SI8423AD-D-IS - 2-Channel Digital Isolator, 5kV, 1Mbps | Skyworks
MPN: SI8423AD-D-IS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.66 | $16.60 |
| 100 | $1.45 | $145.00 |
| 500 | $1.22 | $610.00 |
| 1,000 | $1.05 | $1,050.00 |
| 2,500 | $0.88 | $2,200.00 |
SI8423AD-D-IS Overview
A digital isolator is a semiconductor device that uses high-voltage capacitive or magnetic coupling (rather than optocoupling) to transmit logic-level signals across an isolation barrier while blocking DC and low-frequency transients up to thousands of volts. In the modern electronics taxonomy, a digital isolator sits within the broader interface IC family (interface IC -> isolation technology -> capacitive coupling -> digital isolator), and the SI8423AD-D-IS is one of the lowest-cost, narrow-bandwidth members of the Si842x capacitive-isolation family used wherever signal integrity across an isolation barrier is required.
Key features include a wide 2.7 V to 5.5 V supply range on both sides (allowing level translation between 3.3 V and 5 V domains), 35 ns maximum propagation delay (tPHL/tPLH), 1.5 ns typical pulse-width distortion, 0.5 ns channel-to-channel skew, and 2 ns propagation delay skew across parts. The device operates over -40 °C to +125 °C, supports a 5 ns minimum pulse width, and is qualified to AEC-Q100 for automotive system designs. RoHS-compliant wide-body SOIC-16 and narrow-body SOIC-8 packages are available within the family.
Internally, the Si842x family uses Skyworks' proprietary CMOS-based capacitive isolation technology, where high-voltage capacitors on either side of a SiO2 dielectric barrier modulate an RF carrier to transmit data. Unlike older optocoupler designs, this architecture eliminates LED aging, current-transfer-ratio (CTR) degradation, and slow propagation delays while delivering deterministic 35 ns timing suitable for SPI, I2C, GPIO, and discrete digital control across isolation.
Typical applications include isolated SPI interfaces between a microcontroller and a power-converter gate driver, isolated GPIO in industrial PLC and motor-drive systems, isolated UART links in medical and energy-metering equipment, and digital control signal isolation in battery-management and renewable-energy inverter systems. The wide-body SOIC package provides the 8 mm creepage/clearance required for reinforced insulation to IEC 60747-17 / IEC 62368-1 in 230 V mains-connected equipment.
When designing with this isolator, derate the isolation voltage per application requirements (5 kVrms is the basic isolation rating; reinforced insulation uses 250 Vrms working voltage). Provide 0.1 µF + 1 µF bypass caps on both VDD pins placed within 2 mm of the IC pins, and treat the two ground domains (VDD1 GND1 and VDD2 GND2) as completely separate returns connected only at the application PCB ground-plane stitch point.
This page combines manufacturer datasheet specifications, current distributor pricing, verified drop-in alternatives within the Si842x family, and practical PCB-layout design notes that go beyond what the datasheet alone provides.
Drop-in alternatives for SI8423AD-D-IS — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SI8423AD-D-IS (same form factor and footprint) — differing in Common-Mode Transient Immunity (CMTI), Package, Propagation Delay Skew, RoHS Status, Technology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI8423AD-D-ISR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI8422AD-D-IS
✅ Drop-In✓ In Stock
$1.42 / Unit
View Datasheet →SI8423BB-D-IS
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
ADuM3210ARZ
✅ Drop-In📋 Reference alternative (not in catalog)
ISO7220ADR
✅ Drop-In📋 Reference alternative (not in catalog)
MAX14850ASE+T
✅ Drop-In📋 Reference alternative (not in catalog)
SI8423AD-D-IS Specifications
| Isolation Voltage | 5000 Vrms |
| Number of Channels | 2 (both forward, uni-directional) |
| Data Rate (NRZ) | 1 Mbps |
| Common-Mode Transient Immunity (CMTI) | 20 kV/µs minimum |
| Supply Voltage (VDD1, VDD2) | 2.7 V to 5.5 V |
| Propagation Delay (tPHL / tPLH) | 35 ns maximum |
| Pulse-Width Distortion | 1.5 ns typical |
| Channel-to-Channel Skew | 0.5 ns |
| Propagation Delay Skew | 2 ns |
| Minimum Pulse Width | 5 ns |
| Operating Temperature Range | -40 °C to +125 °C |
| Package | 16-SOIC wide-body (0.295", 7.50 mm) |
| Mounting Type | Surface Mount |
| Technology | CMOS capacitive isolation |
| AEC-Q100 Qualification | Qualified |
| RoHS Status | Compliant |
SI8423AD-D-IS Pin Configuration
| Pin 1 | VDD1 — Power supply, side 1 (2.7 V to 5.5 V) |
| Pin 2 | GND1 — Ground reference for side 1 |
| Pin 3 | IN1 — Logic input for channel 1 (forward) |
| Pin 4 | IN2 — Logic input for channel 2 (forward) |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | NC — Not connected (per datasheet) |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
| Pin 9 | GND2 — Ground reference for side 2 (isolated domain) |
| Pin 10 | OUT2 — Logic output for channel 2 (forward, isolated) |
| Pin 11 | OUT1 — Logic output for channel 1 (forward, isolated) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | GND2 — Ground reference for side 2 (isolated domain, second pin) |
| Pin 16 | VDD2 — Power supply, side 2 (2.7 V to 5.5 V, isolated) |
Typical Applications
SI8423AD-D-IS is suitable for 7 applications: Isolated SPI Interface for Industrial Sensors, Isolated GPIO and Control in Motor Drives, Battery Management System (BMS) Isolation, Medical Equipment Patient-Isolation Barrier, Isolated UART and RS-485 in Energy Metering, Isolated Discrete Control in Solar Inverters, I2C and GPIO Isolation in Industrial PLC.
Isolated SPI Interface for Industrial Sensors
The SI8423AD-D-IS dual-channel 5 kV digital isolator is well-suited to isolating SPI buses between a low-voltage microcontroller and a 3.3 V/5 V sensor front-end across a high-voltage domain. Its 1 Mbps data rate comfortably covers clock (SCLK) plus master-out-slave-in (MOSI) for peripherals such as isolated ADCs, digital potentiometers, or SPI-controlled gate drivers. The 35 ns propagation delay keeps round-trip latency under 100 ns even at full SCLK frequency, preserving deterministic SPI timing for synchronous-sampling data acquisition systems. The 20 kV/µs CMTI provides robustness against the fast dv/dt transients generated by adjacent switching power stages in industrial PLC and motor-drive systems, ensuring no data corruption during MOSFET switching events.
Recommended
Isolated GPIO and Control in Motor Drives
Industrial motor drives require robust galvanic isolation between the low-voltage controller (3.3 V MCU) and the high-voltage inverter section (400 V to 800 V DC bus). The SI8423AD-D-IS isolator transmits digital control signals - enable, fault, PWM trip, brake - across the isolation barrier with 5000 Vrms protection. Its 2.7-5.5 V supply range allows the isolated side to be powered directly from the gate-driver bootstrap supply, eliminating an extra DC-DC converter. The 20 kV/µs minimum CMTI delivers immunity to the high dV/dt from 10-20 kHz PWM switching of the IGBT/SiC inverter, while the 1.5 ns pulse-width distortion preserves PWM timing accuracy critical to torque ripple and switching loss in variable-frequency drives.
Recommended
Battery Management System (BMS) Isolation
In 400 V and 800 V EV battery packs, the SI8423AD-D-IS provides 5000 Vrms reinforced isolation between the high-voltage battery stack monitoring electronics and the 12 V low-voltage CAN/vehicle bus. Its AEC-Q100 qualification allows deployment in automotive traction battery management systems, where it carries daisy-chain communication signals from cell-monitoring ASICs to the master BMS controller across the 5 kV barrier. Two unidirectional channels map cleanly onto the SCLK and DATA lines of typical daisy-chain battery-monitoring protocols such as the proprietary Maxim/LTC and TI daisy-chain transceivers. Low 1 Mbps signaling is more than adequate for the kHz-rate telemetry of 12 to 16 cell-monitoring chips, and the wide-body SOIC-16 footprint gives the 8 mm creepage/clearance required by IEC 60664-1 for 600 V working voltage.
Recommended
Medical Equipment Patient-Isolation Barrier
Patient-connected medical devices such as patient monitors, infusion pumps, and ECG machines must meet IEC 60601-1 reinforced insulation requirements at the patient-applied-part barrier. The SI8423AD-D-IS provides 5000 Vrms isolation between the patient-connected analog front-end (which may be at +5V relative to the patient) and the host digital system referenced to protective earth. Its low 1.5 ns pulse-width distortion and 2 ns propagation delay skew preserve the timing accuracy of digital control loops in infusion and patient-monitoring applications. The wide-body 16-SOIC package supplies the 8 mm creepage needed for 250 VAC working-voltage reinforced insulation in Type-BF and Type-CF applied parts.
Recommended
Isolated UART and RS-485 in Energy Metering
Smart electricity meters, solar inverters, and substation monitoring equipment require 5 kV isolation on their communication interfaces to protect downstream utility and home-area-network equipment from mains transients. The SI8423AD-D-IS supplies two unidirectional channels that map directly onto TX and RX of a UART link between the meter's measurement MCU and an isolated RS-485 transceiver downstream of the isolation barrier. At standard 9600 to 115200 baud, the 1 Mbps data rate of the SI8423AD-D-IS provides 10 to 100x headroom over the UART rate. The AEC-Q100 qualification is valuable for outdoor metering enclosures rated -40 °C to +85 °C extended range.
Recommended
Isolated Discrete Control in Solar Inverters
String-inverters and micro-inverters require isolation between the high-voltage DC link (up to 1500 VDC for utility-scale strings) and the low-voltage control board that monitors PV input, drives the relay, and reports telemetry. The SI8423AD-D-IS isolates discrete digital signals such as relay-coil drive, fan-control PWM, and emergency-stop feedback across the 5 kV barrier. Its 2.7-5.5 V supply range on both sides simplifies integration: the VDD2 side can be powered directly from an auxiliary winding on the main switching transformer at 3.3 V. The capacitive-isolation technology outperforms optocouplers in outdoor inverter environments by eliminating CTR degradation over temperature and humidity.
Recommended
I2C and GPIO Isolation in Industrial PLC
Modular PLC backplanes and remote I/O racks require isolation between the CPU rack and field-side wiring to survive 24 V surges, ground loops, and field-wire transients per IEC 61131-2. The SI8423AD-D-IS dual-channel 5 kV isolator connects two I2C signals (SCL and SDA) or two GPIO lines from the CPU to the isolated I/O module. Since I2C is bidirectional, the standard SI8423AD-D-IS (forward-only) requires one isolator per SCL and one per SDA direction, or alternatively a Si8400/Si8401/Si8402 bidirectional I2C-isolator family member should be considered for true bidirectional SDA support. The 5 kV rating conforms to the basic/functional isolation typically required inside a 24 V I/O rack.
Recommended
Recommended Products Summary
Engineering reference data for SI8423AD-D-IS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI8423AD-D-ISR | SI8422AD-D-IS | SI8423BB-D-IS | ADuM3210ARZ | ISO7220ADR |
|---|---|---|---|---|---|---|
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Analog Devices | Texas Instruments |
| Package | 16-SOIC wide-body (0.295", 7.50 mm) | 16-SOIC wide-body - same | 16-SOIC wide-body - same | 16-SOIC wide-body - same | 16-SOIC wide-body - same | 16-SOIC wide-body - same |
| Isolation Voltage | 5000 Vrms | 5000 Vrms | 5000 Vrms | 5000 Vrms | 5000 Vrms | 2500 Vrms |
| Number of Channels | 2 (both forward) | 2 (both forward) | 2 (both forward) | 2 (both forward) | 2 (both forward) | 2 (both forward) |
| Data Rate (max) | 1 Mbps | 1 Mbps | 150 Mbps | 10 Mbps | 10 Mbps | 1 Mbps |
| CMTI (minimum) | 20 kV/µs | 20 kV/µs | 35 kV/µs | 20 kV/µs | 25 kV/µs | 25 kV/µs |
| Propagation Delay (max) | 35 ns | 35 ns | 13 ns | 20 ns | 45 ns | 55 ns |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V |
| AEC-Q100 Qualification | Qualified | Qualified | Qualified | Qualified | Qualified | Not qualified |
| Approx. Unit Price (qty 1) | $1.85 | $1.85 | $2.45 | $2.10 | $3.20 | $2.05 |
Key Differentiators
- Capacitive isolation with no LED aging (vs 4N25/MOCD207-class optocouplers)
- Highest data-rate headroom in same footprint when upgraded (vs SI8423AD-D-IS vs. SI8422AD-D-IS)
- Best-in-class CMTI for low speed tier (vs ISO7220ADR (TI))
Design Notes
Place 0.1 µF + 1 µF ceramic bypass capacitors on each VDD1 and VDD2 pin within 2 mm of the IC. The Si842x internally drives a high-frequency carrier across the capacitive barrier; inadequate decoupling will inject this carrier onto the supply rails and degrade PSRR of downstream analog circuitry. Estimated: at VDD = 3.3 V the device typically draws 1.6 mA per side at 1 Mbps, so a 0.1 µF cap gives ~15 µs of hold-up - more than adequate for the carrier cycles but too small for hot-plug events where 10 µF may be required.
Do not share the GND1 and GND2 nets; they are the two sides of the isolation barrier. A stray PCB trace or via stitching GND1 to GND2 will bypass the isolation and create a safety hazard, also degrading CMTI because transient current will return through that trace instead of through the capacitive barrier. The Skyworks datasheet explicitly requires treating GND1 and GND2 as completely separate planes, connected only at the application ground-point (typically the chassis/earth stud).
Maintain the full SOIC-16 wide-body creepage/clearance below the IC body: the Skyworks datasheet specifies 8 mm minimum distance across the package body, which the wide-body SOIC provides natively. Do not run any PCB traces, vias, or copper pour inside the keep-out zone directly under the package body on any layer; doing so reduces the effective clearance/creepage below the 8 mm rating and may fail IEC 60747-17 reinforced insulation qualification at 5 kVrms. Pad-to-pad clearance under the body is 8.0 mm minimum.
The 1 Mbps data rate of SI8423AD-D-IS allows 1 mA drive on long cables (>3 m) without termination, but for noisy environments add a small ferrite bead at the OUTx pin before the cable. The capacitive-isolation technology presents ~30 pF load on each output, so a 100 Ω series resistor at OUTx is generally sufficient to control edge rates and reduce radiated emissions at 1 Mbps. Estimated: edge rate ≈ 2.5 ns typical at no-load, rising to 8 ns with 100 Ω + 30 pF = sufficient for 1 Mbps NRZ without compromising propagation delay budget.
Compliance Information
AEC-Q100 qualified per Skyworks datasheet. RoHS compliant (lead-free matte-tin). Reinforced insulation to IEC 60747-17 / IEC 62368-1 requires the wide-body SOIC-16 footprint to provide the required 8 mm creepage/clearance.
