The ISO7240x, ISO7241x, and ISO7242x devices are quad-channel digital isolators with
multiple channel configurations and output-enable functions. These devices have logic-input and
logic-output buffers separated by Texas Instrument’s silicon-dioxide (SiO2)
isolation barrier. Used in conjunction with isolated power supplies, these devices help block high
voltage, isolate grounds, and prevent noise currents from entering the local ground and interfering
with or damaging sensitive circuitry.
The ISO7240x family of devices has all four channels in the same direction. The ISO7241x
family of devices has three channels in the same direction and one channel in the opposition
direction. The ISO7242x family of devices has two channels in each direction.
The devices with the C suffix (C option) have TTL input thresholds and a noise-filter at
the input that prevents transient pulses from being passed to the output of the device. The devices
with the M suffix (M option) have CMOS VCC/2 input thresholds and do not
have the input noise filter or the additional propagation delay.
The ISO7240CF device has an input disable function on pin 7, and a selectable high or low
failsafe-output function with the CTRL pin (pin 10). The failsafe output is a logic high when a
logic high is placed on the CTRL pin or it is left unconnected. If a logic low signal is applied to
the CTRL pin, the failsafe output becomes a logic-low output state. The input disable function of
the ISO7240CF device prevents data from being passed across the isolation barrier to the output.
When the inputs are disabled or VCC1 is powered down, the outputs are set by
the CTRL pin.
These devices can be powered from 3.3-V or 5-V supplies on either side, in any
combination. The signal input pins are 5-V tolerant regardless of the voltage supply level that is
These devices are characterized for operation over the ambient temperature range of –40°C