CY28378 Cypress Semiconductor, CY28378 Datasheet - Page 3

• Manufacturer Part Number: CY28378
• Description: FTG for Pentium 4 and Intel 845 Series Chipset
• Manufacturer: Cypress Semiconductor

Document #: 38-07519 Rev. **
Pin Description
23
27
42
26
25
20
35
19
2, 9, 18, 24, 32, 39,
46
5, 13, 21, 29, 36,
43, 47
34
33
Pin #
24_48MHz/FS1
3V66_3/48MHz_1
PWRDWN#
SCLK
SDATA
RESET#
IREF
VTT_PWRGD#
VDD_REF,
VDD _PCI,
VDD_48MHz,
VDD_3V66,
VDD_CPU
GND_PCI,
GND_48MHz,
GND_3V66,
GND_CPU,
GND_REF,
VDD_CORE
GND_CORE
Name
O (open-drain) System Reset Output: Open-drain system reset output.
Type
I/O
I/O
O
G
G
P
P
I
I
I
I
24 or 48MHz Output/Frequency Select 1: 3.3V fixed 24-MHz or
48-MHz non-spread spectrum output. This pin also serves as a
power-on strap option to determine device operating frequency as
described in Table 2. This output will be used as the reference clock
for SIO devices in Intel 845 (Brookdale) platforms. For Intel Brookdale
– G platforms, this output will be used as the reference clock for both
USB host controller and SIO devices. We recommend system designer
to configure this output as 48 MHz and “HIGH Drive” by setting Byte
[5], Bit [0] and Byte [9], Bit [7], respectively.150k internal pull up.
48MHz or 66MHz Output: 3.3V output.
Power Down Control: 3.3V LVTTL compatible input that places the
device in power down mode when held low. 150k internal pull up.
SMBus Clock Input: Clock pin for serial interface.
SMBus Data Input: Data pin for serial interface.
Current Reference for CPU Output: A precision resistor is attached
to this pin which is connected to the internal current reference.
Powergood from Voltage Regulator Module (VRM): 3.3V LVTTL
input. VTT_PWRGD# is a level sensitive strobe used to determine
when FS0:4 and MULTSEL0:1 inputs are valid and OK to be sampled
(Active LOW). Once VTT_PWRGD# is sampled LOW, the status of this
input will be ignored.
3.3V Power Connection: Power supply for CPU outputs buffers, 3V66
output buffers, PCI output buffers, reference output buffers and
48-MHz output buffers. Connect to 3.3V.
Ground Connection: Connect all ground pins to the common system
ground plane.
3.3V Analog Power Connection: Power supply for core logic, PLL
circuitry. Connect to 3.3V.
Analog Ground Connection: Ground for core logic, PLL circuitry.
Description
CY28378
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