LT3971EMSE - 38V, 1.2A, 2MHz Buck Regulator | Analog Devices
부품 번호: LT3971EMSE ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $10.55 | $10.55 |
| 10 | $9.49 | $94.90 |
| 100 | $8.45 | $845.00 |
| 500 | $7.65 | $3,825.00 |
| 1,000 | $4.2 | $4,200.00 |
LT3971EMSE 개요
What is a buck switching regulator? A buck (step-down) switching regulator is a type of DC-DC converter that efficiently reduces a higher input voltage to a lower regulated output voltage by rapidly switching an inductor and using energy storage elements. Within the broader taxonomy, a buck regulator belongs to switching regulators, which are a subset of DC-DC converters, which in turn are a type of voltage regulator under the power management IC umbrella.
The LT3971 features Burst Mode operation that consumes only 2.8µA of quiescent current while regulating with no load, making it ideal for always-on applications and battery-powered systems where standby current is critical. The accurate 1V threshold enable pin allows the regulator to be shut down, reducing input supply current to 700nA, which preserves battery life during deep sleep states. A capacitor on the SS pin provides programmable soft-start, controlling inrush current at power-up. A power good flag signals when VOUT reaches 91% of the programmed output voltage, useful for multi-rail sequencing in complex systems.
The internal architecture uses a 1.9A peak switch current limit, providing headroom beyond the 1.2A continuous rating for transient loads. The high switching frequency capability (2MHz) allows use of compact inductors and ceramic output capacitors, minimizing the overall solution footprint — particularly valuable in space-constrained portable designs. The MSOP-10 exposed pad package offers a thermal resistance suitable for moderate power dissipation.
Typical applications include automotive battery regulation, portable industrial instruments, distributed supply regulation, battery-powered devices, and always-on systems requiring low standby current. The wide 38V input range tolerates load-dump transients and industrial 24V rails. When designing, pay close attention to the inductor selection: choosing a shielded inductor with appropriate saturation current and DC resistance optimizes efficiency. Place input/output ceramic capacitors close to the IC and route the exposed pad directly to a copper pour for thermal management. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
드롭인 대체품: LT3971EMSE — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: LT3971EMSE (동일 폼 팩터 및 풋프린트) — 차이점: Input Voltage Range, Output Voltage, Package, RoHS Status, Topology.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
LT3971IMSE#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3971EMSE-3.3#PBF
✅ 드롭인✓ 재고 있음
$4.21 / 개
데이터시트 보기 →LT3971EMSE-5#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3971AEMSE#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3971EMSE#TRPBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3971EMSE 최대 정격 & 전기적 특성
| 토폴로지 | Buck (Step-Down) Switching Regulator |
| 입력 전압 범위 | Up to 38 V |
| 최대 출력 전류 | 1.2 A |
| Peak Switch Current | 1.9 A |
| Quiescent Current (Burst Mode, no load) | 2.8 µA |
| Shutdown Supply Current | 700 nA |
| Switching Frequency Range | 200 kHz to 2 MHz |
| 출력 전압 | Adjustable |
| Enable Pin Threshold | 1 V (accurate) |
| Power Good Flag Threshold | 91% of programmed VOUT |
| 소프트 스타트 | Programmable via SS capacitor |
| 동작 접합 온도 | 0°C to +125°C (E grade) |
| Extended Junction Temperature (by design) | -40°C to +125°C |
| 패키지 | 10-MSOP with Exposed Pad |
| 실장 유형 | Surface Mount |
| RoHS 상태 | Compliant |
LT3971EMSE 핀 구성
| 핀 1 | EN/UVLO — Enable/undervoltage lockout pin, accurate 1V threshold |
| 핀 2 | VIN — Input supply voltage (up to 38V) |
| 핀 3 | SW — Switch node — connects to inductor |
| 핀 4 | BST — Boost pin for internal driver supply |
| 핀 5 | GND — Ground return |
| 핀 6 | FB — Feedback voltage input (for adjustable output) |
| 핀 7 | SS — Soft-start programming pin |
| 핀 8 | PG — Power good output flag (91% of VOUT) |
| 핀 9 | RT — Timing resistor for switching frequency |
| 핀 10 | NRT/SYNC — Frequency set / external clock sync input |
일반적인 애플리케이션
LT3971EMSE 적합 용도: 6 애플리케이션s: Automotive Battery Regulation, Portable Industrial Instruments, Distributed Supply Regulation, Always-On Battery-Powered Devices, Industrial 24V/28V Rail Conversion, Portable Medical Monitoring Devices.
Automotive Battery Regulation
The LT3971EMSE is ideal for automotive 12V battery rail regulation because of its 38V maximum input voltage (covering 12V battery plus load-dump transients up to ~35V) and 1.2A continuous output current capability. Its 2.8µA quiescent current in Burst Mode preserves battery life when the vehicle is parked, while the accurate 1V enable pin supports key-off load shedding. The 10-MSOP exposed pad package provides adequate thermal performance for underhood ECU applications. Used between the 12V battery and downstream 5V/3.3V rails powering body electronics, instrument clusters, and infotainment subsystems.
추천
Portable Industrial Instruments
Handheld test and measurement instruments benefit from the LT3971EMSE's combination of 38V wide input tolerance (supporting multi-cell battery packs and bench supplies) and 2.8µA quiescent current for extended field runtime. The 1.2A output handles display backlight, sensor excitation, and MCU core rails simultaneously. Programmable switching frequency from 200kHz to 2MHz allows designers to trade efficiency against component size — for compact handhelds, 1–2 MHz switching enables sub-10mm² inductors. The exposed-pad MSOP package dissipates moderate power without external heatsinking.
추천
Distributed Supply Regulation
In multi-rail systems, the LT3971EMSE acts as a point-of-load (POL) regulator stepping down intermediate bus voltages (e.g., 24V or 12V) to local 5V/3.3V rails at the load. Its Power Good output signals when VOUT reaches 91% of programmed value, enabling sequencing across multiple regulators without external logic. The 200kHz–2MHz programmable frequency avoids interference with sensitive analog/RF subsystems by clocking the converter outside their sensitive bands. With 1.2A capability, it powers FPGAs, MCUs, and transceiver rails independently.
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Always-On Battery-Powered Devices
Battery-powered always-on devices such as smart sensors, asset trackers, and IoT edge nodes leverage the LT3971EMSE's 2.8µA quiescent current and 700nA shutdown current to maximize battery life. The regulator stays in regulation at no load via Burst Mode, eliminating the periodic wake-up burden typical of PWM regulators. The accurate 1V EN threshold supports low-voltage microcontrollers that directly drive enable without level shifting. With 1.2A peak capability, the same IC can power both sleep-mode sensors and high-current transmitters during active transmissions.
추천
Industrial 24V/28V Rail Conversion
Factory automation systems, PLCs, and process controllers run on 24V or 28V industrial rails where the LT3971EMSE's 38V input comfortably covers nominal and transient conditions. The 1.2A output powers analog front-ends, isolated communication interfaces, and local logic from the 24V bus without intermediate regulators. The MSOP-10 exposed pad package fits dense PLC backplane layouts. Burst Mode operation keeps standby power below milliwatts for energy-conscious industrial designs targeting IEC efficiency standards.
추천
Portable Medical Monitoring Devices
Battery-powered patient monitors, glucose meters, and wearable health devices benefit from the LT3971EMSE's 2.8µA quiescent current (extending battery life between charges) and 1.2A peak output (powering BLE radios and display backlights during active measurements). The wide 38V input allows use with USB and external DC adapters interchangeably. The exposed pad MSOP package fits small wearable form factors. The Power Good flag can drive MCU interrupts to confirm stable rail before initiating measurements, improving measurement integrity.
추천
추천 제품 요약
엔지니어링 참조 데이터: LT3971EMSE — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | LT3971IMSE#PBF | LT3971EMSE-3.3#PBF | LT3971EMSE-5#PBF | LT3971AEMSE#PBF | LT3971EMSE#TRPBF |
|---|---|---|---|---|---|---|
| Package | 10-MSOP Exposed Pad | 10-MSOP Exposed Pad — same | 10-MSOP Exposed Pad — same | 10-MSOP Exposed Pad — same | 10-MSOP Exposed Pad — same | 10-MSOP Exposed Pad — same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage (max) | 38 V | 38 V | 38 V | 38 V | 38 V | 38 V |
| Output Current (max) | 1.2 A | 1.2 A | 1.2 A | 1.2 A | 1.2 A | 1.2 A |
| Quiescent Current (no load) | 2.8 µA | 2.8 µA | 2.8 µA | 2.8 µA | 2.8 µA | 2.8 µA |
| Switching Frequency Range | 200 kHz to 2 MHz | 200 kHz to 2 MHz | 200 kHz to 2 MHz | 200 kHz to 2 MHz | 200 kHz to 2 MHz | 200 kHz to 2 MHz |
| Output Voltage | Adjustable | Adjustable | Fixed 3.3 V | Fixed 5.0 V | Adjustable | Adjustable |
| Operating Junction Temperature | 0°C to +125°C (E grade) | -40°C to +125°C (I grade) | 0°C to +125°C (E grade) | 0°C to +125°C (E grade) | 0°C to +125°C (E grade) | 0°C to +125°C (E grade) |
| Reference Accuracy | Standard | Standard | Standard | Standard | Higher accuracy (A-grade) | Standard |
주요 차별점
- Ultra-low 2.8µA quiescent current with 700nA shutdown (vs TPS54360 (TI))
- Wide 38V maximum input voltage in a compact 10-MSOP package (vs LM2596 (legacy 5A buck))
- Programmable switching up to 2MHz enabling compact passives (vs MP1584 (Monolithic))
설계 노트
Estimated: place the input capacitor (≥1µF X7R ceramic) within 5mm of the VIN pin and GND pad to minimize switching-node ringing. The exposed thermal pad must be soldered to a copper pour covering at least 100mm² on the top layer (with thermal vias to inner/ground planes) for theta_JA reduction. Maintain a ground-return path under the SW trace to avoid EMI coupling into adjacent sensitive analog traces.
Do not operate the LT3971EMSE with output voltages above 38V — the absolute maximum VIN rating is 38V and load-dump transients on 12V automotive systems can exceed 35V. Always size the boost capacitor (BST to SW) at 0.1µF ceramic close to the IC. The RT resistor must be placed adjacent to the RT pin to avoid frequency jitter; floating or incorrectly sized RT resistors result in sub-harmonic oscillation or excessive switching losses.
Estimated: at 38V→5V conversion at 1.2A full load, the LT3971EMSE dissipates approximately (38-5) × 1.2 × (1-efficiency) ≈ 4–5W assuming 90% efficiency. The 10-MSOP exposed pad package has theta_JA near 40°C/W on a standard JEDEC 4-layer test board, resulting in a junction temperature rise of ~160–200°C above ambient — well above the 125°C rating. For full-load 38V→5V operation, either derate the output current, add airflow, or use additional copper thermal relief.
Burst Mode operation at light loads achieves the 2.8µA quiescent current specification. To preserve Burst Mode behavior, ensure the output capacitor ESR remains in the ceramic range (≤10 mΩ); high-ESR capacitors force PWM operation and defeat the ultra-low-IQ advantage. The SS capacitor value controls soft-start time per the Analog Devices datasheet — typical 10nF gives ~10ms startup, but larger values (100nF–1µF) extend soft-start for high-capacitive loads.
Keep the feedback (FB) trace short and routed away from the SW node and boost capacitor — capacitive coupling on FB causes output voltage ripple and potential instability. The PG pin is an open-drain output requiring a 100kΩ pull-up resistor to VOUT or an external logic rail. The NRT/SYNC pin accepts an external clock from 200kHz to 2MHz for noise-sensitive multi-rail systems where synchronized switching reduces beat frequencies.
규정 준수 정보
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified — for automotive safety-critical applications, select AEC-Q100 qualified equivalents. Lead-free (Pb-free) confirmed by #PBF suffix on the part number. Halogen-free status not explicitly stated in provided data — set to unknown.
