Table 8-3. Pull-Up Resistor Values

VPU (1) (2)

8mA

5mA

3mA

NOMINAL (Ω)

+10%(3) (Ω)

NOMINAL (Ω)

+10%(3) (Ω)

NOMINAL (Ω)

+10%(3) (Ω)

5V

581

639

930

1023

1550

1705

3.3V

369

406

590

649

983

1082

2.5V

269

296

430

473

717

788

1.8V

181

199

290

319

483

532

1.5V

144

158

230

253

383

422

1.2V

106

117

170

187

283

312

(1)

Calculated for VOL = 0.35V

(2)

Assumes output driver VOL = 0.175V at stated current

(3)

+10% to compensate for VDD range and resistor tolerance

8.2.1.3 Application Curve

Figure 8-2. Open Drain Translation (1.8V to 3.3V at 2.5MHz)

8.2.2 Mixed-Mode Voltage Translation

The supply voltage (VEXT A,B) for each channel can be individually set with a pull-up resistor. Figure 8-3 shows

an example of this mixed-mode multi-voltage translation. For additional details on multi-voltage translation, see

the Multi-voltage Translation with the LSF Family video.

With VEXT,B pulled up to 5V and VEXT,A connected to 1.2V, all channels will be clamped to 1.2V at which point a

pullup can be used to define the high level voltage for a given channel.

• Push-Pull Down Translation (5V to 1.2V): Channel 1 is an example of this setup. When A2 is 5V, B1 is

clamped to 1.2V, and when A1 is LOW, B1 is driven LOW through the switch.

• Push-Pull Up Translation (1.2V to 3.3V): Channel 2 is an example of this setup. When B2 is 1.2V, the

switch is high impedance and the A2 channel is pulled up to 3.3V. When B2 is LOW, A2 is driven LOW

through the switch.

• Push-Pull Down Translation (3.3V to 1.2V): Channels 2 is an example of this setup. When A2 is driven to

3.3V, B2 is clamped to 1.2V, and when A2 is LOW, B2 is driven LOW through the switch.

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