SI8751 Datasheet, PDF (1/27 Pages) Silicon Laboratories – Digital CMOS input option

Si8751/52 Data Sheet
Isolated FET Driver with Pin Control or Diode Emulator Inputs
The Si875x enables new pathways to creating custom solid state relay (SSR) configura-
tions. Supporting customer-selected external FETs, the Si875x combines robust isolation
technology with an SSR FET driver to form a complete, isolated switch. Versatile inputs pro-
vide digital CMOS pin control (Si8751) or diode emulation (Si8752) to best suit the applica-
tion, plus flexible outputs to support driving ac or dc load configurations. A floating secon-
dary side dc voltage source is unnecessary as the product generates its own self-contained
gate drive output voltage, reducing cost, size, and complexity.
The Si875x eliminates the need for bulky mechanical relays which can be difficult to assem-
ble onto PCBs and add switching noise to the system. Further, with the customer selecting
their own flexible FET switch, the design can be completely optimized for the application's
power, cost, and performance requirements. Traditional SSRs also integrate optocoupler-
style LED inputs, which limit the operating temperature range of the solution, but the Si875x,
with its input diode emulator or digital input control, experiences no such limitation and can
support full industrial and automotive temperature ranges with increased stability and longer
life.
The Si875x drives FET gates with a nominal 10 V using as little as 1 mA input current. In-
creasing the input current to 10 mA enables turn-on times as fast as 94 µs. Input side vol-
tages on the Si8751 are flexible from 2.25 V to 5.5 V supporting seamless connection to
low-power controllers. The Si875x devices provide a clamping device to prevent unintended
turn-on of the external FET when a high dV/dt is present on the FET’s drain.
KEY FEATURES
• Digital CMOS input option
• Diode emulation input option
• 10 V output with 1 mA input current
• As fast as 94 µs turn-on time
• Internally-generated secondary side
power supply
• Miller clamp cap support for reducing
inductive chatter
• DC or AC load switching support
• Drives user-selected external FETs
• 2.5 kVrms isolation rating
• UL, CSA, VDE, and CQC certifications
(pending)
• AEC-Q100 qualified
• Industrial –40 to 105 °C or Automotive
–40 to 125 °C temperature ranges
• ROHS-compliant SOIC-8 Package
APPLICATIONS
The Si875x is qualified to the AEC-Q100 standard, making it suitable for automotive applica-
tions. Further, its 2.5 kVrms isolation rating forms the basis for full certification to UL, CSA,
VDE, and CQC (pending).
Applications include mechanical relay , photo switch, or SSR replacement in motor control,
valve control, HVAC relay, automotive, charging, battery monitoring, ac mains line switch-
ing, and more.
• Motor Controls
• Valve Controls
• HVAC Relays
• HEV/EV Automotive Charging
• Battery Monitoring
• AC Mains Line Switching
The Si8751 and Si8752 come in ROHS-compliant SOIC-8 packaging, providing a compact,
industry-standard footprint and generous margin to creepage and clearance requirements.
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This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Preliminary Rev. 0.5