User Defined Fault Protection and Detection, 0.8 pC Q, 8:1 Multiplexer

The ADG5248F and ADG5249F are 8:1 and dual 4:1 analog multiplexers. The ADG5248F switches one of eight inputs to a common output and the ADG5249F switches one of four differential inputs to a common differential output. Each channel conducts equally well in both directions when on, and each channel has an input signal range that extends to the supplies. The primary supply voltages define the on-resistance profile, whereas the secondary supply voltages define the voltage level at which the overvoltage protection engages.

When no power supplies are present, the channel remains in the off condition, and the switch inputs are high impedance. Under normal operating conditions, if the analog input signal levels on any Sx pin exceed positive fault voltage (POSFV) or negative fault voltage (NEGFV) by a threshold voltage (VT), the channel turns off and that Sx pin becomes high impedance. If the switch is selected to be on, then the drain pin is pulled to the secondary supply voltage that was exceeded. Input signal levels up to +55 V or −55 V relative to ground are blocked, in both the powered and unpowered condition.

The low capacitance and charge injection of these switches make them ideal solutions for data acquisition and sample-and-hold applications, where low glitch switching and fast settling times are required.

Note that, throughout this data sheet, multifunction pins, such as A0/F2, are referred to either by the entire pin name or by a single function of the pin, for example, A0, when only that function is relevant.

APPLICATIONS

* Analog input/output modules

* Process control/distributed control systems

* Data acquisition

* Instrumentation

* Avionics

* Automatic test equipment

* Communication systems

* Relay replacement

* User defined secondary supplies set overvoltage level

* Overvoltage protection up to −55 V and +55 V

* Power-off protection up to −55 V and +55 V

* Overvoltage detection on source pins

* Minimum secondary supply level: 4.5 V single-supply

* Interrupt flags indicate fault status

* Low charge injection (QINJ): 0.8 pC