In industrial control, medical equipment, telecommunications modules, and automotive electronics, isolated power supplies are often an “invisible yet indispensable” design element. Traditional isolated flyback solutions rely on optocouplers or a third winding on the transformer to transmit feedback signals, which not only increases the number of components and PCB footprint but is also limited by the optocoupler’s 85°C temperature rating and long-term current transfer ratio drift. ADI’s LT8301 is a micro-power, optocoupler-free isolated flyback converter specifically designed to address these challenges: it samples the output voltage directly from the primary-side flyback waveform, eliminating the need for optocouplers and third windings, and delivers up to 6W of isolated output power in a 5-pin TSOT-23 package. As an independent distributor with a long-standing focus on global brands such as ADI, Mingjiada Electronics continuously supplies the LT8301IS5 series from stock, providing reliable support—from product selection to delivery—for compact isolated power supply designs.
Product Positioning: An Isolated Flyback Controller Designed to “Eliminate the Optocoupler”
In the LT8301IS5’s full part number, “IS5” denotes the industrial temperature grade and TSOT-23-5 package, making it a key model in the LT8301 series. Its core positioning is as a micro-power, optocoupler-free isolated flyback converter, targeting isolated bias, auxiliary power, and signal isolation applications with output power of 6W or less.
Compared to traditional solutions that require optocouplers or third-winding feedback, the LT8301 directly samples the isolated output voltage from the primary-side flyback waveform and allows the output voltage to be programmed using a single external resistor. Internal compensation and soft-start further reduce the number of external components. This means that the isolation breakdown voltage of the isolated power supply is no longer limited by the insulation capability of the optocoupler but depends solely on the selected transformer, giving designers greater flexibility in high-voltage isolation applications.
Key Features: Wide Input Range, Low Quiescent Current, and Dual-Mode Efficiency Optimization
Wide input voltage range: 2.7 V to 42 V. This range covers common voltage levels from single-cell lithium-ion battery power supplies (starting at 2.7 V) to 24 V/36 V industrial buses and telecommunications power rails, enabling a single chip to span multiple power supply environments. The output side integrates a 65V/1.2A DMOS power switch, providing up to 6W of isolated output power to meet the requirements of most low-power isolated bias and auxiliary power supplies.
Low quiescent current. Quiescent current is only 100 µA in sleep mode and approximately 250–350 µA in active mode; for always-on standby auxiliary power supplies or battery-powered isolated modules, this specification directly affects the system’s standby power consumption.
Boundary Mode + Low-Ripple Burst Dual-Mode Operation. Under heavy loads, the chip operates in boundary conduction mode, balancing compact transformer size with good load regulation; under light loads, it automatically switches to low-ripple burst mode, maintaining high efficiency while keeping output voltage ripple at a low level. This combination enables the LT8301 to maintain usable efficiency across a wide range from full load to extremely light loads, with a minimum load as low as 0.5% (typical) of the full-load output, preventing runaway operation or output drift at light loads.
Integration and Protection. The device features precise EN/UVLO thresholds and hysteresis, internal compensation and soft-start, and output short-circuit protection. The power switch and all high-voltage control logic are integrated into a 5-pin TSOT-23 package; only a transformer, input and output capacitors, and a few resistors and capacitors are required to build a complete isolated power supply. The device is also certified for automotive applications under AEC-Q100, providing a ready-to-use qualification foundation for isolated power supplies in industrial and automotive applications.
Typical Applications
Industrial automation and PLC isolated power supplies. In PLC I/O modules, sensor interfaces, and field instruments, the wide 2.7V–42V input range allows power to be drawn directly from a 24V industrial bus or backup battery to generate isolated 5V, 12V, or ±15V analog front-end power supplies. The optocoupler-free architecture eliminates the issue of optocoupler lifespan degradation in high-temperature industrial environments, and the flexible transformer selection facilitates compliance with various isolation voltage requirements.
Isolated Power Supply for Medical Devices. Medical devices have strict requirements for the isolation level of patient-contact parts. The isolation voltage rating of the LT8301 is entirely determined by the external transformer, allowing designers to select a transformer with the appropriate isolation level according to standards such as IEC 60601, without being constrained by the insulation limit of integrated feedback components.
Telecommunications and Data Communications Isolated Bias Power. In 48V telecommunications systems, the LT8301 can generate isolated auxiliary/internal power from a wide input range to power isolated interfaces, digital isolators, and communication modules; its 6W power capability covers most auxiliary power requirements.
Automotive Electronics Isolated Auxiliary Power. AEC-Q100 certification enables its use in automotive isolated auxiliary power designs, such as on-board chargers and isolated sampling and drive bias power supplies in battery management systems, with guaranteed specifications maintained over a junction temperature range of −40°C to 125°C.
Mingjiada LT8301 Supply Value
For R&D teams and procurement departments advancing isolated power supply designs, once a part has been selected, the availability of samples and the stability of volume production often become critical factors in project timelines. Since its establishment in 1996, Mingjiada Electronics (Shenzhen Mingjiada Electronics Co., Ltd.) has established branches in Shenzhen, Hong Kong, Japan, Russia, Taiwan, and other locations. Certified under the ISO 9001 and ISO 14001 systems, the company has long specialized in the authorized and independent distribution of electronic components from global brands such as ADI, TI, and ST.
For the LT8301 series, Mingjiada offers immediate availability of common part numbers for the LT8301IS5, covering packaging formats such as tape-and-reel and cut-to-length, and can provide samples and small-to-medium-volume shipments depending on the project stage. For customers facing fluctuating lead times from original manufacturers or needing to quickly validate isolated power supply solutions, Mingjiada’s in-stock inventory and flexible procurement windows can shorten the wait time from design to mass production without compromising the guarantee of genuine products.
Summary: With its combination of “optocoupler-free design, 2.7V–42V wide input range, 6W output, and 100µA-class quiescent current,” the LT8301 offers a practical choice in the low-power isolated power supply sector, featuring a minimal number of components, wide temperature tolerance, and flexible isolation voltage ratings. Mingjiada Electronics provides traceable, in-stock supply and procurement support for this series, helping designers accelerate the entire process—from component selection to delivery—in industrial, medical, telecommunications, and automotive isolated power supply projects.
Tags: LT8301IS5, LT8301IS, LT8301I, LT8301
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