of the device. The 32-lead LQFP has a 7x7 mm body size with a conservative
0.8 mm pin spacing.
Pentium II is a trademark of Intel Corporation.
IDT™ / ICS™ 1:18 CLOCK DISTRIBUTION CHIP
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MPC940L REV 7 JUNE 5, 2007