mpc904

Manufacturer Part Numbermpc904
DescriptionMpc903 1 6 Pci Clock Generator/ Fanout Buffer
ManufacturerFreescale Semiconductor, Inc
mpc904 datasheet
 


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MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
1:6 PCI Clock Generator/
Fanout Buffer
The MPC903, MPC904 and MPC905 are six output clock generation
devices targeted to provide the clocks required in a 3.3V or 5.0V PCI
environment. The device operates from a 3.3V supply and can interface
to either a TTL input or an external crystal. The inputs to the device can be
driven with 5.0V when the V CC is at 3.3V. The outputs of the
MPC903/904/905 meet all of the specifications of the PCI standard. The
three devices are identical except in the function of the Output Enables.
Six Low Skew Outputs
Synchronous Output Enables for Power Management
Low Voltage Operation
XTAL Oscillator Interface
16-Lead SOIC Package
5.0V Tolerant Enable Inputs
The MPC903/904/905 device is targeted for PCI bus or processor bus
environments with up to 12 clock loads. Each of the six outputs on the
MPC903/904/905 can drive two series terminated 50Ω transmission
lines. This capability effectively makes the MPC903/904/905 a 1:12
fanout buffer.
The MPC903 offers two synchronous enable inputs to allow users
flexibility in developing power management features for their designs.
Both enable signals are active HIGH inputs. A logic ‘0’ on the Enable1
input will pull all of the outputs into the logic ‘0’ state and shut down the
internal oscillator for a zero power sleep state. A logic ‘0’ on the Enable2
input will disable only the BCLK5 output. The Enable2 input can be used to disable any high power device for system power
savings during periods of inactivity. Both enable inputs are synchronized internal to the chip so that the output disabling will
happen only when the outputs are already LOW. This feature guarantees no runt pulses will be generated during enabling and
disabling. Note that when the MPC903 is re-enabled via the Enable1 pin, the user must allow for the oscillator to regain stability.
Thus, the re-enabling of the chip cannot occur instantaneously. The MPC904 and MPC905 Enable functions are slightly different
than the 903 and are outlined in the function tables on the following page.
V DD (3)
XTAL_IN
XTAL_OUT
Enable1
SYNCHRONIZE
Enable2
SYNCHRONIZE
10/96
Motorola, Inc. 1996
GND (3)
Pinout: 16-Lead Plastic Package (Top View)
BCLK0
XTAL_OUT
BCLK1
BCLK2
BCLK3
BCLK4
BCLK5
1
REV 3
MPC903
MPC904
MPC905
1:6 PCI
CLOCK GENERATOR/
FANOUT BUFFER
16
1
D SUFFIX
PLASTIC SOIC PACKAGE
CASE 751B-05
1
16
XTAL_IN
Enable2
Enable1
2
15
GND1
BCLK5
3
14
BCLK0
V DD3
4
13
V DD1
5
12
BCLK4
BCLK1
GND3
6
11
GND2
BCLK3
7
10
BCLK2
V DD2
8
9

mpc904 Summary of contents

  • Page 1

    ... Note that when the MPC903 is re-enabled via the Enable1 pin, the user must allow for the oscillator to regain stability. Thus, the re-enabling of the chip cannot occur instantaneously. The MPC904 and MPC905 Enable functions are slightly different than the 903 and are outlined in the function tables on the following page. ...

  • Page 2

    ... MPC903 MPC904 MPC905 FUNCTION TABLE Outputs ENABLE1 ENABLE2 MPC903 MPC904 0 0 Low Low 0 1 Low Low 1 0 Toggling Toggling 1 1 Toggling Toggling ABSOLUTE MAXIMUM RATINGS* Symbol V DD Supply Voltage V IN Input Voltage T oper Operating Temperature Range T stg Storage Temperature Range ...

  • Page 3

    ... Figure 2. Crystal Oscillator Interface Parameter Value Fundamental AT Cut Parallel Resonance* 75ppm 150pm 5–7pF 50 to 80Ω 100µW 5ppm/Yr (First 3 Years) 3 MPC903 MPC904 MPC905 Max Unit Condition 50 MHz 100 0.60T Periods 0.60T 1 0.55T 2 0.55T Desired Period ...

  • Page 4

    ... MPC903 MPC904 MPC905 BCLK5 BCLK0–4 ENABLE2 ENABLE1 Driving Transmission Lines The MPC903/904/905 clock driver was designed to drive high speed signals in a terminated transmission line environment. To provide the optimum flexibility to the user the output drivers were designed to exhibit the lowest impedance possible. With an output impedance of less than 10Ω ...

  • Page 5

    ... In addition IV characteristics are in the process of being generated to support the other board level simulators in general use MPC903 MPC904 MPC905 50Ω 36Ω 50Ω 36Ω 7Ω + 36Ω 36Ω = 50Ω ...

  • Page 6

    ... MPC903 MPC904 MPC905 –A– –T– SEATING PLANE 0.25 (0.010 Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “ ...