LT8640SIV#PBF - 42V, 6A Silent Switcher 2 Buck | Analog Devices
부품 번호: LT8640SIV#PBF ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 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 개요
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.
드롭인 대체품: LT8640SIV#PBF — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: LT8640SIV#PBF (동일 폼 팩터 및 풋프린트) — 차이점: Output Voltage Range, Architecture, MSL Level, Operating Junction Temperature, Package.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
LT8640SIV-2#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT8640SEV#PBF
✅ 드롭인✓ 재고 있음
$6.93 / 개
데이터시트 보기 →LT8640SHV-2#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT8640SIV#WPBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT8640SIV-1#PBF
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
LT8643SIV#PBF
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
LT8640SIV#PBF 최대 정격 & 전기적 특성
| 토폴로지 | Synchronous Step-Down (Buck) |
| 입력 전압 범위 | 3.4 V to 42 V |
| 출력 전압 범위 | 0.97 V to 10 V (max 41.58 V) |
| 최대 출력 전류 | 6 A |
| 대기 전류 | 2.5 µA (typical) |
| 스위칭 주파수 | Up to 3 MHz |
| Peak Efficiency | 95 % |
| Architecture | Silent Switcher 2 (internal bypass caps, low-noise) |
| 패키지 | 24-LFQFN Exposed Pad (4 mm x 6 mm) |
| 실장 유형 | Surface Mount |
| 동작 온도 | -40 °C to +125 °C |
| 출력 유형 | Adjustable |
| 출력 수 | 1 |
| 동기 정류기 | Yes (internal) |
| MSL 레벨 | 3 (168 hours) |
| RoHS 상태 | Compliant |
| Lead-Free / PBF | Yes (#PBF suffix) |
LT8640SIV#PBF 핀 구성
| 핀 1 | PGND — Power Ground |
| 핀 2 | SW — Switch node (connect to inductor) |
| 핀 3 | SW — Switch node (connect to inductor) |
| 핀 4 | BST — Bootstrap supply for top-side gate driver |
| 핀 5 | VIN — Main input supply |
| 핀 6 | VIN — Main input supply (duplicate) |
| 핀 7 | VIN — Main input supply (duplicate) |
| 핀 8 | EN/UVLO — Enable / Undervoltage Lockout |
| 핀 9 | INTVCC — Internal 5V LDO output (bypass with 1µF) |
| 핀 10 | PG — Power Good open-drain output |
| 핀 11 | SYNC/MODE — Sync input / MODE select (spread-spectrum vs. fixed-frequency) |
| 핀 12 | RT — Timing resistor to GND (programs switching frequency) |
| 핀 13 | SGND — Signal Ground (small-signal return) |
| 핀 14 | FB — Feedback (set Vout via resistor divider to 0.97V ref) |
| 핀 15 | TR/SS — Soft-start / tracking input |
| 핀 16 | VOUT_SNS — Output voltage sense (for power-good and short-circuit protection) |
| 핀 17 | NC — Not connected (per datasheet) |
| 핀 18 | NC — Not connected (per datasheet) |
| 핀 19 | NC — Not connected (per datasheet) |
| 핀 20 | NC — Not connected (per datasheet) |
| 핀 21 | NC — Not connected (per datasheet) |
| 핀 22 | NC — Not connected (per datasheet) |
| 핀 23 | NC — Not connected (per datasheet) |
| 핀 24 | NC — Not connected (per datasheet) |
일반적인 애플리케이션
LT8640SIV#PBF 적합 용도: 7 애플리케이션s: 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.
추천
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.
추천
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.
추천
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.
추천
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.
추천
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.
추천
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.
추천
추천 제품 요약
엔지니어링 참조 데이터: LT8640SIV#PBF — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | 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 |
주요 차별점
- Industry-leading 2.5 µA quiescent current for a 6 A synchronous buck (vs LT8606EDC#TRPBF)
- Silent Switcher 2 architecture eliminates EMI layout complexity (vs LT8390EFE#PBF)
- Direct 42 V input withstands 24 V truck load-dump transients (vs LMR33640ADDAR)
설계 노트
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.
규정 준수 정보
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.
