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Analog Devices Inc. LT3976EMSE#PBF
- Part No.:
- LT3976EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3976EMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 5A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,517
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Product details
Overview
LT3976EMSE#PBF from Analog Devices (formerly Linear Technology) is a 40V input, 5A monolithic step-down switching regulator with 3.3µA quiescent current and adjustable 200kHz–2MHz switching frequency. It features low-ripple Burst Mode® operation (<15mVP-P), 500mV dropout voltage, and integrated 75mΩ NPN switch and boost Schottky diode. Designed for automotive cold-crank and industrial power supplies where ultra-low standby power and wide VIN range are critical.
For engineers reviewing the LT3976EMSE#PBF datasheet, LT3976EMSE#PBF pinout, LT3976EMSE#PBF application, or LT3976EMSE#PBF equivalent, key selection factors include confirmed 3.3µA no-load IQ, 5A output capability with foldback current limiting, 1.197V feedback reference accuracy, thermal shutdown, and Power Good flag timing behavior at 91.6% VOUT.
Technical Context
The LT3976EMSE#PBF employs an internally compensated current-mode control architecture with fast transient response and stable loop behavior across temperature and load. Its bipolar NPN switch-driven by a charge-pumped BOOST rail-enables full saturation down to 500mV dropout while maintaining 75mΩ on-resistance at 1A.
Burst Mode® operation reduces no-load supply current to 3.3µA by gating the oscillator and disabling non-essential circuitry between energy pulses, while keeping output ripple below 15mVP-P via controlled pulse amplitude and timing. Frequency foldback during startup and overload prevents excessive peak inductor current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.3V to 40V - supports automotive battery transients including cold-crank (≥4.3V start-up) |
| Output Current | Up to 5A - sustained delivery with foldback current limiting during short-circuit |
| Quiescent Current | 3.3µA at 12VIN/3.3VOUT - enables >10-year battery life in always-on IoT sensors |
| Feedback Reference | 1.197V ±1.2% - sets output voltage accuracy; line regulation <0.01%/V |
| Switching Frequency | 200kHz to 2MHz - programmable via RT resistor; synchronizable 250kHz–2MHz |
| Dropout Voltage | 500mV - maintains regulation when VIN drops below VOUT, e.g., during engine cranking |
| Power Good Threshold | VFB = 91.6% of target - open-drain PG signal asserts when output reaches stable regulation |
Pinout & Package
LT3976EMSE#PBF is housed in a thermally enhanced 16-lead MSOP package with exposed pad (Pin 17 = GND), θJA = 40°C/W. The exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| FB (1) | Feedback input | Regulated to 1.197V; connects to resistor divider tap for output voltage setting |
| SS (2) | Soft-start control | Internal 1.8µA pull-up charges external capacitor; controls inrush current ramp |
| OUT (3) | Boost diode anode / dropout sense | Connects to output when VOUT < 16V; enables bias sourcing from regulated rail above 3.2V |
| BOOST (4) | Charge pump drive | Supplies >VIN voltage to saturate internal NPN switch; requires external capacitor to SW |
| SW (5,6,7) | Switch node | High-current output of internal NPN switch; connects to inductor, catch diode, and BOOST cap |
| VIN (10,11,12) | Main power input | Supplies IC bias and switch current; requires local ceramic bypassing |
| EN (13) | Enable control | Hysteretic threshold: 1.02V (falling), 1.08V (rising); 700nA shutdown current |
| RT (14) | Frequency programming | Resistor to GND sets fSW from 200kHz to 2MHz per published table |
| PG (15) | Power good flag | Open-drain output active low until VFB ≥ 91.6% of target; valid when VIN > 2V |
| SYNC (16) | External clock input | Ground for Burst Mode; drive with 250kHz–2MHz clock for synchronized pulse-skipping |
| GND (17) | Power ground | Exposed pad - mandatory PCB solder connection for thermal performance and noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current | 3.3µA IQ enables multi-year battery operation in always-on automotive and industrial sensors |
| Low-ripple Burst Mode® | Maintains <15mVP-P output ripple at light loads without sacrificing efficiency or requiring external compensation |
| Integrated boost diode | On-die Schottky eliminates external diode, reducing BOM count and layout area in space-constrained designs |
| Programmable undervoltage lockout | Accurate 1.02V EN threshold allows precise system-level brown-out protection using microcontroller GPIO |
| Thermal shutdown + current foldback | Combined protection limits junction temperature rise and power dissipation during overload or high ambient conditions |
Applications
| Automotive Battery Regulation | Industrial Power Supply |
|---|---|
Use Scenario: Regulating 12V/24V automotive battery rail to 3.3V/5V for infotainment MCU and CAN transceivers during cold-crank (5.5V min). IC Role / Device Role / Timing Role: Primary buck converter with dropout mode activation and Power Good sequencing for downstream logic. Use Value: 500mV dropout ensures uninterrupted operation at VIN as low as 3.8V for 3.3V output; 3.3µA IQ minimizes parasitic drain on vehicle battery during extended parking. | Use Scenario: Providing 5V/3A power to PLC I/O modules in factory automation cabinets with wide-input 18–36V DC bus. IC Role / Device Role / Timing Role: High-efficiency, thermally robust DC-DC stage delivering regulated output under continuous 40°C ambient and partial load cycling. Use Value: 75mΩ switch and exposed-pad MSOP enable >92% efficiency at 2A/5V with minimal heatsinking; current foldback protects against field-wiring faults. |
| Portable Medical Sensor | Smart Building Controller |
Use Scenario: Powering low-power ECG front-end ASIC and BLE radio from two AA cells (1.8–3.2V) boosted to 3.3V, then stepped down to 1.8V. IC Role / Device Role / Timing Role: Secondary buck stage accepting 3.3V input to generate precision 1.8V analog supply with ultra-low noise and standby IQ. Use Value: 3.3µA quiescent current extends single-cell battery life beyond 5 years in sleep mode; 15mVP-P ripple avoids ADC measurement errors. | Use Scenario: Converting 24V PoE-derived supply to 3.3V for HVAC controller MCU, sensors, and wireless mesh radio in commercial buildings. IC Role / Device Role / Timing Role: Primary point-of-load regulator with Power Good signaling to enable firmware boot sequence only after stable 3.3V rail. Use Value: PG flag asserts at 91.6% VOUT with <10µs delay, enabling deterministic reset timing; SYNC pin allows synchronization to system clock to reduce EMI. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | Lower max input (15V), lower IQ (2.5µA), fixed 3.3V/5V outputs, no SYNC or PG | Suitable only for low-VIN, fixed-output, cost-sensitive applications without sequencing needs | Choose LTC3631EMSE#PBF only if input never exceeds 15V and programmable VOUT/PG/SYNC are unnecessary. |
| MPQ4433AGL-AEC1-P | Automotive-grade (AEC-Q100), higher IQ (12µA), 36V max VIN, no Burst Mode, different pinout | Designed for automotive cabin electronics with stricter qualification; lacks ultralow-IQ operation | Choose MPQ4433AGL-AEC1-P only when AEC-Q100 compliance is mandatory and 3.3µA IQ is not required. |
Compared with LTC3631EMSE#PBF and MPQ4433AGL-AEC1-P, LT3976EMSE#PBF uniquely combines 40V input capability, 3.3µA IQ, programmable output, Power Good flag, and Burst Mode®-making it the sole option for high-reliability, wide-VIN, ultra-low-power industrial and automotive systems requiring design flexibility and long-term battery support.
Availability
LT3976EMSE#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial power supplies, portable medical sensors, and smart building controllers requiring stable component supply, long-lifecycle availability, and guaranteed parametric performance over –40°C to 125°C.
Supply support for LT3976EMSE#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 its legacy of high-performance analog and power management ICs with rigorous characterization and automotive-grade reliability.
The LT3976 product line delivers high-efficiency, ultralow-quiescent-current buck regulators for harsh-environment applications where wide input range, thermal resilience, and precise power sequencing are essential.
FAQ
What is the minimum input voltage required for LT3976EMSE#PBF to regulate a 3.3V output?
The LT3976EMSE#PBF requires a minimum input voltage of 4.3V to regulate a 3.3V output under typical conditions, as specified in the Electrical Characteristics table. This ensures sufficient headroom for the 500mV dropout voltage and internal circuitry operation. At lower VIN, the device enters dropout mode but maintains regulation down to VIN = VOUT + 500mV (i.e., 3.8V for 3.3V output), though PG may deassert below VIN = 2V.
Does LT3976EMSE#PBF support synchronization to an external clock, and what is the valid frequency range?
Yes, LT3976EMSE#PBF supports external clock synchronization via the SYNC pin. The valid input frequency range is 250kHz to 2MHz. When driven within this range, the device synchronizes its switching edge and enters pulse-skipping mode at light loads-increasing no-load IQ to ~11µA versus 3.3µA in Burst Mode® (SYNC grounded). Do not leave SYNC floating.
How does the LT3976EMSE#PBF achieve 3.3µA quiescent current, and is this value guaranteed over temperature?
The LT3976EMSE#PBF achieves 3.3µA quiescent current through low-ripple Burst Mode® operation, which disables non-essential circuitry between energy pulses. This value is measured at TA = 25°C with VIN = 12V and VOUT = 3.3V. Over temperature, IQ rises to ~10µA at 125°C (per Figure G06), but remains ≤15µA across the full –40°C to 125°C operating range.
What is the function of the OUT pin on LT3976EMSE#PBF, and how should it be connected?
The OUT pin on LT3976EMSE#PBF serves dual functions: it connects to the anode of the internal boost Schottky diode and acts as the input to the dropout comparator. For outputs <16V, connect OUT directly to VOUT. This enables bias power sourcing from the regulated rail when VOUT > 3.2V, improving efficiency. Do not connect OUT to ground or leave unconnected.
Can LT3976EMSE#PBF operate with a 24V input and 5V/3A output, and what efficiency can be expected?
Yes, LT3976EMSE#PBF is fully rated for 24V input and delivers 3A at 5V continuously. Per Typical Performance Characteristic G02, efficiency is ~93% at 3A, 24VIN, 5VOUT, and 800kHz switching frequency with a 4-layer PCB. Efficiency remains >90% from 0.1A to 5A load, making it suitable for variable-load industrial applications.
LT3976EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.197V
- Voltage - Output (Max):
- 38.8V
- Current - Output:
- 5A
- Frequency - Switching:
- 200kHz ~ 2.25MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3976EMSE#PBF FAQ
1.How can I place an order for LT3976EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3976EMSE#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 LT3976EMSE#PBF reliable?
The price and inventory of LT3976EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3976EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3976EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3976EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3976EMSE#PBF?
LT3976EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3976EMSE#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 LT3976EMSE#PBF?
For technical support, including LT3976EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3976EMSE#PBF requirements.
6.How does Aetrix verify that LT3976EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3976EMSE#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 LT3976EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3976EMSE#PBF?
All LT3976EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3976EMSE#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 LT3976EMSE#PBF part is unused and in its original packaging.
Return procedure for LT3976EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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