Texas Instruments ISO7321CQDRQ1

Overview

ISO7321CQDRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-certified dual-channel digital isolator with opposite-direction channel configuration (channel A input → output, channel B input ← output), 3000 VRMS isolation per UL 1577, 25 Mbps signaling rate, and integrated noise filtering for harsh EMI environments. It enables signal integrity in motor control feedback loops and isolated CAN/RS-485 transceiver interfaces.

For engineers reviewing the ISO7321CQDRQ1 datasheet, ISO7321CQDRQ1 pinout, ISO7321CQDRQ1 application, or ISO7321CQDRQ1 equivalent, key selection criteria include fail-safe default-high output behavior (no suffix F), 65 kV/μs CMTI at 5 V, SOIC-8 narrow-body package compatibility, and dual-supply operation from 3.3 V to 5.5 V on both sides of the isolation barrier.

Technical Context

The ISO7321CQDRQ1 implements capacitive galvanic isolation using silicon dioxide (SiO₂) barriers, with separate input-side (VCCI/GNDI) and output-side (VCCO/GNDO) power domains. Its dual-channel architecture features asymmetric directionality: one channel transmits unidirectionally from input to output, the other from output to input - enabling bidirectional data flow without external logic inversion.

Each channel combines a high-frequency path (100 kbps–25 Mbps) and low-frequency path (DC–100 kbps) with automatic switching via internal decision logic (DCL). Input glitch suppression exceeds 25 ms at 125°C, and fail-safe output delay upon input power loss is 7.4 μs (3.3 V) or 7.5 μs (5 V).

Key Specifications

Pinout & Package

Narrow-body SOIC-8 package with 1.27 mm pitch; meets DIN EN 60112 CTI ≥400 V and 4 mm minimum creepage/clearance per side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel digital isolator applications.

Compared with ISO7321CQDQ1, ISO7321CQDRQ1 provides fail-safe high output critical for active-high safety interlocks; versus SI8621ED-B-IS, it delivers automotive-grade reliability and 3000 VRMS isolation essential for EV powertrain systems, despite lower speed.

Availability

ISO7321CQDRQ1 is available at Aetrix Electronics and suitable for motor control feedback, isolated CAN transceiver interface, servo drive digital I/O, and isolated power supply monitoring requiring stable component supply across automotive production lifecycles.

Supply support for ISO7321CQDRQ1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in automotive-grade isolation solutions.

The ISO732x-Q1 product line was designed specifically for automotive subsystems requiring robust EMC performance, long-term reliability under thermal stress, and regulatory compliance with AEC-Q100 Grade 1 and VDE/UL isolation standards.

FAQ

What is the fail-safe output behavior of ISO7321CQDRQ1 during input-side power loss?

The ISO7321CQDRQ1 defaults to high output state when VCCI drops below 2.1 V (powered-down condition), as confirmed in the Device Functional Modes table. This behavior is inherent to the 'R' suffix and applies to both OUTA and OUTB pins. The fail-safe delay is 7.4 μs at 3.3 V and 7.5 μs at 5 V, ensuring rapid transition to safe state without external circuitry. ISO7321CQDRQ1 maintains this characteristic across its full –40°C to +125°C operating range.

Does ISO7321CQDRQ1 support level translation between 3.3 V and 5 V domains?

Yes, ISO7321CQDRQ1 supports true bidirectional level translation: VCCI can operate at 3.3 V while VCCO runs at 5 V, or vice versa, within the 3 V to 5.5 V range per supply. Input thresholds are TTL-compatible (VIH = 2 V min, VIL = 0.8 V max), and output VOH/VOL specs are guaranteed across both supply combinations. This enables direct interfacing between 3.3 V MCUs and 5 V isolated peripherals without external level shifters. ISO7321CQDRQ1 maintains 25 Mbps data rate regardless of supply voltage pairing.

What is the creepage and clearance distance achieved by the SOIC-8 package of ISO7321CQDRQ1?

The ISO7321CQDRQ1 narrow-body SOIC-8 package provides 4 mm minimum creepage and clearance distances per side, verified per DIN EN 60112 and VDE V 0884-10. This meets reinforced insulation requirements for 400 VRMS working voltage applications. The package uses CTI ≥400 V material (Material Group II), and internal DTI is 13 µm. Board layout must maintain ≥4 mm spacing between primary and secondary side copper to preserve certification. ISO7321CQDRQ1 achieves this without requiring slots or ribs in standard FR-4 layouts.

How does the opposite-direction channel configuration of ISO7321CQDRQ1 differ from ISO7320CQDRQ1?

ISO7321CQDRQ1 has one channel configured input→output (INA→OUTA) and the other output→input (OUTB←INB), enabling true bidirectional communication across the isolation barrier. In contrast, ISO7320CQDRQ1 has both channels unidirectional input→output (INA→OUTA, INB→OUTB). This architectural difference eliminates external inverters needed for return-path signaling in ISO7320CQDRQ1 designs. ISO7321CQDRQ1's pin mapping (INA=Pin2, INB=Pin3, OUTA=Pin7, OUTB=Pin6) reflects this asymmetry and is not interchangeable with ISO7320CQDRQ1.

What safety certifications apply to ISO7321CQDRQ1?

ISO7321CQDRQ1 is certified to UL 1577 (3000 VRMS, 1 min), VDE V 0884-10 (4242 VPK, reinforced insulation), CSA Component Acceptance Notice 5A, and IEC 61010-1. It meets AEC-Q100 Grade 1 qualification (–40°C to +125°C ambient) with HBM ±4 kV and CDM ±1.5 kV ESD ratings. Planned CQC certification per GB4943.1-2011 is documented in the datasheet. These approvals validate ISO7321CQDRQ1 for use in automotive powertrain, chassis, and safety-critical systems where regulatory compliance is mandatory.