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Analog Devices Inc. LT8611IUDD#TRPBF
- Part No.:
- LT8611IUDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT8611IUDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,221
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Product details
Overview
LT8611IUDD#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 accuracy. It operates from 3.4V to 42V input, delivers up to 2.5A output, and supports programmable switching frequency from 200kHz to 2.2MHz - used in automotive infotainment power rails requiring ultra-low IQ and high VIN tolerance.
For engineers reviewing the LT8611IUDD#TRPBF datasheet, LT8611IUDD#TRPBF pinout, LT8611IUDD#TRPBF application, or LT8611IUDD#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-ripple Burst Mode operation below 10mVP-P.
Technical Context
The LT8611IUDD#TRPBF implements peak current mode control with internal compensation, enabling fast transient response and stable loop behavior using small inductors. Its rail-to-rail ISP/ISN inputs support wide common-mode sensing (0–3.3V), while IMON provides 20× scaled ground-referenced output for system-level current monitoring.
Built-in frequency foldback reduces switching frequency during start-up or overcurrent events to limit inductor current; this is disabled when SYNC is held high or driven externally. The EN/UV pin features 1V threshold with 40mV hysteresis, supporting precise VIN undervoltage lockout or shutdown control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports 12V/24V automotive battery systems with cold-crank margin. |
| Max Output Current | 2.5A - determined by bottom FET current limit (3.3A typ) and thermal design in UDD package. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT - enables >10-year battery life in always-on automotive modules. |
| Switching Frequency | 200kHz to 2.2MHz - set via RT resistor; allows EMI optimization and compact magnetics. |
| Feedback Reference | 0.970V ±3mV - enables accurate output regulation with 1% resistors and phase-lead capacitor. |
| Min On-Time | 50ns - supports high VIN-to-low VOUT conversion (e.g., 42V → 3.3V) without pulse skipping. |
| Power-Good Accuracy | ±9% of VOUT - PG asserts when FB reaches 0.97V ±9%, signaling valid regulation or fault. |
Pinout & Package
LT8611IUDD#TRPBF is housed in a thermally enhanced 24-lead 3mm × 5mm plastic QFN (UDD) with exposed pad (Pin 25 = GND). The package has θJA = 40°C/W and θJC(PAD) = 5°C/W; exposed pad must be soldered to PCB for thermal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (13–15) | Switch Node | Drives external inductor; requires minimized PCB area to reduce EMI and switching losses. |
| ISP / ISN (21 / 22) | Current Sense Inputs | Rail-to-rail differential inputs for external sense resistor; support bidirectional current monitoring. |
| IMON (23) | Current Monitor Output | Ground-referenced voltage = 20 × (VISP − VISN); sources up to 200µA for analog current readback. |
| ICTRL (24) | Current Limit Adjustment | Modulates ISP-ISN threshold from 50mV down to ~5mV; float or tie to INTVCC for full-scale limit. |
| EN/UV (4) | Enable / Undervoltage Input | 1.00V rising threshold with 40mV hysteresis; enables VIN-based UVLO or remote enable control. |
| PG (19) | Power-Good Flag | Open-drain output active low when VOUT deviates >±9% from target or fault occurs. |
| TR/SS (2) | Soft-Start / Tracking | Controls output ramp rate via capacitor; enables voltage tracking in multi-rail systems. |
| RT (3) | Frequency Set | Resistor-to-ground sets oscillator frequency; 60.4kΩ yields 700kHz typical at 1A load. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow IQ Burst Mode | 2.5µA input current at no load preserves battery life in always-on automotive ECUs. |
| Rail-to-Rail Current Sense | ISP/ISN accept 0–3.3V common-mode voltage, enabling high-side, low-side, or output current sensing. |
| Programmable Current Limit | ICTRL pin adjusts ISP-ISN threshold from 5mV to 50mV, allowing fine-grained overcurrent protection. |
| Low-Ripple Operation | Output ripple <10mVP-P in Burst Mode - eliminates need for post-regulation LDOs in noise-sensitive analog rails. |
| AEC-Q100 Qualified | Rated for –40°C to +125°C junction temperature - validated for under-hood automotive applications. |
| Thermally Optimized Package | 3mm × 5mm QFN with exposed GND pad achieves θJC = 5°C/W - simplifies thermal design in space-constrained modules. |
Applications
| Automotive Infotainment Power | Industrial Sensor Hub Supply |
|---|---|
Use Scenario: Powering DSP, display controller, and audio codec in head-unit with 12V battery input and cold-crank tolerance. IC Role / Device Role / Timing Role: Primary 3.3V/2.5A buck regulator with current monitoring for load diagnostics. Use Value: 2.5µA IQ extends backup battery life; 42V rating survives load-dump transients; IMON enables real-time current logging. |
Use Scenario: Providing stable 5V rail to multi-sensor node (temperature, pressure, IMU) in factory automation PLC. IC Role / Device Role / Timing Role: High-efficiency step-down converter with programmable frequency to avoid EMI-sensitive bands. Use Value: 700kHz operation enables small 4.7µH inductor; TR/SS supports synchronized power-up across sensor subsystems. |
| Telematics Control Unit (TCU) | CCCV Battery Charger Auxiliary Rail |
Use Scenario: Generating 3.3V supply for LTE modem and GNSS receiver in vehicle telematics module. IC Role / Device Role / Timing Role: Regulator with EN/UV pin configured for ignition-sensed wake-up and sleep control. Use Value: 1V EN threshold enables direct connection to microcontroller GPIO; PG flag confirms rail stability before modem initialization. |
Use Scenario: Delivering precision 5V bias to op-amps and ADCs in constant-current/constant-voltage lithium battery charger. IC Role / Device Role / Timing Role: Secondary regulated rail isolated from main charging path to prevent noise coupling. Use Value: Low 10mVP-P ripple avoids ADC measurement errors; current sense capability validates auxiliary load integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8641IUDD#TRPBF | Higher 4A output current, 2.2µA IQ, same 42V max VIN but adds spread-spectrum modulation. | Better suited for higher-power ADAS camera modules where EMI reduction is critical. | Select when >2.5A load or stricter CISPR-25 Class 5 compliance is required; not drop-in due to different ICTRL behavior. |
| MPQ4420AGU-AEC1-P | 3.5A output, 17µA IQ, 36V max VIN, no integrated current sense amplifier or IMON pin. | Lower-cost alternative for non-diagnostic industrial supplies where current monitoring is unnecessary. | Choose when cost sensitivity outweighs ultra-low IQ and current telemetry needs; requires external sense circuitry. |
Compared with LT8611IUDD#TRPBF, LT8641IUDD#TRPBF offers higher current and EMI mitigation but lacks identical current-sense scaling, while MPQ4420AGU-AEC1-P trades IQ and monitoring capability for cost and simplicity in fixed-rail applications.
Availability
LT8611IUDD#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor hubs, and telematics control units requiring stable component supply, AEC-Q100 qualification, and ultralow quiescent current performance.
Supply support for LT8611IUDD#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 automotive, industrial, communications, and healthcare markets.
The LT8611IUDD#TRPBF belongs to Analog Devices' Power by Linear™ monolithic DC/DC regulator family, engineered for high efficiency, low EMI, and robust operation in harsh environments like automotive under-hood and industrial control systems.
FAQ
What is the operating temperature range for the LT8611IUDD#TRPBF?
The LT8611IUDD#TRPBF is rated for an operating junction temperature range of –40°C to +125°C, meeting AEC-Q100 Grade I requirements. This specification is guaranteed across the full range, with thermal performance dependent on PCB copper area and exposed pad soldering per the datasheet layout guidelines. The LT8611IUDD#TRPBF maintains all electrical characteristics within this range, including feedback reference accuracy and current limit stability.
How does the LT8611IUDD#TRPBF achieve 2.5µA quiescent current?
The LT8611IUDD#TRPBF achieves 2.5µA quiescent current through optimized Burst Mode® operation: during light loads, it delivers discrete energy pulses to the output capacitor and enters deep sleep between bursts, disabling most internal circuitry. This behavior is enabled by grounding the SYNC pin. The LT8611IUDD#TRPBF's internal architecture minimizes bias currents in error amplifiers and reference circuits, and its 0.97V feedback reference reduces divider current dependency - all contributing to the specified 2.5µA at 12VIN → 3.3VOUT.
Can the LT8611IUDD#TRPBF be synchronized to an external clock?
Yes, the LT8611IUDD#TRPBF supports external synchronization via the SYNC pin (Pin 1). When driven with a logic-level clock signal between 200kHz and 2.2MHz, the LT8611IUDD#TRPBF aligns its switching edges to the external source and operates in pulse-skipping mode. This disables frequency foldback and ensures deterministic timing - critical for EMI reduction in multi-converter systems. Do not leave SYNC floating; tie to GND for Burst Mode or to INTVCC/VIN for pulse-skipping if no external clock is available.
What is the function of the ICTRL pin on the LT8611IUDD#TRPBF?
The ICTRL pin (Pin 24) on the LT8611IUDD#TRPBF adjusts the ISP–ISN current-sense threshold from the default 50mV down to approximately 5mV. Applying a voltage between GND and 1V scales the internal comparator trip point linearly, enabling programmable overcurrent protection without changing the sense resistor. Floating ICTRL or tying it to INTVCC selects the full 50mV scale. This feature allows the LT8611IUDD#TRPBF to adapt to varying load profiles while maintaining accurate current limiting across operating conditions.
Does the LT8611IUDD#TRPBF require external compensation components?
No, the LT8611IUDD#TRPBF uses internal compensation with peak current mode control, eliminating the need for external compensation networks. Its architecture stabilizes the control loop using only the RT resistor for frequency setting and standard input/output capacitors. This simplifies design, reduces BOM count, and improves consistency across production units. Layout best practices - such as tight SW-PGND loops and proper FB capacitor placement - remain essential for optimal transient response and noise immunity in the LT8611IUDD#TRPBF application.
LT8611IUDD#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)
LT8611IUDD#TRPBF FAQ
1.How can I place an order for LT8611IUDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8611IUDD#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 LT8611IUDD#TRPBF reliable?
The price and inventory of LT8611IUDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8611IUDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8611IUDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8611IUDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8611IUDD#TRPBF?
LT8611IUDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8611IUDD#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 LT8611IUDD#TRPBF?
For technical support, including LT8611IUDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8611IUDD#TRPBF requirements.
6.How does Aetrix verify that LT8611IUDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8611IUDD#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 LT8611IUDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8611IUDD#TRPBF?
All LT8611IUDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8611IUDD#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 LT8611IUDD#TRPBF part is unused and in its original packaging.
Return procedure for LT8611IUDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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