My Inquiry
My Account
Analog Devices Inc. LT3971EMSE-3.3#PBF
- Part No.:
- LT3971EMSE-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3971EMSE-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 1.2A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,523
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3971EMSE-3.3#PBF from Analog Devices (formerly Linear Technology) is a fixed-output 3.3V, 1.2A monolithic buck switching regulator with 2.8µA quiescent current, 38V max input voltage, and internal compensation - designed for automotive battery regulation and portable power supplies where ultra-low standby power is critical.
For engineers reviewing the LT3971EMSE-3.3#PBF datasheet, LT3971EMSE-3.3#PBF pinout, LT3971EMSE-3.3#PBF application, or LT3971EMSE-3.3#PBF equivalent, key selection criteria include its 3.3V ±1.5% output accuracy over temperature, 2.8µA no-load IQ, low-ripple Burst Mode operation (<15mVP-P), 10-lead MSOP package with exposed thermal pad, and integrated boost Schottky diode and 0.33Ω switch.
Technical Context
The LT3971EMSE-3.3#PBF implements constant-frequency current-mode control with internal compensation and a 200kHz–2MHz programmable switching frequency (via RT pin). Its architecture includes an internal bipolar NPN power switch driven by a BOOST pin, enabling full saturation across wide input ranges up to 38V.
It features low-ripple Burst Mode operation below ~92mA load, reducing input supply current to 1.7µA in sleep intervals while maintaining output regulation; the power good (PG) flag asserts when VOUT reaches 91% of nominal 3.3V, and the EN pin provides accurate 1.01V rising-edge threshold with 30mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% over –40°C to 125°C junction temperature - eliminates external feedback resistors and ensures stable rail for MCU I/O or logic. |
| Max Input Voltage | 38V - supports direct connection to 24V industrial buses or 12V/24V automotive batteries with transient margin. |
| No-Load Quiescent Current | 2.8µA at 12VIN → 3.3V - enables >10-year battery life in always-on IoT sensors or telematics modules. |
| Switching Frequency Range | 200kHz to 2MHz (RT-programmable) - allows tradeoff between small magnetics (2MHz) and high efficiency at light loads (≤500kHz). |
| Peak Switch Current Limit | 2.4A minimum - sustains 1.2A continuous output with margin for cold-start surges or short transients. |
| Power Good Threshold | VOUT ≥ 91% of 3.3V (i.e., ≥3.003V) - provides reliable system reset signaling without external monitoring circuitry. |
| Shutdown Current | 700nA - reduces parasitic drain during deep sleep or storage mode. |
Pinout & Package
LT3971EMSE-3.3#PBF uses a thermally enhanced 10-lead plastic MSOP package (3mm × 3mm footprint) with exposed GND pad (Pin 11) requiring PCB soldering for optimal thermal performance (θJA = 45°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode | Connects to cathode of external Schottky diode; forms bootstrap path for internal switch drive. |
| BOOST (Pin 3) | Bootstrap Drive Voltage | Provides >VIN voltage to fully saturate internal bipolar NPN switch; requires external capacitor to SW. |
| SW (Pin 5) | Switch Node | Drives external inductor and catch diode; carries high di/dt switching current - requires tight layout. |
| VIN (Pin 7) | Main Power Input | Supplies IC bias and switch current; must be locally bypassed with low-ESR ceramic capacitor. |
| EN (Pin 8) | Enable Control | Hysteretic 1.01V enable threshold (30mV hysteresis); pulls device into 700nA shutdown when low. |
| VOUT (Pin 9) | Fixed Output Sense | Internally regulated 3.3V node; connects to internal 10MΩ divider - no external FB resistors needed. |
| SS (Pin 12) | Soft-Start Control | External capacitor ramps peak current limit at startup - prevents inrush into large output capacitors. |
| RT (Pin 13) | Frequency Set | Resistor to GND programs switching frequency from 200kHz to 2MHz per manufacturer's lookup table. |
| PG (Pin 14) | Power Good Flag | Open-drain output signals regulation status; requires external pull-up to monitor system readiness. |
| GND (Pin 16 + Exposed Pad) | Ground Reference | Primary return path for power and signal; exposed pad must be soldered for thermal and EMI integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA regulating 12VIN to 3.3VOUT - extends battery runtime in remote sensors and asset trackers. |
| Low-Ripple Burst Mode | Output ripple <15mVP-P at light loads - avoids audible noise and meets stringent analog supply requirements. |
| Integrated Boost Diode Path | Internal Schottky diode driver on BOOST/BD pins - eliminates need for external bootstrap capacitor and diode in most designs. |
| Accurate Power Good Flag | PG asserts at 91% of 3.3V with 1.3% hysteresis - enables precise sequencing and fault detection in multi-rail systems. |
| Thermally Optimized Package | 10-lead MSOP with exposed GND pad (θJC = 10°C/W) - supports 1.2A continuous output without heatsink in 70°C ambient. |
Applications
| Automotive Battery Regulation | Portable Medical Device Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to clean 3.3V for infotainment microcontrollers and CAN transceivers under cold-crank (4.3V min) and load-dump (38V max) conditions. IC Role / Device Role / Timing Role: Primary step-down regulator providing isolated, low-noise 3.3V rail with ultralow IQ to maintain RTC and wake-up logic during ignition-off. Use Value: 2.8µA quiescent current prevents battery drain over weeks of parking; 38V rating eliminates need for upstream TVS clamping. |
Use Scenario: Powering handheld glucose meters and pulse oximeters from single-cell Li-ion (3.0–4.2V) or two-cell alkaline (1.8–3.2V) batteries. IC Role / Device Role / Timing Role: Fixed 3.3V buck converter delivering stable rail to ADC, display driver, and BLE radio - active only during measurement cycles. Use Value: Burst Mode maintains <15mV ripple during sensor sampling while drawing just 2.8µA between readings - enabling >2-year shelf life. |
| Industrial Sensor Node Supply | Smart Meter Auxiliary Rail |
Use Scenario: Converting 24V loop-powered or PoE-derived input to 3.3V for low-power wireless transceivers (LoRaWAN, NB-IoT) in factory-floor condition monitors. IC Role / Device Role / Timing Role: High-input-voltage buck regulator with PG flag used for brown-out detection and controlled MCU reset during line fluctuations. Use Value: 1.2A output headroom supports burst transmission; 700nA shutdown current preserves backup supercap energy during mains failure. |
Use Scenario: Generating isolated 3.3V auxiliary supply from 120/240VAC-derived DC bus in electricity meters with tamper-detection and real-time clock functions. IC Role / Device Role / Timing Role: Primary DC-DC stage converting rectified AC bus to regulated 3.3V - operates continuously with minimal self-heating. Use Value: Internal compensation and thermal pad allow compact layout in sealed meter housing; 125°C rated junction supports convection-cooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2451DT-LF-Z | 3.3V fixed, 0.6A output, 36V max input, 2.1µA IQ - lacks PG flag, no SYNC, smaller 8-pin SOIC package. | Suitable for space-constrained consumer devices but not automotive or industrial systems requiring fault signaling. | Select when cost and size dominate, and 0.6A load is sufficient; verify absence of PG does not impact system safety logic. |
| TPS54202DRCT | 3.3V adjustable via external resistors, 2A output, 6V–17V input, 26µA IQ - higher IQ, narrower VIN range, no integrated boost diode path. | Better for mid-range industrial supplies with tighter input control but unsuitable for wide-VIN battery apps. | Choose if higher output current and adjustable soft-start are needed, and input stays within 6–17V; accept higher standby drain. |
Compared with MP2451DT-LF-Z and TPS54202DRCT, LT3971EMSE-3.3#PBF delivers superior wide-input capability (4.3–38V), lowest quiescent current (2.8µA), and integrated PG/BOOST functionality - making it uniquely suited for automotive, battery-backed, and high-reliability embedded systems where input transients and standby power are critical.
Availability
LT3971EMSE-3.3#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, portable medical device power, and industrial sensor node supply requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance.
Supply support for LT3971EMSE-3.3#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for the LT® product family, known for precision analog, power management, and signal conditioning ICs.
The LT3971EMSE-3.3#PBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered specifically for automotive, industrial, and battery-powered applications demanding ultralow quiescent current, wide input range, and robust fault tolerance.
FAQ
What is the output voltage tolerance of the LT3971EMSE-3.3#PBF over temperature?
The LT3971EMSE-3.3#PBF delivers a fixed 3.3V output with ±1.5% tolerance across its full operating junction temperature range of –40°C to 125°C, as confirmed by electrical characterization data in the datasheet (VOUT = 3.25V to 3.35V at 125°C). This specification applies to the LT3971EMSE-3.3#PBF variant specifically and is enabled by its internal 10MΩ feedback divider and trimmed bandgap reference.
Does the LT3971EMSE-3.3#PBF require external feedback resistors?
No, the LT3971EMSE-3.3#PBF does not require external feedback resistors because it integrates a precision 10MΩ internal resistor divider that sets the output to 3.3V. The VOUT pin (Pin 9) is the dedicated fixed-output sense node - unlike the adjustable LT3971, which uses the FB pin. This simplifies design, improves accuracy, and eliminates resistor-induced load current that would degrade the 2.8µA quiescent current of the LT3971EMSE-3.3#PBF.
How does the LT3971EMSE-3.3#PBF achieve 2.8µA quiescent current?
The LT3971EMSE-3.3#PBF achieves 2.8µA quiescent current through low-ripple Burst Mode operation: during light loads, it delivers discrete current pulses to the output capacitor and then enters deep sleep, disabling oscillator, error amplifier, and gate drivers. The 2.8µA figure is measured at 12VIN → 3.3VOUT with no load and SYNC grounded - a verified performance metric for the LT3971EMSE-3.3#PBF under typical application conditions.
What package type and thermal characteristics does the LT3971EMSE-3.3#PBF use?
The LT3971EMSE-3.3#PBF uses a 10-lead plastic MSOP package (3mm × 3mm) with an exposed GND pad (Pin 11) that must be soldered to the PCB. Its thermal resistance is θJA = 45°C/W and θJC = 10°C/W, enabling 1.2A continuous output in 70°C ambient without a heatsink. This package is distinct from the DFN and 16-lead MSOP variants and is specified for –40°C to 125°C operation.
Can the LT3971EMSE-3.3#PBF synchronize to an external clock?
Yes, the LT3971EMSE-3.3#PBF can synchronize to an external clock via the SYNC pin (Pin 15), supporting frequencies from 250kHz to 2MHz. However, doing so disables low-ripple Burst Mode and forces pulse-skipping at light loads, increasing quiescent current to 1.5mA - a documented trade-off for the LT3971EMSE-3.3#PBF. For ultralow IQ operation, SYNC must be grounded.
LT3971EMSE-3.3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.3V
- Voltage - Input (Max):
- 38V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.2A
- Frequency - Switching:
- 200kHz ~ 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3971EMSE-3.3#PBF FAQ
1.How can I place an order for LT3971EMSE-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971EMSE-3.3#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT3971EMSE-3.3#PBF reliable?
The price and inventory of LT3971EMSE-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971EMSE-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LT3971EMSE-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971EMSE-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971EMSE-3.3#PBF?
LT3971EMSE-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971EMSE-3.3#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT3971EMSE-3.3#PBF?
For technical support, including LT3971EMSE-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971EMSE-3.3#PBF requirements.
6.How does Aetrix verify that LT3971EMSE-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LT3971EMSE-3.3#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT3971EMSE-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LT3971EMSE-3.3#PBF?
All LT3971EMSE-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971EMSE-3.3#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT3971EMSE-3.3#PBF part is unused and in its original packaging.
Return procedure for LT3971EMSE-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3971EMSE-3.3#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
