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Analog Devices Inc. LT8641HUDC#TRPBF
- Part No.:
- LT8641HUDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8641HUDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,040
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Product details
Overview
LT8641HUDC#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 up to 150°C junction temperature.
For engineers reviewing the LT8641HUDC#TRPBF datasheet, LT8641HUDC#TRPBF pinout, LT8641HUDC#TRPBF application, or LT8641HUDC#TRPBF equivalent, key selection criteria include ultralow EMI performance, spread spectrum modulation capability, AEC-Q100 qualification, and compatibility with high-frequency inductor selection (1.5µH @ 3MHz).
Technical Context
The LT8641HUDC#TRPBF employs peak current mode control with internal 0.8V reference and frequency-programmable oscillator (200kHz–3MHz via RT resistor). Its Silent Switcher architecture uses symmetrical layout and integrated BST capacitor routing to suppress common-mode EMI without external filters.
It features four SYNC/MODE-configurable operating states: Burst Mode (2.5µA IQ), pulse-skipping, spread spectrum (±22% modulation), and external clock synchronization. The device includes built-in overtemperature protection, VIN UVLO with hysteresis, and PG open-drain output signaling ±8% output regulation tolerance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 65V - supports wide-range industrial and automotive battery inputs including 48V systems and cold-crank transients. |
| Continuous Output Current | 3.5A - sufficient for powering FPGA I/O banks, microcontroller cores, or sensor signal chains without external boost stages. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT regulation - enables >10-year battery life in always-on IoT sensors and telematics modules. |
| Minimum On-Time | 35ns - allows direct 48V-to-3.3V conversion at 2MHz, eliminating intermediate buck stages and reducing BOM count. |
| Switching Frequency Range | 200kHz to 3MHz - programmable via RT pin; higher frequencies enable smaller magnetics and faster transient response. |
| Output Ripple | <10mVP-P - meets stringent analog supply requirements for ADCs, DACs, and RF front-ends without additional LDO post-regulation. |
| Junction Temperature Range | –40°C to +150°C - qualified per AEC-Q100 Grade H, suitable for under-hood automotive applications and industrial motor drives. |
Pinout & Package
Package: 18-lead (3mm × 4mm) plastic QFN with exposed SW pads (pins 21, 22); θJA = 40°C/W, θJC(PAD) = 12°C/W. Exposed pads must be soldered to PCB SW trace for thermal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Connect to VOUT (≥3.3V) to reduce VIN current draw; enables <2.5µA IQ by powering INTVCC from output rail. |
| INTVCC (2) | Internal 3.4V regulator bypass | Requires ≥1µF low-ESR ceramic cap to GND; powers gate drivers and control logic; not for external loading. |
| BST (3) | Bootstrap capacitor node | Connect 0.1µF ceramic cap between BST and SW; enables high-side NMOS gate drive above VIN. |
| VIN1/VIN2 (4,13) | Dual high-current input paths | Each requires dedicated 1µF local bypass to respective GND1/GND2; minimizes high-di/dt loop area for EMI reduction. |
| GND1/GND2 (6,7,10,11) | Power switch return paths | Must be tied together and connected to solid ground plane; forms critical return for input capacitor and SW node currents. |
| SW (8,9,21,22) | Switch node outputs | Internally connected; tie externally to inductor and BST cap; exposed pads (21,22) must be soldered to SW copper for thermal management. |
| EN/UV (14) | Enable and input undervoltage lockout | Hysteretic threshold (0.95V–1.07V); resistor divider from VIN sets custom UVLO point for battery monitoring. |
| RT (15) | Frequency programming | Resistor to GND sets switching frequency: 221kΩ → 210kHz, 60.4kΩ → 700kHz, 18.2kΩ → 2.0MHz. |
| TR/SS (16) | Soft-start and tracking | 1.9µA internal pull-up charges external cap for controlled VOUT ramp; also accepts external voltage for output tracking. |
| SYNC/MODE (17) | Operating mode selection | Ground = Burst Mode; float = pulse-skipping; INTVCC = spread spectrum; external clock = sync mode. |
| GND (18) | System ground reference | Connect to system ground plane; complements GND1/GND2 for signal integrity and noise isolation. |
| PG (19) | Power good indicator | Open-drain output asserts high when FB is within ±8% of 0.8V reference and no fault conditions exist. |
| FB (20) | Feedback reference input | Regulated to 0.8V; connect resistor divider from VOUT; add 4.7–22pF phase-lead cap from FB to VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated EMI by >30dB vs conventional buck regulators, meeting CISPR 25 Class 5 limits without ferrite beads or shielding cans. |
| Spread Spectrum Modulation | ±22% triangular frequency dithering lowers peak EMI amplitude across 100kHz–100MHz band, easing EMC certification. |
| Ultralow Quiescent Current | 2.5µA IQ in Burst Mode enables >10-year shelf life in battery-powered automotive modules and remote sensors. |
| Fast Minimum On-Time (35ns) | Enables single-stage 48V-to-3.3V conversion at 2MHz, reducing solution size by 40% vs two-stage approaches. |
| AEC-Q100 Grade H Qualification | Validated for –40°C to +150°C operation with full production lot testing; supports ASIL-B functional safety architectures. |
| Inductor Saturation Tolerance | Continues safe operation during overload even with saturated inductors, eliminating need for current-sense resistors or complex protection circuits. |
Applications
| Automotive ADAS Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powers image signal processor and radar transceiver in forward-facing camera module with 12V battery input and strict EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3.5A buck converter delivering low-noise power to analog front-end and digital core. Use Value: Silent Switcher architecture meets CISPR 25 Class 5 radiated emissions without added filtering, reducing BOM cost and board area by 25%. | Use Scenario: Supplies isolated 3.3V logic rails and 5V analog sensors in DIN-rail mounted programmable logic controller. IC Role / Device Role / Timing Role: Main DC/DC regulator converting 24V industrial bus to stable 3.3V/5V outputs with high efficiency across load range. Use Value: 2.5µA quiescent current extends backup battery runtime during mains failure; 65V input withstands 48V surge transients. |
| GSM Base Station RF Power Amplifier Bias | Medical Portable Ultrasound Transmitter |
Use Scenario: Generates 28V bias voltage for GaN RF power amplifier in small-cell base station using 48V backplane. IC Role / Device Role / Timing Role: High-voltage step-down regulator operating at 1MHz with fast transient response to handle PA envelope modulation. Use Value: 35ns minimum on-time enables direct 48V-to-28V conversion, avoiding inefficient two-stage designs and improving thermal margin by 12°C. | Use Scenario: Powers time-of-flight ultrasound transmitter array requiring ultra-low ripple and precise voltage accuracy. IC Role / Device Role / Timing Role: Precision 3.3V supply with <10mVP-P ripple and ±0.5% line/load regulation for analog beamforming circuitry. Use Value: Integrated 0.8V reference and tight feedback tolerance ensure consistent transmit pulse amplitude across battery discharge cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8645SUDC#TRPBF | Higher 5A continuous output, same 65V input, identical pinout and Silent Switcher architecture; adds internal compensation and improved light-load efficiency. | Supports higher-power SoCs and multi-core processors where 3.5A is insufficient; shares same PCB footprint for easy upgrade path. | Select when output current demand exceeds 3.5A or when simplified design with internal compensation is preferred. |
| MPQ4420AGL-A-Z | 40V max input, 2A output, 17-lead QFN; lacks spread spectrum, Burst Mode IQ = 25µA, no AEC-Q100 qualification. | Targeted at cost-sensitive consumer and industrial applications without automotive or stringent EMI requirements. | Choose only for non-automotive, lower-current designs where EMI compliance is less critical and budget constraints dominate. |
Compared with LT8645SUDC#TRPBF, LT8641HUDC#TRPBF offers lower cost and smaller thermal footprint for 3.5A applications, while MPQ4420AGL-A-Z trades EMI performance and automotive qualification for price-making LT8641HUDC#TRPBF optimal for AEC-Q100-compliant, EMI-sensitive 3.5A designs.
Availability
LT8641HUDC#TRPBF is available at Aetrix Electronics and suitable for automotive ADAS systems, industrial PLCs, and medical portable devices requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant reliability.
Supply support for LT8641HUDC#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.
The LT8641HUDC#TRPBF belongs to the Silent Switcher® monolithic step-down regulator product line, engineered specifically for automotive and industrial applications demanding ultralow EMI, high efficiency across wide load ranges, and extended temperature operation.
FAQ
What is the maximum junction temperature rating for the LT8641HUDC#TRPBF?
The LT8641HUDC#TRPBF is rated for operation from –40°C to +150°C junction temperature and is qualified per AEC-Q100 Grade H. This makes it suitable for under-hood automotive environments and high-ambient industrial applications. Derating curves in the datasheet specify power dissipation limits above 125°C to ensure reliable lifetime operation.
How does the LT8641HUDC#TRPBF achieve ultralow EMI performance?
The LT8641HUDC#TRPBF achieves ultralow EMI through its patented Silent Switcher® architecture, which incorporates symmetrical internal power switch layout, integrated BST capacitor routing, and minimized high-di/dt loop areas. When combined with proper PCB layout-including dual input capacitors on VIN1/VIN2 and soldered SW-exposed pads-it meets CISPR 25 Class 5 radiated emission limits without external filters.
Can the LT8641HUDC#TRPBF operate with a 48V input and 3.3V output at 2MHz?
Yes, the LT8641HUDC#TRPBF supports 48V-to-3.3V conversion at 2MHz using its 35ns minimum on-time capability. With an RT resistor of 18.2kΩ, the switching frequency is programmed to ~2.0MHz. Efficiency exceeds 92% at 1A load, and output ripple remains below 10mVP-P with appropriate output capacitance and layout.
What is the function of the BIAS pin on the LT8641HUDC#TRPBF?
The BIAS pin on the LT8641HUDC#TRPBF provides an alternative power source for the internal 3.4V regulator (INTVCC). When connected to VOUT (≥3.3V), it reduces input supply current and enables the 2.5µA quiescent current specification. If VOUT is below 3.3V or unavailable, BIAS must be tied to GND, and INTVCC draws current from VIN instead.
Does the LT8641HUDC#TRPBF support output voltage tracking during power-up?
Yes, the LT8641HUDC#TRPBF supports output voltage tracking via the TR/SS pin. When a voltage below 0.8V is applied to TR/SS, the regulator forces the FB pin to match that voltage, enabling coordinated ramp-up with other supplies. An internal 1.9µA current source allows simple soft-start implementation using a single capacitor from TR/SS to GND.
LT8641HUDC#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LT8641HUDC#TRPBF FAQ
1.How can I place an order for LT8641HUDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8641HUDC#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 LT8641HUDC#TRPBF reliable?
The price and inventory of LT8641HUDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8641HUDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8641HUDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8641HUDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8641HUDC#TRPBF?
LT8641HUDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8641HUDC#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 LT8641HUDC#TRPBF?
For technical support, including LT8641HUDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8641HUDC#TRPBF requirements.
6.How does Aetrix verify that LT8641HUDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8641HUDC#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 LT8641HUDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8641HUDC#TRPBF?
All LT8641HUDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8641HUDC#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 LT8641HUDC#TRPBF part is unused and in its original packaging.
Return procedure for LT8641HUDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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