FSTU32X800 Datasheet, PDF (1/5 Pages) Fairchild Semiconductor – 20-Bit Bus Switch with Precharged Outputs and -2V Undershoot Protection

November 2002
Revised October 2006
FSTU32X800
20-Bit Bus Switch with Precharged Outputs
and −2V Undershoot Protection
General Description
The Fairchild Switch FSTU32X800 provides 20-bits of
high-speed CMOS TTL-compatible bus switching. The low
On Resistance of the switch allows inputs to be connected
to outputs without adding propagation delay or generating
additional ground bounce noise. The A and B Ports are
protected against undershoot to support an extended
range to 2.0V below ground. Fairchild’s integrated Under-
shoot Hardened Circuit (UHC®) senses undershoot at the
I/O and responds by preventing voltage differentials from
developing and turning the switch on. The device also pre-
charges the B Port to a selectable bias voltage (BiasV) to
minimize live insertion noise.
The device is organized as two 10-bit switches with a bus
enable (OE_n) signal. When OE_n is LOW, the switch is ON
and Port A is connected to Port B. When OE_n is HIGH, the
switch is OPEN and the B Port is precharged to BiasV
through an equivalent 10-kΩ resistor.
Features
s 4Ω switch connection between two ports
s Undershoot Hardened to -2.0V
s Soft enable turn-on to minimize bus-to-bus charge
sharing during enable
s Low l_CC
s Zero bounce in flow-through mode
s Output precharge to minimize live insertion noise
s Control inputs compatible with TTL level
s See Applications Note AN-5008 for details
Ordering Code:
Order Number
Package
Number
Package Description
FSTU32X800QSP MQA48A 48-Lead Quarter Size Very Small Outline Package (QVSOP), JEDEC MO-154, 0.150" Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
UHC® is a registered trademark of Fairchild Semiconductor Corporation.
© 2002 Fairchild Semiconductor Corporation DS500791
www.fairchildsemi.com