Datasheet

V
CCA
A
10 kΩ
B
T1 T2
V
CCB
10 kΩ
One-shot
One-shot
Gate Bias
TXS0104E
www.ti.com SCES651E –JUNE 2006–REVISED AUGUST 2013
PRINCIPLES OF OPERATION
Applications
The TXS0104E can be used in level-translation applications for interfacing devices or systems operating at
different interface voltages with one another. The TXS0104E is ideal for use in applications where an open-drain
driver is connected to the data I/Os. The TXS0104E can also be used in applications where a push-pull driver is
connected to the data I/Os, but the TXB0104 might be a better option for such push-pull applications.
Architecture
The TXS0104E architecture (see Figure 1) does not require a direction-control signal to control the direction of
data flow from A to B or from B to A.
Figure 1. Architecture of a TXS01xx Cell
Each A-port I/O has an internal 10-kΩ pullup resistor to V
CCA
, and each B-port I/O has an internal 10-kΩ 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.
Input Driver Requirements
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 TXS0104E. 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.
Power Up
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.
Enable and Disable
The TXS0104E 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.
Pullup or Pulldown Resistors on I/O Lines
Each A-port I/O has an internal 10-kΩ pullup resistor to V
CCA
, and each B-port I/O has an internal 10-kΩ 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-kΩ resistors).
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