C9630 Datasheet, PDF (4/18 Pages) Cypress Semiconductor – PC133 Clock Generator for SiS630/Pentium III & SiS540/Socket7 Applications

APPROVED PRODUCT
C9630
PC133 Clock Generator for SiS630/Pentium^®III & SiS540/Socket7 Applications
Power on Bi-Directional Pins
Power Up Condition:
Pins 2,7,8,and 26 are Power up bi-directional pins used for selecting the host frequency in page 1, table 1. During
power-up of the device, these pins are in input mode (see Fig 4, below), therefore; they are considered input select pins
internal to the IC. After a settling time, the selection data is latch into the internal control register and these pins become
a clock outputs.
ower Supply
amp
VDD Rail
REF0 / S3
PCI0 / S1
PCI1 / S2
48MHZ / S0
Hi-Z Input
-
Toggle Outputs
Select data is latched into register, then pin becomease ref clock output signal.
Fig.4
Strapping Resistor Options:
VDD
The power up bi-directional pins have a large value pull-
down each (250KΩ), therefore, a selection “0” is the
default. If the system uses a slow power supply (over
5mS settling time), then it is recommended to use an
external Pull-Down (Rdn) in order to insure a Low
selection. In this case, the designer may choose one of
two configurations, see Fig.5A and B.
IMIC9630
10K
JP1
Fig. 5A represents an additional pull down resistor Rdn
Bidirectional
Rd
Load
= 50KΩ connected from the pin to the ground plane,
which allows a faster pull to a low level.
50K
If a selection “1” is desired, then a jumper is placed on
JP1 to a Rup = 10KΩ resistor as implemented as
shown in Fig.5A. Please note the selection resistors
(Rup and Rdn) are placed before the Damping resistor
(Rd) close to the pin.
Fig.5A
Fig. 5B represent a single resistor 10KΩ connected to a
3-way jumper, JP2. When a “1” selection is desired, a
jumper is placed between leads1 and 3. When a “0”
selection is desired, a jumper is placed between leads 3
and 2.
VDD
JP2
1
23
IMIC9630
10K
Bidirectional
Rd
Fig.5B
Load
Cypress Semiconductor Corporation
525 Los Coches St.
Milpitas, CA 95035. Tel: [phone], Fax: [phone]
http://www.cypress.com
Document#: 38-07035 Rev. **
05/02/2001
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