LT3971EMSE-3.3#PBF - 38V, 1.2A, 2MHz Buck Regulator | Analog Devices
MPN: LT3971EMSE-3.3#PBF ✓ فعالLT3971EMSE-3.3#PBF جائزہ
A buck (step-down) switching regulator is a DC-DC converter that efficiently reduces a higher DC input voltage to a lower DC output voltage by rapidly switching a power transistor and smoothing the resulting pulse train with an LC filter. The LT3971 family occupies the hierarchy: buck regulator → switching regulator → DC-DC converter → power management IC → semiconductor. Compared with linear regulators, buck regulators achieve much higher efficiency at large VIN/VOUT ratios, making them preferred for battery-powered and automotive systems where thermal dissipation is a concern.
The LT3971's key features include a 4.3V to 38V input range, integrated power switch, 700 nA shutdown supply current (via an accurate 1V threshold enable pin), programmable soft-start with a capacitor on the SS pin, and a power-good flag that asserts at 91% of the programmed output voltage. The MSE package combines a small 10-pin MSOP outline with an exposed thermal pad for low thermal resistance.
Internally, the LT3971 uses a current-mode control topology with Burst Mode operation that allows the regulator to maintain output voltage with only 2.8 µA quiescent current at no load - ideal for always-on battery systems. The high 2 MHz switching capability supports small inductor and capacitor selection, while the 38V absolute maximum input accommodates load-dump and cold-crank transients in 12V automotive rails.
Typical applications include automotive battery-powered systems, industrial control supplies, portable instrumentation, distributed supply regulation in 24V industrial buses, and always-on housekeeping rails in IoT nodes. The wide VIN range also suits solar and telecom point-of-load regulation downstream of a higher-voltage bus.
When designing, prioritize input bulk capacitance to handle inductor ripple, place the BST capacitor close to the SW and BST pins, and use a low-ESR ceramic output capacitor for ripple performance. The exposed pad must be soldered to a sufficiently large copper pour to keep junction temperature within the 125°C limit.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
کے لیے ڈراپ اِن متبادل LT3971EMSE-3.3#PBF — یکساں پیکیج، پن سے پن مطابقت پذیر۔ مختلف پیکیج والے پرزے جن کے لیے PCB دوبارہ کام درکار ہو، شامل نہیں ہیں۔
اس سیریز میں مختلف ورژن
اسی سیریز کے ماڈلز جو ڈراپ اِن مطابقت رکھتے ہیں LT3971EMSE-3.3#PBF (یکساں فارم فیکٹر اور فٹ پرنٹ) — میں مختلف Package, Quiescent Current, RoHS Status, Switching Frequency, Input Voltage Range.
LT3971EMSE-3.3#TRPBF
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
LT3971EMSE#PBF
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LT3971EMSE-5#PBF
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
LT3971EMSE-3.3
✅ ڈراپ-اِن ⚠️ تفصیلات غیر تصدیق شدہقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LT3971IMSE-3.3#PBF
✅ ڈراپ-اِن ⚠️ تفصیلات غیر تصدیق شدہ📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
LT3971HMSE-3.3#PBF
✅ ڈراپ-اِن ⚠️ تفصیلات غیر تصدیق شدہ📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
LT3971EMSE-3.3#PBF زیادہ سے زیادہ ریٹنگز اور برقی خصوصیات
| ٹوپولوجی | Buck (Step-Down) |
| اِن پٹ وولٹیج رینج | 4.3 V to 38 V |
| آؤٹ پٹ وولٹیج | 3.3 V (fixed) |
| زیادہ سے زیادہ آؤٹ پٹ کرنٹ | 1.2 A |
| سوئچنگ فریکوئنسی | Up to 2 MHz (adjustable) |
| کوئیسینٹ کرنٹ | 2.8 µA (Burst Mode, no load) |
| Shutdown Supply Current | 700 nA |
| آپریٹنگ درجہ حرارت رینج | -40 °C to +125 °C |
| پیکیج | 10-MSOP with Exposed Pad (MSE), 3.00 mm width |
| ماؤنٹنگ ٹائپ | Surface Mount |
| Enable Pin Threshold | 1 V (accurate) |
| Power Good Flag | Asserts at 91% of VOUT |
| سافٹ اسٹارٹ | Programmable via SS capacitor |
| MSL لیول | 1 (unlimited) |
| RoHS اسٹیٹس | Compliant (Pb-free #PBF suffix) |
LT3971EMSE-3.3#PBF پن کنفیگریشن
| پن 1 | OUT — Output voltage sense (3.3 V fixed) |
| پن 2 | VIN — Input supply voltage (4.3 V to 38 V) |
| پن 3 | GND — Signal ground |
| پن 4 | EN — Enable input (1 V threshold, high to enable) |
| پن 5 | SS — Soft-start programming capacitor node |
| پن 6 | RT — Timing resistor for switching frequency |
| پن 7 | PGOOD — Power-good flag (open-drain, asserts at 91% of VOUT) |
| پن 8 | BST — Boost capacitor for high-side gate drive |
| پن 9 | SW — Switch node (connect to inductor) |
| پن 10 | PGND — Power ground (connect to exposed pad) |
عام استعمالات
LT3971EMSE-3.3#PBF کے لیے موزوں ہے 6 ایپلیکیشنs: Automotive 12V Battery-Powered Systems, Industrial 24V Sensor and Actuator Rails, Always-On IoT Housekeeping Supplies, Distributed Point-of-Load Regulation in Telecom Systems, Portable Test and Measurement Instrumentation, Solar-Powered Remote Sensor Nodes.
Automotive 12V Battery-Powered Systems
The LT3971EMSE-3.3#PBF fits automotive 12V battery rails because its 38 V maximum input withstands the ISO 7637-2 load-dump transient (typically 35 V for 400 ms). The 1.2 A output at fixed 3.3 V powers body-control modules, RKE receivers, and sensor hubs directly from the battery without a preregulator. The 2.8 µA Burst Mode quiescent current keeps quiescent drain under 100 µA even when the MCU is asleep, which helps the vehicle meet the < 100 µA quiescent-current budget mandated by many OEMs. Place the exposed pad on a 1 sq. inch copper pour to dissipate the 1 W-3 W typical load power at VIN=13.5 V, VOUT=3.3 V, IOUT=1 A.
تجویز کردہ
Industrial 24V Sensor and Actuator Rails
The LT3971EMSE-3.3#PBF is well-matched to industrial 24V bus rails (18-32 V typical) because its 38 V rating provides 6 V of headroom above the upper bus limit and its 1.2 A capacity handles small PLC sensor banks. The fixed 3.3 V output directly powers 3.3 V analog Micro controllers and HART modems. Compared with a discrete switching controller plus external MOSFET, the integrated LT3971 shrinks the BOM by 60% and eliminates most PCB layout risk. Estimated efficiency at VIN=24 V, VOUT=3.3 V, IOUT=1 A is ~70%; the exposed pad must be soldered to at least 0.5 sq. inch of copper to keep junction temperature below 100 °C in a sealed IP65 enclosure.
تجویز کردہ
Always-On IoT Housekeeping Supplies
The LT3971EMSE-3.3#PBF suits always-on IoT housekeeping because its 2.8 µA Burst Mode quiescent current extends battery life by 5-10× versus a fixed-frequency PFM regulator. At VIN=6 V (two alkaline cells), the 1.2 A output can supply a low-power wireless MCU plus a low-duty-cycle sensor, while drawing under 5 µA when the load is asleep. The PGOOD flag can wake the host MCU only when the rail is healthy, reducing false wake events. The 10-MSOP exposed-pad footprint occupies 9 mm² of PCB, leaving room for a CR2032 coin-cell backup rail on the same board.
تجویز کردہ
Distributed Point-of-Load Regulation in Telecom Systems
The LT3971EMSE-3.3#PBF supports telecom point-of-load regulation because its 38 V input handles -48 V telecom rails through a front-end preregulator that drops to 12 V or 24 V, and its 2 MHz switching frequency enables a 4.7 µH inductor that fits behind a BGA ASIC. The fixed 3.3 V output directly powers DSPs, FPGAs, and clock buffers in line cards. The 700 nA shutdown current allows sleep-mode current budgets to be met when the line card is idle, while the soft-start pin avoids inrush into hot-swapped backplanes. Multiple LT3971s can be paralleled with phased switching to reduce input ripple.
تجویز کردہ
Portable Test and Measurement Instrumentation
The LT3971EMSE-3.3#PBF fits portable battery-powered test gear because its 2.8 µA quiescent current preserves battery life during standby, while its 1.2 A peak output handles the inrush of a brief measurement cycle. The fixed 3.3 V output powers low-power ADCs, op-amps, and display drivers in handheld multimeters and oscilloscope probes. Compared with a SEPIC or flyback topology, the LT3971's simple buck configuration needs only one inductor and one Schottky diode, reducing BOM cost and PCB area by 40% - critical for hand-held form factors.
تجویز کردہ
Solar-Powered Remote Sensor Nodes
The LT3971EMSE-3.3#PBF suits solar-powered remote sensors because its 38 V input tolerates open-circuit voltages of 30 V from small 72-cell solar panels, while its 100% duty-cycle operation maximizes energy harvest as the panel voltage droops during cloud events. The fixed 3.3 V output directly powers LoRa or NB-IoT modems and environmental sensors. Estimated battery life at 1% duty cycle (10 mA average load, 2.8 µA quiescent) exceeds 5 years on a 2.6 Ah LiSOCl2 pack, eliminating field service calls. The exposed pad allows operation at +85 °C ambient without thermal shutdown.
تجویز کردہ
تجویز کردہ پروڈکٹس کا خلاصہ
کے لیے انجینئرنگ ریفرنس ڈیٹا LT3971EMSE-3.3#PBF — موازنہ، ڈیزائن رہنمائی، اور تعمیل کی معلومات۔
انتخاب کی گائیڈ
متبادلات کے ساتھ موازنہ
| پیرامیٹر | یہ پروڈکٹ | LT3971EMSE-3.3#TRPBF | LT3971EMSE#PBF | LT3971EMSE-5#PBF | LT3971IMSE-3.3#PBF | LT3971HMSE-3.3#PBF |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 10-MSOP with Exposed Pad (MSE) | 10-MSOP with Exposed Pad (MSE) - same | 10-MSOP with Exposed Pad (MSE) - same | 10-MSOP with Exposed Pad (MSE) - same | 10-MSOP with Exposed Pad (MSE) - same | 10-MSOP with Exposed Pad (MSE) - same |
| Output Voltage | 3.3 V fixed | 3.3 V fixed | 1.19 V to 30 V adjustable | 5 V fixed | 3.3 V fixed | 3.3 V fixed |
| Maximum Output Current | 1.2 A | 1.2 A | 1.2 A | 1.2 A | 1.2 A | 1.2 A |
| Input Voltage Range | 4.3 V to 38 V | 4.3 V to 38 V | 4.3 V to 38 V | 4.3 V to 38 V | 4.3 V to 38 V | 4.3 V to 38 V |
| Quiescent Current | 2.8 µA (Burst Mode) | 2.8 µA | 2.8 µA | 2.8 µA | 2.8 µA | 2.8 µA |
| Switching Frequency | Up to 2 MHz | Up to 2 MHz | Up to 2 MHz | Up to 2 MHz | Up to 2 MHz | Up to 2 MHz |
| Temperature Grade | E: -40 °C to +125 °C | E: -40 °C to +125 °C | E: -40 °C to +125 °C | E: -40 °C to +125 °C | I: -40 °C to +125 °C (industrial) | H: -40 °C to +150 °C (military) |
اہم امتیازی خصوصیات
- Fixed 3.3 V output eliminates external feedback divider (بمقابلہLT3971EMSE#PBF)
- Same MSE package as 5 V sibling - drop-in on 5 V designs (بمقابلہLT3971EMSE-5#PBF)
- 38 V input withstands 24 V industrial and 12 V automotive load-dump (بمقابلہLT3971IMSE-3.3#PBF)
ڈیزائن نوٹس
Place the input bulk capacitor (≥ 10 µF ceramic plus optional 47 µF aluminum polymer) within 5 mm of the VIN pin to minimize switching noise injection into the input rail. The BST capacitor (≥ 100 nF) must sit within 2 mm of the BST pin with a short, wide trace to SW. The exposed pad must be soldered to a continuous copper pour of at least 0.5 sq. inch on the top layer plus thermal vias to inner ground planes to keep junction temperature below 110 °C at full load.
Estimated: At VIN = 12 V, VOUT = 3.3 V, IOUT = 1 A, the LT3971EMSE-3.3#PBF dissipates roughly (12 - 3.3) × 1 × (1 - 0.82) ≈ 1.6 W (assuming 82% efficiency). With the MSOP-10 exposed-pad thermal resistance of about 45 °C/W on a JEDEC 4-layer test board, junction rise is ~72 °C above ambient, giving a max ambient of about 53 °C at the 125 °C limit. For higher VIN or higher load, expand the copper pour or use multiple vias under the exposed pad.
Do not leave the SS pin floating - it must have a capacitor to ground (≥ 1 nF) or soft-start will not function and inrush current can trip the input fuse. The EN pin has an accurate 1 V threshold; if left floating it may drift into the indeterminate region and cause unreliable startup. Tie EN to VIN through a 100 kΩ resistor when always enabled. Avoid using output capacitors with ESR below 5 mΩ to prevent subharmonic instability in current-mode control.
تعمیل کی معلومات
#PBF suffix indicates Pb-free finish per RoHS. REACH compliance per Analog Devices material declarations. Not AEC-Q100 qualified - for automotive designs requiring AEC-Q100, use a Q100-graded part. Halogen-free status not stated in the verified data.
