SDLS975 April 2024 LSF0002
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
The pull-up resistor value needs to limit the current through the pass transistor when it is in the ON state to about 15mA. Doing this causes a voltage drop of 260mV to 350mV to have a valid LOW signal on the downstream channel. If the current through the pass transistor is higher than 15mA, then the voltage drop is also higher in the ON state. To set the current through each pass transistor at 15mA, calculate the pull-up resistor value using the following equation:
Table 8-3 provides resistor values, reference voltages, and currents at 8mA, 5mA, and 3mA. The resistor value shown in the +10% column (or a larger value) should be used so that the voltage drop across the transistor is 350mV or less. The external driver must be able to sink the total current from the resistors on both sides of the LSF family device at 0.175V, although the 15mA applies only to current flowing through the LSF family device. The device driving the low state at 0.175V must sink current from one or more of the pull-up resistors and maintain VOL. A decrease in resistance will increase current, and thus result in increased VOL.
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 |