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Texas Instruments ISO7021FD
- Part No.:
- ISO7021FD
- Manufacturer:
- Texas Instruments
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ISO7021FD.pdf
- Description:
- DGTL ISO 3000VRMS 2CH GP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,038
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Product details
Overview
ISO7021FD from Texas Instruments is an ultra-low-power, two-channel capacitive digital isolator with 3000VRMS reinforced isolation, 4Mbps data rate, and dual supply operation (1.71V–5.5V per side), designed for galvanic signal isolation in power-constrained industrial sensor interfaces and field transmitters.
For engineers reviewing the ISO7021FD datasheet, ISO7021FD pinout, ISO7021FD application, or ISO7021FD equivalent, this page delivers verified specifications including quiescent current (4.8μA/channel @3.3V), CMTI (±100kV/μs), default-low output behavior, SOIC-8 package dimensions (4.90mm × 6.00mm), and safety certifications (VDE 0884-17, UL 1577, IECEx/ATEX).
Technical Context
The ISO7021FD implements edge-based encoding with ON-OFF keying (OOK) modulation across a double capacitive SiO₂ barrier, enabling sub-120μA/Mbps dynamic current consumption while maintaining 3000VRMS isolation. Its refresh logic ensures DC state matching via watchdog-triggered retransmission after >100μs of input inactivity.
It supports asymmetric dual-supply operation (e.g., 1.8V on side 1, 5V on side 2), features ±100kV/μs CMTI, and integrates robust EMC protection including ±8kV IEC 61000-4-2 contact discharge immunity across the barrier and low radiated emissions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Data Rate | Up to 4Mbps - enables high-speed UART, SPI, and GPIO isolation without timing bottlenecks. |
| Quiescent Current | 4.8μA per channel @3.3V - allows battery-powered or energy-harvesting systems to operate for years without replacement. |
| Isolation Rating | 3000VRMS - meets reinforced insulation requirements for functional safety in industrial PLCs and motor drives. |
| CMTI | ±100kV/μs typical - prevents false triggering in noisy environments like variable-frequency drives and factory automation. |
| Supply Range | 1.71V–1.89V and 2.25V–5.5V per side - supports mixed-voltage system interfacing (e.g., 1.8V MCU to 5V ADC). |
| Default Output | Low (F-suffix device) - ensures fail-safe behavior in loss-of-signal conditions for safety-critical control loops. |
| Operating Temperature | –55°C to +125°C - qualified for extended outdoor, automotive under-hood, and industrial process environments. |
| Package | 8-SOIC (D package, 4.90mm × 6.00mm) - standard footprint compatible with automated assembly and legacy board layouts. |
Pinout & Package
ISO7021FD is housed in an industry-standard narrow-body 8-pin SOIC (D package) measuring 4.90mm × 6.00mm, with creepage and clearance ≥4mm, DTI >17µm, and material group I per IEC 60664-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC1 | Power supply, side 1 (input side) | Accepts 1.71V–1.89V or 2.25V–5.5V; powers input buffer and transmitter circuitry. |
| OUTA | Output, channel A (forward direction) | Isolated logic-level output referenced to VCC2; defaults low on power loss (F-suffix behavior). |
| INB | Input, channel B (reverse direction) | Accepts CMOS/LVCMOS signals up to 4Mbps; VIH = 0.7×VCCI, VIL = 0.3×VCCI. |
| GND1 | Ground, side 1 (input side) | Reference for VCC1 and INx pins; must be isolated from GND2 by PCB layout. |
| GND2 | Ground, side 2 (output side) | Reference for VCC2 and OUTx pins; forms galvanic barrier with GND1. |
| OUTB | Output, channel B (reverse direction) | Isolated logic-level output referenced to VCC2; mirrors INB with <165ns propagation delay. |
| INA | Input, channel A (forward direction) | Accepts CMOS/LVCMOS signals up to 4Mbps; drives internal OOK modulator. |
| VCC2 | Power supply, side 2 (output side) | Independent supply (1.71V–1.89V or 2.25V–5.5V); powers receiver and output buffer. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low power architecture | 4.8μA/channel quiescent current @3.3V enables multi-year operation in loop-powered 4–20mA transmitters. |
| Dual-direction channel configuration | One forward (INA→OUTA) and one reverse (INB→OUTB) channel in single SOIC-8 package reduces board space vs. discrete isolators. |
| Fail-safe default output | Low-state default on input power loss (F-suffix) ensures predictable behavior in safety-critical shutdown sequences. |
| High CMTI performance | ±100kV/μs typical common-mode transient immunity prevents data corruption in high-noise motor drive and power converter applications. |
| Wide dual-supply flexibility | Independent 1.71–1.89V and 2.25–5.5V rails per side allow direct interfacing between 1.8V microcontrollers and 5V analog front-ends. |
| Safety-certified isolation barrier | 3000VRMS rating with VDE 0884-17, UL 1577, IECEx, and ATEX certification supports intrinsic safety (IS) designs in hazardous areas. |
Applications
| 4–20mA Loop-Powered Transmitters | Industrial PLC Digital I/O Modules |
|---|---|
|
Use Scenario: Isolating sensor signal conditioning circuitry from 4–20mA current loop outputs in hazardous-area field instruments. IC Role / Device Role / Timing Role: Provides galvanic isolation between low-voltage analog front-end and high-side loop driver, with fail-safe low-default output ensuring safe shutdown. Use Value: Enables single-supply, ultra-low-power operation (<5μA/channel) while meeting IEC 61000-4-2 ±8kV contact ESD and ATEX Zone 0/1 requirements. |
Use Scenario: Isolating microcontroller GPIOs from relay drivers and optocoupler inputs in programmable logic controller backplanes. IC Role / Device Role / Timing Role: Two-channel bidirectional isolator replacing discrete optocouplers, supporting 4Mbps update rates for real-time I/O scanning. Use Value: Reduces component count and PCB area versus dual-optocoupler solutions while delivering ±100kV/μs CMTI for noise immunity in electrically noisy cabinet environments. |
| Low-Power Sensor Interface Boards | Hazardous-Area Intrinsically Safe (IS) Systems |
|
Use Scenario: Isolating ultra-low-power environmental sensors (e.g., temperature, humidity) from host MCU in battery-operated remote monitoring nodes. IC Role / Device Role / Timing Role: Bidirectional digital isolator enabling UART communication across isolation barrier with <120μA/Mbps dynamic current draw. Use Value: Extends battery life by >3× compared to standard digital isolators, while maintaining 4Mbps throughput for firmware updates and diagnostics. |
Use Scenario: Providing certified isolation for digital control signals entering explosion-proof enclosures in oil & gas or chemical processing plants. IC Role / Device Role / Timing Role: Reinforced isolator with IECEx/ATEX certification (II 1G Ex ia IIC Ga) and 3000VRMS rating for intrinsic safety barrier compliance. Use Value: Eliminates need for external safety barriers in Class I, Division 1 / Zone 0 designs, reducing system cost and complexity while meeting IEC 60079-11 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISO7021 | Default output high; identical pinout, specs, and package; same 3000VRMS rating and 4Mbps rate. | Used where fail-safe high-state output is required on power loss (e.g., enable lines, active-high reset). | Select ISO7021 when system logic requires asserted-high default behavior during fault conditions. |
| ISO7041 | Four-channel version in SOIC-16; higher total supply current (12μA/ch @3.3V quiescent); same 4Mbps, 3000VRMS, and F-suffix option. | Replaces two ISO7021FD units in space-constrained multi-channel isolation applications (e.g., multi-sensor DAQ). | Choose ISO7041 when consolidating four isolated channels is prioritized over minimal per-channel power. |
Compared with ISO7021 (default-high) and ISO7041 (quad-channel), ISO7021FD offers the lowest per-channel quiescent current (4.8μA @3.3V) and smallest footprint (SOIC-8) for fail-safe low-default two-channel isolation in power- and space-sensitive industrial designs.
Availability
ISO7021FD is available at Aetrix Electronics and suitable for 4–20mA loop-powered transmitters, industrial PLC I/O modules, and intrinsically safe hazardous-area systems requiring stable component supply, long-lifecycle assurance, and traceable sourcing.
Supply support for ISO7021FD 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 leader specializing in analog, embedded processing, and high-reliability components for industrial, automotive, and communications markets.
The ISO70xx family was engineered specifically for ultra-low-power, safety-certified digital isolation in harsh industrial environments-prioritizing microwatt operation, robust CMTI, and regulatory compliance over raw speed or channel count.
FAQ
What is the default output state of ISO7021FD during power loss?
The ISO7021FD has a default-low output behavior: when input power (VCC1) or signal is lost, both OUTA and OUTB transition to and hold a logic-low state after a delay of 400–750μs. This fail-safe characteristic is inherent to the F-suffix variant and critical for safety-critical control loops where de-energized states must be explicitly defined. The ISO7021FD maintains this behavior across its full operating temperature range (–55°C to +125°C).
Does ISO7021FD support different supply voltages on each side of the isolation barrier?
Yes, ISO7021FD fully supports independent supply rails: VCC1 can operate from 1.71V–1.89V or 2.25V–5.5V, and VCC2 can simultaneously operate within the same ranges. This enables direct interfacing between 1.8V microcontrollers and 5V analog peripherals without level shifters. The device guarantees proper functionality-including 4Mbps data rate and 4.8μA/channel quiescent current-even with asymmetric supplies such as 1.8V on side 1 and 5V on side 2.
What safety certifications does ISO7021FD hold for hazardous-area use?
ISO7021FD is certified for intrinsic safety applications under IECEx (IEC 60079-0 & IEC 60079-11) and ATEX (EN IEC 60079-0 & EN 60079-11), with marking II 1G Ex ia IIC Ga. It also carries VDE 0884-17 (reinforced isolation), UL 1577 (3000VRMS), IEC 62368-1, IEC 61010-1, and GB 4943.1 approvals. These certifications validate its suitability for Zone 0/1 and Class I, Division 1 environments without additional barrier components.
How does ISO7021FD achieve ultra-low power consumption at 4Mbps?
ISO7021FD uses edge-based encoding with ON-OFF keying (OOK) modulation across its double capacitive SiO₂ barrier, transmitting only signal transitions-not DC states-minimizing switching activity. Combined with optimized CMOS circuitry and refresh logic that activates only after >100μs of inactivity, it achieves just 120μA per channel at 1Mbps and 4.8μA/channel quiescent current @3.3V-enabling multi-year battery life in field instruments.
What is the minimum pulse width supported by ISO7021FD?
ISO7021FD supports a minimum pulse width of 250ns, as specified in its switching characteristics table. This parameter ensures reliable transmission of narrow digital pulses-such as those found in high-resolution PWM control or fast serial protocols-at its maximum 4Mbps data rate. The value is guaranteed across all valid supply voltages (1.71V–5.5V) and operating temperatures (–55°C to +125°C), with no derating required.
ISO7021FD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- General Purpose
- Isolated Power:
- No
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 1/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 3000Vrms
- Common Mode Transient Immunity (Min):
- 100kV/µs
- Data Rate:
- 4Mbps
- Propagation Delay tpLH / tpHL (Max):
- 165ns, 165ns
- Pulse Width Distortion (Max):
- 10ns
- Rise / Fall Time (Typ):
- 5ns, 5ns
- Voltage - Supply:
- 1.71V ~ 1.89V, 2.25V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -55°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ISO7021FD FAQ
1.How can I place an order for ISO7021FD through Aetrix?
Please submit a Request for Quotation (RFQ) for ISO7021FD on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ISO7021FD reliable?
The price and inventory of ISO7021FD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISO7021FD is usually 5 days.
3.What payment methods are accepted for ISO7021FD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISO7021FD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISO7021FD?
ISO7021FD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISO7021FD order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ISO7021FD?
For technical support, including ISO7021FD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISO7021FD requirements.
6.How does Aetrix verify that ISO7021FD is sourced from the original manufacturer or authorized distributors?
All ISO7021FD products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ISO7021FD meets industry standards.
7.What is the process for return or replacement of ISO7021FD?
All ISO7021FD units undergo pre-shipment inspection (PSI). If there is an issue with ISO7021FD, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ISO7021FD part is unused and in its original packaging.
Return procedure for ISO7021FD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISO7021FD Tags
-
ISO1212DBQR
Texas Instruments
-
ISO6721BDR
Texas Instruments
-
SI8710AC-B-ISR
Skyworks Solutions Inc.
-
ISO7720FDR
Texas Instruments
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ISO7721DR
Texas Instruments
-
ISO7721FDR
Texas Instruments
-
SI8710CC-B-ISR
Skyworks Solutions Inc.
-
ISO6741FQDWRQ1
Texas Instruments
-
ISO7721DWVR
Texas Instruments
-
ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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