ISO7742FDBQR Reinforced 4-Channel Digital Isolator: Selection, Design, and Drop-In Alternatives

Quick Answers

The ISO7742FDBQR is a reinforced, quad-channel digital isolator from Texas Instruments, in an active lifecycle with 99,999 units available through XAIPART as of 2026-08-27. It delivers 4 isolation channels in a 2/2 forward/reverse configuration, supports data rates up to 100 Mbps, and provides reinforced isolation rated at 5000 Vrms with 1500-Vrms working voltage and ±100 kV/µs typical CMTI. The device operates from 2.25 V to 5.5 V and across -55°C to 125°C in a 16-pin SSOP (DBQ) package. Pricing starts at $2.7273 for single-unit orders and drops to $1.5909 at 1,000 units. It is ideal for industrial fieldbus, motor drives, power inverters, isolated SPI/UART, medical, and automotive electronics. View live inventory and pricing for ISO7742FDBQR.

This guide covers the verified electrical specifications, package and pinout, typical application circuits, drop-in replacements, current supply status, and buying considerations for engineers evaluating the ISO7742FDBQR.

Technical Guide

When selecting a digital isolator, engineers must first compare channel count and direction, data rate, isolation rating, supply voltage, and operating temperature. The ISO7742FDBQR is a 4-channel device arranged as 2/2 forward/reverse channels. That configuration makes it a flexible choice for bidirectional links such as isolated SPI, UART, RS-485, and CAN interfaces. The 100 Mbps data rate supports high-speed SPI clocks and industrial fieldbus signaling while keeping the part suitable for mixed 3.3-V and 5-V systems.

From a safety perspective, the reinforced isolation rating of 5000 Vrms is the headline specification. The device also carries a 1500-Vrms working voltage and a surge capability up to 12.8 kV. These values matter in motor drives, power inverters, and renewable-energy systems where lightning-induced surges and fast switching transients can threaten signal integrity. The ±100 kV/µs typical CMTI is the metric to watch when placing an isolator between a noisy power stage and a clean control MCU.

Design-In Checklist

Use the following checklist when designing the ISO7742FDBQR into a new board:

• Confirm both sides of the barrier stay within the 2.25 V to 5.5 V supply range. The part supports a wide range of logic levels, so one design can serve 3.3-V and 5-V systems.
• Keep the data rate at or below 100 Mbps. At 10 MHz SPI, the 100 Mbps rating provides a 10x bit-period margin.
• Place decoupling capacitors close to VCC1 and VCC2 to minimize supply noise, as recommended by the TI product description.
• Maintain adequate creepage and clearance on the PCB to preserve the 5000-Vrms reinforced isolation rating.
• Take advantage of the fail-safe outputs, which settle to a defined state during power-up or fault conditions.
• Choose the 2/2 forward/reverse channels carefully: INA/INB on side 1 drive OUTA/OUTB on side 2, while INC/IND on side 2 drive OUTC/OUTD on side 1.

The ISO7742FDBQR uses TI's capacitive isolation technology. This approach delivers high EMI immunity and fast transient rejection through an internal encoding and decoding architecture. The 16-pin SSOP (DBQ) package is surface-mount, lead-free, and RoHS compliant, which simplifies assembly in production environments.

Pinout Quick Reference

The most important pins for functional design are VCC1/GND1, the side-1 signal pins INA, INB, OUTC, OUTD, the side-2 supply pins VCC2/GND2, and the side-2 signal pins OUTA, OUTB, INC, IND. For a full pin-by-pin table, see the product page.

Alternatives & Comparison

Engineers often ask whether the ISO7742FDBQR has a drop-in replacement. The closest verified alternative is the ISO7742DBQR, which has the same package and pinout and is functionally equivalent. If you need a different channel direction arrangement, the ISO7740FDBQR provides a 4-channel, 4/0 configuration and is pin-compatible. The ISO7742FDBQ is the same die with a different ordering option. For automotive programs, the ISO7742FDBQRQ1 is the AEC-Q100-qualified automotive-grade variant. The ISO7742DWR uses a different SOIC package and is not pin-compatible.

For most designs, the ISO7742DBQR is the safest drop-in choice when you need identical package, pinout, and functionality. The ISO7740FDBQR is useful when all four channels must transfer data in the same direction, but verify that the channel direction meets your signal flow before committing.

Industry Insight

The lifecycle status for the ISO7742FDBQR is active, and the XAIPART verified stock is 99,999 units. There is no obsolescence signal in the verified database as of 2026-08-27. The verified pricing tiers are: $2.7273 for qty 1, $1.9697 for qty 10, $1.7424 for qty 100, $1.6667 for qty 500, and $1.5909 for qty 1000.

This pricing profile shows typical volume discounting for an active TI isolator: the per-unit cost drops by roughly 41.7% from 1-piece to 1000-piece quantities. Because the part is active and stocked in deep quantity, supply risk is low for prototype and production orders in the near term.

Trends & Outlook

Buyers should continue to monitor the availability of reinforced isolators with 100 Mbps data rates, 5000-Vrms isolation, and ±100 kV/µs CMTI for industrial and automotive applications. The ISO7742FDBQR's wide 2.25-V to 5.5-V supply range and -55°C to 125°C temperature range keep it relevant across factory automation, power conversion, and medical equipment.

For long-term supply resilience, keep the verified alternatives in mind: ISO7742DBQR is the drop-in-identical option, and ISO7740FDBQR gives a pin-compatible 4/0 channel-direction path if the design evolves. If an automotive-grade component is required, the ISO7742FDBQRQ1 variant addresses AEC-Q100 qualification. Designs that standardize on the SSOP (DBQ) footprint can move among these verified alternatives with minimal layout change.