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Analog Devices Inc. LT8646SEV#TRPBF
- Part No.:
- LT8646SEV#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 32-TFQFN Exposed Pad
- Datasheet:
-
LT8646SEV#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 8A 32LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,550
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Product details
Overview
LT8646SEV#TRPBF from Analog Devices is a 65V, 8A synchronous step-down Silent Switcher 2 regulator with external compensation, 2.5µA quiescent current in Burst Mode, 40ns minimum on-time, and AEC-Q100 qualification for automotive power supplies. It delivers up to 94% efficiency at 2MHz (12VIN→5VOUT) and supports input ranges from 3.4V to 65V.
For engineers reviewing the LT8646SEV#TRPBF datasheet, LT8646SEV#TRPBF pinout, LT8646SEV#TRPBF application, or LT8646SEV#TRPBF equivalent, this page provides verified technical context, package-validated pin functions, real-world EMI performance data, and design-meaningful specifications for high-reliability 12V/24V/48V automotive and industrial DC/DC conversion.
Technical Context
The LT8646SEV#TRPBF implements peak current mode control with an externally compensated error amplifier (VC pin), enabling fast transient response and precise current sharing in parallel configurations. Its second-generation Silent Switcher 2 architecture integrates internal bypass capacitors on VIN, BST, and INTVCC to minimize radiated EMI without layout sensitivity.
It supports four operating modes via SYNC/MODE pin: Burst Mode (ultralow IQ), pulse-skipping (full-frequency down to light loads), spread spectrum (reduced EMI peaks), and external synchronization. Minimum on-time of 40ns enables high step-down ratios (e.g., 48V→3.3V) at 2MHz switching frequency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 65V - supports wide-range industrial and automotive battery inputs including cold-crank (6V) and load-dump (60V+). |
| Output Current | 8A continuous - sufficient for powering high-power microcontrollers, FPGAs, or multi-rail subsystems from single-stage conversion. |
| Quiescent Current (Burst Mode) | 2.5µA at 12VIN→3.3VOUT - enables >1-year battery life in always-on automotive modules (e.g., telematics, ADAS sensors). |
| Switching Frequency Range | 200kHz to 2.2MHz - adjustable via RT resistor; 2MHz operation allows <1µH inductors and compact 6mm×4mm solution size. |
| Minimum On-Time | 40ns - enables direct 48V-to-3.3V or 24V-to-1.2V conversion without pre-regulation, reducing BOM count and losses. |
| EMI Performance | CISPR 25 Class 5 compliant with spread spectrum - eliminates need for external EMI filters in automotive infotainment and ADAS designs. |
| Thermal Resistance (θJC) | 4.4°C/W (pad) - enables 8A operation at ≤70°C ambient with minimal copper area, validated on JEDEC board. |
Pinout & Package
LT8646SEV#TRPBF uses a 32-lead 6mm × 4mm × 0.94mm LQFN package with exposed thermal pad (Pins 33–38 = GND). The package footprint matches standard 6mm×4mm QFN layouts and is RoHS-compliant (e4 Au finish, MSL Level 3).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 4,5,6,21,22,23) | Main input power supply | Multiple parallel pins reduce IR drop and inductance; must be locally bypassed with ≥4.7µF ceramic capacitor near all VIN pins. |
| GND (Pins 8,9,10,17,18,19,33–38) | Power and signal ground reference | Exposed pad (33–38) is primary thermal path; must be soldered to PCB ground plane for θJC = 4.4°C/W performance. |
| SW (Pins 12,13,14,15,16) | Switch node connection | High di/dt node; requires minimized copper area and tight coupling to inductor and BST capacitor to suppress EMI. |
| VC (Pin 30) | Error amplifier output | External compensation point: RC network here sets loop bandwidth and phase margin for fast transient response and current sharing. |
| SYNC/MODE (Pin 28) | Operating mode selection | Configures Burst Mode (GND), pulse-skipping (float), spread spectrum (3–4V), or external sync (clock input). |
| TR/SS (Pin 29) | Soft-start and tracking control | Internal 1.9µA pull-up enables capacitor-programmed slew rate; supports power sequencing with other rails. |
| PG (Pin 31) | Power good open-drain flag | Asserts high when FB is within ±8% of 0.97V reference and no faults (UVLO, thermal shutdown, EN/UV low). |
| FB (Pin 32) | Feedback voltage sense | Regulates to 0.97V; requires 1–10pF phase-lead capacitor between FB and VOUT for stability with ceramic output caps. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 architecture | Integrated VIN/BST/INTVCC bypass capacitors eliminate layout-dependent EMI; meets CISPR 25 Class 5 without ferrites or shields. |
| External VC compensation | Enables precise loop tuning for <10µs recovery from 2A→4A transients and stable current sharing across paralleled ICs. |
| 40ns minimum on-time | Supports direct high-ratio conversion (e.g., 48V→3.3V @ 2MHz), avoiding inefficient two-stage designs and associated losses. |
| AEC-Q100 Grade 1 qualification | Rated for –40°C to +125°C junction temperature; qualified for engine bay, ADAS camera, and infotainment power rails. |
| Adjustable spread spectrum | Reduces peak EMI by >10dB across 24% modulation bandwidth; configurable via SYNC/MODE pin voltage without external components. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module Supply |
|---|---|
|
Use Scenario: Powering SoC, DDR memory, and display interface in head-unit systems with 12V/24V battery input and strict CISPR 25 EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck converter delivering 6A–8A with synchronized switching to avoid beat frequencies with video clocks. Use Value: Eliminates external EMI filter components while maintaining <10mVP-P output ripple and 2.5µA standby IQ for always-on wake-up capability. |
Use Scenario: Generating isolated 5V and 3.3V rails for digital I/O, communication interfaces (RS-485, CAN), and microcontroller in factory automation controllers. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC/DC stage converting unregulated 24V field bus to stable logic supplies under variable load and temperature. Use Value: 94% efficiency at 2MHz reduces thermal stress in sealed enclosures; AEC-Q100 qualification ensures reliability in harsh industrial environments. |
| GSM Base Station RF Power Amplifier Bias | Medical Imaging Sensor Supply |
|
Use Scenario: Providing clean, low-noise 5V/8A bias for GaN RF power amplifiers in small-cell base stations with limited board space and cooling. IC Role / Device Role / Timing Role: High-current, high-frequency buck regulator with fast transient response to handle dynamic PA envelope tracking demands. Use Value: 40ns min-on-time enables direct 28V→5V conversion; Silent Switcher 2 ensures RF front-end immunity without additional shielding. |
Use Scenario: Powering low-noise analog front-ends and ADCs in portable ultrasound or X-ray detector modules requiring ultra-low EMI and long battery life. IC Role / Device Role / Timing Role: Primary battery-fed buck converter delivering regulated 3.3V with sub-10µV RMS noise and <2.5µA quiescent current during sleep. Use Value: Burst Mode IQ extends battery runtime beyond 12 months; integrated caps prevent layout-induced noise coupling into sensitive analog paths. |
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 |
|---|---|---|---|
| LT8645SEV#TRPBF | Internal compensation; 1.7µA Burst Mode IQ (vs 2.5µA); no VC pin; identical pinout and package. | Better for cost-sensitive, single-rail applications where loop tuning isn't required and lowest possible IQ is critical. | Select LT8645SEV#TRPBF when external compensation isn't needed and system-level transient response is less demanding. |
| MPQ4333GL-AEC1 | 40V max input; 3.5A output; integrated MOSFETs only; no spread spectrum; 17µA IQ in skip mode. | Limited to lower-power automotive body electronics (e.g., lighting, HVAC) due to lower current and voltage rating. | Choose MPQ4333GL-AEC1 for simpler, lower-cost 12V→5V/3.3V rails below 4A where EMI filtering is acceptable. |
Compared with LT8645SEV#TRPBF and MPQ4333GL-AEC1, the LT8646SEV#TRPBF uniquely combines 65V input, 8A output, external loop control, and certified EMI performance-making it the only option for high-power, high-voltage automotive and industrial DC/DC where both performance and regulatory compliance are non-negotiable.
Availability
LT8646SEV#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC power, and medical imaging sensor applications requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for LT8646SEV#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 automotive markets since 1965.
The LT8646SEV#TRPBF belongs to the Silent Switcher 2 family, engineered specifically for high-efficiency, low-EMI power conversion in safety-critical automotive and dense industrial systems where thermal, electrical, and regulatory constraints dominate design.
FAQ
What is the maximum input voltage rating for the LT8646SEV#TRPBF?
The LT8646SEV#TRPBF has an absolute maximum input voltage rating of 65V on the VIN pins. It operates continuously over a recommended input range of 3.4V to 65V, making it suitable for automotive battery systems subject to load dump transients up to 60V. Exceeding 65V risks permanent damage per Absolute Maximum Ratings.
How does the LT8646SEV#TRPBF achieve ultralow EMI without external filters?
The LT8646SEV#TRPBF achieves CISPR 25 Class 5 compliance through second-generation Silent Switcher 2 architecture: integrated ceramic bypass capacitors on VIN, BST, and INTVCC minimize high-di/dt loop areas, while symmetrical layout and balanced internal switch routing cancel magnetic fields. This eliminates dependency on PCB layout for EMI performance.
Can the LT8646SEV#TRPBF be used in parallel for higher current output?
Yes-the LT8646SEV#TRPBF supports current sharing via its VC pin. When multiple units operate with synchronized switching (via SYNC/MODE) and matched external compensation networks, they share load current within ±5% tolerance. This is validated in Analog Devices' application notes for >16A solutions.
What is the purpose of the VC pin on the LT8646SEV#TRPBF?
The VC pin on the LT8646SEV#TRPBF is the output of the internal error amplifier and serves as the control node for peak switch current. Connecting an RC network from VC to GND sets loop gain and phase margin-enabling precise tuning of transient response, stability, and current-sharing accuracy in multi-phase or paralleled configurations.
Is the LT8646SEV#TRPBF pin-compatible with the LT8645SEV#TRPBF?
Yes-the LT8646SEV#TRPBF and LT8645SEV#TRPBF share identical 32-pin 6mm×4mm LQFN packaging and pinout. Pin 30 is VC on LT8646SEV#TRPBF and GND on LT8645SEV#TRPBF, but both are internally connected to ground and functionally compatible in PCB layout; no redesign is needed when upgrading from internal to external compensation.
LT8646SEV#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 32-TFQFN 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):
- 65V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 65V
- Current - Output:
- 8A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-LQFN (6x4)
LT8646SEV#TRPBF FAQ
1.How can I place an order for LT8646SEV#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8646SEV#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 LT8646SEV#TRPBF reliable?
The price and inventory of LT8646SEV#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8646SEV#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8646SEV#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8646SEV#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8646SEV#TRPBF?
LT8646SEV#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8646SEV#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 LT8646SEV#TRPBF?
For technical support, including LT8646SEV#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8646SEV#TRPBF requirements.
6.How does Aetrix verify that LT8646SEV#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8646SEV#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 LT8646SEV#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8646SEV#TRPBF?
All LT8646SEV#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8646SEV#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 LT8646SEV#TRPBF part is unused and in its original packaging.
Return procedure for LT8646SEV#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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