Programmable Clock Generator
m Preliminary PLL205-04 o c . Programmable Clock Generator for VIA KT-266 Chipset U 4 t e FEATURES PIN CONFIGURATION e h...
Description
m Preliminary PLL205-04 o c . Programmable Clock Generator for VIA KT-266 Chipset U 4 t e FEATURES PIN CONFIGURATION e h Generates all clock frequencies for VIA KT266 S chipset. a t Support one pair of differential CPU clocks, one a pair of differential push-pull CPU clocks, 3 AGP .D and 10 PCI. w w Enhanced PCI Output Drive selectable by I2C. w One 48MHz clock and 24_48MHz clock via I2C.
Three 3.3V AGP clocks. Three 14.318MHz reference clocks. Power management control to stop CPU, PCI, REF, 24_48MHz, 48MHz and AGP clocks. Supports 2-wire I2C serial bus interface with readback. Single byte micro-step linear Frequency Programming via I2C with glitch free smooth switching. Spread Spectrum ± 0.25% center, ± 0.5% center, ± 0.75% center, and 0 to -0.5% downspread. 50% duty cycle with low jitter. Available in 300 mil 48 Pin SSOP.
BLOCK DIAGRAM
XIN XOUT XTAL OSC
SDATA SCLK
I2C Logic
FS (0:4)*
m o .c U 4 t e e h S a t a .D w w w
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25
VDD1 GND XIN XOUT VDD2 48MHz/FS3*^ 24_48MHz/FS4* v GND PCI_F PCI0 PCI1 GND PCI2 PCI3 VDD3 PCI4 PCI5 PCI6 GND PCI7 PCI8/FS2*^ PCI9_E/SELPCI9_E# VDD3 SEL24_48#^
1 2 3 4 5 6 7 8
48 47 46 45 44 43 42 41
REF0/FS0*^ REF1/FS1*^ REF_F REF_STOP#^ AGP_STOP#^ GND CPUT0 CPUC0 VDDL1 CPUT_CS CPUC_CS GND CPU_STOP#^ PCI_STOP#^ PD# VDDL2 GND SDATA SCLK GND AGP2 AGP1 AGP0 VDD4
Note: ^: Pull up v: Pull down #: Active low * : Bi-directional up latched at...
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