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Analog Devices Inc. LT8640SIV#PBF
- Part No.:
- LT8640SIV#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8640SIV#PBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,457
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Product details
Overview
LT8640SIV#PBF from Analog Devices is a 42V, 6A synchronous step-down Silent Switcher 2 regulator with 2.5µA quiescent current in regulation (12VIN→3.3VOUT), 30ns minimum on-time, and internal compensation - designed for noise-sensitive automotive and industrial power supplies requiring ultralow EMI and high efficiency at 1–3MHz switching frequencies.
For engineers reviewing the LT8640SIV#PBF datasheet, LT8640SIV#PBF pinout, LT8640SIV#PBF application, or LT8640SIV#PBF equivalent, key selection criteria include its integrated bypass capacitors for layout-insensitive EMI performance, AEC-Q100 qualification, 4mm × 4mm LQFN package with exposed GND pads, and Burst Mode® operation enabling µA-level standby consumption.
Technical Context
The LT8640SIV#PBF employs peak current mode control with second-generation Silent Switcher 2 architecture, integrating ceramic bypass capacitors for VIN, BST, and INTVCC to minimize fast-current-loop radiation. Its 30ns minimum on-time enables high step-down ratios (e.g., 36V→3.3V) at 2MHz without pulse-skipping instability.
Burst Mode® operation delivers 2.5µA IQ at no load while maintaining regulation; forced continuous mode (FCM) is selected by floating SYNC/MODE to ensure fixed-frequency operation across full load range and support output current sinking for improved transient response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide-range industrial and automotive battery inputs including cold-crank and load-dump conditions. |
| Output Current | 6A continuous, 7A peak - sustains full-rated load at 125°C junction temperature with proper thermal design. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT in Burst Mode - enables >10-year battery life in always-on systems. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization of size vs. efficiency; 2MHz enables <3mm² inductor footprint. |
| Feedback Reference | 0.970V ±0.006V - tight tolerance enables accurate output regulation with minimal resistor divider error. |
| EMI Performance | CISPR 25 Class 5 compliant with spread spectrum - eliminates need for external EMI filters in most automotive applications. |
| Package | 24-lead 4mm × 4mm × 0.94mm LQFN with exposed GND pads - θJA = 38°C/W (JEDEC board), supports >4W dissipation at 125°C ambient. |
Pinout & Package
LT8640SIV#PBF is housed in a 24-lead LQFN (Laminate QFN) package measuring 4mm × 4mm × 0.94mm, with pins 25–28 as exposed GND pads soldered directly to PCB for optimal thermal and EMI performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator supply input | Connect to VOUT ≥3.3V to reduce VIN current draw; enables efficient biasing of gate drivers and control circuitry. |
| INTVCC (2) | Internal 3.4V regulator output | Must be left floating; powers internal logic and drivers; sourced from BIAS if >3.1V, else from VIN. |
| GND (3, 16, 25–28) | Power and signal ground reference | Multiple low-inductance GND connections required; exposed pad must be soldered for thermal/EMI integrity. |
| VIN (5, 6, 13, 14) | Main input power supply | Four parallel pins reduce resistance and inductance; requires local ≥2.2µF ceramic capacitor placement adjacent to pins. |
| BST (7) | Bootstrap capacitor connection | Connect 0.22µF ceramic between BST and SW; enables high-side NMOS gate drive above VIN. |
| SW (8–12) | Power switch node | Five parallel SW pins connect to inductor; minimized trace area critical for low EMI and voltage ringing control. |
| EN/UV (17) | Enable and undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable input UVLO using resistor divider from VIN. |
| RT (18) | Frequency programming | Resistor to GND sets fSW from 200kHz to 3MHz; determines inductor size, efficiency, and EMI profile. |
| CLKOUT (19) | Switching frequency monitor | Outputs ~200ns pulses at fSW in FCM/spread-spectrum/sync modes; low in Burst Mode. |
| SYNC/MODE (20) | Operating mode select | GND = Burst Mode; float = FCM; INTVCC = spread spectrum; external clock = synchronization. |
| TR/SS (21) | Soft-start and tracking control | 1.9µA internal pull-up enables RC-programmed ramp rate; supports output voltage tracking during startup. |
| GND (22) | Signal ground return | Dedicated ground pin for feedback and soft-start paths; improves noise immunity of sensitive analog nodes. |
| PG (23) | Power good open-drain output | Active-high when FB is within ±8% of 0.97V and no fault (thermal, UVLO, EN); pulls low during faults. |
| FB (24) | Feedback voltage sense | Regulated to 0.970V; connects to resistor divider tap; requires 4.7–22pF phase-lead capacitor to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 architecture | Integrated VIN/BST/INTVCC bypass capacitors eliminate layout sensitivity and reduce radiated EMI by >30dB vs. first-gen parts. |
| Ultralow quiescent current | 2.5µA IQ in Burst Mode enables >10-year battery runtime in always-on telematics and sensor modules. |
| 30ns minimum on-time | Enables direct 36V→3.3V conversion at 2MHz without duty-cycle limitation or external components. |
| AEC-Q100 Grade I qualified | Rated for –40°C to +125°C junction temperature - validated for automotive infotainment, ADAS, and body electronics. |
| Forced Continuous Mode (FCM) | Eliminates frequency variation under light loads, ensuring predictable EMI spectrum and fast load-transient recovery (<10µs). |
| Spread spectrum modulation | Reduces peak EMI amplitude by spreading energy over ±22% bandwidth - simplifies compliance testing for CISPR 25 Class 5. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 5V/3.3V rails for SoC, display, and audio codecs in head units with strict CISPR 25 Class 5 EMI limits. IC Role / Device Role / Timing Role: Primary 42V-input synchronous buck converter delivering regulated 5V@6A with ultralow EMI and 2.5µA standby. Use Value: Eliminates external EMI filters and reduces board area by 35% versus discrete solutions while meeting automotive EMC requirements. | Use Scenario: Generating isolated 5V/3.3V supplies for digital I/O, ADCs, and communication interfaces in harsh factory-floor environments. IC Role / Device Role / Timing Role: High-reliability DC/DC regulator supporting 3.4–42V input transients and operating continuously at 85°C ambient. Use Value: Maintains regulation during 24V brownouts and 42V surges; 6A output supports multiple downstream LDOs and isolated DC/DCs. |
| Medical Portable Monitor | Test & Measurement Equipment |
Use Scenario: Battery-powered patient monitors requiring long runtime and clean analog supply for ECG/SpO₂ front-ends. IC Role / Device Role / Timing Role: Main system buck converter with Burst Mode enabling 2.5µA IQ, low-noise output (<10mVP-P ripple), and fast wake-up. Use Value: Extends lithium battery life to >12 hours per charge while preserving signal integrity in sensitive analog measurement paths. | Use Scenario: Precision bench power supplies needing stable, low-noise 5V/3.3V rails for FPGA, DACs, and reference buffers. IC Role / Device Role / Timing Role: Low-EMI, high-efficiency buck stage preceding ultra-low-noise LDOs; synchronized to system clock via SYNC/MODE. Use Value: Enables deterministic EMI alignment and eliminates beat frequencies with other system clocks, improving measurement SNR. |
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#PBF | External compensation (VC pin), higher IQ (230µA in sleep), supports current sharing and faster transient response. | Preferred for multi-phase designs or applications demanding <5µs load-step recovery with 100µF output capacitance. | Select LT8643SIV#PBF when loop stability tuning or paralleling is required; LT8640SIV#PBF is simpler for single-rail, cost-sensitive designs. |
| MPQ4420AGL-A-Z | 40V max input, 2A output, no spread spectrum, 17µA IQ, QFN-12 package. | Targeted at lower-power consumer and IoT applications where EMI filtering is less stringent and cost is primary. | Choose MPQ4420AGL-A-Z only for ≤2A, non-automotive designs with relaxed EMI and thermal constraints. |
Compared with LT8643SIV#PBF and MPQ4420AGL-A-Z, the LT8640SIV#PBF uniquely combines AEC-Q100 qualification, 6A output, 2.5µA IQ, and integrated Silent Switcher 2 EMI reduction - making it the optimal choice for high-reliability, high-density automotive and industrial power rails.
Availability
LT8640SIV#PBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and portable medical devices requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT8640SIV#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, industrial automation, communications, and automotive markets.
The LT8640S product line delivers high-efficiency, ultralow-EMI synchronous buck regulators for automotive and industrial applications where reliability, small size, and regulatory compliance are critical.
FAQ
What is the maximum continuous output current of the LT8640SIV#PBF?
The LT8640SIV#PBF delivers 6A continuous output current under typical thermal conditions (θJA = 38°C/W, TA = 25°C). At 125°C junction temperature with proper PCB copper area and exposed pad soldering, it maintains full 6A output. Peak current capability reaches 7A for short durations, limited by internal current sensing and thermal foldback.
How does the LT8640SIV#PBF achieve ultralow EMI without external filters?
The LT8640SIV#PBF integrates ceramic bypass capacitors for VIN, BST, and INTVCC directly into the LQFN package - minimizing all high-di/dt current loop areas. Combined with symmetrical layout, balanced SW node routing, and Silent Switcher 2 edge-rate control, this enables CISPR 25 Class 5 compliance on standard 4-layer PCBs without ferrite beads or π-filters.
Can the LT8640SIV#PBF operate from a 3.4V input and still regulate 3.3V output?
Yes, the LT8640SIV#PBF supports dropout operation down to 100mV at 1A load. At 3.4V input and 3.3V output, it operates in 100% duty cycle with minimal conduction loss. The internal top NMOS RDS(on) of 66mΩ ensures <66mV dropout at 1A, allowing stable regulation even at minimum input voltage.
What is the purpose of the TR/SS pin on the LT8640SIV#PBF?
The TR/SS pin on the LT8640SIV#PBF provides soft-start and output voltage tracking functionality. An internal 1.9µA current source charges an external capacitor to control output ramp rate. When driven externally, it forces the FB pin to track the TR/SS voltage below 0.97V - enabling precise sequencing with other rails in multi-voltage systems.
Is the LT8640SIV#PBF AEC-Q100 qualified, and what grade does it meet?
Yes, the LT8640SIV#PBF is AEC-Q100 qualified and rated for Grade I operation (–40°C to +125°C junction temperature). This qualification covers stress testing for automotive environments including temperature cycling, humidity, and ESD - making it suitable for infotainment, ADAS, and body electronics applications.
LT8640SIV#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)
LT8640SIV#PBF FAQ
1.How can I place an order for LT8640SIV#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640SIV#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 LT8640SIV#PBF reliable?
The price and inventory of LT8640SIV#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640SIV#PBF is usually 5 days.
3.What payment methods are accepted for LT8640SIV#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640SIV#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640SIV#PBF?
LT8640SIV#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640SIV#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 LT8640SIV#PBF?
For technical support, including LT8640SIV#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640SIV#PBF requirements.
6.How does Aetrix verify that LT8640SIV#PBF is sourced from the original manufacturer or authorized distributors?
All LT8640SIV#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 LT8640SIV#PBF meets industry standards.
7.What is the process for return or replacement of LT8640SIV#PBF?
All LT8640SIV#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640SIV#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 LT8640SIV#PBF part is unused and in its original packaging.
Return procedure for LT8640SIV#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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