LT8301ES5#TRMPBF - 42V No-Opto Isolated Flyback | Analog Devices
料号： LT8301ES5#TRMPBF ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $4.85 | $4.85 |
| 10 | $4.37 | $43.70 |
| 100 | $3.89 | $389.00 |
| 500 | $3.49 | $1,745.00 |
| 1,000 | $3.1 | $3,100.00 |
LT8301ES5#TRMPBF 概述
What is a flyback converter? A flyback converter is a switched-mode power supply topology that uses a coupled transformer/inductor to transfer power across an isolation barrier, storing energy during the switch on-time and releasing it during the off-time. Isolated flyback converters are essential when the output must be galvanically isolated from the input for safety or noise reasons, such as in industrial bus-powered sensors, medical patient-isolated rails, or interfaces crossing mains-voltage boundaries. Within the broader power management hierarchy, the LT8301 belongs to DC-DC converters -> isolated switching regulators -> power management ICs.
Key features include boundary-mode switching for low primary-side current, internal loop compensation, a single external resistor programming the output voltage, and a quiescent current optimized for always-on applications. The 65V internal DMOS switch supports flyback transformers with high turns ratios, enabling wide VIN-to-VOUT conversion steps from a single stage. The boundary-mode control scheme minimizes switching losses while keeping the transformer core flux balanced.
The LT8301 samples the isolated output voltage directly from the primary-side flyback waveform, eliminating the opto-coupler and TL431 reference typically required. This architecture reduces BOM count by four to six components, simplifies PCB layout, and improves long-term reliability by removing the opto-coupler whose CTR (current transfer ratio) drifts with temperature and age.
Typical applications include isolated industrial sensor supplies, isolated gate-drive bias for IGBT/MOSFET bridges, isolated RS-485/RS-232 transceiver power, medical patient-isolated rails, and 4-20 mA loop-powered instrumentation. Designers choose the LT8301 when they need a small-footprint isolated rail without the cost, complexity, and reliability concerns of an opto-coupler.
Design consideration: select the flyback transformer turns ratio together with the feedback resistor to program the desired VOUT, then verify boundary-mode operation across the full load range. Below minimum load the part enters burst-mode operation, which introduces low-frequency ripple that some noise-sensitive loads may require additional filtering to suppress.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, helping engineers select and source the LT8301ES5#TRMPBF quickly.
直接替换替代料： LT8301ES5#TRMPBF ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
LT8301IS5#TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8301HS5#TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8301JS5#WTRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8301JS5#TRMPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8301ES5#TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8301ES5#TRMPBF 最大额定值与电气特性
| 拓扑 | Isolated Flyback (No-Opto) |
| 输入电压范围 | 2.7 V to 42 V |
| Maximum Switch Voltage | 65 V |
| Switch Current Rating | 1.2 A |
| Maximum Isolated Output Power | 6 W |
| Output Voltage Programming | Single external resistor |
| Control Mode | Boundary-mode (critical conduction) |
| 开关频率 | Up to ~kHz range, load/transformer dependent |
| 工作温度范围 | -40 C to +125 C (E grade) |
| 封装 | TSOT-23-5 (5-lead ThinSOT) |
| 安装类型 | Surface Mount |
| MSL 等级 | 1 (per Analog Devices packaging guidelines) |
| RoHS 状态 | Compliant |
| Lead-Free / Pb-Free | Yes (#PBF suffix) |
| 输出类型 | Positive or Negative, Isolation Capable |
| Internal Switch Type | 65 V DMOS |
LT8301ES5#TRMPBF 引脚配置
| 引脚 1 | SW — Drain of internal 65V/1.2A DMOS switch; tie to flyback transformer primary winding |
| 引脚 2 | GND — Ground return for the IC and primary-side winding |
| 引脚 3 | Vin — Input supply voltage (2.7V to 42V); bypass with local ceramic capacitor |
| 引脚 4 | Vc — Internal bypass node; connect 1uF ceramic capacitor to GND |
| 引脚 5 | FB — Feedback resistor divider node; single external resistor programs VOUT |
典型应用
LT8301ES5#TRMPBF 适用于 7 应用s: Isolated Industrial Sensor Supply, Isolated IGBT/MOSFET Gate-Drive Bias, Isolated RS-485/RS-232 Transceiver Power, Medical Patient-Isolated Rails, Battery-Powered Isolated Measurement, PoE and Telecom Isolated Auxiliary Rails, Isolated Analog Input Module for PLCs.
Isolated Industrial Sensor Supply
The LT8301ES5#TRMPBF is ideal for isolated 24 V industrial sensor supplies in factory automation and 4-20 mA loop-powered instrumentation. Its 2.7 V to 42 V input range accepts 24 V industrial bus rails directly, while the integrated 65 V/1.2 A DMOS switch and no-opto primary-side regulation deliver up to 6 W of isolated output without the reliability concerns of an opto-coupler. Engineers typically use it to generate isolated +15 V/-5 V rails for bridge sensors, strain gauges, and field transmitters in PLC analog input modules, reducing BOM count by 4-6 components and improving long-term drift performance versus TL431-based designs.
推荐
Isolated IGBT/MOSFET Gate-Drive Bias
The LT8301ES5#TRMPBF is well-suited for isolated gate-drive bias supplies in motor drives, solar inverters, and three-phase IGBT/MOSFET bridges. The 65 V/1.2 A internal switch and boundary-mode control deliver fast transient response needed for high-side gate-drive rails switching at kHz rates, while the 2.7 V to 42 V input range accepts rectified 12 V, 24 V, or 48 V bus voltages directly. The +15 V/-8 V or +18 V/0 V isolated rails generated by the LT8301 cleanly bias high-side and low-side drivers such as the Analog Devices ADuM4135 or TI UCC21750, eliminating ground loops in half-bridge topologies.
推荐
Isolated RS-485/RS-232 Transceiver Power
The LT8301ES5#TRMPBF delivers clean isolated +5 V or +3.3 V rails for isolated RS-485 and RS-232 transceiver nodes in industrial networking and building automation. Its no-opto topology provides the reinforced isolation needed to survive ground-potential differences across long cable runs, while the 6 W output capability easily powers transceiver, terminator, and TVS protection networks. Designers pair it with isolated transceivers like the Analog Devices ADM2682E or TI ISO3086 to build fully isolated RS-485 nodes that withstand 5 kV transient events on the bus.
推荐
Medical Patient-Isolated Rails
The LT8301ES5#TRMPBF supports medical patient-isolated rails in ECG, EEG, patient monitoring, and infusion pump designs where patient leakage current must remain below IEC 60601-1 limits. The transformer's galvanic isolation provides 4 kV+ reinforced isolation, and the no-opto control scheme eliminates the high-leakage paths sometimes associated with opto-coupler bias networks. Combined with Analog Devices ADuM4160 USB isolators or ADuM3151 SPI isolators, the LT8301 enables compact patient-isolated front-end modules for portable diagnostic equipment.
推荐
Battery-Powered Isolated Measurement
The LT8301ES5#TRMPBF is well-suited for battery-powered portable instruments that require isolated analog front-end rails, such as handheld oscilloscope probes, isolated DMMs, and field calibration tools. Its 2.7 V minimum input allows direct operation from a single Li-ion cell (3.0 V to 4.2 V), while the no-opto topology minimizes quiescent current draw, extending battery life compared to opto-based flyback designs. The 6 W output easily drives isolated ADC front-ends, op-amp buffers, and isolated digital interfaces in compact handheld form factors.
推荐
PoE and Telecom Isolated Auxiliary Rails
The LT8301ES5#TRMPBF fits Power-over-Ethernet (PoE) and telecom auxiliary isolated rails where the 48 V bus must be stepped down to isolated +3.3 V, +5 V, or +12 V logic rails. Operating from a 42 V maximum input, it pairs well with a small front-end buck or LDO when fed from a 48 V PoE bus, delivering up to 6 W of isolated bias for digital isolators, magnetics, and PHY transceivers. The no-opto control simplifies PCB layout and improves MTBF in always-on telecom infrastructure.
推荐
Isolated Analog Input Module for PLCs
The LT8301ES5#TRMPBF drives isolated analog input modules used in programmable logic controllers and distributed I/O systems. Its 2.7 V to 42 V input range accepts 24 V field supply rails directly, and the no-opto regulation reduces PCB area by eliminating the opto-coupler, TL431, and bias components. Up to 6 W of isolated output powers multi-channel 16-bit ADCs, low-drift reference buffers, and front-end instrumentation amplifiers with stable ground isolation across 2.5 kV+ channel-to-channel barriers.
推荐
推荐产品汇总
工程参考数据： LT8301ES5#TRMPBF ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | LT8301IS5#TRPBF | LT8301HS5#TRPBF | LT8301JS5#WTRPBF | LT8301JS5#TRMPBF | LT8301ES5#TRPBF |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | TSOT-23-5 (5-lead ThinSOT) | TSOT-23-5 - same | TSOT-23-5 - same | TSOT-23-5 - same | TSOT-23-5 - same | TSOT-23-5 - same |
| Input Voltage Range | 2.7 V to 42 V | 2.7 V to 42 V | 2.7 V to 42 V | 2.7 V to 42 V | 2.7 V to 42 V | 2.7 V to 42 V |
| Switch Voltage / Current | 65 V / 1.2 A | 65 V / 1.2 A | 65 V / 1.2 A | 65 V / 1.2 A | 65 V / 1.2 A | 65 V / 1.2 A |
| Maximum Output Power | 6 W | 6 W | 6 W | 6 W | 6 W | 6 W |
| Maximum Operating Temperature | +125 C (E grade) | +125 C (I grade) | +150 C (H grade) | +125 C (J grade, automotive) | +125 C (J grade, automotive) | +125 C (E grade) |
| Automotive Grade (AEC-Q100) | No | No | No | Yes (AEC-Q100, #W suffix) | Yes (AEC-Q100 via #W controlled manufacturing) | No |
| Factory Pack Quantity | 500 (#TRMPBF) | 2500 | 2500 | 2500 | 500 | 2500 (#TRPBF) |
关键差异点
- No-opto primary-side regulation （对比 TL831 + opto-coupler isolated flyback designs)
- Integrated 65 V/1.2 A DMOS switch （对比 External MOSFET flyback designs (e.g., LT3571-based))
- Wide 2.7 V-42 V input range in TSOT-23-5 （对比 Larger-package isolated flybacks (e.g., LT3573 in MSOP-16))
- Automotive-grade drop-in variant available （对比 Standard LT8301ES5#TRMPBF)
设计说明
The TSOT-23-5 package has limited thermal dissipation for a 1.2 A/65 V switch. At 6 W output from a 24 V input delivering 5 V isolated, the part dissipates roughly (24V - 5V*N) / efficiency fraction of total power. Use a 4-layer PCB with at least 1 square inch of top-layer copper under the exposed pad and place the flyback transformer directly adjacent to reduce loop area. For continuous 6 W output, derate by 30% in still air above +85 C ambient. Estimated based on TSOT-23-5 thermal resistance of approximately 60 C/W theta-JA on a standard JEDEC 4-layer board.
Place the input bypass capacitor as close as possible to the VIN and GND pins using a 1uF X7R ceramic. Place the Vc bypass capacitor (1uF X7R) close to the Vc pin to GND with minimum trace inductance. The flyback transformer primary winding should connect directly to the SW pin and GND with the shortest possible loop area to minimize EMI. Keep secondary-side rectifier loop tight; add a small RC snubber (e.g., 100 ohm + 100 pF) across the secondary rectifier for high-voltage spikes.
Do not omit the Vc bypass capacitor - it powers internal logic and its absence causes erratic regulation. The single external FB resistor programs VOUT via the primary-side sampling formula; using the wrong resistance causes under- or over-voltage output. Ensure the transformer primary inductance and turns ratio are matched to VIN range - an undersized primary inductance pushes the part out of boundary mode and reduces efficiency. Below minimum load the LT8301 enters burst-mode operation, introducing low-frequency ripple that may need additional filtering on noise-sensitive rails.
Maintain at least 6 mm creepage distance between primary and secondary PCB copper to meet IEC 62368-1 reinforced isolation requirements when the transformer provides only functional isolation. Route the FB trace away from the SW node to avoid capacitive coupling that disrupts primary-side voltage sampling. Use a guard ring around the SW node connected to GND to reduce radiated EMI. The exposed pad must be soldered to a continuous copper island that is thermally tied to multiple inner-layer planes via thermal vias.
合规信息
RoHS compliant per Analog Devices product page and #TRMPBF suffix. Lead-free finish. Not AEC-Q100 qualified in this E-grade variant; choose LT8301JS5#WTRPBF for AEC-Q100 automotive.
