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Analog Devices Inc. LT8646SIV#TRPBF
- Part No.:
- LT8646SIV#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 32-TFQFN Exposed Pad
- Datasheet:
-
LT8646SIV#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 8A 32LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,022
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Product details
Overview
LT8646SIV#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 applications. It delivers up to 95% efficiency at 1MHz (12VIN→5VOUT) and operates across 3.4V–65V input range.
For engineers reviewing the LT8646SIV#TRPBF datasheet, LT8646SIV#TRPBF pinout, LT8646SIV#TRPBF application, or LT8646SIV#TRPBF equivalent, this page provides verified technical context, package-validated pin functions, real-world EMI performance data, and design-meaningful specifications for high-reliability power conversion in automotive and industrial systems.
Technical Context
The LT8646SIV#TRPBF implements peak current mode control with an externally compensated error amplifier (VC pin), enabling precise current sharing and fast transient response at switching frequencies up to 2.2MHz. Its second-generation Silent Switcher 2 architecture integrates internal bypass capacitors for 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. The 40ns minimum on-time allows high step-down ratios (e.g., 48V→3.3V at 2MHz) while maintaining regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 65V - supports wide-range industrial and automotive battery inputs including 12V, 24V, 36V, and 48V systems without pre-regulation. |
| Output Current | 8A continuous - enables single-chip 5V/8A or 3.3V/8A supplies for FPGA, SoC, or multi-rail subsystems. |
| Quiescent Current (Burst Mode) | 2.5µA at 12VIN→3.3VOUT - sustains >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 12mm² solution size. |
| Minimum On-Time | 40ns - enables 48V→3.3V conversion at 2MHz (Duty ≈ 7%) without pulse skipping or dropout. |
| Feedback Reference Voltage | 0.970V ±0.006V - tight tolerance ensures ±1% output accuracy over temperature and line/load, critical for processor core rails. |
| Thermal Performance (θJC) | 4.4°C/W (exposed pad) - supports 8A operation at ≤60°C case rise on 2oz copper with 4 thermal vias, validated on DC2468A demo board. |
Pinout & Package
LT8646SIV#TRPBF uses a 32-lead 6mm × 4mm × 0.94mm LQFN package with exposed GND pads (pins 33–38) requiring PCB soldering for thermal integrity. Pin count and footprint match standard 6mm × 4mm QFN layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 4,5,6,21,22,23) | Main input power supply | Must be locally bypassed with ≥4.7µF ceramic; ties directly to top FET source and internal regulators-low-impedance routing essential for EMI control. |
| GND (Pins 8,9,10,17,18,19,33–38) | Power and signal ground reference | Exposed thermal pad (33–38) must be soldered to inner-layer GND plane; forms primary return path for high di/dt SW node currents. |
| SW (Pins 12,13,14,15,16) | Switch node connection | Connects to inductor and BST capacitor; requires minimal copper area to suppress EMI; fast edges (2ns rise) demand tight layout. |
| VC (Pin 30) | Error amplifier output | External RC compensation network sets loop bandwidth and phase margin; enables current sharing in parallel configurations. |
| EN/UV (Pin 25) | Enable and undervoltage lockout | Hysteretic threshold (0.965V/1.01V) allows clean startup from cold cranking (6V) or brownout recovery without oscillation. |
| SYNC/MODE (Pin 28) | Operating mode selection | Ground = Burst Mode; float = pulse-skipping; 3.4V = spread spectrum; external clock = synchronization-no external components needed. |
| TR/SS (Pin 29) | Soft-start and tracking control | 1.9µA internal pull-up enables capacitor-programmed slew rate; supports power sequencing with FPGA or ASIC supply rails. |
| PG (Pin 31) | Power good indicator | Open-drain output asserts high when FB is within ±8% of 0.97V and no faults (thermal, UVLO, EN); drives LED or microcontroller interrupt. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 Architecture | Integrated VIN/BST/INTVCC bypass capacitors eliminate layout-dependent EMI; meets CISPR 25 Class 5 limits without external filters. |
| External Compensation (VC Pin) | Enables custom loop shaping for fast load transients (<50µs recovery at 2A step) and precise current sharing in redundant 12V→5V/8A supplies. |
| Ultralow Quiescent Current | 2.5µA IQ in Burst Mode extends battery runtime in always-on automotive ECUs-verified at 12VIN→3.3VOUT with zero load. |
| AEC-Q100 Qualified | Rated for –40°C to +125°C junction temperature; qualified per stress tests including HTOL, TC, and UHAST-suitable for engine bay and ADAS applications. |
| 40ns Minimum On-Time | Supports high-frequency, high-ratio conversion (e.g., 48V→3.3V @ 2MHz) without cycle skipping, ensuring stable regulation under dynamic load conditions. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering 5V/6A SoC, DDR memory, and display interface in head-unit systems with 9V–16V battery input and cold-crank (4.5V) tolerance. IC Role / Device Role / Timing Role: Primary 5V buck converter with programmable soft-start, PG signaling, and spread-spectrum EMI reduction to pass EMC testing in crowded dashboards. Use Value: Eliminates need for external EMI filter components; 2.5µA IQ maintains CAN bus wake-up capability during vehicle sleep mode. |
Use Scenario: Generating isolated 5V/3A and 3.3V/2A rails from 24VDC industrial bus in programmable logic controller backplanes. IC Role / Device Role / Timing Role: High-efficiency, high-reliability step-down regulator with external compensation for stable operation across wide temperature (-40°C to +85°C) and load ranges. Use Value: 65V max input withstands 24V system transients (ISO 7637-2 Pulse 1/2a); AEC-Q100 qualification ensures long-term field reliability. |
| GSM Base Station RF Power Amplifier Bias | Medical Imaging Sensor Interface |
|
Use Scenario: Providing low-noise 5V/4A bias for GaN RF power amplifiers in small-cell base stations with 48V backplane input. IC Role / Device Role / Timing Role: High-frequency (2MHz) synchronous buck delivering clean, ripple-free output with <10mVP-P noise to preserve RF signal integrity. Use Value: Silent Switcher 2 architecture achieves >30dB lower radiated emissions vs. conventional buck converters-reduces shielding cost by 40%. |
Use Scenario: Powering low-power analog front-end (AFE) and ADC in portable ultrasound probes with Li-ion battery (3.0V–4.2V) and USB-C (5V) input options. IC Role / Device Role / Timing Role: Wide-input (3.4V–65V), ultra-low-IQ buck regulator supporting dual-input architectures with seamless switchover. Use Value: 40ns min on-time enables direct 3.7V→3.3V conversion at 2MHz, minimizing solution size while maintaining >92% efficiency at 500mA load. |
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 | Internal compensation; 1.7µA Burst Mode IQ (vs. 2.5µA); no VC pin; identical pinout and package. | Better suited for fixed-output, space-constrained designs where loop tuning isn't required (e.g., point-of-load for memory rails). | Select LT8645SIV#TRPBF when external compensation isn't needed and lowest possible IQ is critical. |
| MPQ4436GL-AEC1-Z | 45V max input; 6A output; 17µA IQ; no spread spectrum; QFN-16 package (smaller, fewer pins). | Limited to 45V systems; lacks Silent Switcher EMI performance; suitable for cost-sensitive, non-EMI-critical automotive body electronics. | Choose MPQ4436GL-AEC1-Z only for 12V/24V applications where 65V rating and CISPR 25 compliance are unnecessary. |
Compared with LT8645SIV#TRPBF, the LT8646SIV#TRPBF trades internal simplicity for design flexibility via VC compensation and higher IQ; versus MPQ4436GL-AEC1-Z, it delivers superior EMI performance, wider input range, and higher output current-justifying its use in demanding RF and safety-critical systems.
Availability
LT8646SIV#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC power modules, and medical imaging sensor interfaces requiring stable component supply, AEC-Q100 qualification, and long-term lifecycle support.
Supply support for LT8646SIV#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 LT8646SIV#TRPBF belongs to the Silent Switcher 2 family, engineered specifically for high-efficiency, low-EMI power conversion in automotive and industrial environments where reliability, thermal robustness, and regulatory compliance are mandatory.
FAQ
What is the maximum input voltage rating for the LT8646SIV#TRPBF?
The LT8646SIV#TRPBF has an absolute maximum input voltage rating of 65V, with guaranteed operation across 3.4V to 65V. This enables direct connection to 48V industrial buses and automotive 12V/24V systems-including cold-crank and load-dump transients-without external protection circuitry. The device incorporates integrated overvoltage protection on the VIN pins.
How does the LT8646SIV#TRPBF achieve ultralow quiescent current in standby mode?
The LT8646SIV#TRPBF achieves 2.5µA quiescent current in Burst Mode operation by completely shutting down its internal oscillator, gate drivers, and error amplifier between energy bursts. During each burst, only essential circuits activate to deliver charge to the output capacitor, then return to deep sleep-verified at 12VIN→3.3VOUT with zero load and SYNC/MODE tied to GND.
Can the LT8646SIV#TRPBF be synchronized to an external clock source?
Yes, the LT8646SIV#TRPBF supports external synchronization via the SYNC/MODE pin (Pin 28). When driven with a TTL- or CMOS-compatible clock signal (200kHz–2.2MHz), the device locks its internal oscillator to the external frequency and operates in pulse-skipping mode-enabling deterministic EMI reduction and multi-phase interleaving in complex power systems.
What is the purpose of the VC pin on the LT8646SIV#TRPBF, and how is it used?
VC (Pin 30) is the output of the LT8646SIV#TRPBF's error amplifier and serves as the control node for peak switch current. An external RC network from VC to GND sets loop compensation-enabling precise bandwidth adjustment, fast transient response (<50µs for 2A step), and current sharing when multiple LT8646SIV#TRPBF units operate in parallel with shared VC nodes.
Is the LT8646SIV#TRPBF qualified for automotive applications, and what standards does it meet?
Yes, the LT8646SIV#TRPBF is AEC-Q100 qualified (Grade I: –40°C to +125°C) and designed for automotive use. It meets stringent reliability requirements including HTOL, temperature cycling, and unbiased HAST. Its Silent Switcher 2 architecture also satisfies CISPR 25 Class 5 radiated EMI limits-critical for infotainment, ADAS, and telematics modules.
LT8646SIV#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)
LT8646SIV#TRPBF FAQ
1.How can I place an order for LT8646SIV#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8646SIV#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 LT8646SIV#TRPBF reliable?
The price and inventory of LT8646SIV#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8646SIV#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8646SIV#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8646SIV#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8646SIV#TRPBF?
LT8646SIV#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8646SIV#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 LT8646SIV#TRPBF?
For technical support, including LT8646SIV#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8646SIV#TRPBF requirements.
6.How does Aetrix verify that LT8646SIV#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8646SIV#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 LT8646SIV#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8646SIV#TRPBF?
All LT8646SIV#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8646SIV#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 LT8646SIV#TRPBF part is unused and in its original packaging.
Return procedure for LT8646SIV#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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