LT8640SIV#PBF - 42V, 6A Silent Switcher 2 Buck | Analog Devices
Артикул: LT8640SIV#PBF ✓ Активен| Кол-во | Цена за ед. | Итого |
|---|---|---|
| 1 | $8.06 | $8,06 |
| 10 | $7.25 | $72,50 |
| 100 | $6.45 | $645,00 |
| 500 | $5.85 | $2.925,00 |
| 1.000 | $5.42 | $5.420,00 |
| 3.000 | $4.95 | $14.850,00 |
LT8640SIV#PBF Обзор
A buck (step-down) switching regulator is a type of DC-DC converter that uses an energy-storage inductor and synchronous MOSFET switches to convert a higher input voltage into a lower regulated output voltage with high efficiency. Within the broader power management hierarchy, the LT8640SIV#PBF belongs to the family of synchronous step-down regulators, which sit above simple linear regulators and below multi-phase point-of-load converters. The Silent Switcher architecture in particular addresses EMI - a chronic challenge for switching regulators - by tightly controlling the high-di/dt current loops that normally radiate noise, eliminating the need for complex shielding or filtering in many designs.
Key specifications include 6A continuous output current, 95% peak efficiency, and a maximum switching frequency up to 3 MHz when configured for low-noise operation. The exposed thermal pad (LQFN-24 with EP) provides low thermal resistance for sustained high-current delivery without external heatsinking. Additional features include internal compensation, internal bootstrap, power-good flag, external synchronization input, and spread-spectrum frequency modulation for further EMI reduction. The output voltage is set by a single external resistor divider.
Typical applications span automotive always-on systems, industrial 24V bus converters, portable instrumentation, battery-powered equipment, and noise-sensitive analog/mixed-signal rails. The ultra-low 2.5 µA quiescent current is particularly valuable in automotive cold-crank and e-call systems where the battery must power standby loads for weeks without recharge. The wide 42V input withstands load-dump transients common in 12V and 24V automotive environments, while the 3 MHz switching capability supports single-chip small-form-factor designs without am radio band interference.
When designing with the LT8640SIV#PBF, place input capacitors as close as possible to the VIN and PGND pins to minimize the high-frequency current-loop area; this preserves the Silent Switcher 2 EMI advantage. Use a minimum of 4.7 µF X7R ceramic input capacitance and a 22 µF or larger output capacitor for stable operation across the full load range.
This page synthesizes distributor pricing, same-family ADI drop-in alternatives (including the -2 spread-spectrum variant and the automotive-grade H-speed grade), and practical design notes that go beyond the manufacturer datasheet.
Аналоги без доработки для LT8640SIV#PBF — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с LT8640SIV#PBF (тот же форм-фактор и посадочное место) — отличается по Output Voltage Range, Architecture, MSL Level, Operating Junction Temperature, Package.
Инструмент быстрого сравнения — выберите альтернативные компоненты для сравнения бок о бок:
LT8640SIV-2#PBF
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LT8640SEV#PBF
✅ Прямая замена✓ В наличии
$6.93 / шт.
Открыть даташит →LT8640SHV-2#PBF
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LT8640SIV#WPBF
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LT8640SIV-1#PBF
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
LT8643SIV#PBF
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
LT8640SIV#PBF Максимальные параметры и электрические характеристики
| Топология | Synchronous Step-Down (Buck) |
| Диапазон входного напряжения | 3.4 V to 42 V |
| Диапазон выходного напряжения | 0.97 V to 10 V (max 41.58 V) |
| Максимальный выходной ток | 6 A |
| Ток покоя | 2.5 µA (typical) |
| Частота переключения | Up to 3 MHz |
| Peak Efficiency | 95 % |
| Architecture | Silent Switcher 2 (internal bypass caps, low-noise) |
| Корпус | 24-LFQFN Exposed Pad (4 mm x 6 mm) |
| Тип монтажа | Surface Mount |
| Рабочая температура | -40 °C to +125 °C |
| Тип выхода | Adjustable |
| Количество выходов | 1 |
| Синхронный выпрямитель | Yes (internal) |
| Уровень MSL | 3 (168 hours) |
| Статус RoHS | Compliant |
| Lead-Free / PBF | Yes (#PBF suffix) |
Конфигурация выводов LT8640SIV#PBF
| Контакт 1 | PGND — Power Ground |
| Контакт 2 | SW — Switch node (connect to inductor) |
| Контакт 3 | SW — Switch node (connect to inductor) |
| Контакт 4 | BST — Bootstrap supply for top-side gate driver |
| Контакт 5 | VIN — Main input supply |
| Контакт 6 | VIN — Main input supply (duplicate) |
| Контакт 7 | VIN — Main input supply (duplicate) |
| Контакт 8 | EN/UVLO — Enable / Undervoltage Lockout |
| Контакт 9 | INTVCC — Internal 5V LDO output (bypass with 1µF) |
| Контакт 10 | PG — Power Good open-drain output |
| Контакт 11 | SYNC/MODE — Sync input / MODE select (spread-spectrum vs. fixed-frequency) |
| Контакт 12 | RT — Timing resistor to GND (programs switching frequency) |
| Контакт 13 | SGND — Signal Ground (small-signal return) |
| Контакт 14 | FB — Feedback (set Vout via resistor divider to 0.97V ref) |
| Контакт 15 | TR/SS — Soft-start / tracking input |
| Контакт 16 | VOUT_SNS — Output voltage sense (for power-good and short-circuit protection) |
| Контакт 17 | NC — Not connected (per datasheet) |
| Контакт 18 | NC — Not connected (per datasheet) |
| Контакт 19 | NC — Not connected (per datasheet) |
| Контакт 20 | NC — Not connected (per datasheet) |
| Контакт 21 | NC — Not connected (per datasheet) |
| Контакт 22 | NC — Not connected (per datasheet) |
| Контакт 23 | NC — Not connected (per datasheet) |
| Контакт 24 | NC — Not connected (per datasheet) |
Типичное применение
LT8640SIV#PBF подходит для 7 применениеs: Automotive 12V/24V Bus Always-On Supply, Industrial 24V PLC and Sensor Power, Portable Battery-Powered Instrumentation, Noise-Sensitive Mixed-Signal / RF Rails, Datacenter and Server Point-of-Load Conversion, USB-PD and High-Power Charging Sinks, Aerospace and Defense Avionics Rails.
Automotive 12V/24V Bus Always-On Supply
The LT8640SIV#PBF is purpose-built for automotive always-on rails that must remain alive during key-off for weeks at a time. The 2.5 µA quiescent current and 42 V maximum input directly accept 12 V crank transients (down to 3.4 V) and 24 V truck load-dump events (up to 42 V) without upstream TVS protection in most cases. Silent Switcher 2 architecture achieves CISPR 25 Class 5 conducted EMI without complex input filtering, allowing the part to power body-control MCUs, eCall modules, and immobilizer receivers directly from the battery. The 6 A capability supports infotainment pre-regulator roles and ADAS sensor rails from a single chip.
Рекомендуется
Industrial 24V PLC and Sensor Power
The LT8640SIV#PBF's 3.4 V to 42 V input range directly accepts industrial 24 V nominal bus rails that swing from 18 V to 36 V under load transients. The 6 A output and 95% peak efficiency support multi-channel PLC digital-output stages, 4-20 mA loop transmitters, and isolated sensor front-ends from a single regulator. Silent Switcher 2 EMI performance eases compliance with EN 61131-2 industrial conducted emissions, while the exposed thermal pad sustains continuous 6 A delivery without heatsinking in compact DIN-rail enclosures. The wide output range (0.97 V to 10 V) covers 3.3 V logic, 5 V analog, and 1.8 V/2.5 V MCU rails with one IC.
Рекомендуется
Portable Battery-Powered Instrumentation
The LT8640SIV#PBF's 2.5 µA quiescent current extends battery life in handheld test instruments, portable medical monitors, and field data loggers. The high 95% peak efficiency at light loads (1 mA to 100 mA) preserves runtime on lithium packs, while the 6 A peak capability supplies pulse loads such as LCD backlights, RFID read bursts, or cellular transmit peaks. Silent Switcher 2 reduces shielding requirements in sensitive measurement chains, allowing the regulator to coexist with 24-bit ADCs and precision analog front-ends without coupling switching noise into the signal path.
Рекомендуется
Noise-Sensitive Mixed-Signal / RF Rails
Silent Switcher 2 architecture makes the LT8640SIV#PBF particularly well-suited to power supply rails for RF transceivers, PLLs, ADCs, and DACs where switching noise would otherwise couple into the signal path. The internal bypass capacitors minimize the high-di/dt current loop area, reducing both conducted and radiated EMI to levels typically reserved for parts costing twice as much. Spread-spectrum modulation (in the -2 variant) further smears residual switching harmonics across a wider band, eliminating discrete spurs visible in FFTs of the powered RF chain. The 6 A capability supports 5G small-cell front-end rails and software-defined-radio baseband sections.
Рекомендуется
Datacenter and Server Point-of-Load Conversion
In 48 V datacenter distribution architectures, the LT8640SIV#PBF can serve as the first-stage step-down from a 48 V bus to an intermediate 12 V or 5 V rail that then feeds downstream multiphase point-of-load converters. The 42 V maximum input also accepts 36 V battery-backed telecom rails directly. The 95% peak efficiency at moderate loads reduces cooling costs in dense server racks, while the LQFN-24 package supports top-side cooling with minimal airflow. Programmable 200 kHz to 3 MHz switching lets designers push the fundamental above the AM radio band to avoid shielding sensitive receive antennas co-located in server rooms.
Рекомендуется
USB-PD and High-Power Charging Sinks
The LT8640SIV#PBF's 6 A continuous output and 3.4 V to 42 V input make it well-suited as the front-end buck in USB-PD charging sinks, power-tool chargers, and e-bike battery management electronics. It accepts the full USB-PD extended-power-profile voltage range (5 V to 20 V, including 28 V EPRMHV) directly, eliminating the need for a pre-regulator. Silent Switcher 2 ensures conducted EMI stays below USB-IF charger radiated-emission limits, while the 95% efficiency preserves energy in compliance-sensitive applications. The exposed thermal pad enables sustained 6 A delivery in sealed enclosures with minimal airflow.
Рекомендуется
Aerospace and Defense Avionics Rails
The LT8640SHV-2#PBF (H-grade variant in the same family as the LT8640SIV#PBF) is qualified to H-grade reliability standards, making this regulator family suitable for non-critical aerospace and defense sub-systems such as cockpit lighting, in-flight entertainment, and cabin communication. The 42 V input covers 28 V avionics bus transients directly, while 95% efficiency eases thermal budgets in sealed equipment bays. Silent Switcher 2 EMI performance helps meet DO-160 conducted emissions without complex shielding, and the exposed thermal pad simplifies mechanical integration into sealed aluminum enclosures where external heatsinks are impractical.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для LT8640SIV#PBF — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | LT8640SIV-2#PBF | LT8640SEV#PBF | LT8640SHV-2#PBF | LT8640SIV#WPBF | LT8640SIV-1#PBF | LT8643SIV#PBF |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 24-LFQFN Exposed Pad (4x6 mm) | 24-LFQFN Exposed Pad (4x6 mm) - same | 24-LFQFN Exposed Pad (4x6 mm) - same | 24-LFQFN Exposed Pad (4x6 mm) - same | 24-LFQFN Exposed Pad (4x6 mm) - same | 24-LFQFN Exposed Pad (4x6 mm) - same | 24-LFQFN Exposed Pad (4x6 mm) - same |
| Input Voltage Range | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V |
| Output Current | 6 A | 6 A | 6 A | 6 A | 6 A | 6 A | 10 A |
| Quiescent Current | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA |
| Switching Frequency | 200 kHz to 3 MHz | 200 kHz to 3 MHz (spread-spectrum default) | 200 kHz to 3 MHz | 200 kHz to 3 MHz | 200 kHz to 3 MHz | 200 kHz to 3 MHz | 200 kHz to 3 MHz |
| Temperature Grade | I-grade (-40 °C to +125 °C) | I-grade | E-grade (0 °C to 125 °C) | H-grade (military/hi-rel) | I-grade | I-grade | I-grade |
| Spread-Spectrum Modulation | No (fixed-frequency) | Yes (factory-enabled) | No | Yes (factory-enabled) | No | No | Optional |
Ключевые отличия
- Industry-leading 2.5 µA quiescent current for a 6 A synchronous buck (против LT8606EDC#TRPBF)
- Silent Switcher 2 architecture eliminates EMI layout complexity (против LT8390EFE#PBF)
- Direct 42 V input withstands 24 V truck load-dump transients (против LMR33640ADDAR)
Заметки по проектированию
The LT8640SIV#PBF relies on its internal bypass capacitors and small exposed-pad package to achieve Silent Switcher 2 EMI performance, but external layout still matters. Place the input ceramic capacitors (≥4.7 µF X7R, multiple in parallel) as close as physically possible to the VIN/PGND pins on the same PCB layer; route the high-di/dt loop on a single inner or top layer with no vias in the current path. The exposed thermal pad must be soldered to a continuous ground copper pour with multiple thermal vias to inner ground planes; this both reduces ground-bounce and provides the primary heat-dissipation path for the 6 A continuous output.
Estimated: at VIN = 24 V, VOUT = 5 V, and IOUT = 6 A, the LT8640SIV#PBF dissipates approximately (24 - 5) × 6 × (1 - η) ≈ 57 W if efficiency were only 50 %, but the Silent Switcher 2 architecture actually delivers ~92 % at this condition, so dissipation is around (24 - 5) × 6 × 0.08 = 9.1 W. With the LQFN-24 package's θJA of approximately 30 °C/W on a 4-layer JEDEC board, the junction rises ~270 °C above ambient - which exceeds the 125 °C junction limit. Practical design requires either VIN/VOUT closer to the duty ratio, larger copper pour, or external heatsinking for sustained 6 A delivery at large step-down ratios. Refer to the LT8640S datasheet thermal-analysis section for the duty-ratio derating curves.
Silent Switcher 2 architecture eliminates most of the layout-driven EMI headaches of conventional buck regulators, but the input-current ripple at the switching frequency still benefits from a small LC pi-filter (1 µH + 10 µF X7R) at the IC's VIN pins for the most demanding CISPR 25 / CISPR 32 Class 5 conducted-emissions tests. The -2 variant adds spread-spectrum modulation, which spreads switching harmonics over a wider band and typically reduces peak emissions by 6-10 dB. Keep the SW-node copper area minimal and surrounded by ground copper on both top and bottom layers to limit near-field magnetic coupling into adjacent signal traces.
Do not operate the LT8640SIV#PBF below 3.4 V input - the internal BST regulator will drop out and cause high-side FET gate drive to fail, resulting in shoot-through. The INTVCC pin must be bypassed with at least 1 µF X7R placed within 2 mm of the pin; failure to bypass INTVCC causes erratic switching and high quiescent current. The RT resistor sets switching frequency and must be a 1 % tolerance part referenced to SGND; using SGND rather than PGND for RT and FB prevents switching-noise coupling into the feedback path. Never leave the BST capacitor absent - it charges through an internal diode on each SW falling edge and must hold sufficient charge for the high-side FET.
Информация о соответствии
Lead-free and RoHS compliant per the '#PBF' suffix and DigiKey product listing. AEC-Q100 status not explicitly stated in the LT8640S datasheet Rev. D; the part is characterized for -40 °C to +125 °C operation (I-grade) but AEC-Q100 qualification should be confirmed directly with Analog Devices for automotive safety-critical applications.
