MPC93H51
Rev 4, 10/2004
Freescale Semiconductor
Technical Data
Low Voltage PLL Clock Driver
MPC93H51
The MPC93H51 is a 3.3 V compatible, PLL based clock generator targeted for
high performance clock distribution systems. With output frequencies of up to
240 MHz and a maximum output skew of 150 ps the MPC93H51 is an ideal
solution for the most demanding clock tree designs. The device offers 9 low skew
clock outputs. Each is configurable to support the clocking needs of the various
high-performance microprocessors including the PowerQuicc II integrated
communication microprocessor. The devices employs a fully differential PLL
design to minimize cycle-to-cycle and long-term jitter.
LOW VOLTAGE 3.3 V
PLL CLOCK GENERATOR
Features
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9 outputs LVCMOS PLL clock generator
25 – 240 MHz output frequency range
Fully integrated PLL
Compatible to various microprocessors such as PowerQuicc II
Supports networking, telecommunications and computer applications
Configurable outputs: divide-by-2, 4 and 8 of VCO frequency
LVPECL and LVCMOS compatible inputs
FA SUFFIX
32-LEAD LQFP PACKAGE
CASE 873A-03
External feedback enables zero-delay configurations
Output enable/disable and static test mode (PLL enable/disable)
Low skew characteristics: maximum 150 ps output-to-output
32-lead LQFP package
AC SUFFIX
32-LEAD LQFP PACKAGE
Pb-FREE PACKAGE
CASE 873A-03
32-lead Pb-free Package Available
Ambient Temperature Range 0°C to +70°C
Pin & Function Compatible with the MPC951
Functional Description
The MPC93H51 utilizes PLL technology to frequency and phase lock its outputs onto an input reference clock. Normal oper-
ation of the MPC93H51 requires a connection of one of the device outputs to the EXT_FB input to close the PLL feedback path.
The reference clock frequency and the output divider for the feedback path determine the VCO frequency. Both must be selected
to match the VCO frequency range. With available output dividers of divide-by-4 and divide-by-8, the internal VCO of the
MPC93H51 is running at either 4x or 8x of the reference clock frequency. The frequency of the QA, QB, QC and QD outputs is
either one half, one fourth or one eighth of the selected VCO frequency and can be configured for each output bank using the
FSELA, FSELB, FSELC and FSELD pins, respectively. The available output-to-input frequency ratios are 4:1, 2:1, 1:1, 1:2 and
1:4. The REF_SEL pin selects the differential LVPECL (PCLK and PCLK) or the LVCMOS compatible reference input (TCLK).
The MPC93H51 also provides a static test mode when the PLL enable pin (PLL_EN) is pulled to logic low state. In test mode,
the selected input reference clock is routed directly to the output dividers bypassing the PLL. The test mode is intended for system
diagnostics, test and debug purpose. This test mode is fully static, and the minimum clock frequency specification does not apply.
The outputs can be disabled by deasserting the OE pin (logic high state). In PLL mode, deasserting OE causes the PLL to loose
lock due to no feedback signal presence at EXT_FB. Asserting OE will enable the outputs and close the phase locked loop, also
enabling the PLL to recover to normal operation. The MPC93H51 is 3.3 V compatible and requires no external loop filter compo-
nents. All inputs except PCLK and PCLK accept LVCMOS signals while the outputs provide LVCMOS compatible levels with the
capability to drive terminated 50 Ω transmission lines. For series terminated transmission lines, each of the MPC93H51 outputs
can drive one or two traces giving the devices an effective fanout of 1:18. The device is packaged in a 7x7 mm2 32-lead LQFP
package.
Application Information
The fully integrated PLL of the MPC93H51 allows the low skew outputs to lock onto a clock input and distribute it with essen-
tially zero propagation delay to multiple components on the board. In zero-delay buffer mode, the PLL minimizes phase offset
between the outputs and the reference signal.
This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2004. All rights reserved.