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Analog Devices Inc. LT8611EUDD#TRPBF
- Part No.:
- LT8611EUDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT8611EUDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,701
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Product details
Overview
LT8611EUDD#TRPBF from Analog Devices is a 42V, 2.5A synchronous step-down regulator with integrated current sense amplifier, 2.5µA quiescent current in Burst Mode, 50ns minimum on-time, and ±9% power-good flag accuracy. It operates from 3.4V to 42V input, delivers up to 2.5A output, and supports adjustable switching frequency from 200kHz to 2.2MHz - used in automotive infotainment power rails requiring ultra-low IQ and high efficiency at light loads.
For engineers reviewing the LT8611EUDD#TRPBF datasheet, LT8611EUDD#TRPBF pinout, LT8611EUDD#TRPBF application, or LT8611EUDD#TRPBF equivalent, key selection criteria include input voltage range (3.4–42V), current-sense monitor capability (IMON/ICTRL), thermal performance in 3mm × 5mm QFN, AEC-Q100 qualification, and low-EMI synchronous operation with programmable soft-start and tracking.
Technical Context
The LT8611EUDD#TRPBF implements peak current mode control with internal compensation, enabling fast transient response and stable loop behavior using small inductors. Its dual-stage current sensing - via ISP/ISN differential inputs and ICTRL-adjustable threshold - supports precise input/output current regulation and limiting across wide common-mode ranges (0–3.3V).
Burst Mode operation maintains <10mVP-P output ripple while achieving 2.5µA no-load IQ; synchronization via SYNC pin disables frequency foldback and enables pulse-skipping or external clock alignment. The 24-lead 3mm × 5mm QFN package features exposed pad (Pin 25 = GND) for θJC(PAD) = 5°C/W thermal resistance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports 12V/24V/36V automotive and industrial bus inputs without pre-regulation. |
| Max Output Current | 2.5A - determined by bottom NMOS current limit (typ. 3.3A) and thermal limits in UDD package. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT - enables always-on systems with multi-year battery life in low-power modes. |
| Switching Frequency | 200kHz to 2.2MHz - set by RT resistor; allows EMI optimization and compact magnetics selection. |
| Feedback Reference | 0.970V ±3mV - high-accuracy reference enables tight output regulation (±1%) with 1% FB resistors. |
| Min On-Time | 50ns - enables high step-down ratios (e.g., 42V→3.3V at 2MHz) without pulse skipping. |
| Power-Good Accuracy | ±9% of VFB - PG asserts when VOUT reaches 0.883V–1.057V (for 3.3V output), supporting reliable system sequencing. |
Pinout & Package
LT8611EUDD#TRPBF is housed in a thermally enhanced 24-lead 3mm × 5mm plastic QFN (UDD) package with exposed pad (Pin 25) soldered to PCB ground for low thermal resistance (θJA = 40°C/W, θJC(PAD) = 5°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SYNC (1) | External clock sync input | Enables pulse-skipping mode or external frequency lock; must not be floated - tie to GND for Burst Mode. |
| TR/SS (2) | Soft-start and tracking control | Capacitor here sets output ramp rate; voltage <0.97V forces FB tracking - critical for supply sequencing. |
| RT (3) | Frequency programming | Resistor to GND sets fSW (200kHz–2.2MHz); determines inductor size, EMI profile, and light-load behavior. |
| EN/UV (4) | Enable and input UVLO control | 1.00V rising threshold with 40mV hysteresis - allows programmable VIN undervoltage shutdown via resistor divider. |
| VIN (5,6) | Main power input | Supplies topside switch and internal circuitry; requires local high-frequency bypassing near pins. |
| PGND (7,8) | Power ground return | Low-inductance return path for bottom switch; must connect directly to input capacitor negative terminal. |
| SW (13–15) | Switch node | Drives inductor and BST capacitor; layout minimization essential for EMI and efficiency. |
| BST (16) | Bootstrap supply | Requires 0.1µF ceramic cap to SW - enables high-side NMOS gate drive above VIN. |
| INTVCC (17) | Internal 3.4V regulator output | Bypass with ≥1µF ceramic; powers control logic - sourcing from BIAS improves efficiency at VOUT ≥3.3V. |
| BIAS (18) | Efficiency-optimized bias supply | Tie to VOUT when ≥3.3V to reduce VIN current draw and improve full-load efficiency. |
| PG (19) | Open-drain power-good flag | Signals VOUT within ±9% of target and absence of faults - used for MCU reset or downstream enable. |
| FB (20) | Feedback input | Regulated to 0.970V; connects to resistor divider - phase-lead cap (4.7–10pF) recommended for stability. |
| ISP (21), ISN (22) | Differential current sense inputs | Rail-to-rail inputs monitor VISP–VISN up to 50mV; support input/output/system current measurement. |
| IMON (23) | Current monitor output | Sources VIMON = 20×(VISP–VISN); provides ground-referenced analog current readout (200µA drive). |
| ICTRL (24) | Current limit adjustment | Modulates ISP–ISN threshold from 5mV to 50mV - enables dynamic current limiting or fault margin tuning. |
| GND (25) | Exposed thermal pad | Must be soldered to PCB ground plane - primary thermal path; failure to connect degrades θJA by >20°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow IQ Burst Mode | 2.5µA input current at no load preserves battery life in always-on automotive modules. |
| Integrated current sense amp | Direct ISP/ISN monitoring + IMON scaling eliminates external op-amp and reduces BOM count. |
| AEC-Q100 qualified | Rated for –40°C to +125°C junction temperature - validated for under-hood automotive use. |
| Low-EMI Silent Switcher topology | Controlled SW edge rates and symmetrical layout minimize conducted/radiated emissions per CISPR 25 Class 5. |
| Programmable soft-start & tracking | TR/SS pin enables controlled power-up sequencing and voltage ramp matching across multiple rails. |
| Fast minimum on-time (50ns) | Supports high-frequency, high-step-down designs (e.g., 42V→3.3V @ 2MHz) without duty-cycle limitation. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Supply |
|---|---|
|
Use Scenario: Powering display controllers, audio DSPs, and CAN transceivers in head units with cold-crank (4.5V) and load-dump (42V) resilience. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck regulator with current monitoring for overcurrent protection and diagnostics. Use Value: 2.5µA IQ extends backup battery runtime; ±9% PG enables safe MCU boot sequencing; AEC-Q100 ensures reliability. |
Use Scenario: Providing regulated 3.3V for wireless sensor nodes in remote industrial monitoring (e.g., vibration, temperature) powered by LiSOCl₂ batteries. IC Role / Device Role / Timing Role: Always-on step-down converter with programmable current limit to prevent battery over-discharge. Use Value: 2.5µA IQ enables >10-year battery life; ISP/ISN+IMON enables self-diagnostic current logging; 42V tolerance handles surge events. |
| CCCV Battery Charger Bias | Rail-to-Rail Current Monitor Reference |
|
Use Scenario: Generating stable 5V bias for charging ICs in portable medical devices with USB-C PD input (5–20V). IC Role / Device Role / Timing Role: Pre-regulator supplying constant-current/constant-voltage (CCCV) charger IC with accurate current feedback. Use Value: ICTRL-adjustable current limit prevents overcurrent during CC phase; TR/SS enables smooth charger enable timing. |
Use Scenario: Monitoring input current of FPGA power supplies or motor drivers where rail-to-rail sensing is required across 0–3.3V common-mode range. IC Role / Device Role / Timing Role: Precision current sense amplifier with 20× gain and 50mV full-scale range, referenced to system ground. Use Value: Eliminates need for isolated amplifiers; IMON provides direct ADC-compatible output; ISP/ISN inputs tolerate 0–3.3V common-mode. |
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 |
|---|---|---|---|
| LT8640S-1#TRPBF | Higher 6A rating, 2.2µA IQ, same 42V input, but uses different pinout and lacks IMON/ICTRL current monitor interface. | Preferred for higher-current rails (>3A); unsuitable where ISP/ISN-based current telemetry is required. | Select LT8611EUDD#TRPBF when current monitoring, AEC-Q100, or 2.5A/2.5µA balance is critical - not a drop-in replacement. |
| MPQ4420AGL-AEC1-Z | 42V, 2A, 17µA IQ, AEC-Q100, but no integrated current sense amplifier or IMON output. | Lower cost for basic automotive buck conversion without current telemetry or ultra-low IQ demands. | Choose LT8611EUDD#TRPBF for systems needing diagnostic current monitoring or sub-3µA IQ - MPQ4420AGL-AEC1-Z lacks both capabilities. |
Compared with LT8640S-1#TRPBF and MPQ4420AGL-AEC1-Z, the LT8611EUDD#TRPBF uniquely combines AEC-Q100 qualification, 2.5µA IQ, and integrated rail-to-rail current sense with IMON/ICTRL - making it optimal for automotive and industrial applications requiring both ultra-low standby power and real-time current diagnostics.
Availability
LT8611EUDD#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, and CCCV battery charger bias applications requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for LT8611EUDD#TRPBF 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 precision instrumentation, industrial automation, and automotive markets.
The LT8611EUDD#TRPBF belongs to the Silent Switcher® monolithic buck regulator product line, designed specifically for noise-sensitive automotive and industrial applications demanding ultra-low EMI, high efficiency at light loads, and robust current monitoring.
FAQ
What is the maximum continuous output current of the LT8611EUDD#TRPBF?
The LT8611EUDD#TRPBF delivers up to 2.5A continuous output current under typical thermal conditions in its 3mm × 5mm QFN package. This is limited by the bottom NMOS current limit (min 2.5A, typ 3.3A) and junction temperature rise - derating is required above +85°C ambient or with insufficient PCB copper area for the exposed pad.
Does the LT8611EUDD#TRPBF support AEC-Q100 qualification?
Yes, the LT8611EUDD#TRPBF is AEC-Q100 qualified for automotive applications (Grade 1: –40°C to +125°C junction temperature). This qualification covers stress testing for temperature cycling, humidity, ESD, and lifetime reliability - confirmed in Analog Devices' Automotive Reliability Reports for the #W and #U suffix variants.
How does the IMON pin function on the LT8611EUDD#TRPBF?
The IMON pin on the LT8611EUDD#TRPBF outputs a ground-referenced voltage equal to 20 × (VISP – VISN). For example, a 25mV sense voltage produces 0.5V on IMON. It can source up to 200µA and sink 10µA, enabling direct connection to an ADC or comparator for real-time current monitoring without external signal conditioning.
Can the LT8611EUDD#TRPBF operate with input voltages below 3.4V?
No - the absolute minimum input voltage for regulation is 3.4V (per Absolute Maximum Ratings and Electrical Characteristics tables). At VIN < 3.4V, the internal regulators (INTVCC, BIAS path) cannot sustain proper gate drive or error amplifier operation, and EN/UV may assert undervoltage lockout even if externally held high.
What is the purpose of the ICTRL pin on the LT8611EUDD#TRPBF?
The ICTRL pin on the LT8611EUDD#TRPBF adjusts the ISP–ISN current sense threshold from 5mV to 50mV. Applying 0V–1V to ICTRL scales the internal current limit proportionally - e.g., 0.5V reduces full-scale sense voltage to ~25mV - enabling programmable overcurrent protection or dynamic current margining without changing the sense resistor.
LT8611EUDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LT8611EUDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8611EUDD#TRPBF 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#TRPBF reliable?
The price and inventory of LT8611EUDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8611EUDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8611EUDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8611EUDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8611EUDD#TRPBF?
LT8611EUDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8611EUDD#TRPBF 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#TRPBF?
For technical support, including LT8611EUDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8611EUDD#TRPBF requirements.
6.How does Aetrix verify that LT8611EUDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8611EUDD#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8611EUDD#TRPBF?
All LT8611EUDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8611EUDD#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LT8611EUDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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