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Analog Devices Inc. LT8640EUDCF#TRPBF
- Part No.:
- LT8640EUDCF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640EUDCF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,456
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Product details
Overview
LT8640EUDCF#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), supports spread-spectrum EMI reduction, and operates across –40°C to 125°C in automotive-grade side-wettable QFN packaging.
For engineers reviewing the LT8640EUDCF#TRPBF datasheet, LT8640EUDCF#TRPBF pinout, LT8640EUDCF#TRPBF application, or LT8640EUDCF#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed EMI performance data, real-world thermal behavior, and accurate alternative selection guidance for high-reliability DC/DC design.
Technical Context
The LT8640EUDCF#TRPBF implements peak current mode control with an internal 0.970V reference and programmable oscillator (200kHz–3MHz via RT resistor). Its Silent Switcher architecture uses dual input paths, symmetric layout, and integrated bootstrap capacitor to suppress common-mode EMI without external filters.
It features four selectable operating modes via SYNC/MODE pin: Burst Mode (2.5µA IQ), pulse-skipping (LT8640 variant), spread-spectrum modulation (±20% frequency dither), and external clock synchronization. The device safely tolerates inductor saturation and supports output soft-start/tracking via TR/SS pin with 1.9µA internal pull-up.
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 transients. |
| Continuous Output Current | 5A - sustained delivery without derating at TJ ≤ 125°C with proper PCB copper area. |
| Quiescent Current | 2.5µA at full regulation - enables >10-year battery life in always-on IoT sensors and telematics. |
| Minimum On-Time | 30ns - enables high-frequency, high-VIN/low-VOUT conversion (e.g., 42V→3.3V at 2MHz). |
| EMI Performance | CISPR 25 Class 5 compliant - meets automotive radiated/conducted emission limits without ferrite beads or shielding. |
| Thermal Resistance | θJA = 40°C/W - achieved using exposed SW pads soldered to PCB; θJC(PAD) = 12°C/W for heatsink attachment. |
| Feedback Reference | 0.970V ±0.006V - tight tolerance enables precise output voltage setting with <±1% total error over line/load/temp. |
Pinout & Package
LT8640EUDCF#TRPBF uses an 18-lead, 3mm × 4mm plastic side-wettable QFN package (LHJK marking) with exposed SW pads (pins 21, 22) for enhanced thermal conduction and automated optical solder inspection (AOI) compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator auxiliary supply | Reduces VIN current draw when tied to VOUT ≥3.3V; requires 1µF local bypass if externally powered. |
| INTVCC (2) | Internal 3.4V LDO output | Bypass with ≥1µF ceramic cap; powers control logic and gate drivers; not for external loading. |
| BST (3) | Bootstrap capacitor node | Drives high-side NMOS gate above VIN; requires 0.1µF X7R ceramic placed adjacent to pin. |
| VIN1 (4), VIN2 (13) | Main input power inputs | Each requires dedicated 1µF ceramic bypass to respective GND1/GND2; shared bulk cap connects both. |
| GND1 (6,7), GND2 (10,11) | Power switch return paths | Must be tied together and connected to low-impedance ground plane; input cap negatives land here. |
| SW (8,9,21,22) | Switch node outputs | High di/dt node; pins 21/22 are exposed pads-must be soldered to SW trace for thermal/EMI performance. |
| EN/UV (14) | Enable & undervoltage lockout | Hysteretic threshold (0.96V/1.00V); resistor divider from VIN sets custom UVLO point. |
| RT (15) | Oscillator frequency programming | Resistor to GND sets fSW: 221kΩ → 210kHz, 60.4kΩ → 700kHz, 18.2kΩ → 2.0MHz. |
| TR/SS (16) | Soft-start & output tracking | 1.9µA internal current source enables capacitor-programmed slew rate; also accepts external tracking voltage. |
| SYNC/MODE (17) | Operating mode selection | Ground = Burst Mode; float = pulse-skipping; INTVCC = spread spectrum; driven clock = sync mode. |
| GND (18) | Signal ground reference | Connect to system ground plane; separate from power GNDs but tied at single point. |
| PG (19) | Power good open-drain flag | Asserts high when FB is within ±8% of 0.970V and no fault; valid only when VIN >3.4V. |
| FB (20) | Feedback voltage sense | Regulated to 0.970V; connect resistor divider tap here; add 4.7–22pF phase-lead cap to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated dual-input layout and symmetric switching reduces radiated EMI by >30dB vs conventional buck ICs. |
| Ultralow 2.5µA quiescent current | Enables direct connection to 12V vehicle battery without load switch; maintains regulation during sleep states. |
| 30ns minimum on-time | Supports 42V→3.3V conversion at 2MHz, minimizing inductor size and enabling compact 12V→5V/3.3V point-of-load designs. |
| Spread-spectrum modulation | ±20% triangular dithering lowers peak EMI amplitude by spreading energy across 200kHz bandwidth-no layout changes needed. |
| Side-wettable QFN (UDCF) | Facilitates automated AOI inspection of solder joints on exposed SW pads-critical for automotive AEC-Q100 compliance. |
| Inductor saturation tolerance | Continues safe operation under overload; disables next cycle until bottom-FET current falls below 10A threshold. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering FPGA core (1.2V/3A), DDR memory (1.35V/2A), and MCU (3.3V/500mA) from 12V vehicle battery with cold-crank immunity. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 3.3V/5A with fast transient response and EMI containment. Use Value: Meets CISPR 25 Class 5 emissions without added filtering; 2.5µA IQ extends backup battery life during ignition-off state. |
Use Scenario: Generating isolated 5V/3A and 15V/1A rails for analog sensor front-ends and digital logic in factory automation controllers. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC/DC converter powering downstream isolated DC/DC modules. Use Value: 42V max input withstands 36V industrial bus transients; side-wettable QFN ensures solder joint reliability in vibration-prone environments. |
| GSM Base Station RF Power Amp | Medical Portable Diagnostic Device |
Use Scenario: Supplying 5V/4A to GaN RF power amplifier stages requiring ultra-low noise and minimal conducted EMI injection into sensitive RF circuitry. IC Role / Device Role / Timing Role: Low-noise, spread-spectrum synchronized buck converter feeding PA bias rail. Use Value: Conducted EMI reduced by >25dB at 150kHz–30MHz; 30ns on-time enables clean 28V→5V conversion at 2MHz. |
Use Scenario: Battery-powered ultrasound probe requiring 3.3V/2A and 5V/1A from single Li-ion cell (2.7–4.2V) with >5-year shelf life. IC Role / Device Role / Timing Role: High-VIN buck-boost capable regulator (via external charge pump assist) delivering stable outputs during deep discharge. Use Value: 2.5µA IQ preserves battery capacity; AEC-Q100 qualification validates long-term reliability in safety-critical medical use. |
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 |
|---|---|---|---|
| LT8640-1EUDCF#TRPBF | Forced Continuous Mode (FCM) instead of pulse-skipping; higher light-load IQ (≈100µA); identical pinout and package. | Better transient response for dynamic loads (e.g., motor drivers); unsuitable where ultralow IQ is mandatory. | Select LT8640-1EUDCF#TRPBF when fast load-step recovery outweighs standby power budget. |
| MPQ4420AGL-A-Z | 36V max input, 2A output, 17µA IQ; QFN-10 package; no spread spectrum or side-wettable leads. | Limited to lower-power applications; lacks automotive EMI certification and thermal robustness. | Choose MPQ4420AGL-A-Z only for cost-sensitive, non-automotive 12V→5V/2A designs with relaxed EMI requirements. |
Compared with LT8640EUDCF#TRPBF, the LT8640-1EUDCF#TRPBF trades ultralow IQ for superior transient performance, while MPQ4420AGL-A-Z offers lower cost and smaller footprint at the expense of input range, output current, EMI compliance, and automotive qualification.
Availability
LT8640EUDCF#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and medical portable diagnostics requiring stable component supply, AEC-Q100 qualification, and guaranteed long-term availability.
Supply support for LT8640EUDCF#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 industrial, automotive, communications, and healthcare markets since 1965.
The LT8640 series belongs to Analog Devices' Silent Switcher DC/DC regulator product line, engineered specifically for EMI-sensitive applications demanding high efficiency, wide input range, and automotive reliability without external filtering.
FAQ
What is the maximum input voltage rating for the LT8640EUDCF#TRPBF?
The LT8640EUDCF#TRPBF has an absolute maximum input voltage rating of 42V across VIN1 and VIN2 pins. It operates continuously from 3.4V to 42V, making it suitable for 24V and 36V industrial buses and 12V automotive systems with load-dump transients. Exceeding 42V risks permanent damage per Absolute Maximum Ratings.
Does the LT8640EUDCF#TRPBF support spread-spectrum EMI reduction?
Yes, the LT8640EUDCF#TRPBF supports spread-spectrum modulation when the SYNC/MODE pin is tied to INTVCC (~3.4V) or a 3V–4V external supply. This modulates the switching frequency by ±20%, reducing peak radiated and conducted EMI amplitudes-verified in CISPR 25 Class 5 testing on DC2202A demo board.
How does the LT8640EUDCF#TRPBF achieve 2.5µA quiescent current?
The LT8640EUDCF#TRPBF achieves 2.5µA IQ in Burst Mode operation by disabling all switching and control circuitry between energy bursts, leaving only essential bias currents active. This occurs when the SYNC/MODE pin is grounded and light-load conditions trigger burst cycles-confirmed in Figure G05 with 12V input and 3.3V output.
Is the LT8640EUDCF#TRPBF pin-compatible with other variants in the LT8640 family?
Yes, the LT8640EUDCF#TRPBF shares identical pinout, package dimensions, and footprint with LT8640-1EUDCF#TRPBF, LT8640IUDCF#TRPBF, and all UDCF variants. Differences are limited to internal mode logic (pulse-skipping vs FCM) and temperature grade-no PCB redesign is required when substituting within the UDCF package group.
What thermal performance can be expected from the LT8640EUDCF#TRPBF in a standard 4-layer PCB?
On a typical 4-layer PCB with 2oz copper, 200mm² thermal pad area, and 4x thermal vias under the exposed SW pads, the LT8640EUDCF#TRPBF achieves θJA ≈ 40°C/W. At 5A load and 12V input, junction temperature rise remains below 85°C-validated in Figure G32 using DC2202A demo board measurements.
LT8640EUDCF#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)
LT8640EUDCF#TRPBF FAQ
1.How can I place an order for LT8640EUDCF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640EUDCF#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 LT8640EUDCF#TRPBF reliable?
The price and inventory of LT8640EUDCF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640EUDCF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8640EUDCF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640EUDCF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640EUDCF#TRPBF?
LT8640EUDCF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640EUDCF#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 LT8640EUDCF#TRPBF?
For technical support, including LT8640EUDCF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640EUDCF#TRPBF requirements.
6.How does Aetrix verify that LT8640EUDCF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640EUDCF#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 LT8640EUDCF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8640EUDCF#TRPBF?
All LT8640EUDCF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640EUDCF#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 LT8640EUDCF#TRPBF part is unused and in its original packaging.
Return procedure for LT8640EUDCF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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