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Analog Devices Inc. LT8640IUDCF#PBF
- Part No.:
- LT8640IUDCF#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640IUDCF#PBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:196
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Product details
Overview
LT8640IUDCF#PBF 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 200kHz–3MHz programmable switching frequency, and operates across –40°C to 125°C junction temperature - ideal for automotive infotainment power rails requiring ultra-low EMI and high light-load efficiency.
For engineers reviewing the LT8640IUDCF#PBF datasheet, LT8640IUDCF#PBF pinout, LT8640IUDCF#PBF application, or LT8640IUDCF#PBF equivalent, key selection criteria include its side-wettable QFN-18 package for automated optical inspection, forced continuous mode capability (LT8640-1 variant), spread spectrum EMI reduction, and AEC-Q100 qualification for automotive-grade reliability.
Technical Context
The LT8640IUDCF#PBF implements peak current-mode control with an internal 0.970V reference and programmable oscillator (RT pin). 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 operating modes selected via SYNC/MODE pin: Burst Mode (2.5µA IQ), forced continuous mode (FCM) for fast transient response, spread spectrum modulation (±20% frequency dither), and external clock synchronization - all while maintaining <10mVP-P output ripple and 100mV dropout at 1A.
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 | 5A continuous, 7A peak - sustains transient loads without foldback or shutdown. |
| Quiescent Current | 2.5µA in regulation - enables >10-year battery life in always-on automotive modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics and avoids AM band interference. |
| Min On-Time | 30ns - enables high VIN-to-low VOUT conversion (e.g., 42V→3.3V) at 2MHz. |
| Feedback Reference | 0.970V ±0.006V - ensures tight output regulation across temperature and line/load variations. |
| EMI Performance | CISPR 25 Class 5 compliant with filter - meets stringent automotive radiated emission limits in horizontal/vertical polarization. |
Pinout & Package
LT8640IUDCF#PBF uses an 18-lead 3mm × 4mm plastic side-wettable QFN package (exposed SW pads on pins 21/22), optimized for automated optical inspection (AOI) and thermal performance (θJC = 12°C/W). The package includes dual GND paths (GND1, GND2), dual VIN inputs (VIN1, VIN2), and dedicated BIAS/INTVCC for efficient biasing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | External bias supply input | Reduces input supply current by powering internal circuitry from VOUT (≥3.3V); bypass with 1µF ceramic. |
| INTVCC (2) | Internal 3.4V regulator output | Supplies gate drivers and control logic; requires ≥1µF low-ESR ceramic decoupling to GND. |
| BST (3) | Bootstrap capacitor connection | Drives high-side NMOS gate above VIN; requires 0.1µF ceramic placed adjacent to IC. |
| VIN1 (4), VIN2 (13) | Dual input power inputs | Enable low-inductance dual-path input filtering; each requires dedicated 1µF ceramic close to pin. |
| GND1 (6,7), GND2 (10,11), GND (18) | Power and signal ground returns | Must be tied together and connected to solid ground plane; minimizes switching loop area for EMI control. |
| SW (8,9,21,22) | Power switch node | Connects to inductor and BST cap; exposed pads (21/22) must be soldered to SW trace for thermal integrity. |
| EN/UV (14) | Enable and input undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable VIN start-up; tie to VIN if unused. |
| RT (15) | Frequency programming resistor | Sets fSW from 200kHz–3MHz via resistor to GND (e.g., 60.4kΩ = ~2MHz). |
| TR/SS (16) | Soft-start and tracking control | 1.9µA internal current source enables voltage-ramp control; pulled low during fault/shutdown. |
| SYNC/MODE (17) | Operating mode selection | Selects Burst Mode (GND), FCM (float), spread spectrum (3–4V), or sync (external clock). |
| PG (19) | Power good open-drain output | Asserts high when FB is within ±8% of 0.970V and no faults exist; valid above 3.4VIN. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V; connect resistor divider tap and 4.7–22pF phase-lead cap to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated dual-input paths and symmetrical layout reduce EMI by >30dB vs conventional buck regulators - eliminates need for external EMI filters in most automotive designs. |
| Ultralow 2.5µA quiescent current | Enables >10-year standby operation in always-on vehicle systems (e.g., telematics, ADAS sensors) without battery drain. |
| 30ns minimum on-time | Supports direct 42V→3.3V/5V conversion at 2MHz, reducing solution size by eliminating intermediate stages. |
| Forced Continuous Mode (FCM) | Eliminates pulse-skipping discontinuities, enabling <50µs load-step response and seamless transition between light/heavy loads. |
| AEC-Q100 Grade I qualified | Guaranteed operation from –40°C to +125°C junction temperature with full parametric validation - suitable for engine bay and infotainment applications. |
| Side-wettable QFN package | Enables automated optical inspection (AOI) of solder joints on production lines - improves manufacturing yield and field reliability. |
Applications
| Automotive Infotainment Power Supply | ADAS Camera Module Power |
|---|---|
Use Scenario: Powers SoC, display, and audio subsystems in head units with strict CISPR 25 radiated emission limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck converter delivering regulated power with spread spectrum EMI suppression. Use Value: Meets Class 5 peak limits without external filters, reducing BOM cost and PCB area by >30% vs legacy solutions. | Use Scenario: Supplies image sensor and ISP in rear-view or surround-view cameras requiring low noise and fast transient response. IC Role / Device Role / Timing Role: High-efficiency, low-ripple DC/DC converter with FCM mode for minimal output voltage deviation during exposure bursts. Use Value: Maintains <±10mV output deviation during 1A–2A load steps, preserving image quality and avoiding frame corruption. |
| Industrial IoT Gateway Power | GSM/Baseband Power Management |
Use Scenario: Powers LTE/Wi-Fi modules and microcontrollers in battery-backed industrial gateways with multi-year runtime requirements. IC Role / Device Role / Timing Role: Always-on buck regulator operating in Burst Mode to minimize sleep-state current draw. Use Value: Achieves 2.5µA IQ at no load, extending coin-cell or supercapacitor backup runtime beyond 10 years. | Use Scenario: Generates stable 3.3V rail for GSM modem baseband processors subject to high-current TDMA burst loads. IC Role / Device Role / Timing Role: High-current synchronous buck with 7A peak capability and low dropout (<100mV @ 1A). Use Value: Sustains regulation during 2A GSM transmit pulses without brownout, eliminating communication dropouts. |
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 |
|---|---|---|---|
| LT8640S-1EUDCF#PBF | Same architecture but LQFN package with internal compensation; supports higher ambient temperature (150°C junction). | Targeted at under-hood applications exceeding 125°C ambient; not pin-compatible due to different pinout and compensation scheme. | Select only if extended temperature range or simplified design (no external compensation) is required - requires PCB redesign. |
| MPQ4433AGL-AEC1-Z | 45V, 3.5A AEC-Q100 buck with 17µA IQ; lacks spread spectrum and side-wettable QFN. | Lower current rating and higher IQ limit use in always-on systems; no built-in EMI mitigation features. | Consider for cost-sensitive, non-EMI-critical automotive applications where 3.5A output suffices and external filtering is acceptable. |
Compared with LT8640S-1EUDCF#PBF and MPQ4433AGL-AEC1-Z, the LT8640IUDCF#PBF uniquely combines AEC-Q100 Grade I qualification, side-wettable QFN for AOI, 2.5µA IQ, and integrated spread spectrum - making it optimal for space-constrained, EMI-sensitive automotive infotainment and ADAS power rails.
Availability
LT8640IUDCF#PBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and industrial IoT gateways requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT8640IUDCF#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 automotive, industrial, communications, and healthcare markets.
The LT8640 product line delivers high-efficiency, low-EMI DC/DC conversion for automotive and industrial applications where reliability, small size, and regulatory compliance are critical - with the LT8640IUDCF#PBF specifically engineered for AEC-Q100-compliant, space-constrained power rails.
FAQ
What is the maximum junction temperature rating for LT8640IUDCF#PBF?
The LT8640IUDCF#PBF is rated for operation from –40°C to +125°C junction temperature (Grade I). This specification is guaranteed across the full temperature range, with thermal derating applied above 125°C to ensure long-term reliability in automotive environments.
Does LT8640IUDCF#PBF support external frequency synchronization?
Yes, the LT8640IUDCF#PBF supports external clock synchronization via the SYNC/MODE pin. When driven with a clean CMOS clock signal, the device synchronizes its internal oscillator to the external frequency while maintaining forced continuous mode operation - essential for noise-sensitive systems like radar or audio processing.
How does the side-wettable QFN package of LT8640IUDCF#PBF improve manufacturing yield?
The side-wettable QFN package of LT8640IUDCF#PBF exposes solder along the vertical sidewalls of each lead, enabling automated optical inspection (AOI) to verify solder joint integrity without X-ray. This significantly improves first-pass yield and field reliability in high-volume automotive PCB assembly.
Can LT8640IUDCF#PBF operate with a 3.3V input voltage?
No - the LT8640IUDCF#PBF has a minimum input voltage of 3.4V per datasheet specifications. Operation below this threshold may result in unstable regulation or startup failure. For 3.3V-input applications, consider alternative regulators with lower VIN(min) such as the LT8609.
What is the purpose of the dual VIN inputs (VIN1 and VIN2) on LT8640IUDCF#PBF?
The dual VIN inputs (VIN1 and VIN2) on LT8640IUDCF#PBF enable low-inductance, symmetric input current paths that minimize high-frequency switching loop area - a core element of the Silent Switcher architecture. Each requires a dedicated 1µF ceramic capacitor placed adjacent to the pin to suppress input ripple and reduce radiated EMI.
LT8640IUDCF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®1
- Package/Case:
- 20-WFQFN, 18 Leads, Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LT8640IUDCF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640IUDCF#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 LT8640IUDCF#PBF reliable?
The price and inventory of LT8640IUDCF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640IUDCF#PBF is usually 5 days.
3.What payment methods are accepted for LT8640IUDCF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640IUDCF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640IUDCF#PBF?
LT8640IUDCF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640IUDCF#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 LT8640IUDCF#PBF?
For technical support, including LT8640IUDCF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640IUDCF#PBF requirements.
6.How does Aetrix verify that LT8640IUDCF#PBF is sourced from the original manufacturer or authorized distributors?
All LT8640IUDCF#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 LT8640IUDCF#PBF meets industry standards.
7.What is the process for return or replacement of LT8640IUDCF#PBF?
All LT8640IUDCF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640IUDCF#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 LT8640IUDCF#PBF part is unused and in its original packaging.
Return procedure for LT8640IUDCF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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