TXB0104 Datasheet, PDF (9/12 Pages) Texas Instruments – 4-BIT BIDIRECTIONAL VOLTAGE-LEVEL TRANSLATOR WITH AUTO DIRECTION SENSING AND ±15-kV ESD PROTECTION

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TXB0104
4-BIT BIDIRECTIONAL VOLTAGE-LEVEL TRANSLATOR
WITH AUTO DIRECTION SENSING AND ±15-kV ESD PROTECTION
SCES650 – APRIL 2006
PRINCIPLES OF OPERATION
Applications
The TXB0104 can be used in level-translation applications for interfacing devices or systems operating at
different interface voltages with one another.
Architecture
The TXB0104 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. In a dc state, the output drivers of the TXB0104 can maintain a high or low,
but are designed to be weak, so that they can be overdriven by an external driver when data on the bus starts
flowing the opposite direction.
The output one shots detect rising or falling edges on the A or B ports. During a rising edge, the one shot turns
on the PMOS transistors (T1, T3) for a short duration, which speeds up the low-to-high transition. Similarly,
during a falling edge, the one shot turns on the NMOS transistors (T2, T4) for a short duration, which speeds up
the high-to-low transition.
V_CCA
V_CCB
One
T1
Shot
4k
One
T2
Shot
A
B
T3
One
Shot
4k
T4
One
Shot
Figure 1. Architecture of TXB0104 I/O Cell
Input Driver Requirements
Typical I_IN vs V_IN characteristics of the TXB0104 are shown in Figure 2. For proper operation, the device driving
the data I/Os of the TXB0104 must have drive strength of at least ±2 mA.
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