LT8331IMSE#PBF - 140V 0.5A Boost/SEPIC/Flyback Conv | ADI
料号： LT8331IMSE#PBF ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $6.5 | $6.50 |
| 10 | $6.18 | $61.80 |
| 100 | $5.46 | $546.00 |
| 500 | $4.91 | $2,455.00 |
| 1,000 | $4.36 | $4,360.00 |
LT8331IMSE#PBF 概述
A switching converter (also called a DC/DC switching regulator or SMPS - Switch-Mode Power Supply) uses energy storage elements (inductors and capacitors) and a power switch to convert one DC voltage to another DC voltage with much higher efficiency than linear regulators. The LT8331 belongs to the boost/SEPIC/flyback/inverting sub-family of non-isolated/isolated-capable switching regulators, which sits within the broader power management IC category. These topologies are preferred over linear regulators when high step-up ratios, high step-down ratios, or negative rails are required, especially at input voltages above 30V.
Key specifications include a programmable switching frequency range of 100 kHz to 500 kHz, 6 uA quiescent current in Burst Mode operation, a SYNC/MODE pin for external clock synchronization or Burst/pulse-skipping selection, and a BIAS pin that allows the IC to be powered from its own output for increased efficiency. The internal current-mode architecture provides stable operation across a wide range of input and output voltages.
The LT8331 employs a high-voltage DMOS power switch with current-mode control and internal compensation. The unique single FB pin allows the same IC to be reconfigured for boost, SEPIC, flyback, or inverting configurations simply by changing the external component connections - a significant engineering advantage for multi-rail designs. The 100V max Vin+ tolerance supports 4:1 input range industrial bus systems and automotive load-dump transients.
Typical applications include industrial 24V/48V bus converters, automotive power conditioning, isolated flyback bias supplies, negative voltage generators for op-amp and ADC rails, battery-powered systems requiring high step-up ratios, and telecom infrastructure. The wide input range makes it especially attractive for systems that must survive wide input transients.
When designing with the LT8331, carefully calculate maximum switch voltage stress in flyback/SEPIC topologies - the 140V internal switch rating provides generous headroom but requires proper snubber design for reliable operation. Use the SYNC pin to synchronize multiple converters in noise-sensitive systems.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： LT8331IMSE#PBF ——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：
LT8331EMSE#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8331IMSE#WPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8331IMSE#WTRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8331IMSE#TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT3571EUB#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8331IMSE#PBF 最大额定值与电气特性
| 拓扑 | Boost, SEPIC, Flyback, Inverting |
| 输入电压范围 | 4.5 V to 100 V |
| Internal Switch Voltage Rating | 140 V |
| Internal Switch Current | 0.5 A |
| 输出数量 | 1 |
| 输出电压 | Adjustable (Positive or Negative) |
| 开关频率 | 100 kHz to 500 kHz (programmable) |
| Quiescent Current (Burst Mode) | 6 uA |
| 反馈电压 | 1.6 V (positive), -0.8 V (negative) |
| Synchronization | Yes (SYNC/MODE pin) |
| BIAS Pin | Yes (for efficiency optimization) |
| Control Mode | Current Mode (internally compensated) |
| 封装 | 16-TFSOP (MSOP-16) with 12 leads and exposed pad |
| 工作温度范围 | -40 C to +125 C (I grade) |
| 安装类型 | Surface Mount |
| RoHS 状态 | Compliant |
LT8331IMSE#PBF 引脚配置
| 引脚 1 | SW — Switch node - connect to inductor/transformer primary |
| 引脚 2 | VIN — Input supply voltage (4.5V to 100V) |
| 引脚 3 | BIAS — Optional second supply input for improved efficiency |
| 引脚 4 | SS — Soft-start programming pin |
| 引脚 5 | RT — Timing resistor for switching frequency programming |
| 引脚 6 | SYNC/MODE — External clock sync or Burst Mode/pulse-skipping selection |
| 引脚 7 | FB — Feedback (1.6V positive / -0.8V negative reference) |
| 引脚 8 | GND — Ground |
| 引脚 9 | NC — Not connected (per datasheet) |
| 引脚 10 | NC — Not connected (per datasheet) |
| 引脚 11 | NC — Not connected (per datasheet) |
| 引脚 12 | NC — Not connected (per datasheet) |
| 引脚 13 | PGND — Power ground (exposed pad internally connected) |
| 引脚 14 | PGND — Power ground (exposed pad internally connected) |
| 引脚 15 | PGND — Power ground (exposed pad internally connected) |
| 引脚 16 | PGND — Power ground (exposed pad internally connected) |
典型应用
LT8331IMSE#PBF 适用于 6 应用s: Industrial 24V/48V Bus Converter, Automotive Power Conditioning, Isolated Flyback Bias Supply, Negative Voltage Generator for Op-Amp and ADC Rails, Battery-Powered High Step-Up Systems, Telecom and PoE Auxiliary Bias.
Industrial 24V/48V Bus Converter
The LT8331IMSE#PBF is well-matched to 24V and 48V industrial bus inputs because of its 100V maximum continuous input rating and 140V internal switch, which together provide generous transient margin for inductive kickback and load-dump events. The device's 4.5V minimum input supports battery-backed 24V systems during brownout, while the 0.5A internal switch delivers up to several watts of regulated output in boost, SEPIC, or buck-derived topologies. Industrial designers favor the part's SYNC/MODE pin, which allows multiple converters to be clocked from a common oscillator to avoid beat-frequency EMI in densely packed control cabinets. The MSOP-16 footprint with exposed pad keeps the solution size compact for DIN-rail mounted PLCs and sensor hubs.
推荐
Automotive Power Conditioning
The LT8331IMSE#PBF's 100V input tolerance handles automotive load-dump transients up to ISO 7637-2 severity levels when paired with a simple upstream TVS clamp, making it suitable for body electronics and 12V/24V truck systems. The 140V internal switch supports boost topologies that step up cranking transients to stable 15V or 18V rails for downstream ECU microcontrollers and CAN transceivers. For automotive designs requiring formal qualification, the pin-compatible LT8331IMSE#WPBF variant offers AEC-Q100 controlled manufacturing. The 6 uA Burst Mode IQ is critical for key-off quiescent current budgets in always-powered telematics modules, where standby drain directly affects battery life over months of parking.
推荐
Isolated Flyback Bias Supply
The LT8331IMSE#PBF in flyback configuration delivers isolated bias voltages for gate drivers, isolated signal acquisition, and industrial fieldbus interfaces. The 140V internal switch and 100V input tolerance support wide-input isolated converters commonly used in 24V-to-5V or 48V-to-3.3V telecom and factory-automation rails. The single FB pin simplifies primary-side regulation design, while the BIAS pin can power the LT8331's internal circuitry from the auxiliary winding to maximize efficiency across the full load range. With proper snubber design, the flyback topology achieves 80%+ efficiency at moderate loads - significantly higher than linear regulators at large VIN-VOUT deltas. Designers should validate peak switch voltage stress including leakage inductance spikes.
推荐
Negative Voltage Generator for Op-Amp and ADC Rails
The LT8331IMSE#PBF in inverting configuration generates negative rails such as -5V, -12V, or -15V needed by legacy op-amps, precision ADCs, and biasing circuits from a single positive supply. The unique single FB pin with -0.8V reference eliminates the dual-feedback networks required by some competing converters, simplifying the BOM. With 0.5A switch current and 100V input tolerance, the LT8331 can generate negative rails from high-voltage positive inputs while maintaining the -40C to +125C operating range required by industrial test equipment. The SYNC/MODE pin allows the negative rail converter to be synchronized away from sensitive analog sampling windows in mixed-signal data acquisition systems.
推荐
Battery-Powered High Step-Up Systems
The LT8331IMSE#PBF excels in battery-powered applications requiring high step-up ratios - for example, boosting a single-cell Li-ion (3.0V-4.2V) up to 24V or 36V for sensor excitation or LCD bias. The 4.5V minimum input supports two-cell Li-ion packs and 5V USB inputs, while the 140V internal switch tolerates high reflected voltages in extreme step-up ratios. Burst Mode operation with 6 uA quiescent current extends battery life in always-on IoT sensor nodes that spend most of their time in standby. The MSOP-16 footprint suits space-constrained wearable and IoT designs where every square millimeter of PCB counts toward miniaturization targets.
推荐
Telecom and PoE Auxiliary Bias
The LT8331IMSE#PBF supports telecom infrastructure designs that require auxiliary bias supplies derived from 48V backplane rails. The 100V input rating covers the full 36V-72V telecom range plus transient headroom, while the 140V internal switch provides margin for boost-derived housekeeping rails. The LT8331's SYNC/MODE pin can synchronize to a master system clock to keep switching harmonics out of sensitive RF bands. In PoE Powered Device (PD) applications, the LT8331 can derive secondary rails after the PD interface IC has negotiated power with the Power Sourcing Equipment - useful for IP phones, wireless access points, and security cameras.
推荐
推荐产品汇总
工程参考数据： LT8331IMSE#PBF ——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 | LT8331EMSE#PBF | LT8331IMSE#WPBF | LT8331IMSE#WTRPBF | LT8331IMSE#TRPBF | LT3571EUB#PBF |
|---|---|---|---|---|---|---|
| Package | 16-TFSOP (MSOP-16, 12-lead EP) | 16-TFSOP (MSOP-16, 12-lead EP) - same | 16-TFSOP (MSOP-16, 12-lead EP) - same | 16-TFSOP (MSOP-16, 12-lead EP) - same | 16-TFSOP (MSOP-16, 12-lead EP) - same | 10-MSOP - smaller package |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage Range | 4.5 V to 100 V | 4.5 V to 100 V | 4.5 V to 100 V | 4.5 V to 100 V | 4.5 V to 100 V | 2.5 V to 75 V |
| Internal Switch Voltage | 140 V | 140 V | 140 V | 140 V | 140 V | 75 V |
| Operating Temperature | -40 C to +125 C (I grade) | 0 C to +125 C (E grade) | -40 C to +125 C (AEC-Q100) | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C |
| Automotive Qualified (AEC-Q100) | No (industrial I grade) | No | Yes (controlled manufacturing) | Yes (controlled manufacturing) | No | No |
关键差异点
- Wide 100V input range with 140V internal switch （对比 LT8330 (60V max VIN))
- Single FB pin supports 4 topologies (boost/SEPIC/flyback/inverting) （对比 LT3571EUB#PBF (boost/SEPIC/inverting only, no flyback))
- AEC-Q100 controlled manufacturing variant available （对比 LT8331IMSE#PBF (industrial I grade))
设计说明
The MSOP-16 package with exposed thermal pad requires direct soldering of the EP to a PCB ground plane with thermal vias to a copper pour on inner layers. Estimated: at VIN=24V, VOUT=12V (boost), IOUT=0.3A, the LT8331 internal switch dissipates roughly (1-D)*VIN*ISW ≈ 0.5W steady state. With a 4-layer JEDEC board theta_JA ≈ 40 C/W, junction temperature rise above ambient is about 20C - well within the 125C limit. At VIN=72V boost to VOUT=12V, dissipation increases to roughly 1.2W and thermal analysis becomes more critical. Always populate enough copper area around the EP to keep theta_JA below 45 C/W.
In flyback and SEPIC topologies, peak switch voltage equals VIN plus the reflected output voltage plus leakage inductance spikes. The 140V internal switch rating provides margin, but designers MUST add an RCD snubber or clamp across the transformer primary if calculated worst-case stress exceeds 80% of 140V (i.e., 112V). Estimating leakage spike amplitude requires measuring the transformer's primary leakage inductance (typically 1-3% of magnetizing inductance) and the peak switching current at maximum load. Skipping this analysis is a common cause of field returns with high-voltage switching converters.
Keep the SW node trace short and narrow to minimize radiated EMI, and surround it with a ground copper pour. Place input ceramic bypass capacitors (1uF X7R minimum, 4.7uF recommended for high-voltage transients) within 5mm of the VIN pin. The RT resistor should be placed close to the RT pin with the SYNC/MODE trace routed away from the SW node to avoid capacitive coupling that can disrupt synchronization. The exposed pad ground must use multiple thermal vias (at least 9 vias in a 3x3 pattern with 0.3mm drill) for proper heat extraction in sustained-load applications.
合规信息
Lead-free per the #PBF suffix. The #WPBF variant is AEC-Q100 qualified for automotive; the standard LT8331IMSE#PBF (I grade) is industrial-grade.
