74FCT388915TDJG IDT, 74FCT388915TDJG Datasheet - Page 8

• Manufacturer Part Number: 74FCT388915TDJG
• Description: Clock Drivers & Distribution
• Manufacturer: IDT

Specifications of 74FCT388915TDJG

• Product Category: Clock Drivers & Distribution
• Rohs: yes
• Part # Aliases: IDT74FCT388915TDJG

FCT388915T SYSTEM LEVEL TESTING
FUNCTIONALITY
is in low frequency "test mode". In test mode (with FREQ_SEL HIGH), the 2Q
output is inverted from the selected SYNC input, and the Q outputs are divide-
by-2 (negative edge triggered) of the SYNC input, and the Q/2 output is divide-
by-4 (negative edge triggered). With FREQ_SEL LOW the 2Q output is divide-
by-2 of the SYNC, the Q outputs divide-by-4, and the Q/2 output divide-by-8.
IDT74FCT388915T
3.3V LOW SKEW PLL-BASED CMOS CLOCK DRIVER (3-STATE)
When the PLL_EN pin is LOW, the PLL is bypassed and the FCT388915T
CLOCK @ 2f
at point of use
DISTRIBUTE
CLO CK @ f
Figure 4. Multiprocessing Application Using the FCT388915T for Frequency Multiplication
SYSTEM
CLO CK
SO UR CE
CLOCK
@ f
FCT388915T
FCT388915T
PLL
PLL
and Low Board-to-Board skew
2f
2f
FCT388915T
PLL
MEMORY
CAR DS
CMMU
CMMU
CMMU
CMMU
2f
CPU
CPU
8
These relationships can be seen in the block diagram. A recommended test
configuration would be to use SYNC0 or SYNC1 as the test clock input, and tie
PLL_EN and REF_SEL together and connect them to the test select logic.
below, and theFCT 388915T cannot lock onto that low of an input frequency.
In the test mode described above, any test frequency test can be used.
This functionality is needed since most board-level testers run at 1 MHz or
MEMORY
CO NTROL
CM MU
CM MU
CM MU
CM MU
CM MU
CM MU
CLOCK @ 2f
at point of use
CPU
CARD
CPU
CARD
COMMERCIAL TEMPERATURE RANGE