1.8 V

Vref_A

VCCB

EN

200 k

Vref_B

3.3 V

A1

B1

0.1 F

Figure 8-1. EN Pin Tied to Vref_B Directly and to VCCB Through a Pull-Up Resistor

The supply voltage of open drain I/O devices can be completely different from the supplies used for the LSF and

has no impact on the operation. For additional details on how to use the enable pin, see the Using the Enable

Pin with the LSF Family video.

Table 8-1. EN Pin Function Table

INPUT EN(1) PIN

Data Port State

Tied directly to Vref_B

An = Bn

L

Hi-Z

(1)

EN is controlled by Vref_B logic levels.

8.3.3 Device Functional Modes

For each channel (n), when either the An or Bn port is LOW, the switch provides a low impedance path between

the An and Bn ports; the corresponding Bn or An port will be pulled LOW. The low RON of the switch allows

connections to be made with minimal propagation delay and signal distortion.

Table 8-1 provides a summary of device operation. For additional details on the functional operation of the LSF

family of devices, see the Down Translation with the LSF Family and Up Translation with the LSF Family videos.

Table 8-2. Device Functionality

Signal Direction(1)

Input State

Switch State

Functionality

B to A (Down Translation)

B = LOW

ON

(Low Impedance)

A-side voltage is pulled low through the switch to the B-side voltage

B = HIGH

OFF

(High Impedance)

A-side voltage is clamped at Vref_A (2)

A to B (Up Translation)

A = LOW

ON

(Low Impedance)

B-side voltage is pulled low through the switch to the A-side voltage

A = HIGH

OFF

(High Impedance)

B-side voltage is clamped at Vref_A and then pulled up to the VPU

supply voltage

(1)

The downstream channel should not be actively driven through a low impedance driver, or else bus contention may occur.

(2)

The A-side can have a pullup to Vref_A for additional current drive capability or may also be pulled above Vref_A with a pullup resistor.

Specifications in the Recommended Operating Conditions section should always be followed.

LSF0102-Q1

SDLS969B – MAY 2018 – REVISED MAY 2023

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