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Analog Devices Inc. LT8611EUDD#PBF
- Part No.:
- LT8611EUDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT8611EUDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:9,637
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Product details
Overview
LT8611EUDD#PBF from Analog Devices is a 42V, 2.5A synchronous step-down regulator with integrated top/bottom MOSFETs, 2.5µA quiescent current in Burst Mode, 0.97V feedback reference, and rail-to-rail current sense amplifier for input/output current regulation. It operates from 3.4V to 42V input and delivers up to 2.5A output current with <10mVP-P ripple - used in automotive infotainment power supplies requiring ultra-low IQ and high efficiency across wide load ranges.
For engineers reviewing the LT8611EUDD#PBF datasheet, LT8611EUDD#PBF pinout, LT8611EUDD#PBF application, or LT8611EUDD#PBF equivalent, key selection criteria include ultralow quiescent current (2.5µA), programmable switching frequency (200kHz–2.2MHz), ±9% power-good accuracy, 50ns minimum on-time, and AEC-Q100 qualification for automotive environments.
Technical Context
The LT8611EUDD#PBF implements peak current mode control with internal compensation, enabling fast transient response and stable operation with small inductors. Its dual-path current sensing (ISP/ISN) supports accurate input or output current limiting, while the ICTRL pin allows dynamic adjustment of the 50mV default current-sense threshold down to ~5mV.
Burst Mode operation maintains high efficiency at light loads by disabling switching circuitry between energy pulses, keeping output ripple below 10mVP-P. The SYNC pin enables external clock synchronization or pulse-skipping mode, disabling frequency foldback when driven high or clocked - critical for EMI-sensitive automotive applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports 12V/24V/36V automotive battery rails with cold-crank tolerance down to 3.4V. |
| Output Current | 2.5A continuous - determined by thermal design and PCB layout; top FET current limit is 4.8A typical. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT - enables >10-year battery life in always-on automotive modules. |
| Feedback Reference | 0.970V ±3mV - enables precise output voltage setting with 1% resistors and low divider current. |
| Switching Frequency | 200kHz to 2.2MHz - programmable via RT resistor; 700kHz typical for optimal size/efficiency trade-off. |
| Minimum On-Time | 50ns - supports high VIN-to-VOUT ratios (e.g., 36V→3.3V) without pulse skipping. |
| Power-Good Accuracy | ±9% of VFB - PG asserts when VOUT is within ±9% of 0.97V reference, ensuring reliable system sequencing. |
Pinout & Package
The LT8611EUDD#PBF is housed in a thermally enhanced 24-lead 3mm × 5mm QFN package with exposed pad (Pin 25 = GND), θJC(PAD) = 5°C/W. Pin assignment follows UDD package outline per Rev. D datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SYNC (1) | External clock sync input | Enables synchronization to external clock or selects pulse-skipping vs. Burst Mode; must not be floated. |
| TR/SS (2) | Soft-start & tracking control | Programs output ramp rate via capacitor; enables voltage tracking during startup or sequencing. |
| RT (3) | Frequency programming | Resistor to GND sets switching frequency from 200kHz to 2.2MHz; 60.4kΩ yields 700kHz. |
| EN/UV (4) | Enable & input UVLO control | 1.00V rising threshold; external resistor divider programs VIN undervoltage lockout. |
| VIN (5,6) | Main power input | Supplies internal circuitry and top FET; requires local 0.1µF + bulk capacitance near pins. |
| PGND (7,8) | Power ground return | Return path for bottom FET; must be tied together and connected to input cap negative terminal. |
| SW (13–15) | Switch node | Drives external inductor; multiple pins reduce parasitic inductance and improve EMI performance. |
| ISP/ISN (21,22) | Current sense inputs | Rail-to-rail differential inputs for monitoring input/output current via external sense resistor. |
| IMON (23) | Proportional current monitor | Outputs 20×(VISP−VISN); provides ground-referenced analog current readout (200µA source capability). |
| ICTRL (24) | Current limit adjustment | Modulates ISP-ISN threshold from 50mV down to ~5mV; internal 1.4µA pull-up if left floating. |
| GND (25) | Exposed thermal pad | Must be soldered to PCB plane for thermal conduction; electrically connected to PGND and signal GND. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow IQ Burst Mode | 2.5µA input current at no load preserves battery life in always-on systems like telematics and ADAS sensors. |
| Rail-to-rail current sense | ISP/ISN inputs operate from 0V to VIN, enabling accurate monitoring of input current, output current, or intermediate rail currents. |
| Adjustable current limit | ICTRL pin scales the 50mV default ISP-ISN threshold linearly - supports flexible overcurrent protection across varying load profiles. |
| Low EMI Silent Switcher® architecture | Integrated boost capacitor, split SW pins, and fast 50ns min on-time reduce high-frequency noise and simplify EMI filtering. |
| AEC-Q100 Grade 1 qualified | Rated for −40°C to +125°C junction temperature - validated for under-hood automotive applications including engine control and lighting. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Supply |
|---|---|
Use Scenario: Powering display controllers, audio codecs, and USB hubs in head units with 12V battery input and strict sleep-mode IQ limits. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck converter with programmable soft-start, PG signaling, and current monitoring for fault logging. Use Value: 2.5µA quiescent current extends vehicle battery life during extended parking; ±9% PG ensures safe MCU boot sequencing. | Use Scenario: Providing regulated 5V/3.3V to wireless sensor transceivers in remote industrial IoT nodes powered by 24V DC rails. IC Role / Device Role / Timing Role: High-efficiency step-down regulator with adjustable current limit to protect against short-circuit events in unattended deployments. Use Value: 42V max input withstands industrial transients; 50ns min on-time supports 24V→3.3V conversion without duty-cycle limitation. |
| CCCV Battery Charger Bias Supply | Rail-Switching Power for ADAS Cameras |
Use Scenario: Generating bias voltage for charging ICs in constant-current/constant-voltage (CCCV) Li-ion charger designs with wide input range. IC Role / Device Role / Timing Role: Auxiliary supply delivering stable voltage to charger controller ICs while monitoring input current for charge-stage validation. Use Value: IMON pin provides real-time current telemetry; ISP/ISN sense enables input-side current limiting independent of battery voltage. | Use Scenario: Powering high-speed image sensors and SerDes interfaces in automotive camera modules requiring clean, sequenced 1.2V/2.8V/3.3V rails. IC Role / Device Role / Timing Role: Primary 5V intermediate rail generator with TR/SS-controlled soft-start and PG flag for downstream LDO enable timing. Use Value: Synchronizable switching frequency avoids beat frequencies with image sensor clocks; low EMI prevents pixel noise corruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EUDD#PBF | No current sense amplifier or IMON/ICTRL pins; lacks rail-to-rail ISP/ISN and programmable current limit. | Suitable only where basic regulation suffices; cannot support input/output current monitoring or adaptive OCP. | Select LT8610EUDD#PBF only if current sensing is unnecessary and cost reduction is prioritized over diagnostic capability. |
| MPQ4420AGL-A-Z | 40V max input, 2A output, 17µA IQ; no current sense monitor, no SYNC, no PG, no soft-start control. | Targeted at cost-sensitive industrial DC/DC; lacks automotive qualification and advanced protection features. | Choose MPQ4420AGL-A-Z for non-automotive applications where AEC-Q100, PG, and current telemetry are not required. |
Compared with LT8610EUDD#PBF and MPQ4420AGL-A-Z, the LT8611EUDD#PBF uniquely integrates rail-to-rail current sensing, programmable current limit, and AEC-Q100 qualification - making it the only option among the three suitable for automotive systems requiring real-time current diagnostics and robust fault handling.
Availability
LT8611EUDD#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, and CCCV battery charger bias supplies requiring stable component supply, long-term lifecycle support, and AEC-Q100 compliance.
Supply support for LT8611EUDD#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT8611EUDD#PBF belongs to the Silent Switcher® monolithic buck regulator product line, designed specifically for automotive and industrial applications demanding ultralow EMI, ultralow quiescent current, and high reliability under harsh electrical and thermal conditions.
FAQ
What is the maximum input voltage rating for the LT8611EUDD#PBF?
The LT8611EUDD#PBF has an absolute maximum input voltage rating of 42V on VIN, EN/UV, PG, ISP, and ISN pins. Operation is specified from 3.4V to 42V, supporting 12V and 24V automotive battery systems including cold-crank and load-dump conditions. Exceeding 42V risks permanent damage per Absolute Maximum Ratings.
How does the LT8611EUDD#PBF achieve 2.5µA quiescent current?
The LT8611EUDD#PBF achieves 2.5µA quiescent current through optimized Burst Mode® operation: internal control circuitry shuts down between energy pulses, reducing supply current to 1.7µA in deep sleep. Combined with minimal feedback divider current (e.g., ~0.8µA reflected from 3.3V/1.412MΩ), total input IQ reaches 2.5µA at 12VIN→3.3VOUT with no load.
Can the LT8611EUDD#PBF be synchronized to an external clock?
Yes, the LT8611EUDD#PBF supports external clock synchronization via the SYNC pin (Pin 1). Applying a logic-level clock signal (0.8V–2.4V thresholds) synchronizes switching to the external frequency and forces pulse-skipping mode. This eliminates beat frequencies in noise-sensitive applications like automotive cameras and radar modules.
What is the function of the ICTRL pin on the LT8611EUDD#PBF?
The ICTRL pin (Pin 24) on the LT8611EUDD#PBF adjusts the ISP-ISN current-sense threshold from the default 50mV down to ~5mV. Applying a voltage between GND and 1V linearly scales the threshold; tying to INTVCC or floating retains full-scale 50mV. This enables adaptive overcurrent protection tailored to specific load requirements.
Is the LT8611EUDD#PBF qualified for automotive applications?
Yes, the LT8611EUDD#PBF is AEC-Q100 Grade 1 qualified (−40°C to +125°C junction temperature) and designated for automotive use. The "E" grade in LT8611EUDD#PBF indicates automotive qualification; datasheet Rev. D explicitly lists AEC-Q100 qualification under FEATURES and ORDER INFORMATION sections.
LT8611EUDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN 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):
- 3.4V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 40V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (3x5)
LT8611EUDD#PBF FAQ
1.How can I place an order for LT8611EUDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8611EUDD#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 LT8611EUDD#PBF reliable?
The price and inventory of LT8611EUDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8611EUDD#PBF is usually 5 days.
3.What payment methods are accepted for LT8611EUDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8611EUDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8611EUDD#PBF?
LT8611EUDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8611EUDD#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 LT8611EUDD#PBF?
For technical support, including LT8611EUDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8611EUDD#PBF requirements.
6.How does Aetrix verify that LT8611EUDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT8611EUDD#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 LT8611EUDD#PBF meets industry standards.
7.What is the process for return or replacement of LT8611EUDD#PBF?
All LT8611EUDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8611EUDD#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 LT8611EUDD#PBF part is unused and in its original packaging.
Return procedure for LT8611EUDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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