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Analog Devices Inc. LT8643SEV-2#TRPBF
- Part No.:
- LT8643SEV-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8643SEV-2#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,091
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Product details
Overview
LT8643SEV-2#TRPBF from Analog Devices is a 42V, 6A synchronous step-down Silent Switcher regulator with external compensation, 2.5µA quiescent current in Burst Mode, 30ns minimum on-time, and spread-spectrum EMI reduction. It delivers up to 95% efficiency at 2MHz (12VIN→5VOUT) and targets automotive power rails, industrial DC/DC conversion, and noise-sensitive instrumentation.
For engineers reviewing the LT8643SEV-2#TRPBF datasheet, LT8643SEV-2#TRPBF pinout, LT8643SEV-2#TRPBF application, or LT8643SEV-2#TRPBF equivalent, key selection criteria include external VC-loop compensation for current sharing, SYNC/MODE-configurable operating modes (Burst/FCM/Spread Spectrum/Sync), 0.97V feedback reference, thermal shutdown at 150°C, and AEC-Q100 qualification for automotive use.
Technical Context
The LT8643SEV-2#TRPBF implements peak current mode control with an externally accessible VC node enabling precise loop compensation, fast transient response, and parallel current sharing. Its Silent Switcher architecture uses symmetrical layout and integrated bypass capacitors to suppress common-mode EMI.
It supports four distinct operating modes via the SYNC/MODE pin: Burst Mode (ultralow IQ), forced continuous mode (stable frequency across load), spread-spectrum modulation (±22% frequency dithering), and external clock synchronization (200kHz–3MHz). The 30ns minimum on-time enables high step-down ratios at 2MHz+ switching frequencies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide automotive battery transients and industrial 24/36V rails. |
| Output Current | 6A continuous, 7A peak - sufficient for powering FPGA cores, DSPs, or multi-rail PMICs. |
| Quiescent Current | 2.5µA (Burst Mode, 12VIN→3.3VOUT) - enables always-on systems with >1-year battery life. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization of size vs. efficiency vs. EMI. |
| Feedback Reference | 0.970V ±0.006V - enables accurate output regulation with standard resistor dividers. |
| Min On-Time | 30ns - supports 12VIN→1.2VOUT at 2MHz without pulse-skipping instability. |
| EMI Reduction | Spread spectrum modulation (±22% range, 3kHz rate) - lowers peak radiated emissions by >10dB. |
Pinout & Package
LT8643SEV-2#TRPBF is housed in a thermally enhanced 24-lead LQFN package (4mm × 4mm × 0.94mm) with exposed GND pads (pins 25–28) requiring PCB soldering for optimal thermal performance (θJC = 7°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | External bias supply input | Reduces VIN current draw when tied to VOUT ≥3.3V; mandatory for <230µA sleep IQ. |
| INTVCC (2) | Internal 3.4V regulator bypass | Requires ≥1µF low-ESR ceramic cap; powers internal logic and gate drivers. |
| GND (3,16,25–28) | Power and signal ground | Multiple GND pins and exposed pad minimize ground impedance and thermal resistance. |
| VIN (5,6,13,14) | Main input power supply | Four dedicated pins reduce IR drop and enable distributed high-frequency decoupling. |
| BST (7) | Bootstrap capacitor connection | Supports high-side NMOS gate drive; requires 0.1µF ceramic cap between BST and SW. |
| SW (8–12) | Power switch node | Five paralleled SW pins reduce conduction loss and EMI radiation path inductance. |
| EN/UV (17) | Enable and undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables reliable startup under brownout conditions. |
| RT (18) | Frequency programming resistor | Resistor to GND sets fSW: 221kΩ = 210kHz, 60.4kΩ = 700kHz, 18.2kΩ = 2.1MHz. |
| CLKOUT (19) | Switching clock monitor | Outputs ~200ns pulses at fSW in FCM/SS/Sync modes; low in Burst Mode. |
| SYNC/MODE (20) | Operating mode selector | GND = Burst Mode; float = FCM; INTVCC = Spread Spectrum; external clock = Sync. |
| TR/SS (21) | Soft-start and tracking control | 1.9µA internal pull-up enables RC-programmed slew rate; <1.6V enables tracking. |
| VC (22) | Error amplifier output | External RC compensation network connects here for loop stability and current sharing. |
| PG (23) | Power good open-drain flag | Active-high when FB is within ±8% of 0.97V and no faults (thermal, UVLO, overcurrent). |
| FB (24) | Feedback voltage sense | Regulated to 0.970V; connect resistor divider tap and 4.7–22pF phase-lead capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Integrated input caps and symmetrical layout reduce radiated EMI by >30dB vs. conventional buck ICs. |
| External VC compensation | Enables precise loop tuning for fast transient response (<50µs recovery) and stable current sharing in parallel configurations. |
| Spread spectrum modulation | ±22% frequency dithering at 3kHz lowers peak CISPR25 radiated emissions below Class 5 limits without filters. |
| AEC-Q100 Grade E qualification | Guaranteed operation from –40°C to +125°C junction temperature for automotive infotainment and ADAS power supplies. |
| Ultralow dropout | 100mV dropout at 1A enables high-efficiency regulation near input rail (e.g., 5.0V→4.9V at 1A). |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 3.3V/5V rails for SoC, display controller, and audio codec in head unit under cold-crank (4.5V) and load-dump (40V) conditions. IC Role / Device Role / Timing Role: Primary synchronous buck regulator with input transient protection, soft-start sequencing, and EMI-compliant operation. Use Value: 2.5µA Burst Mode IQ extends battery backup time; 42V max input withstands ISO 16750-2 load dump; spread spectrum meets CISPR25 Class 5. | Use Scenario: Generating isolated 5V/3.3V supplies for digital I/O, analog sensor front-ends, and communication interfaces (RS-485, CAN) in factory automation controllers. IC Role / Device Role / Timing Role: High-reliability DC/DC converter with robust thermal management and fault reporting (PG pin). Use Value: 6A output supports multiple downstream LDOs; 150°C thermal shutdown prevents field failures; external VC loop ensures stability with long trace inductance. |
| Medical Imaging Sensor Bias | Test & Measurement Equipment |
Use Scenario: Providing ultra-low-noise 5V bias for CCD/CMOS image sensors and precision ADCs in portable ultrasound devices. IC Role / Device Role / Timing Role: Low-ripple, low-EMI power source with tight output regulation and fast transient response to sensor burst loads. Use Value: <10mVP-P output ripple minimizes sensor noise floor; 30ns min on-time enables clean 5V generation from 12V intermediate bus at 2MHz. | Use Scenario: Supplying 5V/3.3V rails for FPGA configuration, high-speed DACs, and RF front-ends in benchtop signal analyzers and arbitrary waveform generators. IC Role / Device Role / Timing Role: Precision programmable power stage with synchronized switching to avoid beat frequencies with internal clocks. Use Value: SYNC/MODE pin enables deterministic clock alignment with system master clock; 0.97V reference ensures <±1% output accuracy over temperature. |
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 |
|---|---|---|---|
| LT8640SEV-2#TRPBF | Internal compensation; 1.7µA Burst Mode IQ; no VC pin; identical pinout and package. | Lacks current sharing capability; slower transient response; simpler layout for single-rail designs. | Select when external compensation complexity is unnecessary and lowest possible IQ is critical. |
| MPQ4433AGL-Z | 36V max input; 6A; internal compensation; 2.5µA IQ; no spread spectrum; QFN-20 package. | Lower voltage rating; no SYNC/MODE flexibility; smaller footprint but higher θJA (45°C/W). | Select for cost-sensitive industrial applications where 42V rating and CISPR25 compliance are not required. |
Compared with LT8640SEV-2#TRPBF, the LT8643SEV-2#TRPBF trades slightly higher light-load IQ for design flexibility via VC compensation and current sharing-critical for multi-phase or high-transient systems. Versus MPQ4433AGL-Z, it offers superior EMI performance, wider input range, and automotive qualification at the cost of package size and BOM count.
Availability
LT8643SEV-2#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC power supplies, and medical imaging sensor biasing requiring stable component supply, AEC-Q100 compliance, and low-EMI operation.
Supply support for LT8643SEV-2#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 industrial, automotive, communications, and healthcare markets.
The LT8643S-2 product line delivers high-efficiency, low-EMI synchronous step-down regulation for noise-sensitive and safety-critical applications, emphasizing automotive-grade reliability and flexible control architecture.
FAQ
What is the maximum input voltage rating for LT8643SEV-2#TRPBF?
The LT8643SEV-2#TRPBF has an absolute maximum input voltage rating of 42V on the VIN pins, with guaranteed operation across 3.4V to 42V. This enables robust performance during automotive load-dump events (ISO 16750-2) and compatibility with 24V/36V industrial buses. Exceeding 42V risks permanent damage per Absolute Maximum Ratings.
How does the VC pin on LT8643SEV-2#TRPBF enable current sharing in parallel configurations?
The VC pin on LT8643SEV-2#TRPBF provides direct access to the error amplifier output, allowing external RC networks to set loop dynamics. In parallel operation, connecting VC pins through small resistors forces equal peak inductor currents by equalizing the control voltage driving each switch, enabling precise current balancing without additional master-slave circuitry.
Can LT8643SEV-2#TRPBF operate without an external BIAS supply?
Yes, LT8643SEV-2#TRPBF can operate without an external BIAS supply by tying the BIAS pin to GND. However, this increases VIN quiescent current in Burst Mode from 230µA to 290µA (at VBIAS = 0V) and reduces light-load efficiency. For optimal IQ and thermal performance, BIAS should be connected to VOUT ≥3.3V or an external 3.3–25V supply.
What is the purpose of the TR/SS pin on LT8643SEV-2#TRPBF, and how is it configured for soft-start?
The TR/SS pin on LT8643SEV-2#TRPBF controls output voltage ramp rate during startup and enables output tracking. For soft-start, a capacitor from TR/SS to GND is charged by the internal 1.9µA current source, generating a linear voltage ramp that the regulator follows. A 100nF capacitor yields ~52ms rise time to 5V, preventing inrush current and ensuring controlled power-up sequencing.
Does LT8643SEV-2#TRPBF support synchronization to an external clock, and what are the voltage requirements?
Yes, LT8643SEV-2#TRPBF supports external clock synchronization via the SYNC/MODE pin. When driven with a CMOS-compatible clock signal (200kHz–3MHz), the device locks its switching frequency and phase to the external source. The clock high level must be ≥2.2V and low level ≤0.7V, with rise/fall times <100ns to ensure reliable edge detection and avoid metastability.
LT8643SEV-2#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-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):
- 3V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 6A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-LQFN (4x4)
LT8643SEV-2#TRPBF FAQ
1.How can I place an order for LT8643SEV-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8643SEV-2#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 LT8643SEV-2#TRPBF reliable?
The price and inventory of LT8643SEV-2#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8643SEV-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8643SEV-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8643SEV-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8643SEV-2#TRPBF?
LT8643SEV-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8643SEV-2#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 LT8643SEV-2#TRPBF?
For technical support, including LT8643SEV-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8643SEV-2#TRPBF requirements.
6.How does Aetrix verify that LT8643SEV-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8643SEV-2#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 LT8643SEV-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8643SEV-2#TRPBF?
All LT8643SEV-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8643SEV-2#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 LT8643SEV-2#TRPBF part is unused and in its original packaging.
Return procedure for LT8643SEV-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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