SN74CBT16244C_08 Datasheet, PDF (2/13 Pages) Texas Instruments – 16-BIT FET BUS SWITCH 5-V BUS SWITCH WITH-2-V UNDERSHOOT PROTECTION

SN74CBT16244C
16ĆBIT FET BUS SWITCH
5ĆV BUS SWITCH WITH ć2ĆV UNDERSHOOT PROTECTION
SCDS134A − SEPTEMBER 2003 − REVISED OCTOBER 2003
description/ordering information (continued)
The SN74CBT16244C is a high-speed TTL-compatible FET bus switch with low ON-state resistance (r_on),
allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the
SN74CBT16244C provides protection for undershoot up to −2 V by sensing an undershoot event and ensuring
that the switch remains in the proper OFF state.
The SN74CBT16244C is organized as four 4-bit bus switches with separate output-enable (1OE, 2OE, 3OE,
4OE) inputs. It can be used as four 4-bit bus switches, two 8-bit bus switches, or as one 16-bit bus switch. When
OE is low, the associated 4-bit bus switch is ON, and the A port is connected to the B port, allowing bidirectional
data flow between ports. When OE is high, the associated 4-bit bus switch is OFF, and the high-impedance state
exists between the A and B ports.
This device is fully specified for partial-power-down applications using I_off. The I_off feature ensures that
damaging current will not backflow through the device when it is powered down. The device has isolation during
power off.
To ensure the high-impedance state during power up or power down, OE should be tied to V_CC through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
INPUT
OE
L
H
FUNCTION TABLE
(each 4-bit bus switch)
INPUT/OUTPUT
A
FUNCTION
B
A port = B port
Z
Disconnect
logic diagram (positive logic)
47
2
41
1A1
SW
1B1
2A1
SW
8
2B1
43
1A4
1
1OE
6
37
SW
1B4
2A4
48
2OE
12
SW
2B4
36
3A1
32
3A4
25
3OE
13
30
SW
3B1
4A1
17
26
SW
3B4
4A4
24
4OE
19
SW
4B1
23
SW
4B4
2
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