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Analog Devices Inc. LT8641ARUDCM#PBF
- Part No.:
- LT8641ARUDCM#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad, 18 Leads
- Datasheet:
-
LT8641ARUDCM#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,410
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Product details
Overview
LT8641ARUDCM#PBF from Analog Devices is a 65V, 3.5A continuous/5A peak synchronous step-down Silent Switcher regulator with 2.5µA quiescent current in Burst Mode, 35ns minimum on-time, and integrated power switches in a 3mm × 4mm side-wettable QFN package. It delivers up to 95% efficiency at 1MHz (12VIN→5VOUT) and supports automotive-grade operation per AEC-Q100.
For engineers reviewing the LT8641ARUDCM#PBF datasheet, LT8641ARUDCM#PBF pinout, LT8641ARUDCM#PBF application, or LT8641ARUDCM#PBF equivalent, key selection criteria include ultralow IQ for battery-powered systems, spread spectrum EMI reduction, true 2MHz operation with 24VIN input, and robust overload tolerance with inductor saturation immunity.
Technical Context
The LT8641ARUDCM#PBF employs constant-frequency current-mode control with internal top/bottom NMOS switches, programmable switching frequency (200kHz–3MHz via RT resistor), and dual ground paths (GND1/GND2) optimized for low-EMI layout. Its Silent Switcher architecture uses symmetrical hot-loop routing and integrated bootstrap capacitor connection (BST pin) to suppress common-mode EMI.
It features four operating modes selected via SYNC/MODE pin: Burst Mode (ultralow IQ), pulse-skipping, spread-spectrum modulation (±22% Δf), and external clock synchronization. The TR/SS pin enables output voltage tracking and soft-start, while PG provides open-drain power-good signaling with ±8% FB threshold hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 65V - supports wide-range industrial and automotive battery inputs including 24V, 36V, and 48V systems without pre-regulation. |
| Output Current | 3.5A continuous / 5A peak - enables single-chip conversion for mid-power applications such as ADAS cameras and infotainment supplies. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT - extends battery life in always-on automotive modules (e.g., telematics, body control units). |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics: 2MHz operation supports ≤2.2µH inductors for space-constrained PCBs. |
| Min. On-Time | 35ns - enables high-step-down ratios (e.g., 48VIN→3.3VOUT) at 2MHz without pulse skipping or instability. |
| EMI Performance | Meets CISPR 25 Class 5 radiated/ conducted limits - eliminates need for external EMI filters in automotive designs. |
| Package | 18-lead 3mm × 4mm side-wettable QFN - improves solder joint reliability for automated optical inspection (AOI) and thermal performance via exposed SW pad. |
| AEC-Q100 Grade | Qualified for automotive applications (Grade 1: –40°C to +125°C ambient) - suitable for under-hood and cabin electronics. |
Pinout & Package
LT8641ARUDCM#PBF is housed in an 18-lead, 3mm × 4mm plastic QFN with side-wettable flanks and an exposed SW pad (Pin 21) for enhanced thermal conduction. The package includes dual GND paths (GND1 Pins 6/7, GND2 Pins 10/11) and dual VIN inputs (VIN1 Pin 4, VIN2 Pin 13) to minimize high-current loop area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 BIAS | Internal regulator bias supply | Reduces IQ by sourcing INTVCC from VOUT (≥3.3V); bypass with 1µF ceramic if tied to external supply. |
| 2 INTVCC | Internal 3.4V regulator output | Bypass with ≥1µF ceramic to GND; powers control logic and gate drivers - must not be loaded externally. |
| 3 BST | Bootstrap capacitor connection | Drives top switch gate above VIN; requires 0.1µF ceramic placed adjacent to IC for stable high-side drive. |
| 4 VIN1, 13 VIN2 | Dual input power inputs | Split input paths reduce high-di/dt loop area; each requires dedicated 0.1µF ceramic bypass to respective GND1/GND2. |
| 6/7 GND1, 10/11 GND2, 18 GND | Power and signal ground returns | GND1/GND2 serve bottom switch return; all must connect to low-impedance ground plane - critical for EMI suppression. |
| 8/9/21 SW | Switch node | Exposed pad (Pin 21) and Pins 8/9 form single high-current SW node; must connect directly to inductor and BST cap with minimal trace area. |
| 14 EN/UV | Enable and input undervoltage lockout | Hysteretic threshold (1.01V rise / 0.965V fall); resistor divider from VIN sets custom UVLO point for battery monitoring. |
| 15 RT | Frequency programming | Resistor to GND sets fSW: 60.4kΩ → 700kHz, 18.2kΩ → 2MHz - enables precise trade-off between efficiency and size. |
| 16 TR/SS | Tracking and soft-start | 2µA internal pull-up enables capacitor-based slew rate control; voltage <0.81V forces FB regulation to match TR/SS. |
| 17 SYNC/MODE | Mode selection and sync input | Ground = Burst Mode; float = pulse-skip; >3V = spread spectrum; AC-coupled clock = external sync - no external components needed. |
| 19 PG | Power-good indicator | Open-drain output asserts high when FB is within ±8% of 0.81V reference - used for system sequencing and fault detection. |
| 20 FB | Feedback input | Regulates to 0.810V ±0.6%; connects to resistor divider from VOUT - phase-lead capacitor (4.7pF–22pF) improves stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Integrated dual-input, dual-GND layout with symmetrical hot loops reduces radiated EMI by >30dB vs. conventional buck regulators. |
| Ultralow Quiescent Current | 2.5µA IQ in Burst Mode enables >10-year battery life in always-on automotive modules (e.g., CAN wake-up receivers). |
| True 2MHz Operation | Stable 2MHz switching at 24VIN→5VOUT with 35ns min on-time - supports <3mm × 3mm total solution size including inductor. |
| Spread Spectrum Modulation | ±22% frequency dithering (2.5kHz triangle wave) lowers peak EMI amplitude without affecting regulation or efficiency. |
| Inductor Saturation Tolerance | Safe operation during overload: bottom switch valley limit (4.8A–7.25A) prevents destructive current runaway even with saturated inductors. |
| Side-Wettable QFN | Visible solder fillets on package edges enable automated optical inspection (AOI) - critical for zero-defect automotive manufacturing. |
Applications
| ADAS Camera Power Supply | Automotive Infotainment Core Rail |
|---|---|
Use Scenario: Powering 5V/3A image sensor and ISP in forward-facing camera module with strict CISPR 25 Class 5 EMI limits. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 5V from 8V–16V battery rail with spread spectrum enabled. Use Value: Eliminates external EMI filter components while maintaining 94% efficiency at 2MHz, reducing BOM cost and PCB area by 35%. |
Use Scenario: Generating 3.3V/2.5A core supply for SoC in head-unit with cold-crank (4.5V) and load-dump (65V) transients. IC Role / Device Role / Timing Role: High-input-voltage buck converter with AEC-Q100 qualification and 65V absolute max rating. Use Value: Survives automotive transients without protection circuitry; 2.5µA IQ extends backup battery runtime during ignition-off state. |
| Industrial PLC I/O Module | Electric Vehicle Battery Management |
Use Scenario: Converting 24VDC field bus to isolated 5V/1.5A for digital I/O conditioning circuits in harsh factory environments. IC Role / Device Role / Timing Role: Robust step-down regulator with 35ns min on-time enabling direct 24V→5V conversion at 2MHz. Use Value: Enables compact 2-layer PCB design with no external EMI filtering - meets IEC 61000-4-3/6 immunity requirements. |
Use Scenario: Powering 3.3V microcontroller and CAN transceiver in BMS slave board connected to 48V–60V battery stack. IC Role / Device Role / Timing Role: High-reliability buck converter with side-wettable QFN for AOI-compatible assembly and thermal derating to 150°C junction. Use Value: Qualified to AEC-Q100 Grade 1 with 130mV dropout at 1A ensures stable MCU operation during battery sag events. |
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 |
|---|---|---|---|
| LT8640SIV#PBF | Same architecture but 42V max input, 4A continuous, 2.5µA IQ, 3mm × 4mm QFN - lacks AEC-Q100 qualification and 65V rating. | Targeted at industrial/commercial systems without automotive transient requirements. | Select when 42V input suffices and AEC-Q100 is unnecessary - lower cost, identical layout compatibility. |
| MPQ4433AGL-A-Z | 45V max input, 3.5A continuous, 17µA IQ, 3mm × 4mm QFN - no spread spectrum, no side-wettable leads, no AEC-Q100. | Suitable for cost-sensitive consumer or industrial applications where EMI is less stringent. | Choose for non-automotive designs requiring basic high-efficiency buck conversion without EMI certification overhead. |
Compared with LT8640SIV#PBF and MPQ4433AGL-A-Z, the LT8641ARUDCM#PBF uniquely combines 65V operation, AEC-Q100 qualification, side-wettable packaging, and certified CISPR 25 Class 5 EMI performance - making it the only drop-in solution for safety-critical automotive power rails.
Availability
LT8641ARUDCM#PBF is available at Aetrix Electronics and suitable for automotive ADAS, industrial PLCs, and EV battery management systems requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT8641ARUDCM#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.
The LT8641A belongs to Analog Devices' Silent Switcher® DC/DC regulator product line, engineered specifically for automotive and industrial applications demanding ultra-low EMI, high efficiency across light-to-full load, and robust operation under extreme voltage transients.
FAQ
What is the maximum input voltage rating for the LT8641ARUDCM#PBF?
The LT8641ARUDCM#PBF has an absolute maximum input voltage rating of 65V, with guaranteed operation from 3V to 65V. This enables direct integration into 48V automotive systems and industrial 24V/36V/48V rails without pre-regulation stages. The device includes built-in input overvoltage protection that disables switching if VIN exceeds 65V.
How does the LT8641ARUDCM#PBF achieve ultralow 2.5µA quiescent current?
The LT8641ARUDCM#PBF achieves 2.5µA IQ in Burst Mode by completely disabling its internal oscillator, gate drivers, and error amplifier between energy bursts, retaining only essential bias circuitry. This occurs when the SYNC/MODE pin is grounded and load current drops below ~10mA. The BIAS pin further reduces IQ by powering internal regulators from VOUT instead of VIN when VOUT ≥ 3.3V.
Can the LT8641ARUDCM#PBF synchronize to an external clock?
Yes, the LT8641ARUDCM#PBF can synchronize to an external clock applied to the SYNC/MODE pin. When driven with a clean CMOS-level clock signal (1.5V–6V swing), the device locks its internal oscillator to the external frequency and operates in pulse-skipping mode. This enables deterministic EMI placement and eliminates beat frequencies in multi-rail systems using the same LT8641ARUDCM#PBF.
What is the purpose of the dual GND1 and GND2 pins on the LT8641ARUDCM#PBF?
The LT8641ARUDCM#PBF separates power ground returns into GND1 (Pins 6/7) and GND2 (Pins 10/11) to isolate high-di/dt switching currents from sensitive feedback and control circuitry. GND1 carries top-switch discharge current; GND2 carries bottom-switch conduction current. Routing them separately minimizes ground bounce and preserves EMI performance - a key element of the Silent Switcher architecture.
Is the LT8641ARUDCM#PBF qualified for automotive applications?
Yes, the LT8641ARUDCM#PBF is AEC-Q100 qualified for automotive applications (Grade 1: –40°C to +125°C ambient). It undergoes stress testing for temperature cycling, humidity, mechanical shock, and ESD per AEC standards. The side-wettable QFN package also supports AOI inspection required by Tier 1 automotive suppliers, ensuring zero-defect manufacturing compliance.
LT8641ARUDCM#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad, 18 Leads
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 65V
- Voltage - Output (Min/Fixed):
- 0.81V
- Voltage - Output (Max):
- 65V
- Current - Output:
- 3.5A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 20-QFN (3x4)
LT8641ARUDCM#PBF FAQ
1.How can I place an order for LT8641ARUDCM#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8641ARUDCM#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 LT8641ARUDCM#PBF reliable?
The price and inventory of LT8641ARUDCM#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8641ARUDCM#PBF is usually 5 days.
3.What payment methods are accepted for LT8641ARUDCM#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8641ARUDCM#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8641ARUDCM#PBF?
LT8641ARUDCM#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8641ARUDCM#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 LT8641ARUDCM#PBF?
For technical support, including LT8641ARUDCM#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8641ARUDCM#PBF requirements.
6.How does Aetrix verify that LT8641ARUDCM#PBF is sourced from the original manufacturer or authorized distributors?
All LT8641ARUDCM#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 LT8641ARUDCM#PBF meets industry standards.
7.What is the process for return or replacement of LT8641ARUDCM#PBF?
All LT8641ARUDCM#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8641ARUDCM#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 LT8641ARUDCM#PBF part is unused and in its original packaging.
Return procedure for LT8641ARUDCM#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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