ISO1430DWR datasheet(26/49 Pages) TI2

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the device is disabled when the die temperature becomes 170

℃ (typical) which lets the device decrease the

temperature. The device is enabled when the junction temperature becomes 165

℃ (typical).

Bus short circuit for an extended duration and/or beyond voltage levels specified in recommended operating

condition should be avoided. Repeated or prolonged exposure to bus shorts can result in high junction

temperatures and affect device reliability.

9.3.4 Glitch-Free Power Up and Power Down

Communication on the bus that already exist between a master node and slave node in an RS485 network must

not be disturbed when a new node is swapped in or out of the network. No glitches on the bus occur when the

device is:

• Hot plugged into the network in an unpowered state

• Hot plugged into the network in a powered state and disabled state

• Powered up or powered down in a disabled state when already connected to the bus

The ISO14xx devices do not cause any false data toggling on the bus when powered up or powered down in a

disabled state with supply ramp rates from 100 µs to 10 ms.

9.4 Device Functional Modes

Table 9-1 shows the driver functional modes.

Table 9-1. Driver Functional Table

VCC1 (1)

VCC2 (1)

INPUT D

DRIVER ENABLE DE

OUTPUTS(3)

Y, A

Z, B

Hi-Z

Open

Hi-Z

Open

PD(2)

Hi-Z

(1)

PU = Powered Up; PD = Powered Down; H = High Level; L = Low level; X = Irrelevant, Hi-Z = High impedance state

(2)

A strongly driven input signal can weakly power the floating VCC1 through an internal protection diode and cause an undetermined

output.

(3)

The driver outputs are Y and Z for a full-duplex device. The driver outputs are A and B for a half-duplex device.

The description that follows is specific to half-duplex device but the same logic applies to full-duplex device with

the outputs being Y and Z.

When the driver enable pin, DE, is logic high, the differential outputs, A and B, follow the logic states at data

input, D. A logic high at the D input causes the A output to go high and the B output to go low. Therefore the

differential output voltage defined by Equation 1 is positive.

VOD = VA – VB

(1)

A logic low at the D input causes the B output to go high and the A output to go low. Therefore the differential

output voltage defined by Equation 1 is negative. A logic low at the DE input causes both outputs to go to the

high-impedance (Hi-Z) state. The logic state at the D pin is irrelevant when the DE input is logic low. The DE pin

has an internal pulldown resistor to ground. The driver is disabled (bus outputs are in the Hi-Z) by default when

the DE pin is left open. The D pin has an internal pullup resistor. The A output goes high and the B output goes

low when the D pin is left open while the driver enabled.

Table 9-2 shows the receiver functional modes.

ISO1450, ISO1452, ISO1410, ISO1412, ISO1430, ISO1432

SLLSF22H – APRIL 2018 – REVISED JUNE 2024

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