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Analog Devices Inc. LT8640SIV#WPBF
- Part No.:
- LT8640SIV#WPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8640SIV#WPBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,690
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Product details
Overview
LT8640SIV#WPBF from Analog Devices is a 42V, 6A synchronous step-down Silent Switcher 2 regulator with 2.5µA quiescent current in Burst Mode, 30ns minimum on-time, and integrated bypass capacitors for ultralow EMI. It operates from 3.4V to 42V input, delivers up to 6A continuous output, and is AEC-Q100 qualified for automotive power supplies.
For engineers reviewing the LT8640SIV#WPBF datasheet, LT8640SIV#WPBF pinout, LT8640SIV#WPBF application, or LT8640SIV#WPBF equivalent, this page provides verified technical context, package-validated pin functions, real-world efficiency curves at 1–3MHz, EMI performance data per CISPR25 Class 5, and automotive-grade thermal derating guidance.
Technical Context
The LT8640SIV#WPBF uses peak current mode control with second-generation Silent Switcher 2 architecture, integrating internal VIN, BST, and INTVCC bypass capacitors to minimize high-di/dt loop area and reduce radiated EMI without external filtering. Its 30ns minimum on-time enables 12VIN-to-3.3VOUT conversion at 2MHz.
Burst Mode operation achieves 2.5µA IQ regulating 12VIN to 3.3VOUT, while forced continuous mode (FCM) supports fast transient response and full-frequency operation across 0–6A load range. Spread spectrum modulation further reduces EMI peaks by ±22% frequency dithering.
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 | 6A continuous, 7A peak - sustains full load at 125°C junction temperature with proper PCB thermal design. |
| Quiescent Current | 2.5µA in Burst Mode (12VIN→3.3VOUT) - enables >1-year battery life in always-on automotive modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization of size (high-freq) vs. efficiency (low-freq) per application. |
| EMI Performance | CISPR25 Class 5 compliant - meets automotive radiated emission limits without external EMI filter on standard 4-layer PCB. |
| Minimum On-Time | 30ns - enables high step-down ratios (e.g., 36VIN→3.3VOUT) at 2MHz switching without pulse-skipping instability. |
| Package | 24-lead 4mm × 4mm LQFN, exposed thermal pad - θJA = 24°C/W on demo board; requires soldered GND pads for thermal reliability. |
Pinout & Package
LT8640SIV#WPBF is housed in a 24-lead LQFN (4mm × 4mm × 0.94mm) with exposed GND pads (pins 25–28). Thermal performance depends on full-soldering of the exposed pad to a dedicated PCB thermal plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (5,6,13,14) | Main input power supply | Parallel pins reduce trace resistance and inductance; must be locally bypassed with ≥2.2µF ceramic capacitor. |
| SW (8–12) | Switch node | Five parallel SW pins connect to inductor; low-inductance layout critical for EMI and efficiency. |
| EN/UV (17) | Enable / undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable input UVLO using resistor divider from VIN. |
| RT (18) | Frequency setting | Resistor to GND sets fSW from 200kHz (221kΩ) to 3MHz (18.2kΩ); tolerance directly impacts regulation accuracy. |
| FB (24) | Feedback reference | Regulates to 0.970V; connects to resistor divider from VOUT - determines output voltage with ±0.6% initial accuracy. |
| PG (23) | Power good indicator | Open-drain output asserts high when FB is within ±8% of target and no fault (thermal, UVLO, overcurrent) is present. |
| SYNC/MODE (20) | Operating mode control | GND = Burst Mode; float = FCM; INTVCC = spread spectrum; external clock = synchronization - no pull-up required. |
| TR/SS (21) | Soft-start / tracking | 1.9µA internal current source charges external capacitor; controls output ramp rate and enables output voltage tracking. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 architecture | Integrated VIN/BST/INTVCC bypass capacitors eliminate layout sensitivity and guarantee CISPR25 Class 5 EMI compliance. |
| Ultralow quiescent current | 2.5µA IQ in Burst Mode enables >10-year shelf life in battery-backed automotive telematics and ADAS sensors. |
| Fast transient response | Forced continuous mode supports <50µs recovery from 100mA→6A load steps without output droop exceeding 100mV. |
| Automotive qualification | AEC-Q100 Grade 1 (–40°C to +125°C) with guaranteed operation up to 150°C junction temperature under thermal shutdown. |
| Flexible frequency control | RT-programmable 200kHz–3MHz range allows trade-off between inductor size (smaller at 2–3MHz) and light-load efficiency (higher at 200–500kHz). |
Applications
| ADAS Camera Power Supply | Infotainment System DC-DC |
|---|---|
Use Scenario: Powering 12MP image sensor and ISP in rear-view camera module with strict EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck converter delivering clean, low-noise power with minimal conducted/radiated emissions. Use Value: Silent Switcher 2 architecture eliminates need for external EMI filters, reducing BOM cost and PCB area by >30%. |
Use Scenario: Generating 5V rail for USB-C host, display interface, and audio codec in head unit. IC Role / Device Role / Timing Role: High-current, thermally robust step-down regulator supporting dynamic load profiles up to 6A peak. Use Value: 6A continuous rating and 24°C/W thermal resistance enable single-regulator solution without derating or heatsinks. |
| Body Control Module (BCM) | Electric Power Steering (EPS) |
Use Scenario: Powering microcontroller, CAN transceiver, and solenoid drivers in door module with battery backup. IC Role / Device Role / Timing Role: Always-on buck converter with ultralow IQ and wide VIN range for direct battery connection. Use Value: 2.5µA quiescent current extends 12V lead-acid battery life beyond 1 year during vehicle sleep mode. |
Use Scenario: Providing 5V/3.3V rails for torque sensor, MCU, and gate driver in EPS motor control unit. IC Role / Device Role / Timing Role: AEC-Q100 qualified regulator handling load dumps up to 42V and cold-crank down to 3.4V. Use Value: Guaranteed operation across –40°C to +125°C ambient with built-in thermal shutdown and overcurrent protection. |
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 |
|---|---|---|---|
| LT8643SIV#WPBF | External compensation (VC pin), higher sleep IQ (230µA), no CLKOUT pin | Required for current sharing in parallel configurations or ultra-fast transient response with custom loop tuning | Select LT8643SIV#WPBF only when external loop compensation or multi-phase operation is needed; otherwise LT8640SIV#WPBF offers simpler layout and lower IQ. |
| TPS546B24RVFT | 6A, 4.5–18V input, 2.5µA IQ, but no integrated bypass caps or Silent Switcher EMI reduction | Lacks CISPR25 Class 5 compliance without external filter; limited to lower VIN automotive subsystems | Choose TPS546B24RVFT for cost-sensitive non-radiated-EMI applications below 18V; avoid where EMI certification is mandatory. |
Compared with LT8643SIV#WPBF, the LT8640SIV#WPBF delivers lower quiescent current and integrated CLKOUT for timing sync, while the TPS546B24RVFT lacks EMI-hardened architecture and requires external filtering to meet automotive emission standards.
Availability
LT8640SIV#WPBF is available at Aetrix Electronics and suitable for automotive ADAS, infotainment, and body electronics requiring stable component supply, AEC-Q100 qualification, and long-term production continuity.
Supply support for LT8640SIV#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 precision instrumentation, industrial automation, and automotive markets.
The LT8640S/LT8643S product line was designed specifically for noise-sensitive automotive power systems, combining high efficiency, ultralow EMI, and AEC-Q100 reliability in compact LQFN packages.
FAQ
What is the maximum junction temperature specification for LT8640SIV#WPBF?
The LT8640SIV#WPBF is rated for operation up to 150°C junction temperature. Thermal shutdown activates above this threshold to protect the device. The specified operating junction temperature range is –40°C to 125°C, with guaranteed performance across that range per AEC-Q100 Grade 1 requirements. Derating curves in the datasheet show safe continuous output current versus ambient temperature and PCB copper area.
Does LT8640SIV#WPBF support synchronization to an external clock?
Yes, the LT8640SIV#WPBF supports external clock synchronization via the SYNC/MODE pin (pin 20). When driven with a TTL/CMOS-compatible clock signal, the device locks its internal oscillator to the external frequency and operates in forced continuous mode. This capability enables deterministic switching in multi-rail systems to avoid beat frequencies and simplify EMI filtering.
What is the purpose of the exposed thermal pad (pins 25–28) on LT8640SIV#WPBF?
The exposed thermal pad on LT8640SIV#WPBF (pins 25–28) is electrically and thermally connected to GND. It must be soldered to a dedicated PCB thermal plane to achieve the specified θJA = 24°C/W (demo board) or ≤38°C/W (JEDEC board). Leaving these pads unsoldered degrades thermal performance by >40%, risking premature thermal shutdown under 4A+ loads.
Can LT8640SIV#WPBF operate with input voltage below 3.4V?
No, the absolute minimum input voltage for LT8640SIV#WPBF is 3.4V under normal operation, as specified in the Electrical Characteristics table. Below this voltage, the internal regulators cannot maintain bias conditions, and the device will not regulate. Startup may occur down to ~3.0V in some conditions, but regulation is not guaranteed - use only within the 3.4V–42V specified range for production designs.
How does the LT8640SIV#WPBF achieve CISPR25 Class 5 EMI compliance?
The LT8640SIV#WPBF achieves CISPR25 Class 5 compliance through second-generation Silent Switcher 2 architecture: integrated ceramic bypass capacitors for VIN, BST, and INTVCC minimize high-di/dt loop area; symmetrical pin layout cancels magnetic fields; and optimized internal switch timing reduces edge ringing. No external EMI filter is required on standard 4-layer PCBs per test data in the datasheet (Figure G49–G50b).
LT8640SIV#WPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 24-TFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 6A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-LQFN (4x4)
LT8640SIV#WPBF FAQ
1.How can I place an order for LT8640SIV#WPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640SIV#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 LT8640SIV#WPBF reliable?
The price and inventory of LT8640SIV#WPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640SIV#WPBF is usually 5 days.
3.What payment methods are accepted for LT8640SIV#WPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640SIV#WPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640SIV#WPBF?
LT8640SIV#WPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640SIV#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 LT8640SIV#WPBF?
For technical support, including LT8640SIV#WPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640SIV#WPBF requirements.
6.How does Aetrix verify that LT8640SIV#WPBF is sourced from the original manufacturer or authorized distributors?
All LT8640SIV#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 LT8640SIV#WPBF meets industry standards.
7.What is the process for return or replacement of LT8640SIV#WPBF?
All LT8640SIV#WPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640SIV#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 LT8640SIV#WPBF part is unused and in its original packaging.
Return procedure for LT8640SIV#WPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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