Datasheet

V
CCB
B
V
CCA
V
CCB
GateBias
One-
shot
One-
shot
10k 10k
T1 T2
A
Input Driver Requirements
Power Up
Enable and Disable
Pullup or Pulldown Resistors on I/O Lines
TXS0101
www.ti.com ............................................................................................................................................. SCES638B – OCTOBER 2007 – REVISED JANUARY 2009
Figure 1. Architecture of a TXS01xx Cell
Each A-port I/O has an internal 10-k Ω pullup resistor to V
CCA
, and each B-port I/O has an internal 10-k Ω pullup
resistor to V
CCB
. The output one-shots detect rising edges on the A or B ports. During a rising edge, the one-shot
turns on the PMOS transistors (T1,T2) for a short duration, which speeds up the low-to-high transition.
The fall time (t
fA
, t
fB
) of a signal depends on the output impedance of the external device driving the data I/Os of
the TXS0101. Similarly, the t
PHL
and max data rates also depend on the output impedance of the external driver.
The values for t
fA
, t
fB
, t
PHL
, and maximum data rates in the data sheet assume that the output impedance of the
external driver is less than 50 Ω .
During operation, ensure that V
CCA
≤ V
CCB
at all times. During power-up sequencing, V
CCA
≥ V
CCB
does not
damage the device, so any power supply can be ramped up first.
The TXS0101 has an OE input that is used to disable the device by setting OE low, which places all I/Os in the
Hi-Z state. The disable time (t
dis
) indicates the delay between the time when OE goes low and when the outputs
actually get disabled (Hi-Z). The enable time (t
en
) indicates the amount of time the user must allow for the
one-shot circuitry to become operational after OE is taken high.
Each A-port I/O has an internal 10-k Ω pullup resistor to V
CCA
, and each B-port I/O has an internal 10-k Ω pullup
resistor to V
CCB
. If a smaller value of pullup resistor is required, an external resistor must be added from the I/O
to V
CCA
or V
CCB
(in parallel with the internal 10-k Ω resistors).
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Product Folder Link(s): TXS0101