LT8609SIV#PBF - 42V 2A/3A Peak Sync Buck Regulator | Analog Devices
料号： LT8609SIV#PBF ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $6.78 | $6.78 |
| 10 | $6.1 | $61.00 |
| 100 | $5.42 | $542.00 |
| 500 | $4.89 | $2,445.00 |
| 1,000 | $4.36 | $4,360.00 |
LT8609SIV#PBF 概述
A buck switching regulator (step-down converter) is a type of DC-DC switching regulator that efficiently converts a higher DC input voltage to a lower DC output voltage using an internal switch, an external inductor, and control loop. Synchronous buck regulators use a MOSFET in place of the traditional freewheeling diode to reduce conduction loss and improve efficiency, especially at high load currents. The LT8609S sits within the power management hierarchy of: switching regulator -> DC-DC converter -> voltage regulator -> power management IC -> semiconductor.
Key features include a 1.7 µA quiescent current that makes the part ideal for always-on applications, a wide 3.0 V to 42 V input range that survives automotive load-dump transients, and a programmable output down to 0.782 V for powering modern low-voltage MCUs and SoCs. The part uses a constant-frequency peak current-mode architecture up to 2 MHz, and the SYNC/MODE pin allows synchronization to an external clock. Internal MOSFETs (top + bottom) eliminate the need for an external Schottky diode.
The LT8609S uses a peak current-mode control architecture with a precision reference and internal loop compensation, which simplifies schematic design by reducing the external component count to just an inductor, input/output capacitors, and feedback resistors. The 42 V absolute maximum input makes the part attractive for 12 V and 24 V industrial or automotive buses. The exposed pad on the TFQFN-16 package provides a low theta_JA thermal path for sustained 2 A operation.
Typical applications include automotive always-on systems, industrial 24 V sensor and actuator rails, battery-powered portable instruments, and general-purpose 5 V/3.3 V/1.8 V point-of-load conversion in telecom and factory automation. The low IQ also makes the part attractive for solar- or battery-energy-harvested systems.
When designing with the LT8609S, place the input capacitor as close as possible to the IN and GND pins to minimize switching loop area and EMI. Choose the inductor based on the 1.5 A to 3 A saturation current rating to handle the peak current-mode ripple. Use a feedforward capacitor (CFF) in parallel with the top feedback resistor to improve transient response when VOUT is well above the 0.782 V reference.
直接替换替代料： LT8609SIV#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：
LT8609SEV#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8609SIV#WPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8609SIV#TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8609SIV#PBF 最大额定值与电气特性
| 拓扑 | Synchronous Buck (Step-Down) |
| 输入电压范围 | 3.0 V to 42 V |
| 输出电压范围 | 0.782 V to V_IN (adjustable) |
| Continuous Output Current | 2 A |
| Peak Output Current | 3 A (less than 1 second) |
| Non-Switching Quiescent Current | 1.7 µA |
| 开关频率 | Up to 2 MHz (programmable, synchronizable) |
| 基准电压 | 0.782 V |
| Internal MOSFETs | Yes (synchronous top + bottom) |
| 封装 | 16-TFQFN Exposed Pad |
| 安装类型 | Surface Mount |
| 工作结温 | -40 °C to +125 °C (LT8609SIV grade) |
| RoHS 状态 | Compliant (PBF suffix) |
LT8609SIV#PBF 引脚配置
| 引脚 1 | AGND — Analog ground reference for the internal control circuitry |
| 引脚 2 | FB — Feedback input to the internal error amplifier (0.782 V reference) |
| 引脚 3 | RT — Timing resistor pin to program switching frequency |
| 引脚 4 | SYNC/MODE — Synchronization input / Burst Mode or pulse-skipping mode selection |
| 引脚 5 | EN/UVLO — Enable and undervoltage lockout threshold programming |
| 引脚 6 | BST — Bootstrap pin for the internal high-side MOSFET gate drive |
| 引脚 7 | SW — Switch node connection to the external inductor |
| 引脚 8 | SW — Switch node (continued for higher current handling) |
| 引脚 9 | PGND — Power ground return for the internal low-side MOSFET |
| 引脚 10 | PGND — Power ground (continued) |
| 引脚 11 | IN — Main input voltage supply (3.0 V to 42 V) |
| 引脚 12 | IN — Input voltage (continued for higher current handling) |
| 引脚 13 | PGND — Power ground (continued) |
| 引脚 14 | PGND — Power ground (continued) |
| 引脚 15 | PGND — Power ground (continued) |
| 引脚 16 | PGND — Power ground (continued) |
典型应用
LT8609SIV#PBF 适用于 6 应用s: Automotive Always-On Power Supply, Industrial 24 V Sensor and Actuator Rails, Battery-Powered Portable Instruments, General-Purpose 5 V / 3.3 V / 1.8 V Point-of-Load Conversion, Telecom and Networking Equipment Rails, Solar and Energy-Harvested Systems.
Automotive Always-On Power Supply
The LT8609SIV#PBF's 1.7 µA non-switching quiescent current and 42 V input tolerance make it ideal for automotive always-on systems that remain active when the ignition is off, such as body control modules and CAN transceivers. The part survives 12 V battery cold-crank (down to 3.0 V) and 24 V load-dump transients up to 42 V without external protection. Its 2 A continuous / 3 A peak output supports wake-up transients for downstream MCUs and sensors while drawing only microamps in standby, directly extending battery life for vehicles parked for weeks at a time.
推荐
Industrial 24 V Sensor and Actuator Rails
Industrial 24 V bus systems benefit from the LT8609SIV#PBF's wide 3.0 V to 42 V input range, which accommodates typical 24 V nominal rails with substantial transient margin. The 2 A continuous output can drive multiple 24 V-to-3.3 V/5 V sensor nodes or a single high-current actuator driver stage from a compact TFQFN-16 footprint. The 2 MHz programmable switching frequency allows designers to place the switching frequency above the AM band or synchronize to a system clock to avoid interference with nearby analog sensor front ends.
推荐
Battery-Powered Portable Instruments
The LT8609SIV#PBF's 1.7 µA quiescent current is the headline feature for battery-powered portable instruments such as handheld multimeters, portable gas detectors, and field data loggers. The wide input range (3.0 V to 42 V) allows direct operation from a multi-cell lithium pack, a 9 V battery, or even an unregulated solar/battery-harvested supply. The 2 A continuous output is more than sufficient for MCUs, BLE radios, and small displays, while the 2 MHz switching frequency keeps the external inductor small enough for handheld form factors.
推荐
General-Purpose 5 V / 3.3 V / 1.8 V Point-of-Load Conversion
The LT8609SIV#PBF serves as a versatile point-of-load (POL) converter in distributed power architectures, stepping down 12 V or 24 V intermediate buses to local 5 V, 3.3 V, or 1.8 V rails for MCUs, SoCs, and FPGAs. The 0.782 V minimum reference allows direct generation of 1.0 V and 0.85 V core voltages for low-power processors. With synchronous internal MOSFETs, designers avoid an external Schottky diode, reducing both BOM count and PCB area in dense digital designs where each square millimeter counts.
推荐
Telecom and Networking Equipment Rails
In telecom and networking line cards, the LT8609SIV#PBF's 42 V input range covers -48 V telecom bus systems after a downstream hot-swap or front-end converter provides a 12 V or 24 V intermediate rail. The 1.7 µA IQ supports sleep-mode efficiency requirements, while the 2 A continuous output handles PHY, MAC, and small FPGA rails. The exposed-pad TFQFN-16 footprint supports reflow soldering compatible with standard telecom PCB assembly processes.
推荐
Solar and Energy-Harvested Systems
Energy-harvested systems that operate from small solar panels or thermoelectric generators benefit from the LT8609SIV#PBF's 1.7 µA quiescent current, which minimizes standby losses and allows the system to operate from the harvester's residual energy. The 3.0 V minimum input supports direct operation from a single-cell Li-ion or a low-voltage harvester, while the 42 V maximum protects against open-circuit panel transients. The high switching frequency allows a small inductor that fits in harvester nodes with strict size constraints.
推荐
推荐产品汇总
工程参考数据： LT8609SIV#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 | LT8609SEV#PBF | LT8609SIV#WPBF | LT8609SIV#TRPBF |
|---|---|---|---|---|
| Package | 16-TFQFN Exposed Pad | 16-TFQFN Exposed Pad - same | 16-TFQFN Exposed Pad - same | 16-TFQFN Exposed Pad - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage Range | 3.0 V to 42 V | 3.0 V to 42 V | 3.0 V to 42 V | 3.0 V to 42 V |
| Continuous Output Current | 2 A | 2 A | 2 A | 2 A |
| Peak Output Current | 3 A (<1 sec) | 3 A (<1 sec) | 3 A (<1 sec) | 3 A (<1 sec) |
| Non-Switching Quiescent Current | 1.7 µA | 1.7 µA | 1.7 µA | 1.7 µA |
| Minimum Output Voltage | 0.782 V | 0.782 V | 0.782 V | 0.782 V |
| Operating Junction Temperature | -40 °C to +125 °C | 0 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
关键差异点
- Industrial temperature grade (-40 °C to +125 °C) （对比 LT8609SEV#PBF)
- Identical electrical performance across packaging codes （对比 LT8609SIV#WPBF / LT8609SIV#TRPBF)
设计说明
Place the input bypass capacitor as close as possible to the IN and PGND pins of the LT8609SIV#PBF to minimize the high-frequency switching loop area. Use a 1 µF or 2.2 µF X7R ceramic with low ESR, and pair it with a larger 10 µF or 22 µF bulk capacitor to handle input current ripple. The exposed pad must be soldered to a continuous PGND copper pour that covers at least 1 square inch on the top and inner layers to provide a low-thermal-impedance path for sustained 2 A operation.
Estimated: at VIN = 12 V, VOUT = 5 V, IOUT = 2 A, the LT8609SIV#PBF dissipates approximately (12 - 5) V × 2 A × (1 - efficiency) W; assuming 90% efficiency this is roughly 1.6 W. The TFQFN-16 package typically has theta_JA around 35 °C/W on a 1 sq inch 4-layer PCB, resulting in approximately 56 °C junction temperature rise above ambient. For continuous 2 A operation at higher VIN/VOUT differentials, additional copper area or airflow may be required to keep the junction below the 125 °C maximum.
Do not exceed 42 V at the IN pin, even transiently, as this can damage the internal MOSFETs. Place the BST capacitor as close to the BST and SW pins as possible; a missing or poorly placed bootstrap capacitor will cause the high-side FET to fail to enhance, leading to poor efficiency or destruction. Use a feedforward capacitor (CFF) of around 10 pF to 100 pF in parallel with the upper feedback resistor when the output is well above the 0.782 V reference, to compensate the loop and improve transient response.
合规信息
RoHS compliant per PBF suffix. Not AEC-Q100 qualified; for AEC-Q100 automotive grade, contact Analog Devices about automotive-qualified variants.
