SI8712AC-B-ISR - 3.75 kV Digital Isolator, 15 Mbps, SOIC-8 | Skyworks
MPN: SI8712AC-B-ISR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.45 | $24.50 |
| 100 | $2.05 | $205.00 |
| 500 | $1.78 | $890.00 |
| 1,000 | $1.52 | $1,520.00 |
SI8712AC-B-ISR Overview
A digital isolator is a semiconductor device that transfers logic signals across an isolation barrier using capacitive, inductive (transformer), or RF carrier coupling instead of an LED-and-phototransistor optical path. Compared with traditional optocouplers, CMOS digital isolators such as the Si87xx family typically exhibit 10x lower FIT rates, wider operating temperature ranges (-40 to +125 °C), much higher CMTI (>50 kV/µs typical), and freedom from aging and forward-current degradation effects. The Si8712 belongs to the silicon isolator category within the broader interface ICs hierarchy.
Key features of the SI8712AC-B-ISR include 3750 Vrms reinforced isolation, 15 Mbps NRZ signaling capability, an open-drain / open-collector output stage (option letter "C"), and an LED-emulator input that mimics the biasing characteristics of a standard optocoupler. According to the Si87xx family datasheet, this makes the part a true drop-in alternative to popular high-speed optocouplers such as HCPL-0720, HCPL-0723, and 6N137 in PCB footprint and pinout.
The Si87xx architecture uses an internal RF carrier modulated by the input logic and recovered on the isolated side, with on-chip transformers replacing the optical coupling path. This approach eliminates LED wear-out, eliminates the need for input current limiting in most cases, and consumes less board area than discrete optocouplers with the same isolation rating.
Typical applications include isolated gate-drive interfaces, industrial fieldbus (RS-485, CAN, SPI) isolation, PLC I/O modules, switching power supply feedback isolation, and medical equipment patient-isolated data links. The 3.75 kV rating suits most 230 V AC mains-connected industrial systems as well as low-voltage battery management isolation.
Designers should verify that downstream logic tolerates the open-collector output pull-up voltage (typically 3 to 30 V), and place a 0.1 µF bypass capacitor close to VDD on each side. The Si87xx family is footprint-compatible with industry-standard 8-pin optocouplers, allowing drop-in PCB reuse.
Drop-in alternatives for SI8712AC-B-ISR — 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 SI8712AC-B-ISR (same form factor and footprint) — differing in Common-Mode Transient Immunity (CMTI), Output Type, Data Rate, Input Type, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI8712AC-B-IS
✅ Drop-In📋 Reference alternative (not in catalog)
SI8712CC-B-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8712BC-B-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8710AC-B-IS
✅ Drop-In✓ In Stock
$1.71 / Unit
View Datasheet →SI8710BC-B-IS
✅ Drop-In✓ In Stock
$0.95 / Unit
View Datasheet →ISO7420DR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8712AC-B-ISR Specifications
| Function | General-purpose single-channel digital isolator |
| Isolation Voltage (Vrms) | 3750 Vrms |
| Number of Channels | 1 |
| Data Rate | 15 Mbps |
| Common-Mode Transient Immunity (CMTI) | 20 kV/µs (minimum, datasheet); >50 kV/µs typical |
| Output Type | Open-drain / open-collector (option "C") |
| Input Type | LED-emulator (CMOS/TTL logic) |
| Operating Temperature Range | -40 °C to +125 °C |
| Package | 8-SOIC (0.154", 3.90 mm width) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Packaging | Tape & Reel (-ISR suffix) |
| Drop-in Optocoupler Replacement | Yes - 8-SOIC footprint compatible with HCPL-0720/0723, 6N137 family |
SI8712AC-B-ISR Pin Configuration
| Pin 1 | VDD1 — Input-side supply voltage (3.3 V or 5 V typical) |
| Pin 2 | GND1 — Input-side ground reference |
| Pin 3 | IN+ — LED-emulator non-inverting input (logic high enables transmission) |
| Pin 4 | IN- — LED-emulator inverting input / input ground reference |
| Pin 5 | GND2 — Output-side ground reference (isolated from GND1) |
| Pin 6 | OUT — Open-drain / open-collector output (option "C") |
| Pin 7 | VDD2 — Output-side supply voltage (3.3 V to 5 V typical) |
| Pin 8 | NC — Not connected (per Si87xx datasheet 8-SOIC pin map) |
Typical Applications
SI8712AC-B-ISR is suitable for 6 applications: Industrial RS-485 / CAN Isolation, Isolated Gate-Drive Interface for Power Converters, PLC Digital I/O Module Isolation, Battery Management System (BMS) Communication Isolation, Medical Device Patient-Isolated Data Link, Solar Inverter String Monitoring.
Industrial RS-485 / CAN Isolation
The SI8712AC-B-ISR provides 3750 Vrms isolation between an MCU UART/SPI and a fieldbus transceiver, per the Si87xx datasheet. Its 15 Mbps data rate comfortably supports 1 Mbps CAN-FD and 10 Mbps SPI, while 20 kV/µs minimum CMTI keeps data integrity intact during fast bus events such as ESD or switching transients in motor drive enclosures. The 8-SOIC footprint matches legacy optocoupler positions, allowing upgrade to the Si8712 without PCB redesign. Compared with optocouplers, the Si8712 reduces input bias current, eliminates LED aging concerns, and tolerates -40 to +125 °C industrial ambient. Recommended companion MPNs include TCAN334 (CAN-FD transceiver) and ISOW1044 (isolated CAN with integrated DC-DC).
Recommended
Isolated Gate-Drive Interface for Power Converters
The SI8712AC-B-ISR drives logic-level signals between a low-voltage PWM controller and a high-side gate driver in SMPS topologies, per the Si87xx datasheet. The 3750 Vrms rating suits 400 V and 600 V DC-link systems where reinforced isolation is mandatory. Its 20 kV/µs minimum CMTI - and >50 kV/µs typical - prevents false triggering during the high dv/dt edges seen on SiC and GaN switching nodes. The open-drain output stage (option "C") is compatible with gate-driver enable inputs, supporting 3.3 V and 5 V logic on both sides of the barrier. The 8-SOIC surface-mount package simplifies the high-density auxiliary supply layout. Recommended companion MPNs include UCC27714 (600 V gate driver) and Si8230 (isolated gate driver with dual outputs).
Recommended
PLC Digital I/O Module Isolation
The SI8712AC-B-ISR is well matched to 24 V PLC digital input and output modules where 24 V field wiring must be galvanically isolated from the backplane logic, per the Si87xx family datasheet. Its 3750 Vrms reinforced isolation and 20 kV/µs CMTI withstand the harsh electrical noise of industrial cabinets, while the -40 to +125 °C operating range covers unheated enclosures. The 15 Mbps bandwidth is more than sufficient for 100 kHz and below fieldbus, encoder, and discrete I/O rates. The open-drain output stage interfaces directly with 24 V PLC logic via external pull-up. The 8-SOIC package, identical to optocouplers, lets designers upgrade reliability without changing the I/O footprint. Recommended companion MPNs include TPS7A4010 (24 V LDO) and MAX31912 (octal digital input serializer).
Recommended
Battery Management System (BMS) Communication Isolation
The SI8712AC-B-ISR isolates SPI or isolated daisy-chain communication between a battery-pack monitor IC and the main vehicle ECU in lithium-ion BMS applications, per the Si87xx family datasheet. The 3750 Vrms rating is well above typical 400 V and 800 V traction-pack requirements, providing reinforced isolation against ground faults during vehicle crash events. With 15 Mbps capability, the device supports 1 MHz to 5 MHz daisy-chain protocols used by modern BMS ICs. The 8-SOIC surface-mount package, combined with low quiescent current, fits densely populated BMS slave boards where board area is at a premium. Compared with optocouplers, the Si8712 avoids LED degradation over the 10+ year service life of traction batteries. Recommended companion MPNs include BQ79616 (16-cell battery monitor) and ISOW1044 (isolated CAN).
Recommended
Medical Device Patient-Isolated Data Link
The SI8712AC-B-ISR supports 3750 Vrms patient-isolated data transfer in medical electronics such as patient monitors, infusion pumps, and diagnostic imaging subsystems, per the Si87xx family datasheet. While full IEC 60601-1 patient isolation requires 2 MOPP (typically 4 kVrms or higher) which must be verified by the system-level certification, the Si8712 is well suited for the 1 MOPP (1.5 kVrms) signal-isolation layer. Its 15 Mbps bandwidth supports SPI display data and isolated USB-to-UART bridges. The wide -40 to +125 °C operating range and high CMTI suit electrically noisy RF ablation and electrosurgery environments. The 8-SOIC footprint enables compact handheld designs. Recommended companion MPNs include ADS131A04 (medical ADC) and ISO1050 (isolated CAN for medical networking).
Recommended
Solar Inverter String Monitoring
The SI8712AC-B-ISR isolates DC-optimizers and string-monitoring interfaces in photovoltaic inverter systems, per the Si87xx family datasheet. The 3750 Vrms isolation barrier separates floating panel-side electronics from grounded inverter-side control, surviving line-to-line transient events up to 1.5 kV per typical PV safety standards. With 15 Mbps data rate, the part supports rapid panel-level telemetry and DC optimizer control loops. The 8-SOIC surface-mount package is small enough to fit inside integrated DC optimizer housings, replacing legacy optocouplers. The -40 to +125 °C operating range covers rooftop thermal extremes. Compared with optocouplers, the Si8712's 10x lower FIT rate supports the 25+ year service life demanded by solar installations. Recommended companion MPNs include TMS320F28x (C2000 MCU) and ISO1212 (isolated digital input for solar).
Recommended
Recommended Products Summary
Engineering reference data for SI8712AC-B-ISR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI8712AC-B-IS | SI8712CC-B-ISR | SI8712BC-B-ISR | SI8710AC-B-IS | SI8710BC-B-IS | ISO7420DR |
|---|---|---|---|---|---|---|---|
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Texas Instruments |
| Package | 8-SOIC (0.154", 3.90 mm) | 8-SOIC (0.154", 3.90 mm) - same | 8-SOIC (0.154", 3.90 mm) - same | 8-SOIC (0.154", 3.90 mm) - same | 8-SOIC (0.154", 3.90 mm) - same | 8-SOIC (0.154", 3.90 mm) - same | 8-SOIC - same body size, different pinout |
| Isolation Voltage | 3750 Vrms | 3750 Vrms | 3750 Vrms | 3750 Vrms | 3750 Vrms | 3750 Vrms | 2500 Vrms (lower isolation) |
| Data Rate | 15 Mbps | 15 Mbps | 15 Mbps | 15 Mbps | 1 Mbps (lower speed grade) | 1 Mbps (lower speed grade) | 1 Mbps (lower speed grade) |
| Output Type | Open-drain (option "C") | Open-drain (option "C") | Open-drain (option "C") | Open-drain (option "B") | Open-drain (option "C") | Open-drain (option "B") | Push-pull CMOS |
| CMTI (minimum) | 20 kV/µs | 20 kV/µs | 20 kV/µs | 20 kV/µs | 20 kV/µs | 20 kV/µs | 25 kV/µs |
| Channels | 1 | 1 | 1 | 1 | 1 | 1 | 2 (dual channel) |
| Operating Temperature | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
Key Differentiators
- Higher CMTI than typical optocouplers (vs HCPL-0720 optocoupler (typical 10 kV/µs CMTI))
- 10x lower FIT rate than optocouplers (vs HCPL-0720 optocoupler (typical 1-10 FIT))
- Single-package family covers 1 Mbps to 15 Mbps (vs Discrete optocouplers (HCPL-0720 25 Mbps, HCPL-4504 1 Mbps))
- Pin-compatible drop-in replacement for optocouplers (vs ISO7420DR (Texas Instruments))
Design Notes
Provide local 0.1 µF ceramic bypass capacitors on both VDD1 (pin 1) and VDD2 (pin 7), placed within 2 mm of each supply pin per the Si87xx datasheet. The input-side LED-emulator input (pin 3, IN+) typically requires an external current-limiting resistor; recommended values are 1 kΩ to 4.7 kΩ for 3.3 V or 5 V CMOS drive. The open-drain output (pin 6) requires a pull-up resistor to VDD2 on the isolated side - typically 10 kΩ for low-speed signals or 1 kΩ for high-speed 15 Mbps operation. Estimated: input bias current at IN+ is on the order of 1-3 mA based on LED-emulator design.
Maintain at least 8 mm of creepage and clearance between the input-side ground plane (GND1, pin 2) and the output-side ground plane (GND2, pin 5) for the rated 3750 Vrms isolation per the Si87xx datasheet. Cut the ground plane beneath the SOIC body so that no copper trace or via bridges the isolation barrier. Place a keep-out zone of at least 1 mm width along the SOIC body sides that separate the two ground domains. Do not route any signal traces beneath the isolator body, as they may compromise the isolation barrier over surface contamination.
Do not substitute SI8712AC-B-ISR for an optocoupler without re-checking input bias requirements - the LED-emulator input has different drive characteristics than a real LED, and the input resistor must be sized accordingly per the Si87xx datasheet. Do not connect VDD1 and VDD2 together across the isolation barrier; doing so defeats the isolation. Verify that downstream logic tolerates the open-drain output pull-up range (typically 3.3 V to 30 V), not all logic families accept pull-ups beyond their VDD. Estimated: propagation delay is on the order of 30-50 ns based on Si87xx family typical performance.
For 15 Mbps NRZ signaling, keep the trace length from the SI8712AC-B-ISR output to the receiver under 50 mm to minimize reflections. Use a 50 Ω characteristic impedance microstrip if traces exceed 25 mm, and add a series 22-33 Ω damping resistor at the output if ringing is observed. The open-drain output stage can support 3.3 V or 5 V logic on the receiver side by selecting the pull-up to the appropriate rail. For high-noise environments, add a small RC filter (100 Ω + 100 pF) on the output to reject short glitches below the CMTI rating of 20 kV/µs.
Compliance Information
RoHS and lead-free compliant per Skyworks Solutions product listing. AEC-Q100 not applicable for industrial-grade general-purpose isolator. Conflict-mineral reporting compliant per manufacturer policy. Halogen-free status not explicitly confirmed in available data.
