Isolators

Isolators

Isolators are components used to transmit signals across two sections of a circuit that must remain electrically separated for safety, noise immunity, or functional reasons. This electrical separation—called galvanic isolation—prevents current flow while still allowing data or control signals to pass through. Isolators are especially important in high-voltage or noisy environments, such as industrial automation, motor control systems, or medical electronics. Isolators are signal-level devices that facilitate safe communication between subsystems without direct electrical contact. There are two primary types of isolators: optical isolators (also known as optocouplers) and digital isolators. Optical isolators use light to transmit information across an isolation barrier. A typical optocoupler consists of an LED on the input side and a phototransistor, photodiode, SCR, or Triac on the output side. When current flows through the LED, it emits light that activates the output component, allowing the signal to be reproduced on the isolated side. Optocouplers are widely used in applications requiring moderate speed and high-voltage isolation—such as microcontroller interfaces, SMPS (switch mode power supply) feedback loops, or PLC input modules. They are favored for their simplicity and excellent electrical noise immunity. Digital isolators, on the other hand, do not rely on light. Instead, they typically use capacitive or magnetic coupling to transmit digital signals across the isolation barrier. These isolators offer several advantages over optocouplers, including higher data rates, lower power consumption, better temperature stability, and longer lifespan since they avoid LED aging. Digital isolators are particularly well-suited for high-speed communication interfaces like SPI, I²C, or UART, where timing and signal integrity are critical. However, they may be more sensitive to certain types of transient interference, depending on the design and application. Choosing between an optical and a digital isolator depends on several factors: signal type (analog or digital), speed, voltage isolation requirements, environmental conditions, and reliability expectations. For example, optocouplers might still be preferred in high-voltage analog feedback paths due to their robust noise immunity, while digital isolators may be better suited for fast, compact, low-power digital systems.

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Select productsMfrDescriptionPackageSupplier Device PackageMounting TypeSeriesOperating Temperature
IS357A
IS357A
$0.38000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SMDTape & Reel (TR),Cut Tape (CT)4-SMDSurface MountIS357-55°C ~ 100°C
IS357B
IS357B
$0.38000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SMDTape & Reel (TR),Cut Tape (CT)4-SMDSurface MountIS357-55°C ~ 100°C
IS357C
IS357C
$0.38000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SMDTape & Reel (TR),Cut Tape (CT)4-SMDSurface MountIS357-55°C ~ 100°C
IS357D
IS357D
$0.38000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SMDTape & Reel (TR),Cut Tape (CT)4-SMDSurface MountIS357-55°C ~ 100°C
IS383
IS383
$0.64000
Isocom Components 2004 LTDOPTOISOLATOR 5KV 1CH TRANSTape & Reel (TR),Cut Tape (CT)-Surface Mount--55°C ~ 125°C
IS3H4
IS3H4
$0.57000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SOPTape & Reel (TR),Cut Tape (CT)4-SOPSurface MountIS3H4-55°C ~ 100°C
IS3H7
IS3H7
$0.50000
Isocom Components 2004 LTDOPTOISO 3.75KV 1CH TRANS 4-SOPTape & Reel (TR),Cut Tape (CT)4-SOPSurface Mount--55°C ~ 110°C
IS4100
IS4100
$1.31000
Isocom Components 2004 LTD16PIN TRANSISTOR,SMD HALF PITCHTape & Reel (TR),Cut Tape (CT)----
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