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12-12-0003

PT0334-3

12/18/12

8

The

PI4ULS5V102

can

be

used

in

level-translation

applications for interfacing devices or systems operating at

different interface voltages with one another.

The PI4ULS5V102 architecture(see Figure1) 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 PI4ULS5V102 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. The

typical output impedance during output transition is 70 Ω at

shown in Figure 2. For proper operation, the device driving

the data I/Os of the PI4ULS5V102 must have drive strength of

at least ±2mA.

power-up sequencing, VCCA ≥ VCCB does not damage the

device, so any power supply can be ramped up first. The

PI4ULS5V102 has circuitry that disables all output ports

The PI4ULS5V102 has an OE input that is used to disable the

device by setting OE = low, which places all I/Os in the high-

delay between when OE goes low and when the outputs

acutally get disabled (Hi-Z). The enable time (ten) indicates

the amount of time the user must allow for the one-shot

circuitry to become operational after OE is taken high.

The PI4ULS5V102 is designed to drive capacitive loads of up

to 70 pF. The output drivers of the PI4ULS5V102 have low dc

drive strength. If pullup or pulldown resistors are connected

externally to the data I/Os, their values must be kept higher

than 50 kΩ to ensure that they do not contend with the output

drivers of the PI4ULS5V102.

For the same reason, the PI4ULS5V102 should not be used in

applications such as I2C or 1-Wire where an open-drain driver

is connected on the bidirectional data I/O.