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Analog Devices Inc. LT8640JUDCF-1#WPBF
- Part No.:
- LT8640JUDCF-1#WPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640JUDCF-1#WPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:121
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Product details
Overview
LT8640JUDCF-1#WPBF from Analog Devices is a 42V, 5A synchronous step-down Silent Switcher regulator with forced continuous mode (FCM), 2.5µA quiescent current in regulation, 30ns minimum on-time, and AEC-Q100 Grade J (–40°C to 150°C) qualification - deployed in automotive infotainment power rails, ADAS camera modules, and industrial PLC I/O supplies.
For engineers reviewing the LT8640JUDCF-1#WPBF datasheet, LT8640JUDCF-1#WPBF pinout, LT8640JUDCF-1#WPBF application, or LT8640JUDCF-1#WPBF equivalent, key selection criteria include ultralow EMI performance (<10mVP-P ripple), spread spectrum modulation support, FCM transient response capability, and side-wettable QFN thermal reliability under sustained 5A load.
Technical Context
The LT8640JUDCF-1#WPBF implements peak current mode control with internal 0.97V reference and programmable oscillator (200kHz–3MHz via RT resistor). Its Silent Switcher architecture uses symmetrical layout and integrated bypass capacitors to suppress common-mode EMI without external filters.
SYNC/MODE pin configures four operating modes: Burst Mode (ground), forced continuous mode (floating), spread spectrum (3–4V), or external clock synchronization - with FCM enabling negative inductor current and output sink capability up to 0.6A at 3.3VOUT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports 12V/24V/36V automotive battery rails with cold-crank margin. |
| Output Current | 5A continuous, 7A peak - sustains full load across –40°C to 150°C junction temperature. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT regulation - enables >10-year battery life in always-on vehicle modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics (e.g., 1µH at 3MHz) and avoids AM band interference. |
| EMI Performance | Meets CISPR 25 Class 5 radiated limits - validated with EMI filter on DC2202A demo board at 4A/2MHz. |
| Minimum On-Time | 30ns - enables high VIN-to-low VOUT conversion (e.g., 36V→3.3V at 2MHz) without pulse skipping. |
| Thermal Rating | AEC-Q100 Grade J (–40°C to 150°C) - qualified for engine bay and transmission control unit environments. |
Pinout & Package
LT8640JUDCF-1#WPBF uses an 18-lead, 3mm × 4mm side-wettable QFN package (LHGX marking) with exposed SW pads (Pins 21, 22) for enhanced thermal dissipation. The package supports automated optical inspection (AOI) of solder joints.
| 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 capacitor; powers gate drivers and control logic - not for external loading. |
| BST (3) | Bootstrap capacitor node | Requires 0.1µF ceramic capacitor to enable top NMOS gate drive above VIN - critical for high-side switch operation. |
| VIN1/VIN2 (4,13) | Main input power inputs | Each requires dedicated 1µF local ceramic bypass; dual-input path reduces high-frequency loop inductance. |
| GND1/GND2 (6,7,10,11) | Power switch return paths | Must be tied together and connected to low-impedance ground plane - separates power and signal return currents. |
| SW (8,9,21,22) | Power switch output node | Exposed pads (21,22) must be soldered to SW trace for θJC = 12°C/W thermal performance. |
| EN/UV (14) | Enable and undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable input UVLO using resistor divider from VIN. |
| RT (15) | Oscillator frequency set | Resistor to GND sets fSW: 221kΩ = 210kHz, 60.4kΩ = 700kHz, 18.2kΩ = 2.0MHz - determines inductor size and efficiency trade-off. |
| TR/SS (16) | Soft-start and tracking | 1.9µA internal current source enables voltage-controlled ramp rate; supports output sequencing with other rails. |
| SYNC/MODE (17) | Operating mode select | Floating = FCM; grounded = Burst Mode; 3–4V = spread spectrum FCM; driven = external sync - no pull-up/pull-down required. |
| GND (18) | Signal ground reference | Connects to system ground plane - provides stable reference for FB, PG, and error amplifier. |
| PG (19) | Power good open-drain output | Active-high when FB is within ±7.5% of 0.97V - drives microcontroller reset or enable signals with 2kΩ pull-up. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V ±0.006V; requires 4.7pF–22pF phase-lead capacitor between FB and VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Integrated input capacitors and symmetrical layout reduce radiated EMI by >30dB vs conventional buck regulators. |
| Forced Continuous Mode (FCM) | Enables fast load-step response (±1A in <5µs) and negative inductor current - critical for camera sensor burst power delivery. |
| Side-wettable QFN package | LHGX footprint supports AOI inspection of solder fillets on all 18 leads - improves automotive manufacturing yield and field reliability. |
| Spread spectrum modulation | ±22% triangular frequency dithering (e.g., 2MHz → 1.56–1.92MHz) lowers peak EMI amplitude without affecting regulation accuracy. |
| AEC-Q100 Grade J qualification | Validated for 150°C junction operation with lifetime derating - meets requirements for under-hood and transmission control applications. |
Applications
| Automotive Infotainment Power | ADAS Camera Module Supply |
|---|---|
Use Scenario: Powering SoC, display driver, and audio codec in head-unit systems with 12V battery input and strict EMC limits. IC Role / Device Role / Timing Role: Primary 5V/5A buck converter with spread spectrum enabled to pass CISPR 25 Class 5 radiated emissions testing. Use Value: Eliminates need for external EMI filters, reducing BOM cost by $0.35 and PCB area by 120mm². | Use Scenario: Providing clean, low-noise 3.3V rail for CMOS image sensors in surround-view cameras exposed to engine bay temperatures. IC Role / Device Role / Timing Role: High-efficiency, thermally robust step-down regulator operating continuously at 150°C junction temperature. Use Value: Maintains <10mVP-P output ripple at 5A load - prevents image sensor noise bands and frame corruption. |
| Industrial PLC I/O Module | Electric Power Steering (EPS) Control |
Use Scenario: Generating isolated 5V supply for digital I/O expansion cards in DIN-rail mounted controllers with wide input range. IC Role / Device Role / Timing Role: Input-flexible buck converter accepting 18–36VDC industrial bus while delivering regulated 5V/5A with UVLO protection. Use Value: 30ns minimum on-time supports direct 36V→5V conversion at 1MHz - avoids cascaded regulation stages. | Use Scenario: Powering motor control MCU and gate drivers in EPS ECUs requiring high transient immunity and functional safety compliance. IC Role / Device Role / Timing Role: AEC-Q100 qualified primary power stage with PG monitoring and thermal shutdown for ASIL-B system partitioning. Use Value: PG pin asserts within 100µs of output deviation >±7.5% - enables safe torque reduction per ISO 26262 requirements. |
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 |
|---|---|---|---|
| LT8640JUDCF#WPBF | Pulse-skipping mode instead of FCM; lacks output sink capability in light load. | Suitable for lower-cost infotainment displays where transient response is less critical than efficiency. | Select when Burst Mode efficiency at µA loads outweighs FCM's fast transient requirement. |
| MPQ4433AGL-AEC1-Z | 3.5A max output, 40V max input, no spread spectrum, 17µA IQ in sleep mode. | Targeted at cost-sensitive body electronics; lacks side-wettable QFN and CISPR 25 validation data. | Choose for non-safety-critical interior lighting or HVAC controls where EMI filtering is acceptable. |
Compared with LT8640JUDCF#WPBF and MPQ4433AGL-AEC1-Z, the LT8640JUDCF-1#WPBF uniquely delivers 5A FCM operation with AEC-Q100 Grade J rating and factory-validated CISPR 25 Class 5 compliance - making it the only option for high-reliability ADAS and EPS subsystems requiring simultaneous high current, fast transients, and ultra-low EMI.
Availability
LT8640JUDCF-1#WPBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, industrial PLC I/O, electric power steering ECUs, and industrial automation controllers requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT8640JUDCF-1#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 was designed specifically for automotive and industrial applications demanding ultralow EMI, high efficiency across wide load ranges, and AEC-Q100 reliability - with LT8640JUDCF-1#WPBF representing the Grade J, FCM-optimized variant.
FAQ
What is the maximum junction temperature rating for LT8640JUDCF-1#WPBF?
The LT8640JUDCF-1#WPBF is AEC-Q100 Grade J qualified with a guaranteed operating junction temperature range of –40°C to 150°C. Thermal derating begins above 125°C, and lifetime is reduced at sustained temperatures exceeding this threshold. The device includes overtemperature protection that activates above 150°C to prevent permanent damage, but continuous operation at or above this limit is not recommended.
How does the SYNC/MODE pin configure forced continuous mode on LT8640JUDCF-1#WPBF?
On the LT8640JUDCF-1#WPBF, forced continuous mode (FCM) is activated when the SYNC/MODE pin is left floating (high-impedance), with leakage currents held below 1µA. In FCM, the oscillator runs continuously, negative inductor current is permitted, and the IC can sink up to 0.6A from the output - enabling superior load-step transient response compared to pulse-skipping alternatives.
Can LT8640JUDCF-1#WPBF operate with a 36V input and 3.3V output at 2MHz switching frequency?
Yes, the LT8640JUDCF-1#WPBF supports 36V→3.3V conversion at 2MHz due to its 30ns minimum on-time - yielding a theoretical minimum duty cycle of ~18.3%, well within operational limits. This configuration requires appropriate RT resistor selection (e.g., 60.4kΩ) and careful layout to maintain stability and EMI performance, as validated in typical application circuits.
What is the purpose of the side-wettable QFN package used in LT8640JUDCF-1#WPBF?
The side-wettable QFN package (LHGX) on the LT8640JUDCF-1#WPBF enables automated optical inspection (AOI) of solder fillets along all 18 peripheral leads - a critical requirement for automotive manufacturing process control. This feature improves first-pass yield and long-term field reliability by verifying solder joint integrity without requiring X-ray inspection.
Does LT8640JUDCF-1#WPBF require external components for EMI compliance in automotive applications?
No, the LT8640JUDCF-1#WPBF achieves CISPR 25 Class 5 radiated emissions compliance without external EMI filters when used with the recommended layout and DC2202A demo board configuration. Its Silent Switcher architecture - including integrated input capacitors, symmetrical power loops, and optimized SW node routing - inherently suppresses common-mode EMI, eliminating the need for costly ferrite beads or LC filters in most automotive implementations.
LT8640JUDCF-1#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-1#WPBF FAQ
1.How can I place an order for LT8640JUDCF-1#WPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640JUDCF-1#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-1#WPBF reliable?
The price and inventory of LT8640JUDCF-1#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-1#WPBF is usually 5 days.
3.What payment methods are accepted for LT8640JUDCF-1#WPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640JUDCF-1#WPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640JUDCF-1#WPBF?
LT8640JUDCF-1#WPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640JUDCF-1#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-1#WPBF?
For technical support, including LT8640JUDCF-1#WPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640JUDCF-1#WPBF requirements.
6.How does Aetrix verify that LT8640JUDCF-1#WPBF is sourced from the original manufacturer or authorized distributors?
All LT8640JUDCF-1#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-1#WPBF meets industry standards.
7.What is the process for return or replacement of LT8640JUDCF-1#WPBF?
All LT8640JUDCF-1#WPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640JUDCF-1#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-1#WPBF part is unused and in its original packaging.
Return procedure for LT8640JUDCF-1#WPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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