Applications Information; Power Supply Rails; Power Supply Sequencing Protection; Signal Range - Analog Devices ADG5412BF Datasheet

Data Sheet

APPLICATIONS INFORMATION

The overvoltage protected family of switches and multiplexers
provide a robust solution for instrumentation, industrial,
aerospace, and other harsh environments where overvoltage
signals can be present and the system must remain operational
both during and after the overvoltage has occurred.

POWER SUPPLY RAILS

To guarantee correct operation of the device, 0.1 μF decoupling
capacitors are required.
The ADG5412BF and the ADG5413BF
supplies between ±5 V and ±22 V. The supplies on VDD and
VSS need not be symmetrical but the VDD to VSS range must
not exceed 44 V. The ADG5412BF
also operate with single supplies between 8 V and 44 V with
VSS connected to GND.
These devices are fully specified at ±15 V, ±20 V, +12 V, and
+36 V supply ranges.

POWER SUPPLY SEQUENCING PROTECTION

The switch channel remains open when the device is unpowered
and signals from −55 V to +55 V can be applied without damaging
the device. Only when the supplies are connected and a suitable
digital control signal is placed on the INx pin does the switch
channel close and then allow a signal to pass. Placing the
ADG5412BF/ADG5413BF between external connectors and
sensitive components offers protection in systems where a
signal is presented to the switch pins before the supply voltages
are available.

SIGNAL RANGE

The ADG5412BF/ADG5413BF
circuitry on their inputs that compares the voltage levels at the
switch terminals with V and V
DD
downstream circuitry from overvoltages, supply the ADG5412BF/
ADG5413BF by voltages that match the intended signal range.
The low on-resistance switch allows signals up to the supply
rails to be passed with very little distortion. A signal that
exceeds the supply rail by the threshold voltage is then blocked.
This offers protection to both the device and any downstream
circuitry.

LOW IMPEDANCE CHANNEL PROTECTION

The ADG5412BF/ADG5413BF
elements in signal chains that are sensitive to both channel
impedance and overvoltage signals. Traditionally, series
resistors are used to limit the current during an overvoltage
condition to protect susceptible components. These series
resistors affect the performance of the signal chain and reduce
the precision that can be reached. A compromise must be
reached on the value of the series resistance that is high enough
to sufficiently protect sensitive components but low enough that
the precision performance of the signal chain is not sacrificed.
can operate with bipolar
and the ADG5413BF can
switches have fault detection
, relative to ground. To protect
SS
can be used as protective
The ADG5412BF/ADG5413BF
these resistors and retain the precision performance without
compromising the protection of the circuit.

HIGH VOLTAGE SURGE SUPPRESSION

The ADG5412BF/ADG5413BF
high voltage applications. The maximum operating voltage of
the transistor is 80 V. In applications where the inputs are likely
to be subject to overvoltages exceeding the breakdown voltage,
use transient voltage suppressors (TVSs), or similar.

INTELLIGENT FAULT DETECTION

The ADG5412BF/ADG5413BF
interface with a microprocessor or control system and be used
as an interrupt flag. This feature provides real-time diagnostic
information on the state of the device and the system to which it
connects.
The control system can use the digital interrupt to start a variety
of actions, such as

Initiating investigation into the source of the overvoltage fault

Shutting down critical systems in response to the overvoltage

Data recorders marking data during these events as
unreliable or out of specification
For systems that are sensitive during a start-up sequence, the
active low operation of the flag allows the system to ensure that
the ADG5412BF/ADG5413BF
input voltages are within normal operating range before
initiating operation.
The FF pin is a weak pull-up, which allows the signals to be
combined into a single interrupt for larger modules that contain
multiple devices.
The recovery time, t
to 600 ns by using a 1 kΩ pull-up resistor.

LARGE VOLTAGE, HIGH FREQUENCY SIGNALS

Figure 31 illustrates the voltage range and frequencies that the
ADG5412BF/ADG5413BF
extend across the full signal range from V
frequency below 3 MHz. If the required frequency is greater
than 3 MHz, decrease the signal voltage appropriately to ensure
signal integrity.
Rev. B | Page 27 of 28
ADG5412BF/ADG5413BF
enable the designer to remove
is not intended for use in very
digital output pin, FF, can
are powered on and that all
, can be decreased from a typical 60 μs
DIGREC
can reliably convey. For signals that
to V
SS DD
, keep the