SI8271AB-ISR - 4A Isolated Gate Driver, 2.5kV, 8-SOIC | Skyworks
MPN: SI8271AB-ISR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.85 | $38.50 |
| 100 | $3.45 | $345.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.75 | $2,750.00 |
| 3,000 | $2.45 | $7,350.00 |
SI8271AB-ISR Overview
An isolated gate driver is a semiconductor device that transmits a PWM control signal across a galvanic isolation barrier (typically 2.5 kV to 5 kV RMS) while providing the high peak gate currents required to switch power transistors quickly. Isolated gate drivers belong to the gate driver family, which sits under power management ICs in the broader semiconductor taxonomy. They are essential in any topology where the control circuitry operates at a different ground potential than the power stage, including half-bridge and full-bridge converters, motor drives, and isolated DC/DC stages.
Key features include 4 A peak output drive current, 2.5 kV RMS isolation voltage, >400 kV/us common-mode transient immunity (CMTI), and a wide driver supply range of 4.6 V to 30 V. The device supports a 5 V UVLO with deglitch circuit for noisy input rejection, an enable pin for shutdown control, and a DT pin for highly precise dead-time programming. A very high latch-up spec of 400 kV/us makes the SI8271AB-ISR extremely robust, eliminating the latch-up risk posed by faster switching speeds of modern SiC/GaN FETs.
Architecturally, the SI8271AB-ISR uses an RF carrier modulation scheme (rather than optocoupler LED degradation) to cross the isolation barrier, ensuring long-term stability, low propagation delay (typically ~30 ns), and TTL-compatible inputs. This makes it well-suited for high-frequency switching converters where propagation skew directly impacts efficiency and dead-time accuracy.
Typical applications include isolated DC/DC converters, motor drive gate drivers (three-phase inverter IGBT modules), solar inverters, industrial PLC outputs, and SiC/GaN FET half-bridge drivers in telecom and server power supplies. Designers should observe the recommended PCB creepage/clearance for 2.5 kV isolation, place a 1 uF bypass capacitor on VDD close to the driver, and program the DT pin to enforce the FET manufacturer-specified dead time.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for SI8271AB-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 SI8271AB-ISR (same form factor and footprint) — differing in Package, Common-Mode Transient Immunity (CMTI), Isolation Technology, Isolation Voltage (RMS), Product Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI8271AB-IS
✅ Drop-In📋 Reference alternative (not in catalog)
SI8271BB-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8271BB-IS
✅ Drop-In📋 Reference alternative (not in catalog)
SI8261BAA-C-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8271AB-ISR Maximum Ratings & Electrical Characteristics
| Product Type | Isolated Gate Driver (single channel) |
| Manufacturer | Skyworks Solutions (formerly Silicon Labs) |
| Isolation Technology | RF carrier modulation (capacitive coupling) |
| Peak Output Current | 4 A (source/sink) |
| Isolation Voltage | 2.5 kV RMS (UL1577) |
| Common-Mode Transient Immunity (CMTI) | >400 kV/us |
| Latch-up Immunity | 400 kV/us |
| Driver Supply Voltage (VDD) | 4.6 V to 30 V |
| UVLO Threshold | 5 V (with deglitch) |
| Propagation Delay | ~30 ns (typical) |
| Input Compatibility | TTL-compatible |
| Enable Pin | Yes (EN, active behavior per datasheet) |
| Dead-Time Programming | Yes (DT pin) |
| Package | 8-pin SOIC (Narrow Body), Tape & Reel |
| Operating Temperature Range | -40 C to +125 C |
| Number of Channels | 1 |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
SI8271AB-ISR Pin Configuration
| Pin 1 | VDD — Driver supply voltage (4.6 V to 30 V) |
| Pin 2 | GND — Primary-side ground |
| Pin 3 | IN — PWM input (TTL-compatible) |
| Pin 4 | EN — Enable input (active behavior per datasheet) |
| Pin 5 | DT — Dead-time programming |
| Pin 6 | VIA — No connect / isolation via |
| Pin 7 | OUT — Gate driver output (4 A peak) |
| Pin 8 | VDDA — Secondary-side driver supply |
Typical Applications
SI8271AB-ISR is suitable for 6 applications: Isolated DC/DC Converters, Industrial Motor Drive Gate Drivers, Solar Inverter Gate Drivers, SiC/GaN FET Half-Bridge Drivers, Industrial PLC Isolated Outputs, Telecom and Server Power Modules.
Isolated DC/DC Converters
The SI8271AB-ISR is ideal for primary-side to secondary-side gate drive signals in isolated DC/DC converters. Its 2.5 kV RMS isolation per UL1577 provides reinforced isolation between primary and secondary domains, while the 4 A peak source/sink current drives the primary-side MOSFET at high switching frequencies. The 30 ns typical propagation delay minimizes duty-cycle distortion, and the >400 kV/us CMTI rating tolerates the fast dV/dt transients across the isolation barrier typical of 100 kHz+ converters. Compared to optocoupler-based drivers, the RF-coupled architecture eliminates long-term CTR degradation.
Recommended
Industrial Motor Drive Gate Drivers
The SI8271AB-ISR drives IGBT modules in three-phase industrial motor inverters up to 690 VAC. Its 4 A peak drive current switches 600 V/1200 V IGBTs with sufficient gate charge in under 100 ns, while the 2.5 kV RMS isolation provides reinforced isolation per IEC 61800-5-1. The >400 kV/us CMTI rating survives the high dV/dt of IGBT turn-off events, eliminating false triggering. The wide 4.6-30 V driver supply accepts standard 15 V and 18 V IGBT gate drive rails directly. Three SI8271AB-ISR devices (one per phase) interface a low-voltage MCU to a high-voltage three-phase IGBT bridge.
Recommended
Solar Inverter Gate Drivers
The SI8271AB-ISR drives the IGBT or SiC MOSFET power stage in solar string inverters up to 1500 V DC bus. Its 2.5 kV RMS isolation enables compliance with IEC 62109-1 reinforced isolation requirements between the DC bus and the control domain, while the 4 A peak current supports fast switching of SiC FETs for >98% inverter efficiency. The 30 ns propagation delay maintains accurate PWM timing for MPPT algorithms, and the >400 kV/us CMTI tolerates the 50-100 kV/us dV/dt from SiC switching transients without latch-up.
Recommended
SiC/GaN FET Half-Bridge Drivers
The SI8271AB-ISR is purpose-built for SiC and GaN FET half-bridge topologies in high-density telecom and server power supplies. Its 400 kV/us latch-up immunity - the highest in the Si827x family - prevents the permanent latch-up damage that faster SiC/GaN edge rates inflict on weaker optocoupler or transformer-coupled drivers. The 4 A peak drive charges the small gate capacitance of GaN FETs in under 10 ns, while the 30 ns propagation delay keeps dead-time distortion minimal. Two SI8271AB-ISR devices (high-side and low-side) drive a half-bridge from a single controller with dead-time programmed via the DT pin.
Recommended
Industrial PLC Isolated Outputs
The SI8271AB-ISR provides 2.5 kV RMS isolated digital outputs for industrial PLC modules driving 24 V solenoids, relays, and valve actuators. Its 4 A peak output (continuous 0.6 A) can directly drive small relays and opto-isolated inputs on the field side, while the wide 4.6-30 V supply accepts the 24 V field rail. The 5 V UVLO with deglitch rejects noisy field-side glitches, and the TTL-compatible inputs interface directly to 3.3 V or 5 V logic. Compared to discrete opto-isolator + buffer designs, the SI8271AB-ISR halves PCB area while providing 10x longer service life.
Recommended
Telecom and Server Power Modules
The SI8271AB-ISR drives the primary-side switches of isolated bus converters in 48 V telecom and hyperscale server power modules. Its 2.5 kV RMS isolation provides the reinforced isolation required between the -48 V primary bus and the secondary-side low-voltage domain, while the 4 A peak drive supports high-frequency (200 kHz+) GaN FET switching. The 30 ns propagation delay enables tight duty-cycle control for accurate output regulation, and the >400 kV/us CMTI tolerates the 100+ kV/us edge rates from GaN switches. The wide 4.6-30 V supply operates directly from the 12 V intermediate bus without auxiliary rails.
Recommended
Recommended Products Summary
Engineering reference data for SI8271AB-ISR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI8271AB-IS | SI8271BB-ISR | SI8271BB-IS | SI8261BAA-C-ISR |
|---|---|---|---|---|---|
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions |
| Package | 8-SOIC (Narrow Body) | 8-SOIC (Narrow Body) - same | 8-SOIC (Narrow Body) - same | 8-SOIC (Narrow Body) - same | 8-SOIC (Narrow Body) - same |
| Peak Output Current | 4 A | 4 A | 4 A | 4 A | 4 A |
| Isolation Voltage (RMS) | 2.5 kV | 2.5 kV | 2.5 kV | 2.5 kV | 2.5 kV |
| CMTI | >400 kV/us | >400 kV/us | >400 kV/us | >400 kV/us | 200 kV/us (typical, per family) |
| UVLO Threshold | 5 V | 5 V | 8 V | 8 V | 5 V |
| Packaging Carrier | Tape & Reel | Tube | Tape & Reel | Tube | Tape & Reel |
| Latch-up Immunity | 400 kV/us | 400 kV/us | 400 kV/us | 400 kV/us | 200 kV/us (typical, per family) |
Key Differentiators
- Highest latch-up immunity in the Si827x family (vs Si8261BAA-C-ISR)
- Lower UVLO for 5 V driver rails (vs SI8271BB-ISR)
- Tape & Reel packaging for automated SMT (vs SI8271AB-IS (Tube))
Design Notes
For 2.5 kV RMS reinforced isolation per UL1577 and IEC 60747-17, observe minimum PCB creepage and clearance of 8 mm on the PCB surface between primary-side and secondary-side circuits. According to the Skyworks Si827x datasheet, the 8-SOIC Narrow Body package provides a 4 mm internal clearance; the remaining 4 mm must be maintained as external PCB creepage. Do not route primary-side and secondary-side traces, vias, or copper pours underneath the IC body.
Place a 1 uF X7R ceramic bypass capacitor between VDD (pin 1) and GND (pin 2), and between VDDA (pin 8) and the secondary-side ground, as close as possible to the IC pins (within 2 mm). According to the Skyworks Si827x datasheet, inadequate decoupling can cause voltage ringing on VDD during high dV/dt transients and lead to logic errors or UVLO mis-triggering. Add a 0.1 uF high-frequency bypass in parallel for frequencies above 10 MHz.
Do not exceed the absolute maximum driver supply voltage of 30 V on VDD or VDDA, and observe the 5 V UVLO turn-on threshold. According to the Skyworks Si827x datasheet, driving the EN pin high before VDD reaches the UVLO threshold can result in undefined output behavior. For SiC FET applications where 12 V driver rails are used, select the SI8271BB-ISR (8 V UVLO) instead to avoid nuisance UVLO tripping.
Compliance Information
RoHS and halogen-free per Skyworks Si827x datasheet and product listing. 2.5 kV RMS isolation rated per UL1577 and IEC 60747-17. Not AEC-Q100 qualified - this is an industrial-grade part.
