Features and Benefits
- Overvoltage fault protection up to ±60 V on S1 and S2 pins
- Power-off protection up to ±60 V on S1 and S2 pins
- Overvoltage detection on S1 and S2 pins
- Known state output without digital inputs present
- Low on resistance: 12 Ω typical
- Ultraflat, on resistance: 0.005 Ω typical
- Low fault detection threshold voltage: 0.1 V typical
- 3 kV HBM ESD rating
- Latch-up immune under any circumstance
- ±1.8 V to ±2.5 V dual supply operation
- 1.8 V to 5.5 V single-supply operation
- 10-Lead, 3 mm × 2 mm LFCSP
The ADG7421F is a low voltage, dual single-pole/single-throw (SPST), low on-resistance switch that features overvoltage protection, power-off protection, and overvoltage detection on the source pins.
When no power supplies are present, the switch remains in the off condition, and the switch inputs are high impedance. When powered, if the analog input signal levels on the Sx pins exceed VDD or VSS by a threshold voltage, VT, the switch automatically turns off and the digital FF (fault flag) pin drops to a logic low to indicate a fault.
Input signal levels up to +60 V or −60 V relative to ground are blocked, in both the powered and unpowered condition. The switches turn on with a Logic 1 input and conducts equally well in both directions with an analog signal range of VSS + 0.1 V to VDD − 0.55 V for a 5 V single supply. The digital input is compatible with 1.8 V logic inputs over the full operating supply range.
The ADG7421F is ideal for providing overvoltage protection for small signals such as resistance temperature device (RTD) inputs (see Figure 56 in the data sheet) and thermocouple inputs (see Figure 55). The ability to protect against high voltages up to ±60 V coupled with a low voltage supply can enable complete low voltage input stages for industrial applications.
- Analog input/output modules
- Process control/distributed control systems
- Data acquisition
- Automatic test equipment
- Communication systems
- Relay replacement
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
The EVAL-ADG7421FEBZ is the evaluation board for the ADG7421F, which features two single-pole/single-throw (SPST) switch channels. The ADG7421F has overvoltage detection and protection circuitry on the source pins and is protected against signals up to −60 V and +60 V in both the powered and unpowered states.
Figure 1 shows the EVAL-ADG7421FEBZ in a typical evaluation setup. The ADG7421F is soldered to the center of the evaluation board, and two wire screw terminals are provided to connect to each of the source and drain pins. Three screw terminals are used to power the device. A fourth terminal is used to provide a user defined digital voltage, to supply the LED, which is mounted to provide visual indication of the fault status of the switch.
Full specifications on the ADG7421F are available in the product data sheet, which must be consulted in conjunction with this user guide when using the evaluation board.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
ADG7421F Companion Parts
Recommended Analog to Digital Converters
- 8-Channel, Low Noise, Low Power, 24-Bit, Sigma-Delta ADC with PGA and Reference: AD7124-8.
- 4-Channel, Low Noise, Low Power, 24-Bit, Sigma-Delta ADC with PGA and Reference: AD7124-4.
Recommended Power Products
- Ultralow Quiescent Current, 150 mA, CMOS Linear Regulators: ADP162.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.