Datasheet

SN74CB3T16211
SCDS147C –OCTOBER 2003–REVISED AUGUST 2012 www.ti.com
DESCRIPTION/ORDERING INFORMATION
The SN74CB3T16211 is a high-speed TTL-compatible FET bus switch with low ON-state resistance (r
on
),
allowing for minimal propagation delay. The device fully supports mixed-mode signal operation on all data I/O
ports by providing voltage translation that tracks V
CC
. The SN74CB3T16211 supports systems using 5-V TTL,
3.3-V LVTTL, and 2.5-V CMOS switching standards, as well as user-defined switching levels (see Figure 1).
DESCRIPTION/ORDERING INFORMATION (CONTINUED)
Figure 1. Typical DC Voltage-Translation Characteristics
The I/O port of this device has a pullup current source that maintains the output voltage at V
CC
when the device
is ON, and the input is greater than or equal to V
CC
– 1. Because of the pullup current source, the output voltage
level may be less than V
CC
when the operating frequency is low and the I/O port is connected to a pulldown
resistor. In order to maintain the output voltage at V
CC
, a pullup resistor must be connected to V
CC
instead of a
pulldown resistor to ground.
The SN74CB3T16211 is organized as two 12-bit bus switches with separate output-enable (1OE, 2OE) inputs. It
can be used as two 12-bit bus switches or as one 24-bit bus switch. When OE is low, the associated 12-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 12-bit bus switch is OFF, and a 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.
Table 1. ORDERING INFORMATION
T
A
PACKAGE
(1)
ORDERABLE PART NUMBER TOP-SIDE MARKING
Tube SN74CB3T16211DL
SSOP – DL CB3T16211
Tape and reel SN74CB3T16211DLR
Tube SN74CB3T16211DGG
TSSOP – DGG CB3T16211
–40°C to 85°C Tape and reel SN74CB3T16211DGGR
TVSOP – DGV Tape and reel SN74CB3T16211DGVR KR211
VFBGA – GQL (Pb-free) Tape and reel SN74CB3T16211GQLR KR211
VFBGA – ZQL (Pb-free) Tape and reel SN74CB3T16211ZQLR KR211
(1) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at
www.ti.com/sc/package.
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Product Folder Links: SN74CB3T16211