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Analog Devices Inc. LT8643SEV#TRPBF
- Part No.:
- LT8643SEV#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8643SEV#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,160
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Product details
Overview
LT8643SEV#TRPBF from Analog Devices is a 42V, 6A synchronous step-down DC/DC regulator with Silent Switcher 2 architecture, 2.5µA quiescent current in Burst Mode, external compensation for fast transient response and current sharing, and 30ns minimum on-time enabling high step-down ratios at up to 3MHz switching frequency. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT) and operates across 3.4V–42V input range.
For engineers reviewing the LT8643SEV#TRPBF datasheet, LT8643SEV#TRPBF pinout, LT8643SEV#TRPBF application, or LT8643SEV#TRPBF equivalent, key selection considerations include ultralow EMI emissions without shielding, external loop compensation capability, AEC-Q100 qualification for automotive use, and support for spread spectrum modulation and synchronization.
Technical Context
The LT8643SEV#TRPBF implements peak current mode control with second-generation Silent Switcher 2 architecture, integrating internal bypass capacitors on VIN, BST, and INTVCC pins to minimize radiated EMI and reduce PCB layout sensitivity. Its external compensation network (VC pin) enables precise loop tuning for multi-phase current sharing and optimized transient response under dynamic loads.
It supports four operating modes via SYNC/MODE pin: Burst Mode (ultralow IQ), Forced Continuous Mode (full-frequency operation), Spread Spectrum (EMI reduction), and external clock synchronization. The 30ns minimum on-time and 80ns minimum off-time allow stable regulation down to 0.97V output across wide input ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports automotive cold-crank (4.5V) and industrial 24/36V rails without pre-regulation. |
| Output Current | 6A continuous / 7A peak - sustains full load at 125°C junction temperature with proper thermal design. |
| Quiescent Current | 2.5µA in Burst Mode regulating 12VIN→3.3VOUT - enables >1-year battery life in always-on IoT sensors. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows optimization of size (high-f) vs. efficiency (low-f) and avoids AM band interference. |
| Feedback Reference | 0.970V ±6mV over –40°C to 125°C - enables accurate low-VOUT regulation with standard resistor tolerances. |
| Minimum On-Time | 30ns - supports 12VIN→1VOUT at 2MHz (12:1 ratio) without pulse-skipping instability. |
| EMI Performance | CISPR 25 Class 5 compliant with integrated caps and spread spectrum - eliminates need for external EMI filters in automotive modules. |
Pinout & Package
LT8643SEV#TRPBF uses a 24-lead 4mm × 4mm LQFN package (JEDEC MS-026) with exposed thermal pad (pins 25–28). Package thermal resistance is θJA = 38°C/W (JEDEC board), θJC(PAD) = 7°C/W - requires soldered GND pad for thermal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator supply | Reduces VIN current draw when tied to VOUT ≥3.3V; improves efficiency at high VIN/VOUT ratios. |
| INTVCC (2) | Internal 3.4V rail bypass | Must be floated; local 2.2µF capacitor required if BIAS not used - critical for gate drive stability. |
| GND (3,16,25–28) | Power and signal ground | Multiple GND pins + exposed pad minimize ground impedance and EMI loop area. |
| VIN (5,6,13,14) | Main input power | Four parallel pins reduce IR drop and AC impedance; require local ≥2.2µF ceramic capacitor. |
| BST (7) | Bootstrap supply | Floats during operation; 0.1µF ceramic capacitor between BST and SW sets high-side gate drive voltage. |
| SW (8–12) | Power switch node | Five parallel SW pins reduce trace inductance and EMI; must connect directly to inductor with minimal copper area. |
| EN/UV (17) | Enable/undervoltage lockout | Hysteretic threshold (1.00V rise / 0.96V fall) enables programmable input UVLO using resistor divider. |
| RT (18) | Frequency set resistor | Resistor to GND sets fSW: 221kΩ = 210kHz, 60.4kΩ = 700kHz, 18.2kΩ = 1.95MHz - enables precise EMI band avoidance. |
| CLKOUT (19) | Switching clock output | 200ns pulse at fSW in FCM/sync modes; low in Burst Mode - useful for timing-critical downstream circuits. |
| SYNC/MODE (20) | Operating mode select | Ground = Burst Mode; float = FCM; INTVCC = spread spectrum; external clock = sync - single-pin multimode control. |
| TR/SS (21) | Soft-start/tracking | 1.9µA internal pull-up enables RC-programmed slew rate; supports output tracking in multi-rail systems. |
| VC (22) | Error amplifier output | External RC compensation network (RC/CC) sets loop bandwidth and phase margin for fast transient response. |
| PG (23) | Power good indicator | Open-drain output asserts high when FB is within ±7.5% of 0.97V and no faults - drives enable signals for downstream rails. |
| FB (24) | Feedback input | Regulates to 0.970V; requires 4.7–22pF phase-lead capacitor from FB to VOUT for stability with ceramic output caps. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 Architecture | Integrated VIN/BST/INTVCC bypass capacitors reduce radiated EMI by >30dB vs. first-gen, eliminating shield cans in space-constrained designs. |
| External Compensation (VC Pin) | Enables custom loop shaping for <10µs load transient recovery and precise current sharing in parallel configurations. |
| Ultralow Quiescent Current | 2.5µA IQ in Burst Mode maintains regulation at microamp loads - essential for battery-powered telematics and ADAS sensors. |
| Spread Spectrum Modulation | 22% frequency dithering reduces peak EMI by 10dB, easing CISPR 25 Class 5 compliance without filter redesign. |
| AEC-Q100 Qualified | Rated for –40°C to 125°C junction temperature with automotive reliability testing - qualified for engine control, infotainment, and ADAS power rails. |
| Robust Protection Suite | Includes thermal shutdown (150°C), overcurrent limiting (7.5–12.5A), input UVLO, and PG fault reporting - reduces system-level monitoring overhead. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 5V/3.3V rails for SoC, display, and audio codecs in head units with strict EMI limits. IC Role / Device Role / Timing Role: Primary 12V→5V buck converter with spread spectrum enabled to meet CISPR 25 Class 5 radiated emissions. Use Value: Eliminates external EMI filter components and metal shielding, reducing BOM cost by $0.35 and PCB area by 120mm². |
Use Scenario: Generating isolated 5V/2A supply for digital I/O expansion cards in factory automation controllers. IC Role / Device Role / Timing Role: High-reliability 24V→5V regulator with forced continuous mode for stable operation under 100Hz PWM load transients. Use Value: 30ns min-on-time ensures regulation stability during 24V brownouts; AEC-Q100 qualification validates long-term field reliability. |
| Medical Patient Monitor | Avionics Data Acquisition |
Use Scenario: Providing ultra-low-noise 3.3V supply for ADCs and sensor interfaces in portable ECG devices. IC Role / Device Role / Timing Role: Low-IQ 9V→3.3V converter in Burst Mode during standby, transitioning to FCM during measurement bursts. Use Value: 2.5µA quiescent current extends single-cell Li-ion battery life to >18 months in sleep mode. |
Use Scenario: Powering 5V FPGA configuration and interface logic in DO-160G-compliant flight data recorders. IC Role / Device Role / Timing Role: 28V aircraft bus → 5V regulator with synchronization to system clock to avoid beat frequencies. Use Value: SYNC/MODE pin enables deterministic switching aligned to avionics timing bus, preventing spectral interference with RF receivers. |
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#TRPBF | Internal compensation; 5A continuous output; lower IQ (1.7µA) but no VC pin for loop tuning. | Preferred for fixed-output, cost-sensitive designs where transient response requirements are moderate. | Select LT8640SEV#TRPBF when external compensation is unnecessary and peak current is ≤5A. |
| LM61480RQR | Texas Instruments part; 42V input, 8A output, 15µA IQ; no integrated EMI caps; requires external compensation. | Higher current capability but lacks Silent Switcher 2 EMI performance - needs additional filtering for automotive use. | Choose LM61480RQR only if higher output current is mandatory and EMI filtering budget exists. |
Compared with LT8640SEV#TRPBF, the LT8643SEV#TRPBF trades slightly higher quiescent current for external loop control and 6A capability, while LM61480RQR offers higher current but demands more board area and filtering effort to match LT8643SEV#TRPBF's EMI performance.
Availability
LT8643SEV#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC power supplies, and medical patient monitors requiring stable component supply, AEC-Q100 qualification, and ultralow EMI emissions.
Supply support for LT8643SEV#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 since 1965.
The LT8643S series belongs to Analog Devices' Silent Switcher 2 power management portfolio, designed specifically for noise-sensitive automotive, medical, and industrial applications demanding high efficiency, low EMI, and robust operation across wide input ranges.
FAQ
What is the maximum output current capability of the LT8643SEV#TRPBF?
The LT8643SEV#TRPBF delivers 6A continuous output current and supports 7A peak current. This rating assumes proper thermal management - including soldering the exposed thermal pad (pins 25–28) to a ≥4cm² copper pour - and operation within the –40°C to 125°C junction temperature range specified in the datasheet.
How does the LT8643SEV#TRPBF achieve ultralow EMI without external filters?
The LT8643SEV#TRPBF integrates ceramic bypass capacitors for VIN, BST, and INTVCC directly into its LQFN package, minimizing high-di/dt loop areas. Combined with Silent Switcher 2 symmetric layout and optional spread spectrum modulation, this enables CISPR 25 Class 5 compliance on standard PCBs without ferrite beads or metal shields - a key advantage over conventional buck regulators.
Can the LT8643SEV#TRPBF operate with an input voltage below 3.4V?
No - the absolute minimum input voltage for the LT8643SEV#TRPBF is 3.4V per the datasheet's electrical characteristics table. Attempting operation below this threshold may result in regulation failure or undefined behavior. For sub-3.4V inputs, consider alternative regulators such as the LT8609S (2.8V min VIN).
What is the function of the VC pin on the LT8643SEV#TRPBF?
The VC pin on the LT8643SEV#TRPBF is the error amplifier output, providing direct access to the control loop for external compensation. Connecting an RC network from VC to GND sets loop bandwidth and phase margin, enabling fast transient response and precise current sharing in multi-phase configurations - a capability absent in the internally compensated LT8640S variants.
Is the LT8643SEV#TRPBF qualified for automotive applications?
Yes - the LT8643SEV#TRPBF is AEC-Q100 qualified for automotive applications, rated for operation from –40°C to 125°C junction temperature. It meets stringent automotive reliability standards including HTOL, TC, and ESD testing, making it suitable for engine control units, ADAS cameras, and infotainment systems.
LT8643SEV#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#TRPBF FAQ
1.How can I place an order for LT8643SEV#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8643SEV#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#TRPBF reliable?
The price and inventory of LT8643SEV#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#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8643SEV#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8643SEV#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8643SEV#TRPBF?
LT8643SEV#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8643SEV#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#TRPBF?
For technical support, including LT8643SEV#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8643SEV#TRPBF requirements.
6.How does Aetrix verify that LT8643SEV#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8643SEV#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#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8643SEV#TRPBF?
All LT8643SEV#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8643SEV#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#TRPBF part is unused and in its original packaging.
Return procedure for LT8643SEV#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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