SI8751AB-IS - 2.5kV Isolated FET Driver, CMOS Input | Skyworks
MPN: SI8751AB-IS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.41 | $4.41 |
| 10 | $3.97 | $39.70 |
| 100 | $3.55 | $355.00 |
| 500 | $3.18 | $1,590.00 |
| 1,000 | $2.84 | $2,840.00 |
SI8751AB-IS Overview
An isolated gate driver, also called a digital isolator with FET driver, is a category of semiconductor that combines galvanic isolation with high-side/low-side gate-drive capability for power MOSFETs, IGBTs, or external SSR FETs. The SI8751AB-IS belongs to the isolated gate driver / isolator hierarchy above simple optocouplers, opto-isolated triac drivers, and transformer-coupled gate drivers, offering superior common-mode transient immunity, lower propagation delay, and significantly lower BOM count than discrete alternatives built from optocouplers plus isolated bias supplies.
Key features include an input-side supply range of 2.25 V to 5.5 V, single-channel operation, internal clamp to prevent unintended FET turn-on during fast dV/dt transients, and pin-control digital CMOS input that suits low-power microcontrollers and logic-level GPIO. The 8-SOIC package provides 2.5 kVrms isolation per UL 1577 and supports creepage/clearance appropriate for many industrial 24 V switching applications.
Architecturally, the Si875x family uses capacitive isolation across the SOIC die-stitch boundary rather than LEDs, achieving CMOS-equivalent reliability without the aging or CTR-degradation concerns of optocouplers. Device variants differ by input protocol: the SI8751 family uses pin-control CMOS digital inputs, while the SI8752 family provides diode-emulation inputs for synchronous-rectifier-style applications.
Typical applications include solid-state relay (SSR) modules, programmable logic controller (PLC) discrete output cards, industrial HVAC control, home-appliance switching, and battery-management or photovoltaic isolator drivers. The integrated 10 V gate drive is sufficient to enhancement-mode N-channel MOSFETs commonly used in AC and DC load switching.
When designing in this part, ensure that the upstream CMOS driver has sufficient current drive (typically 1 mA to 10 mA) to program the desired turn-on time, and select the external FET based on drain-source blocking voltage and continuous drain current the load demands - the Si8751AB-IS itself does not limit load current.
This page synthesizes distributor pricing, drop-in alternatives from the Skyworks Si87xx and Si875x families, and application design notes drawn from the Si8751/52 datasheet.
Drop-in alternatives for SI8751AB-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 SI8751AB-IS (same form factor and footprint) — differing in Package, Number of Channels, Input Type, MSL Level, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI8752AB-IS
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI8751AB-ISR
✅ Drop-In✓ In Stock
$1.65 / Unit
View Datasheet →SI8751AB-AS
✅ Drop-In📋 Reference alternative (not in catalog)
SI8640BD-B-IS
✅ Drop-In✓ In Stock
$1.89 / Unit
View Datasheet →SI8710BC-B-IS
✅ Drop-In✓ In Stock
$0.95 / Unit
View Datasheet →SI8641BD-B-ISR
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →SI8751AB-IS Maximum Ratings & Electrical Characteristics
| Isolation Voltage | 2500 Vrms |
| Isolation Type | Capacitive Coupling |
| Channels | 1 |
| Input Type | CMOS digital (pin control) |
| Input Supply Voltage | 2.25 V to 5.5 V |
| Output Drive Voltage | 10 V nominal |
| Input Current (turn-on) | 1 mA to 10 mA (programmable) |
| Turn-on Time (10 mA input) | 94 us |
| dV/dt Clamp | Internal (prevents unintended FET turn-on) |
| Package | 8-SOIC (narrow body) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +125C |
| Automotive Qualification | AEC-Q100 (per Arrow listing) |
| RoHS Status | Compliant |
| Datasheet Revision | 27 pages, 783 KB per alldatasheet |
SI8751AB-IS Pin Configuration
| Pin 1 | VDD — Input-side logic supply voltage (2.25 V to 5.5 V) |
| Pin 2 | IN+ — Positive CMOS input pin (logic high enables gate drive) |
| Pin 3 | IN- — Negative/return input reference for CMOS logic |
| Pin 4 | GND1 — Input-side ground reference |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | GND2 — Output-side (isolated) ground reference |
| Pin 7 | SRC — Source connection of the internal gate drive network |
| Pin 8 | OUT — Gate-drive output (10 V nominal to external FET gate) |
Typical Applications
SI8751AB-IS is suitable for 6 applications: Solid-State Relay (SSR) Modules, PLC Discrete Output Cards, Industrial HVAC and Appliance Switching, Battery Management and Photovoltaic Isolators, Home Appliance and White Goods Controllers, Automotive Isolated Switching.
Solid-State Relay (SSR) Modules
The SI8751AB-IS is purpose-built as the integrated isolated FET driver inside solid-state relay modules replacing electromechanical relays (EMRs) in industrial switching. Its 2.5 kVrms capacitive isolation and internal 10 V gate drive eliminate the discrete optocoupler plus isolated bias plus gate driver triplet, cutting BOM and PCB area. With 1 mA to 10 mA programmable input current the SI8751AB-IS accepts direct MCU GPIO drive, and an internal clamp prevents unintended turn-on during fast dV/dt transients on the load-side FET. Designers get a single-IC isolated switch ready to control AC or DC loads up to the external FET's voltage and current ratings.
Recommended
PLC Discrete Output Cards
In PLC discrete output modules the SI8751AB-IS provides isolated MOSFET control for 24 V industrial loads with 2.5 kVrms isolation per UL 1577, eliminating LED-aging concerns that affect optocoupler-based designs. The internal 10 V gate drive and internal dV/dt clamp support the high-side or low-side switching topologies commonly used in 24 V digital outputs. CMOS pin-control input connects directly to a 3.3 V or 5 V MCU GPIO, allowing standard PLC firmware to drive the relay stage without additional level translation. A single SI8751AB-IS replaces one optocoupler + isolated bias + driver per channel and aligns with the Si8751AB-ISR/A variants used for high-density card designs.
Recommended
Industrial HVAC and Appliance Switching
The SI8751AB-IS serves appliance and HVAC switching boards where 24 V to 240 V AC or DC loads must be controlled by a low-power micro. The 2.5 kVrms galvanic isolation protects the user-facing logic from mains-borne transients while the internal 10 V gate drive energizes the load-side MOSFET reliably. The -40C to +125C operating range suits outdoor equipment enclosures, and the AEC-Q100 qualified SI8751AB-AS variant supports the automotive appliance market. Compared with electromechanical relays the SI8751AB-IS offers silent switching, longer life, and immunity to contact bounce without requiring a separate isolated supply.
Recommended
Battery Management and Photovoltaic Isolators
In battery management systems (BMS) and photovoltaic (PV) combiner boxes, the SI8751AB-IS isolates the low-voltage controller from the high-voltage battery stack or PV string switching. The CMOS capacitive isolation provides 2.5 kVrms dielectric withstanding while the integrated 10 V gate drive simplifies the high-side driver that disconnects the pack during fault conditions. The internal dV/dt clamp is especially valuable in PV applications where fast inverter transients could otherwise couple to the gate of an external switching MOSFET. Compared with discrete opto-isolators the SI8751AB-IS uses no LEDs, removing CTR-degradation over time as a failure mode.
Recommended
Home Appliance and White Goods Controllers
Home appliances including washing machines, dishwashers, and induction cooktops use the SI8751AB-IS as an isolated driver for heating elements, pumps, and motor-control relays controlled by a low-power MCU. The CMOS pin-control input maps cleanly onto 3.3 V or 5 V GPIO and the 2.5 kVrms isolation meets IEC 60335 household appliance safety requirements for reinforced isolation between user-accessible controls and mains. Internal 10 V gate drive simplifies the BOM by eliminating the discrete bootstrap supply that an optocoupler solution would need. The result is a smaller, more reliable, and lower-cost isolated switch section than legacy photo-isolated designs.
Recommended
Automotive Isolated Switching
For automotive applications the SI8751AB-AS variant provides AEC-Q100 qualification, allowing the Si875x platform to drive MOSFETs isolating 12 V/48 V loads from the controller, including electric power steering, battery disconnect units, and HV heater control. The 2.5 kVrms capacitive isolation supports functional insulation across 12 V or 48 V battery rails and the internal 10 V drive energizes the switching FET reliably across automotive temperature extremes. The CMOS pin-control input pairs with 3.3 V or 5 V automotive MCUs, and the same SOIC-8 footprint enables drop-in qualification across automotive and non-automotive designs.
Recommended
Recommended Products Summary
Engineering reference data for SI8751AB-IS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI8752AB-IS | SI8751AB-ISR | SI8751AB-AS | SI8640BD-B-IS | SI8710BC-B-IS |
|---|---|---|---|---|---|---|
| Brand | Skyworks | Skyworks | Skyworks | Skyworks | Skyworks | Skyworks |
| Package | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC |
| Function | Isolated FET driver | Isolated FET driver (diode-emu input) | Isolated FET driver | Isolated FET driver (AEC-Q100) | 4-ch digital isolator (no driver) | 1-ch digital isolator (no driver) |
| Isolation Voltage | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms | 3750 Vrms |
| Input Supply | 2.25 V to 5.5 V | 2.25 V to 5.5 V | 2.25 V to 5.5 V | 2.25 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V |
| Gate Drive Output | 10 V internal | 10 V internal | 10 V internal | 10 V internal | Logic-level (no driver) | Logic-level (no driver) |
| Channels | 1 | 1 | 1 | 1 | 4 | 1 |
| Input Current Programming | 1 mA to 10 mA (turn-on 94 us at 10 mA) | 1 mA to 10 mA | 1 mA to 10 mA | 1 mA to 10 mA | N/A (logic input) | N/A (logic input) |
| Automotive Grade | Optional (AS variant) | Optional | Standard | AEC-Q100 | Optional | Optional |
Key Differentiators
- Integrated 10 V gate drive removes the isolated bias supply (vs SI8640BD-B-IS)
- Single-channel integrated SSR replacement in 8-SOIC (vs SI8710BC-B-IS)
- AEC-Q100 variant for automotive designs (vs SI8752AB-IS)
Design Notes
The SI8751AB-IS is a driver, not a switch - it does NOT carry the load current directly. The external MOSFET/IGBT must be sized for the load's voltage, current, thermal dissipation, and switching losses. Designers sometimes expect the isolated driver to limit output current; it does not - it only develops approximately 10 V gate drive referenced to the load-side source pin.
Estimated: at maximum input voltage 5.5 V and maximum programmed input current 10 mA, the SI8751AB-IS dissipates about 55 mW internally on the input side plus gate-drive switching losses in the external FET. In an 8-SOIC with theta_JA around 100-150 C/W, junction rise above ambient stays well under 10 C. However the external switching MOSFET is the dominant thermal element and must be heatsinked if load current is high.
Place decoupling capacitors on VDD (input side) directly adjacent to pins 1 and 4 with a 0.1 uF ceramic in parallel with 1 uF bulk, and keep the high-voltage dV/dt node (output side source and load-side traces) physically separated from the input-side CMOS traces by at least the SOIC clearance and a guard band to preserve 2.5 kVrms isolation and avoid common-mode coupling that can mis-trigger the internal clamp.
Drive the Si8751AB-IS input pins with a CMOS source capable of sourcing 1 mA to 10 mA. According to the Skyworks datasheet, the input current controls turn-on time - 1 mA yields slower but lower-noise turn-on, while 10 mA achieves the 94 us fastest turn-on. For pulse transformer or long-trace driving add a local series resistor and bypass the input capacitance to avoid ringing at the gate threshold.
Compliance Information
AEC-Q100 qualification applies to the SI8751AB-AS automotive variant per Arrow listing. Standard SI8751AB-IS is industrial AEC-Q100 capable. RoHS/REACH compliance and halogen-free status per Skyworks product page.
