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Analog Devices Inc. LT8641IUDC#TRPBF
- Part No.:
- LT8641IUDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8641IUDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,847
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Product details
Overview
LT8641IUDC#TRPBF from Analog Devices is a 65V input, 3.5A synchronous step-down DC/DC regulator with Silent Switcher architecture, 2.5µA quiescent current in regulation, 35ns minimum on-time, and integrated power switches in a 18-lead 3mm × 4mm QFN package. It delivers up to 95% efficiency at 1MHz (12VIN→5VOUT) and supports automotive-grade operation from –40°C to 125°C.
For engineers reviewing the LT8641IUDC#TRPBF datasheet, LT8641IUDC#TRPBF pinout, LT8641IUDC#TRPBF application, or LT8641IUDC#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed EMI performance data, real-world transient response metrics, and cross-referenced automotive-qualified alternatives for high-reliability power design.
Technical Context
The LT8641IUDC#TRPBF implements peak current mode control with an internal 0.8V reference and programmable oscillator (200kHz–3MHz via RT resistor). Its dual-VIN/GND architecture isolates high-di/dt paths, while the Silent Switcher layout minimizes magnetic field emissions through symmetrical hot-loop cancellation.
It features four operating modes selected via SYNC/MODE pin: Burst Mode (2.5µA IQ), pulse-skipping, spread-spectrum modulation (±22% frequency dither), and external clock synchronization. Built-in frequency foldback protects during startup and overload, and BIAS pin sourcing enables >94% efficiency at 2MHz across 3.3V–25V output ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 65V - supports wide industrial and automotive battery inputs including 48V systems and cold-crank transients. |
| Continuous Output Current | 3.5A - sustained delivery without thermal derating under full load at 125°C junction temperature. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT regulation - enables >10-year battery life in always-on IoT sensors and telematics. |
| Minimum On-Time | 35ns - enables direct 48V-to-3.3V conversion at 2MHz without intermediate stages. |
| EMI Performance | CISPR 25 Class 5 compliant in spread-spectrum mode - eliminates need for external EMI filters in automotive infotainment. |
| Feedback Reference | 0.804V ±1.5% over –40°C to 125°C - ensures stable output accuracy across automotive temperature extremes. |
| Package | 18-lead 3mm × 4mm QFN with exposed SW pads - provides 12°C/W θJC(PAD) for high-power density thermal management. |
Pinout & Package
LT8641IUDC#TRPBF is housed in an 18-lead plastic QFN (UDC package), 3mm × 4mm footprint, with exposed SW pads (pins 21, 22) requiring solder connection to PCB for optimal thermal and EMI performance. Pins 5 and 12 are omitted per JEDEC outline deviation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Reduces VIN current draw when tied to VOUT ≥3.3V - improves light-load efficiency by shifting bias current source. |
| INTVCC (2) | Internal 3.4V regulator bypass | Must be decoupled with ≥1µF ceramic capacitor - stabilizes gate drivers and control logic during fast load transients. |
| BST (3) | Bootstrap capacitor node | Requires 0.1µF low-ESR capacitor - enables high-side NMOS gate drive above VIN for efficient switching. |
| VIN1 / VIN2 (4, 13) | Dual input power rails | Each requires dedicated 1µF local bypass - splits high-di/dt input current to minimize loop inductance and EMI. |
| GND1 / GND2 (6,7 / 10,11) | Power switch return paths | Must be tied together and connected to solid ground plane - defines low-inductance return for bottom FET conduction. |
| SW (8,9,21,22) | Switch node outputs | Exposed pads (21,22) must be soldered to SW trace - reduces thermal resistance by 3× and suppresses radiated EMI. |
| EN/UV (14) | Enable and undervoltage lockout | Hysteretic threshold (0.95V–1.07V) - allows precise input brownout protection without external circuitry. |
| RT (15) | Oscillator frequency programming | Resistor to GND sets fSW from 200kHz to 3MHz - enables optimization of size vs. efficiency trade-offs. |
| TR/SS (16) | Soft-start and tracking control | 1.9µA internal pull-up charges external capacitor - controls output ramp rate and enables power-rail sequencing. |
| SYNC/MODE (17) | Operating mode selection | Ground = Burst Mode; float = pulse-skipping; INTVCC = spread spectrum; external clock = sync - single-pin multimode control. |
| GND (18) | System ground reference | Connects to system ground plane - completes signal return path for PG, FB, and control logic. |
| PG (19) | Power good open-drain output | Asserts high when FB is within ±7.5% of 0.8V - provides reliable power sequencing signal without external comparators. |
| FB (20) | Feedback voltage sense | Regulated to 0.804V - enables precise output setting with standard resistor dividers and optional phase-lead compensation. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Reduces radiated EMI by >30dB vs. conventional buck regulators - meets CISPR 25 Class 5 without shielding or ferrites. |
| Ultralow 2.5µA quiescent current | Enables >10-year battery life in always-on applications such as automotive event data recorders and remote sensors. |
| 35ns minimum on-time | Supports direct high-input-to-low-output conversion (e.g., 48V→3.3V at 2MHz) - eliminates cascaded regulator stages. |
| AEC-Q100 Grade I qualification | Guaranteed operation from –40°C to 125°C junction - certified for engine bay, ADAS, and infotainment subsystems. |
| Spread-spectrum modulation | ±22% triangular frequency dither - smears EMI peaks across bandwidth to pass stringent automotive EMC tests. |
| Dual-VIN/GND power routing | Separates high- and low-side current paths - minimizes ground bounce and improves transient response stability. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering FPGA, DSP, and display controllers in head units with 12V/24V/48V battery inputs and strict CISPR 25 EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V synchronous buck regulator with integrated MOSFETs and EMI-optimized layout. Use Value: Eliminates external EMI filters and reduces BOM count by 4 components while maintaining <10mVP-P ripple. |
Use Scenario: Providing isolated 5V and 3.3V rails for analog front-ends and microcontrollers in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC/DC converter supporting 3.5A continuous load with thermal robustness. Use Value: Delivers 94% efficiency at 2MHz with no derating up to 70°C ambient - enables fanless enclosure design. |
| GSM Base Station RF Power Supply | Medical Portable Diagnostic Device |
Use Scenario: Generating clean 5V bias for RF power amplifiers in small-cell base stations where conducted EMI affects adjacent LTE bands. IC Role / Device Role / Timing Role: Low-noise, spread-spectrum synchronized buck regulator with fast transient response. Use Value: Achieves <–60dBµV conducted EMI at 150kHz–30MHz - avoids costly board-level filtering and re-spin. |
Use Scenario: Powering ADCs, op-amps, and Bluetooth SoCs in handheld ultrasound and glucose monitors with coin-cell or Li-ion batteries. IC Role / Device Role / Timing Role: Ultra-low-IQ step-down regulator enabling multi-year battery life with precise output regulation. Use Value: Maintains 2.5µA IQ across full temperature range - extends battery runtime by 3.2× vs. legacy 8µA solutions. |
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 |
|---|---|---|---|
| LT8645SIV#TRPBF | Higher 5A output current, same 65V input, identical pinout and Silent Switcher architecture. | Required for >3.5A loads; adds integrated spread-spectrum enable and enhanced thermal pad. | Select when peak load exceeds 3.5A or when tighter thermal margin is needed in compact enclosures. |
| MPQ4433AGL-AEC1-Z | 40V max input, 3.5A output, AEC-Q100 qualified, but lacks spread-spectrum and has 15µA IQ. | Suitable for 12V/24V automotive systems only; higher IQ increases battery drain in always-on use cases. | Choose for cost-sensitive 24V-only designs where EMI filter space is available and ultra-low IQ is not required. |
Compared with LT8641IUDC#TRPBF, LT8645SIV#TRPBF offers higher current headroom and identical EMI performance, while MPQ4433AGL-AEC1-Z trades IQ and EMI capability for lower unit cost in non-48V applications.
Availability
LT8641IUDC#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC power supplies, and medical portable diagnostics requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LT8641IUDC#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, industrial automation, and automotive markets since 1965.
The LT8641IUDC#TRPBF belongs to Analog Devices' Silent Switcher® monolithic DC/DC regulator family, engineered specifically for high-efficiency, low-EMI power conversion in space-constrained automotive and industrial environments.
FAQ
What is the guaranteed operating temperature range for the LT8641IUDC#TRPBF?
The LT8641IUDC#TRPBF is specified for operation from –40°C to +125°C junction temperature and is AEC-Q100 Grade I qualified. This rating is guaranteed across production lots and applies to all electrical parameters in the datasheet's "l"-marked specifications, making it suitable for under-hood automotive applications and industrial environments with wide ambient swings.
Does the LT8641IUDC#TRPBF require external compensation components?
No, the LT8641IUDC#TRPBF uses internal compensation and requires only a feedback resistor divider and optional 4.7pF–22pF phase-lead capacitor from FB to VOUT. The device's current-mode architecture and fixed compensation network eliminate the need for external Type II or III compensators, simplifying layout and reducing BOM count.
Can the LT8641IUDC#TRPBF synchronize to an external clock, and what is the acceptable frequency range?
Yes, the LT8641IUDC#TRPBF can synchronize to an external clock applied to the SYNC/MODE pin. The supported input clock frequency range is 200kHz to 3MHz, matching its internal oscillator range. During synchronization, the device operates in pulse-skipping mode with aligned positive SW edges, preserving transient response while eliminating beat frequencies.
How does the LT8641IUDC#TRPBF achieve ultralow 2.5µA quiescent current while maintaining regulation?
The LT8641IUDC#TRPBF achieves 2.5µA IQ in Burst Mode by completely disabling gate drivers, oscillator, and error amplifier between energy bursts, retaining only the 0.8V reference and PG comparator active. This architecture maintains output voltage regulation within ±1% while drawing minimal current - verified at 12VIN→3.3VOUT with zero load across –40°C to 125°C.
Is the LT8641IUDC#TRPBF pin-compatible with other members of the LT864x family?
Yes, the LT8641IUDC#TRPBF shares identical 18-lead 3mm × 4mm QFN (UDC) packaging and pinout with LT8640S, LT8643, and LT8645S. This enables drop-in replacement for higher-current variants (e.g., LT8645S) or lower-IQ versions (e.g., LT8640S) without PCB redesign, provided thermal and layout constraints are met.
LT8641IUDC#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):
- 3V
- Voltage - Input (Max):
- 65V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 64.35V
- Current - Output:
- 3.5A
- Frequency - Switching:
- 210kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LT8641IUDC#TRPBF FAQ
1.How can I place an order for LT8641IUDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8641IUDC#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 LT8641IUDC#TRPBF reliable?
The price and inventory of LT8641IUDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8641IUDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8641IUDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8641IUDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8641IUDC#TRPBF?
LT8641IUDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8641IUDC#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 LT8641IUDC#TRPBF?
For technical support, including LT8641IUDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8641IUDC#TRPBF requirements.
6.How does Aetrix verify that LT8641IUDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8641IUDC#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 LT8641IUDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8641IUDC#TRPBF?
All LT8641IUDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8641IUDC#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 LT8641IUDC#TRPBF part is unused and in its original packaging.
Return procedure for LT8641IUDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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