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Analog Devices Inc. LT8640SEV#PBF
- Part No.:
- LT8640SEV#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8640SEV#PBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,068
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Product details
Overview
LT8640SEV#PBF from Analog Devices is a 42V, 6A synchronous step-down Silent Switcher 2 regulator with internal compensation, 2.5µA quiescent current in regulation (12VIN→3.3VOUT), 30ns minimum on-time, and 24-lead 4mm × 4mm LQFN package. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT) and supports automotive-grade operation from –40°C to 125°C junction temperature.
For engineers reviewing the LT8640SEV#PBF datasheet, LT8640SEV#PBF pinout, LT8640SEV#PBF application, or LT8640SEV#PBF equivalent, key selection criteria include ultralow EMI performance in noise-sensitive systems, forced continuous mode for fast transient response, spread spectrum modulation capability, and AEC-Q100 qualification for automotive power rails.
Technical Context
The LT8640SEV#PBF implements peak current mode control with second-generation Silent Switcher 2 architecture, integrating internal bypass capacitors for VIN, BST, and INTVCC to minimize high-frequency loop area and reduce radiated EMI without external filtering. Its 30ns minimum on-time enables high step-down ratios (e.g., 36V→3.3V) at 2MHz switching.
Burst Mode® operation achieves 2.5µA input quiescent current while regulating 12VIN to 3.3VOUT, and forced continuous mode (FCM) - selected by floating SYNC/MODE - ensures full-frequency operation across 0–6A load range with negative inductor current capability for improved load-step recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide industrial and automotive battery inputs including cold-crank and load-dump conditions. |
| Output Current | 6A continuous, 7A peak - sufficient for powering FPGA cores, DSPs, or multi-rail PMIC front-ends. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT in Burst Mode - enables >1-year battery life in always-on telematics modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization of size (high-freq) vs. efficiency (low-freq) per design constraints. |
| EMI Performance | CISPR 25 Class 5 compliant with spread spectrum enabled - eliminates need for external EMI filters in automotive infotainment systems. |
| Package | 24-lead 4mm × 4mm × 0.94mm LQFN with exposed GND pad - provides θJA = 24°C/W on demo board for high-power density thermal management. |
| Operating Temp | –40°C to 125°C junction - qualified per AEC-Q100 Grade 1 for under-hood and ADAS camera power supplies. |
Pinout & Package
LT8640SEV#PBF uses a 24-lead LQFN (Laminate QFN) package measuring 4mm × 4mm × 0.94mm with an exposed thermal pad (Pins 25–28, GND). The package is RoHS-compliant (Au finish, e4 code) and MSL Level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (BIAS) | Internal regulator bias supply | Connect to VOUT ≥ 3.3V to reduce input current draw; improves efficiency at high VIN/low ILOAD. |
| 2 (INTVCC) | Internal 3.4V regulator bypass | Must be left floating; supplies gate drivers and control logic; sourcing from BIAS if >3.1V, else from VIN. |
| 3, 16, 25–28 (GND) | Power and signal ground | Multiple GND pins and exposed pad must be soldered to PCB plane for low-impedance return and thermal conduction. |
| 5, 6, 13, 14 (VIN) | Main input power supply | Parallel VIN pins reduce trace resistance and inductance; require local ≥2.2µF ceramic capacitor placement. |
| 7 (BST) | Bootstrap capacitor node | Connect 0.22µF ceramic between BST and SW; enables high-side NMOS gate drive above VIN. |
| 8–12 (SW) | Power switch output | Five paralleled SW pins connect directly to inductor; minimize loop area to suppress EMI and voltage spikes. |
| 17 (EN/UV) | Enable and undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable input UVLO using resistor divider from VIN. |
| 18 (RT) | Frequency setting resistor | Resistor to GND sets fSW: 221kΩ = 210kHz, 60.4kΩ = 700kHz, 18.2kΩ = 2.1MHz - enables precise frequency planning. |
| 19 (CLKOUT) | Switching clock monitor | Outputs ~200ns pulses at fSW in FCM/spread-spectrum/sync modes; low in Burst Mode - useful for system timing sync. |
| 20 (SYNC/MODE) | Operating mode select | GND = Burst Mode; float = Forced Continuous Mode; INTVCC = Spread Spectrum; external clock = Sync - single-pin multimode control. |
| 21 (TR/SS) | Soft-start and tracking | 1.9µA internal pull-up enables RC-programmed VOUT ramp rate; <0.97V forces FB tracking for power sequencing. |
| 22 (GND) | Signal ground reference | Dedicated GND for feedback and error amplifier reference - separate from power GND for noise immunity. |
| 23 (PG) | Power good open-drain | Active-high when FB is within ±8% of 0.97V and no faults (thermal, UVLO, EN low); requires external pull-up. |
| 24 (FB) | Feedback voltage sense | Regulated to 0.970V ±0.6%; connect resistor divider from VOUT; add 4.7–22pF phase-lead cap from FB to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 Architecture | Integrated VIN/BST/INTVCC ceramic capacitors reduce layout sensitivity and enable CISPR 25 Class 5 compliance without added filters. |
| Ultralow Quiescent Current | 2.5µA IQ in Burst Mode at 12VIN→3.3VOUT extends battery runtime in always-on automotive modules like GPS trackers. |
| 30ns Minimum On-Time | Enables direct 36V→3.3V conversion at 2MHz, eliminating intermediate stages and reducing BOM count in high-input systems. |
| Forced Continuous Mode (FCM) | Eliminates switching frequency variation across load range, enabling predictable EMI filtering and fast load-step recovery (<50µs). |
| Spread Spectrum Modulation | Reduces peak EMI amplitude by spreading energy over ±22% bandwidth - critical for meeting stringent automotive EMC requirements. |
| AEC-Q100 Qualified | Grade 1 (–40°C to 125°C) qualification ensures reliability in engine control units, ADAS cameras, and infotainment head units. |
Applications
| Automotive Infotainment Power | ADAS Camera Module Supply |
|---|---|
|
Use Scenario: Powering SoC, DDR memory, and display interface in head-unit systems with 9–16V battery input and strict CISPR 25 emissions limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck converter delivering 6A with spread spectrum and internal compensation to meet EMI and transient requirements. Use Value: Eliminates external EMI filter components and reduces PCB area by 35% versus legacy solutions while maintaining AEC-Q100 compliance. |
Use Scenario: Providing stable 3.3V rail to image sensor and ISP in rear-view or surround-view cameras operating under hood temperatures. IC Role / Device Role / Timing Role: High-efficiency, low-noise step-down regulator with 125°C junction rating and 2.5µA quiescent current for parking-mode operation. Use Value: Enables >10-year MTBF at 125°C and supports instant wake-from-sleep via fast soft-start (<1ms) and precise PG signaling. |
| Industrial PLC I/O Module | Medical Portable Monitor |
|
Use Scenario: Generating isolated 5V/3.3V supplies for microcontroller, CAN transceiver, and analog front-end in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Input-stage buck converter handling 24VDC industrial bus with surge tolerance up to 42V and robust thermal shutdown. Use Value: Withstands 42V transients per IEC 61000-4-5 and maintains regulation during brownouts down to 3.4V input. |
Use Scenario: Powering ARM-based display processor and touch controller in battery-operated patient monitors requiring FDA-grade reliability. IC Role / Device Role / Timing Role: Low-noise, low-IQ DC/DC converter supplying 3.3V at 2A with soft-start tracking for sequenced power-up of analog and digital subsystems. Use Value: Achieves >12-hour runtime on single Li-ion cell and meets IEC 60601-1 EMI limits without shielding enclosures. |
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 |
|---|---|---|---|
| LT8643SEV#PBF | External compensation (VC pin), higher sleep IQ (230µA), no dedicated GND pin 22 | Better suited for current-sharing parallel configurations and ultra-fast transient loads (>10A step) | Select LT8643SEV#PBF when designing for multi-phase or high-dV/dt loads; LT8640SEV#PBF is preferred for simpler single-rail designs. |
| MPQ4433AGL-AEC1-Z | 3.8V–60V input, 3.5A, 15µA IQ, no spread spectrum, QFN-16 | Limited to lower current and lacks Silent Switcher EMI suppression - requires external filter for automotive Class 5 | Choose MPQ4433AGL-AEC1-Z only for cost-sensitive, non-CISPR 25 applications where 3.5A output suffices and layout space is constrained. |
Compared with LT8643SEV#PBF and MPQ4433AGL-AEC1-Z, the LT8640SEV#PBF uniquely balances ultralow IQ (2.5µA), integrated EMI mitigation, and 6A output in a compact LQFN - making it optimal for single-rail automotive and industrial systems demanding both efficiency and regulatory compliance.
Availability
LT8640SEV#PBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, industrial PLC I/O, medical portable monitors, and test equipment requiring stable component supply with AEC-Q100 qualification and long-term lifecycle support.
Supply support for LT8640SEV#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.
The LT8640S product line delivers high-efficiency, low-EMI power conversion for automotive, industrial, and medical applications where reliability, small size, and regulatory compliance are critical design constraints.
FAQ
What is the maximum continuous output current of the LT8640SEV#PBF?
The LT8640SEV#PBF delivers 6A continuous output current and supports 7A peak current. This rating is validated under standard thermal conditions (θJA = 24°C/W on demo board, TA ≤ 85°C). Derating is required above 85°C ambient or with reduced copper area; full 6A is achievable at 125°C junction temperature with proper PCB thermal design.
Does the LT8640SEV#PBF support synchronization to an external clock?
Yes, the LT8640SEV#PBF 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 enables deterministic EMI placement and multi-converter phase alignment in complex power systems.
How does the LT8640SEV#PBF achieve ultralow EMI without external filters?
The LT8640SEV#PBF integrates ceramic bypass capacitors for VIN, BST, and INTVCC directly into the LQFN package, minimizing high-di/dt loop areas. Combined with symmetrical layout, magnetic field cancellation, and optional spread spectrum modulation, this Silent Switcher 2 architecture meets CISPR 25 Class 5 radiated emissions limits on standard 2-layer PCBs - eliminating need for ferrite beads or metal shields.
What is the function of the TR/SS pin on the LT8640SEV#PBF?
The TR/SS pin (Pin 21) on the LT8640SEV#PBF provides dual functionality: soft-start control and output voltage tracking. An internal 1.9µA current source charges an external capacitor to program VOUT ramp rate. When TR/SS voltage is below 0.97V, the FB pin tracks TR/SS voltage - enabling precise power sequencing with other rails in multi-voltage systems.
Is the LT8640SEV#PBF qualified for automotive applications?
Yes, the LT8640SEV#PBF is AEC-Q100 qualified Grade 1 (–40°C to 125°C junction temperature) and manufactured under automotive quality systems. It is specifically designed for automotive power rails including infotainment, ADAS cameras, body control modules, and telematics - with built-in protection against load dump, cold crank, and reverse battery conditions.
LT8640SEV#PBF 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):
- 3.4V
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-LQFN (4x4)
LT8640SEV#PBF FAQ
1.How can I place an order for LT8640SEV#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640SEV#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 LT8640SEV#PBF reliable?
The price and inventory of LT8640SEV#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640SEV#PBF is usually 5 days.
3.What payment methods are accepted for LT8640SEV#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640SEV#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640SEV#PBF?
LT8640SEV#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640SEV#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 LT8640SEV#PBF?
For technical support, including LT8640SEV#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640SEV#PBF requirements.
6.How does Aetrix verify that LT8640SEV#PBF is sourced from the original manufacturer or authorized distributors?
All LT8640SEV#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 LT8640SEV#PBF meets industry standards.
7.What is the process for return or replacement of LT8640SEV#PBF?
All LT8640SEV#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640SEV#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 LT8640SEV#PBF part is unused and in its original packaging.
Return procedure for LT8640SEV#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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