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Analog Devices Inc. LT8640JUDCF#WPBF
- Part No.:
- LT8640JUDCF#WPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640JUDCF#WPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:172
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Product details
Overview
LT8640JUDCF#WPBF 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 Grade J (–40°C to 150°C) qualification. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT), supports spread spectrum EMI reduction, and operates in Burst Mode or forced continuous mode via SYNC/MODE pin control - ideal for automotive infotainment power rails.
For engineers reviewing the LT8640JUDCF#WPBF datasheet, LT8640JUDCF#WPBF pinout, LT8640JUDCF#WPBF application, or LT8640JUDCF#WPBF equivalent, key selection criteria include its side-wettable QFN-18 package for automated optical inspection, ultralow IQ under light load, robust 7A peak transient capability, and integrated Silent Switcher architecture enabling CISPR 25 Class 5 radiated EMI compliance without external filters.
Technical Context
The LT8640JUDCF#WPBF implements peak current-mode control with an internal 0.970V reference and programmable oscillator (200kHz–3MHz via RT resistor). Its dual-input VIN1/VIN2 and dual-ground GND1/GND2 layout minimizes high-di/dt loop area, while integrated BST capacitor drive and synchronous NMOS switches (67mΩ top / 28mΩ bottom) enable high-efficiency operation across wide input (3.4V–42V) and output (0.97V–42V) ranges.
Silent Switcher architecture uses symmetrical internal power switch routing and integrated input capacitors to cancel magnetic fields, reducing radiated emissions by >30dB versus conventional buck regulators. The SYNC/MODE pin configures four distinct operating modes: Burst Mode (IQ = 2.5µA), pulse-skipping (LT8640 variant), forced continuous mode (FCM), or external clock synchronization - with FCM enabled by floating SYNC/MODE on this LT8640-1 variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports 12V/24V/36V automotive battery systems with cold-crank margin down to 3.4V. |
| Output Current | 5A continuous, 7A peak - sustains transient loads like microprocessor wake-up without dropout. |
| Quiescent Current | 2.5µA in regulation - enables >10-year battery life in always-on automotive modules (e.g., telematics). |
| Min On-Time | 30ns - allows direct 42V-to-3.3V conversion at 2MHz without intermediate stages. |
| EMI Performance | CISPR 25 Class 5 compliant (radiated & conducted) - eliminates need for external EMI filters in automotive designs. |
| Thermal Rating | AEC-Q100 Grade J (–40°C to +150°C junction) - qualified for under-hood and transmission-control applications. |
| Package | 18-lead 3mm × 4mm side-wettable QFN - enables automated solder-joint inspection per IPC-A-610. |
Pinout & Package
LT8640JUDCF#WPBF uses an 18-lead plastic side-wettable QFN (3mm × 4mm, exposed SW pad), optimized for thermal performance and AOI-compatible assembly. Pins 21 and 22 are exposed SW pads requiring PCB connection for optimal thermal conduction (θJC = 12°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Connect to VOUT ≥3.3V to reduce VIN current draw; enables <10mA BIAS pin consumption at 5VOUT. |
| INTVCC (2) | Internal 3.4V LDO output | Bypass with ≥1µF ceramic; powers gate drivers and control logic - 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 (4), VIN2 (13) | Dual input power inputs | Each requires dedicated 1µF local bypass; splits high-frequency input current path to minimize loop inductance. |
| GND1 (6,7), GND2 (10,11) | Power switch return paths | Must be tied together and connected to low-impedance ground plane; forms critical high-di/dt return for SW node. |
| SW (8,9,21,22) | Switch node outputs | Pins 8/9 are signal SW; pins 21/22 are exposed thermal pads - all must connect to same SW copper pour. |
| EN/UV (14) | Enable & input undervoltage lockout | Hysteresis of 40mV; rising threshold = 1.00V - enables programmable start-up voltage via resistor divider. |
| RT (15) | Oscillator frequency programming | Resistor to GND sets fSW from 200kHz to 3MHz; e.g., 60.4kΩ = ~2MHz. |
| TR/SS (16) | Soft-start & output tracking | 1.9µA internal current source charges external capacitor; controls VOUT ramp rate during startup. |
| SYNC/MODE (17) | Operating mode selection | Float = forced continuous mode (FCM); ground = Burst Mode; INTVCC = spread spectrum FCM. |
| GND (18) | System ground reference | Connect to main system ground plane; separates signal ground from power ground return paths. |
| PG (19) | Power good open-drain output | Active-low when FB is within ±8% of 0.970V; valid only when VIN >3.4V regardless of EN state. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V ±0.6%; requires 4.7pF–22pF phase-lead capacitor from FB to VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Integrated input capacitors and symmetrical SW routing reduce radiated EMI by >30dB, meeting CISPR 25 Class 5 without ferrites or shields. |
| Ultralow 2.5µA quiescent current | Enables >10-year battery standby in always-on automotive modules (e.g., CAN gateway, ADAS sensors) while maintaining full regulation. |
| 30ns minimum on-time | Supports single-stage 42V-to-3.3V conversion at 2MHz, eliminating cascaded regulators and reducing BOM count. |
| Forced continuous mode (FCM) | Eliminates low-load frequency variation; enables fast load-transient response (<50µs) and predictable EMI spectrum for EMC testing. |
| Side-wettable QFN package | Enables automated optical inspection of solder joints on all 18 leads - critical for zero-defect automotive manufacturing requirements. |
| AEC-Q100 Grade J qualification | Validated for operation from –40°C to +150°C junction temperature - suitable for engine control units and transmission modules. |
Applications
| Automotive Infotainment Power | ADAS Camera Module Supply |
|---|---|
Use Scenario: Powering SoC, display interface, and audio codecs in head-unit systems with 12V battery input and strict EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck converter delivering 5A continuous with spread spectrum mode enabled for CISPR 25 compliance. Use Value: Eliminates external EMI filters, reduces board area by 35%, and maintains <10mVP-P ripple at 2A load for clean video signal integrity. | Use Scenario: Supplying image sensor, ISP, and MIPI serializer in rear-view camera modules mounted near exhaust systems. IC Role / Device Role / Timing Role: High-reliability 3.3V/2A regulator operating continuously at 125°C ambient with forced continuous mode for stable timing. Use Value: Sustains 5A peak during sensor initialization without thermal shutdown; side-wettable QFN ensures solder joint reliability under thermal cycling. |
| Telematics Control Unit (TCU) | Electric Power Steering (EPS) MCU Supply |
Use Scenario: Providing always-on 3.3V rail for LTE modem, GNSS receiver, and secure element in cellular-connected vehicle platforms. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter with Burst Mode active during sleep states to extend backup battery life. Use Value: Draws only 2.5µA from 12V battery during deep sleep, enabling >12 months of GPS tracking on 10Ah backup battery. | Use Scenario: Generating 5V/4A supply for EPS microcontroller and motor gate drivers in safety-critical steering systems. IC Role / Device Role / Timing Role: AEC-Q100 Grade J regulator with 7A peak current capability to handle motor stall transients. Use Value: Maintains regulation during 100ms 7A pulses without dropout; thermal derating validated to 150°C junction for ASIL-B compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8640S-1JUDCF#WPBF | Same architecture but with external compensation (no internal caps), enabling custom loop response tuning. | Required where dynamic load transient requirements exceed standard internal compensation bandwidth. | Select when designing for >10A/s load steps or needing adjustable phase margin via external RC network. |
| MPQ4433GL-AEC1-P | 42V, 3.5A AEC-Q100 Grade 1 buck; lacks Silent Switcher EMI suppression and has 15µA IQ. | Suitable for cost-sensitive non-safety-critical modules where EMI filtering is acceptable. | Choose only if board space allows external EMI filters and 15µA IQ meets battery-life targets. |
Compared with LT8640S-1JUDCF#WPBF, the LT8640JUDCF#WPBF offers plug-and-play stability with internal compensation but less loop tuning flexibility; versus MPQ4433GL-AEC1-P, it delivers superior EMI performance and 6× lower quiescent current, justifying premium cost in noise-sensitive or battery-constrained automotive systems.
Availability
LT8640JUDCF#WPBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, telematics control units, and electric power steering systems requiring stable component supply with AEC-Q100 qualification and long-term production support.
Supply support for LT8640JUDCF#WPBF 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 delivers high-efficiency, low-EMI DC/DC conversion for automotive and industrial applications demanding ultra-low quiescent current, wide input range, and AEC-Q100 reliability.
FAQ
What is the maximum junction temperature rating for LT8640JUDCF#WPBF?
The LT8640JUDCF#WPBF is rated for operation from –40°C to +150°C junction temperature and is AEC-Q100 Grade J qualified. This specification is validated across process corners and lifetime stress tests, making it suitable for under-hood applications such as transmission control modules where ambient temperatures exceed 125°C.
Does LT8640JUDCF#WPBF support external synchronization of switching frequency?
Yes, the LT8640JUDCF#WPBF supports external clock synchronization via the SYNC/MODE pin. When driven with a TTL/CMOS clock signal between 200kHz and 3MHz, the device locks its internal oscillator to the external frequency while maintaining forced continuous mode operation - essential for EMI spectral shaping in multi-rail automotive systems.
How does the side-wettable QFN package of LT8640JUDCF#WPBF improve manufacturing yield?
The side-wettable QFN package of LT8640JUDCF#WPBF exposes solder along the vertical sidewalls of all 18 leads, enabling automated optical inspection (AOI) to verify solder joint integrity without X-ray. This directly supports zero-defect goals in automotive Tier-1 manufacturing, reducing field returns caused by intermittent opens in high-vibration environments.
Can LT8640JUDCF#WPBF operate with a 48V input in automotive 48V mild-hybrid systems?
No, the LT8640JUDCF#WPBF has an absolute maximum input voltage rating of 42V. Applying 48V exceeds its safe operating area and risks permanent damage. For 48V mild-hybrid applications, consider the LT8645S (65V-rated) or LTC3310S (60V-rated) as functionally compatible alternatives with similar Silent Switcher benefits.
What is the purpose of the dual VIN1/VIN2 and dual GND1/GND2 pins on LT8640JUDCF#WPBF?
The dual VIN and dual GND pins on LT8640JUDCF#WPBF physically separate high-frequency input current paths to minimize parasitic inductance in the critical hot-loop (VIN → top switch → SW → inductor → GND → VIN). This layout reduces voltage spikes, improves efficiency at high frequencies (>2MHz), and is fundamental to achieving the Silent Switcher's low-EMI performance.
LT8640JUDCF#WPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®1
- Package/Case:
- 20-WFQFN, 18 Leads, 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):
- 42V
- Current - Output:
- 5A
- Frequency - Switching:
- 210kHz ~ 2MHz
- 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#WPBF FAQ
1.How can I place an order for LT8640JUDCF#WPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640JUDCF#WPBF 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#WPBF reliable?
The price and inventory of LT8640JUDCF#WPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640JUDCF#WPBF is usually 5 days.
3.What payment methods are accepted for LT8640JUDCF#WPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640JUDCF#WPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640JUDCF#WPBF?
LT8640JUDCF#WPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640JUDCF#WPBF 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#WPBF?
For technical support, including LT8640JUDCF#WPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640JUDCF#WPBF requirements.
6.How does Aetrix verify that LT8640JUDCF#WPBF is sourced from the original manufacturer or authorized distributors?
All LT8640JUDCF#WPBF 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#WPBF meets industry standards.
7.What is the process for return or replacement of LT8640JUDCF#WPBF?
All LT8640JUDCF#WPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640JUDCF#WPBF, 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#WPBF part is unused and in its original packaging.
Return procedure for LT8640JUDCF#WPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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