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Analog Devices Inc. LT8640JUDCF#WTRPBF
- Part No.:
- LT8640JUDCF#WTRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640JUDCF#WTRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,590
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Product details
Overview
LT8640JUDCF#WTRPBF from Analog Devices is a 42V, 5A synchronous step-down Silent Switcher regulator with 2.5µA quiescent current in regulation, 30ns minimum on-time, and AEC-Q100 qualification for automotive applications. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT) and supports adjustable switching frequency from 200kHz to 3MHz.
For engineers reviewing the LT8640JUDCF#WTRPBF datasheet, LT8640JUDCF#WTRPBF pinout, LT8640JUDCF#WTRPBF application, or LT8640JUDCF#WTRPBF equivalent, key selection criteria include ultralow EMI performance, forced continuous mode capability (LT8640-1 variant), thermal robustness to 150°C junction, side-wettable QFN package for solder inspection, and compatibility with high-frequency, low-inductance designs.
Technical Context
The LT8640JUDCF#WTRPBF implements peak current mode control with an internal 0.97V reference and integrated top/bottom NMOS power switches (67mΩ/28mΩ typical RDS(on)). Its Silent Switcher architecture uses symmetrical layout and integrated bypass capacitors to suppress common-mode EMI.
Operating modes are selected via the SYNC/MODE pin: Burst Mode (ground), forced continuous mode (floating), spread spectrum modulation (3–4V), or external clock synchronization. The part features internal compensation, soft-start/tracking via TR/SS, and PG open-drain fault signaling with ±8% output voltage window.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide automotive battery transients including cold-crank (4.5V) and load-dump (40V+). |
| Output Current | 5A continuous, 7A peak - enables single-chip 5V/5A or 3.3V/5A supplies without external boost or parallel stages. |
| Quiescent Current | 2.5µA at full regulation - sustains >10-year battery life in always-on automotive modules (e.g., telematics, ADAS sensors). |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization for size (high-freq + small inductor) or efficiency (low-freq + low core loss). |
| Min On-Time | 30ns - enables high VIN-to-low VOUT conversion (e.g., 42V→3.3V @ 2MHz) without pulse skipping or instability. |
| Junction Temp Range | –40°C to 150°C - qualified per AEC-Q100 Grade J, enabling under-hood deployment without derating. |
| EMI Performance | CISPR 25 Class 5 compliant - meets automotive radiated/conducted emission limits without external ferrite beads or shielding. |
Pinout & Package
LT8640JUDCF#WTRPBF uses an 18-lead, 3mm × 4mm plastic side-wettable QFN package (LHJK marking) with exposed SW pads (pins 21, 22) for thermal and electrical connection. The package supports automated optical inspection (AOI) of solder joints via side-wettable flanks.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Accepts 3.1–25V input; reduces VIN current draw when tied to VOUT ≥3.3V, improving light-load efficiency. |
| INTVCC (2) | Internal 3.4V LDO output | Bypassed with ≥1µF ceramic; powers control logic and gate drivers; not for external loading. |
| BST (3) | Bootstrap capacitor node | Requires 0.1µF ceramic placed adjacent to IC; enables high-side NMOS gate drive above VIN. |
| VIN1/VIN2 (4,13) | Main input power inputs | Dual input pins reduce high-frequency loop inductance; each requires dedicated 1µF local ceramic bypass. |
| GND1/GND2 (6,7,10,11) | Power switch return paths | Four dedicated ground pins minimize ground bounce and EMI; must be tied together and connected to solid ground plane. |
| SW (8,9,21,22) | Power switch output node | Exposed pad (21,22) must be soldered to SW trace for thermal conduction and low-inductance path to inductor. |
| EN/UV (14) | Enable and input undervoltage lockout | Hysteretic threshold (1.00V rise / 0.96V fall); resistor divider from VIN sets custom UVLO point. |
| RT (15) | Frequency programming resistor | Resistor to GND sets fSW: 221kΩ = 210kHz, 60.4kΩ = 700kHz, 18.2kΩ = 2.0MHz - enables precise EMI band placement. |
| TR/SS (16) | Soft-start and output tracking | 1.9µA internal current source charges external capacitor; controls VOUT ramp rate and enables power sequencing. |
| SYNC/MODE (17) | Mode selection and sync input | Configures Burst Mode (GND), FCM (float), spread spectrum (3–4V), or external clock sync (AC-coupled square wave). |
| GND (18) | Signal ground reference | Connects to system ground plane; separates signal integrity from high-current power grounds (GND1/GND2). |
| PG (19) | Power good indicator | Open-drain output asserts high when FB is within ±8% of 0.97V and no faults (thermal, UVLO, overcurrent) exist. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V ±0.6%; requires resistor divider and 4.7–22pF phase-lead capacitor from FB to VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated dual-input/dual-GND layout and internal bypass caps reduce EMI by >30dB vs conventional buck regulators. |
| Ultralow 2.5µA IQ | Enables direct connection to vehicle battery in always-on systems without auxiliary LDOs or sleep controllers. |
| 30ns minimum on-time | Supports 42V→3.3V conversion at 2MHz, eliminating need for pre-regulator stages in high-ratio automotive supplies. |
| AEC-Q100 Grade J qualification | Validated for –40°C to 150°C operation with lifetime reliability data; approved for safety-critical ADAS and powertrain use. |
| Forced Continuous Mode (FCM) | Eliminates low-load frequency variation and output ripple discontinuities; improves transient response for radar and camera modules. |
| Side-wettable QFN package | Enables automated X-ray or AOI verification of solder joint integrity - critical for zero-defect automotive manufacturing. |
Applications
| Automotive Infotainment Power | ADAS Camera Module Supply |
|---|---|
|
Use Scenario: Powering SoC, DDR memory, and display interfaces in head units with 12V battery input and strict CISPR 25 Class 5 EMI limits. IC Role / Device Role / Timing Role: Primary 5V/5A DC/DC converter with integrated Silent Switcher EMI suppression and soft-start sequencing. Use Value: Eliminates external EMI filters and shielding, reducing BOM cost and PCB area while meeting OEM EMC requirements. |
Use Scenario: Generating stable 3.3V/3A supply for high-speed image sensors and ISP processors in surround-view cameras. IC Role / Device Role / Timing Role: High-efficiency, low-noise buck regulator with 30ns min on-time enabling direct 12V→3.3V conversion. Use Value: Avoids cascaded regulation, cuts thermal dissipation by 40% vs. 5V intermediate stage, and ensures clean power for low-noise analog front-ends. |
| Telematics Control Unit (TCU) | Electric Power Steering (EPS) MCU Supply |
|
Use Scenario: Always-on 3.3V/1A supply for cellular modem, GNSS receiver, and CAN controller in connected vehicle gateways. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter with programmable UVLO and power-good signaling for system wake-up control. Use Value: Achieves <2.5µA shutdown current, extending backup battery life to >10 years in disconnected state. |
Use Scenario: Robust 5V/4A supply for safety-critical MCU and motor drivers in EPS systems operating near engine compartments. IC Role / Device Role / Timing Role: AEC-Q100 Grade J buck regulator with 150°C junction rating and forced continuous mode for fast torque-step response. Use Value: Maintains regulation during 140°C ambient conditions without thermal foldback, ensuring uninterrupted steering assist. |
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 |
|---|---|---|---|
| LT8640-1JUDCF#WTRPBF | Forced Continuous Mode (FCM) enabled by default; higher light-load current (~600µA vs 2.5µA) in FCM; identical pinout and package. | Better for fast-transient loads (e.g., radar bursts); less suitable for ultra-low-power always-on functions. | Select LT8640-1JUDCF#WTRPBF when output ripple and transient response outweigh quiescent current requirements. |
| MPQ4433AGL-AEC1-Z | 36V max input, 3.5A output, 17µA IQ, no spread spectrum; QFN-16 package with different pin assignment and no side-wettable leads. | Lacks Silent Switcher EMI performance and AEC-Q100 Grade J rating; requires external EMI filtering for automotive use. | Consider MPQ4433AGL-AEC1-Z only for cost-sensitive non-safety applications where EMI margins are relaxed. |
Compared with LT8640-1JUDCF#WTRPBF and MPQ4433AGL-AEC1-Z, the LT8640JUDCF#WTRPBF uniquely balances ultralow IQ, automotive-grade thermal robustness, and certified EMI performance in a manufacturable side-wettable package - making it optimal for next-generation ADAS and infotainment power rails.
Availability
LT8640JUDCF#WTRPBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and telematics control units requiring stable component supply with AEC-Q100 compliance, 150°C operation, and CISPR 25 Class 5 EMI certification.
Supply support for LT8640JUDCF#WTRPBF 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 LT8640/LT8640-1 product line was designed specifically for automotive power systems demanding ultralow EMI, extreme temperature resilience, and high efficiency across wide load ranges - targeting ADAS, infotainment, and electrification subsystems.
FAQ
What is the maximum junction temperature rating for LT8640JUDCF#WTRPBF?
The LT8640JUDCF#WTRPBF is rated for operation from –40°C to 150°C junction temperature and is AEC-Q100 Grade J qualified. This specification is validated per JEDEC standards and supports under-hood deployment in electric power steering and engine control units without thermal derating below 150°C.
Does LT8640JUDCF#WTRPBF support forced continuous mode (FCM)?
No - LT8640JUDCF#WTRPBF is the standard LT8640 variant and supports Burst Mode, pulse-skipping, spread spectrum, and external clock sync. Forced Continuous Mode is exclusive to the LT8640-1 family (e.g., LT8640-1JUDCF#WTRPBF). The LT8640JUDCF#WTRPBF uses pulse-skipping when SYNC/MODE is floating.
What package type does LT8640JUDCF#WTRPBF use, and why is it significant for automotive manufacturing?
LT8640JUDCF#WTRPBF uses a 18-lead, 3mm × 4mm side-wettable QFN (LHJK). Its flank-plated leads enable automated optical inspection (AOI) of solder joints - a mandatory requirement for zero-defect automotive assembly lines - unlike standard QFN packages that require costly X-ray verification.
How does LT8640JUDCF#WTRPBF achieve CISPR 25 Class 5 compliance?
LT8640JUDCF#WTRPBF achieves CISPR 25 Class 5 compliance through its Silent Switcher architecture: symmetrical internal power loops, integrated input bypass capacitors, and optimized pinout that minimizes high-di/dt loop area. No external EMI filters or metal shielding are required on the DC2202A demo board at 4A/2MHz operation.
Can LT8640JUDCF#WTRPBF operate with a 48V input?
No - the absolute maximum input voltage for LT8640JUDCF#WTRPBF is 42V, as specified in the Absolute Maximum Ratings table. Applying 48V exceeds this limit and risks permanent damage. For 48V automotive architectures, consider the LT8645S (65V-rated) or design a two-stage solution with an upstream pre-regulator.
LT8640JUDCF#WTRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN, 18 Leads, 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):
- 2.9V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 41.58V
- Current - Output:
- 5A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 20-QFN (3x4)
LT8640JUDCF#WTRPBF FAQ
1.How can I place an order for LT8640JUDCF#WTRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640JUDCF#WTRPBF 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 LT8640JUDCF#WTRPBF reliable?
The price and inventory of LT8640JUDCF#WTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640JUDCF#WTRPBF is usually 5 days.
3.What payment methods are accepted for LT8640JUDCF#WTRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640JUDCF#WTRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640JUDCF#WTRPBF?
LT8640JUDCF#WTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640JUDCF#WTRPBF 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 LT8640JUDCF#WTRPBF?
For technical support, including LT8640JUDCF#WTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640JUDCF#WTRPBF requirements.
6.How does Aetrix verify that LT8640JUDCF#WTRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640JUDCF#WTRPBF 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 LT8640JUDCF#WTRPBF meets industry standards.
7.What is the process for return or replacement of LT8640JUDCF#WTRPBF?
All LT8640JUDCF#WTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640JUDCF#WTRPBF, 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 LT8640JUDCF#WTRPBF part is unused and in its original packaging.
Return procedure for LT8640JUDCF#WTRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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