Data de postagem: 2015-09-23
Texas Instruments has introduced the LSF series of bidirectional voltage-level translators, which operate from 0.95 to 4.5V (Vref_A) and 1.8 to 5.5V (Vref_B). This allows bidirectional voltage transitions between 1V and 5V in open-drain or push-pull applications that do not require a direction pin. The LSF series supports open-drain systems using 30pF capacitors and 250ohm pull-up resistors, and their level-shifting applications have transmission speeds greater than 100Mbps.
When the An or Bn port is LOW, the switch is ON, and there is a low resistance connection between the An and Bn ports. The switch's low Ron allows connections with minimal propagation delay and signal distortion. Assuming that when the Bn port is HIGH, there is a higher voltage on the Bn port, the voltage on the An port will be limited to the voltage set by Vref_A. When the An port is HIGH, the Bn port is pulled up to the drain pull-up power supply voltage (Vpu #) by a pull-up resistor. This feature allows a seamless transition between the higher and lower voltages selected by the user, without the need for directional control.
