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Analog Devices Inc. LT8640IUDCF#TRPBF
- Part No.:
- LT8640IUDCF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640IUDCF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,506
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Product details
Overview
LT8640IUDCF#TRPBF 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 integrated power MOSFETs. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT) and supports forced continuous mode (FCM) for fast transient response in automotive and industrial power supplies.
For engineers reviewing the LT8640IUDCF#TRPBF datasheet, LT8640IUDCF#TRPBF pinout, LT8640IUDCF#TRPBF application, or LT8640IUDCF#TRPBF equivalent, key selection criteria include ultralow EMI performance, AEC-Q100 qualification, 3.4V–42V input range, 0.97V feedback reference, and side-wettable QFN thermal reliability for high-density PCB layouts.
Technical Context
The LT8640IUDCF#TRPBF implements peak current-mode control with an 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 radiated EMI without external filters.
It features dual ground paths (GND1/GND2), dedicated SW pins (8,9,21,22), and a SYNC/MODE pin that selects Burst Mode, spread spectrum, external synchronization, or forced continuous mode-enabling optimized trade-offs between light-load efficiency, transient response, and EMI compliance.
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 | 5A continuous, 7A peak - enables single-chip 5V/5A or 3.3V/5A rails for microcontrollers, FPGAs, and sensors. |
| Quiescent Current | 2.5µA in regulation - sustains >10-year battery life in always-on IoT nodes and telematics modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics and avoids AM/FM bands in automotive EMI-sensitive zones. |
| Feedback Reference | 0.970V ±0.006V - enables precise output voltage setting with <±1% total error over temperature and line/load. |
| Min On-Time | 30ns - supports high-frequency, high-VIN-to-low-VOUT conversion (e.g., 42V→3.3V at 2MHz). |
| EMI Performance | CISPR 25 Class 5 compliant (with filter) - meets stringent automotive radiated emission limits without ferrite beads or shielding cans. |
Pinout & Package
LT8640IUDCF#TRPBF uses an 18-lead, 3mm × 4mm plastic side-wettable QFN package (exposed SW pad on pins 21/22) rated for –40°C to 125°C junction temperature and qualified per AEC-Q100 Grade I.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Reduces VIN current draw when tied to VOUT ≥3.3V; enables >95% efficiency at light loads. |
| INTVCC (2) | Internal 3.4V LDO output | Bypassed with ≥1µF ceramic; powers gate drivers and control logic-must not be loaded externally. |
| BST (3) | Bootstrap capacitor connection | Drives top N-MOSFET gate above VIN; requires 0.1µF low-ESR ceramic placed adjacent to IC. |
| VIN1 (4), VIN2 (13) | Main input power inputs | Split-input design minimizes high-di/dt loop area; each requires dedicated 1µF ceramic bypass to GND1/GND2. |
| GND1 (6,7), GND2 (10,11) | Power switch return paths | Separate ground pins reduce noise coupling; must be tied together and connected to solid ground plane. |
| SW (8,9,21,22) | Switch node outputs | Exposed pads (21/22) must be soldered to SW trace for thermal conduction; critical for EMI and 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 programs fSW from 200kHz to 3MHz; sets minimum off-time and ripple trade-off. |
| TR/SS (16) | Soft-start and tracking | 1.9µA internal current source enables controlled VOUT ramp; supports power sequencing with other rails. |
| SYNC/MODE (17) | Operating mode control | Selects Burst Mode (ground), FCM (float), spread spectrum (3–4V), or external sync (clock input) - defines light-load behavior and EMI profile. |
| GND (18) | System ground reference | Connects to system ground plane; completes control circuit return path independent of power grounds. |
| PG (19) | Power good open-drain output | Asserts high when FB is within ±7.5% of 0.97V and no fault; drives MCU reset or enable signals. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V; connects to resistor divider tap; requires 4.7pF–22pF phase-lead capacitor to VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated input caps and symmetrical layout reduce radiated EMI by >30dB vs conventional buck regulators-eliminates need for shielding cans in automotive ECUs. |
| Forced Continuous Mode (FCM) | Enables zero-current-crossing operation across full 0–5A load range, delivering <50µs load-step response time for real-time control systems. |
| Side-wettable QFN package | Facilitates automated optical inspection (AOI) of solder joints on production lines-critical for AEC-Q100-compliant automotive manufacturing. |
| Spread spectrum modulation | ±20% triangular frequency dithering spreads EMI energy across bandwidth, easing CISPR 25 Class 5 compliance without added BOM cost. |
| AEC-Q100 Grade I qualification | Validated for –40°C to +125°C operation with HTOL, TC, and ESD testing-supports under-hood and ADAS power supply requirements. |
Applications
| Automotive ADAS Camera Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 3.3V image sensor and ISP in forward-facing camera module exposed to engine bay temperatures. IC Role / Device Role / Timing Role: Primary 42V→3.3V/3A DC/DC converter with soft-start sequencing and PG monitoring for safe boot. Use Value: 2.5µA IQ extends battery backup runtime during vehicle sleep; side-wettable QFN ensures solder joint reliability at 125°C ambient. |
Use Scenario: Generating isolated 5V/2A rail for digital I/O isolation barriers and fieldbus transceivers in modular PLC backplane. IC Role / Device Role / Timing Role: High-efficiency, low-noise buck regulator feeding downstream isolated DC/DC converters. Use Value: 96% efficiency at 1MHz reduces thermal load in confined chassis; spread spectrum mode prevents interference with CAN FD communication. |
| GSM Base Station RF Power Amp | Medical Patient Monitor Display |
Use Scenario: Supplying 5V/4A to GaN RF power amplifier stage requiring ultra-low ripple and fast transient recovery. IC Role / Device Role / Timing Role: Main intermediate bus converter operating in Forced Continuous Mode for <100ns load-step response. Use Value: 30ns min on-time enables direct 28V→5V conversion at 2MHz; <10mVP-P ripple eliminates need for post-regulator LDOs. |
Use Scenario: Providing regulated 3.3V/1.5A to LCD backlight driver and touch controller in portable diagnostic device with Li-ion battery. IC Role / Device Role / Timing Role: Always-on power rail with Burst Mode operation during standby to minimize self-discharge. Use Value: 2.5µA IQ extends 7-day battery life in clinical settings; AEC-Q100 qualification ensures long-term reliability under vibration and thermal cycling. |
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 |
|---|---|---|---|
| LT8640-1IUDCF#TRPBF | Identical package and pinout; differs only in FCM default behavior (LT8640-1 forces continuous mode when SYNC/MODE floated, while LT8640 defaults to pulse-skipping). | Preferred where fast transient response is mandatory across full load range (e.g., servo drives), not just burst efficiency. | Select LT8640-1IUDCF#TRPBF if forced continuous mode is required without external mode control logic. |
| MPQ4433AGL-AEC1-Z | 40V, 3.5A AEC-Q100 buck; higher IQ (15µA), no spread spectrum, smaller 3x4 QFN but non-side-wettable. | Suitable for cost-sensitive automotive body electronics where EMI margin is less constrained. | Choose MPQ4433AGL-AEC1-Z only if 3.5A output and relaxed EMI requirements suffice and AOI is not required. |
Compared with LT8640-1IUDCF#TRPBF, the LT8640IUDCF#TRPBF offers superior light-load efficiency via Burst Mode but requires explicit SYNC/MODE control for FCM; versus MPQ4433AGL-AEC1-Z, it delivers higher current, lower IQ, certified EMI performance, and manufacturable side-wettable packaging.
Availability
LT8640IUDCF#TRPBF is available at Aetrix Electronics and suitable for automotive ADAS systems, industrial PLCs, medical monitors, and GSM base station power supplies requiring stable component supply, AEC-Q100 qualification, and high-reliability packaging.
Supply support for LT8640IUDCF#TRPBF 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 LT8640/LT8640-1 belongs to Analog Devices' Silent Switcher family-designed specifically for automotive and industrial applications demanding ultra-low EMI, high efficiency across wide load ranges, and robust thermal performance in compact form factors.
FAQ
What is the maximum input voltage rating for the LT8640IUDCF#TRPBF?
The LT8640IUDCF#TRPBF has an absolute maximum input voltage rating of 42V on VIN1 and VIN2 pins. It operates continuously over 3.4V to 42V, making it suitable for 24V and 36V industrial systems and 12V automotive applications with load-dump protection. Exceeding 42V risks permanent damage per Absolute Maximum Ratings.
Does the LT8640IUDCF#TRPBF support external clock synchronization?
Yes, the LT8640IUDCF#TRPBF supports external clock synchronization via its SYNC/MODE pin (Pin 17). When driven with a clean CMOS clock signal between 200kHz and 3MHz, the device locks its internal oscillator and operates in pulse-skipping mode (LT8640 variant) or forced continuous mode (LT8640-1 variant), enabling deterministic timing in multi-rail systems.
How does the side-wettable QFN package of the LT8640IUDCF#TRPBF improve manufacturing yield?
The side-wettable QFN package of the LT8640IUDCF#TRPBF exposes solder along the vertical sidewalls of all perimeter leads, enabling automated optical inspection (AOI) to verify solder joint integrity without X-ray. This directly supports AEC-Q100 process validation and improves first-pass yield in high-volume automotive PCB assembly lines.
Can the LT8640IUDCF#TRPBF operate with a 3.3V output and maintain 2.5µA quiescent current?
Yes-the LT8640IUDCF#TRPBF achieves 2.5µA quiescent current while regulating a 3.3V output from 12VIN, as confirmed in the datasheet's Burst Mode Efficiency curves (Figure G05). This performance requires proper BIAS pin connection to VOUT and operation in Burst Mode (SYNC/MODE = GND), enabling decade-long battery life in always-on applications.
What is the function of the TR/SS pin on the LT8640IUDCF#TRPBF?
The TR/SS (Track/Soft-Start) pin on the LT8640IUDCF#TRPBF provides dual functionality: (1) Soft-start control via internal 1.9µA current source charging an external capacitor to limit output voltage slew rate; (2) Output voltage tracking by connecting to another regulator's feedback or reference node. It also pulls low during faults to disable downstream circuitry.
LT8640IUDCF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®1
- Package/Case:
- 20-WFQFN, 18 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 20-QFN (3x4)
LT8640IUDCF#TRPBF FAQ
1.How can I place an order for LT8640IUDCF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640IUDCF#TRPBF 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 LT8640IUDCF#TRPBF reliable?
The price and inventory of LT8640IUDCF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640IUDCF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8640IUDCF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640IUDCF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640IUDCF#TRPBF?
LT8640IUDCF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640IUDCF#TRPBF 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 LT8640IUDCF#TRPBF?
For technical support, including LT8640IUDCF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640IUDCF#TRPBF requirements.
6.How does Aetrix verify that LT8640IUDCF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640IUDCF#TRPBF 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 LT8640IUDCF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8640IUDCF#TRPBF?
All LT8640IUDCF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640IUDCF#TRPBF, 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 LT8640IUDCF#TRPBF part is unused and in its original packaging.
Return procedure for LT8640IUDCF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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