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Active termination pulls bus pins to rails
Holds last value of input signal
Ideal replacement for resistive termination
Ultra low 3碌A(chǔ) DC quiescent current
碌
Bus-hold eliminates floating bus lines and reduces static
power consumption
Low power QCMOS technology
Operates over 2.7V to 5.5V Vcc range
TTL-compatible input and output levels
No added noise or ground bounce
20 independent terminator circuits
Available in QSOP package
IDTQS3389
DESCRIPTION:
The QS3389 provides a set of 20 active termination circuits which pull data
bus signals to the voltage rails. This feature prevents bus signals from floating
in the threshold region of standard TTL I/O devices. The QS3389 can
replace resistor termination solutions which add DC power dissipation and
increase component count. Input clamp diodes help to reduce reflections
and undershoot in transmission line environments. Importantly, the termi-
nator circuits pull signals to whichever logic state the signal previously held
(high or low). For this reason, this device is also referred to as a last value
latch. This device is appropriate for data bus applications where interfacing
devices have CMOS inputs with low input currents. These terminators
provide sufficient drive to overcome leakage currents and drive corre-
sponding signals away from the TTL threshold region.
The QS3389 is characterized for operation at 0擄C to +70擄C.
APPLICATIONS:
鈥?Bus termination
鈥?Extend data hold time
FUNCTIONAL BLOCK DIAGRAM
T
0
7K
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T
19
7K
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The IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
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c
1999 Integrated Device Technology, Inc.
DECEMBER 1999
DSC-5733/1
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