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Analog Devices Inc. LT8643SIV-2#TRPBF
- Part No.:
- LT8643SIV-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-TFQFN Exposed Pad
- Datasheet:
-
LT8643SIV-2#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 6A 24LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,005
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Product details
Overview
LT8643SIV-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 AEC-Q100 qualification for automotive applications. It delivers up to 95% efficiency at 2MHz (12VIN→5VOUT) and supports spread spectrum modulation to reduce EMI.
For engineers reviewing the LT8643SIV-2#TRPBF datasheet, LT8643SIV-2#TRPBF pinout, LT8643SIV-2#TRPBF application, or LT8643SIV-2#TRPBF equivalent, key selection criteria include external loop compensation capability, ultralow IQ in sleep mode (230µA at VBIAS = 0V), forced continuous/sync/spread-spectrum mode flexibility, and 24-lead LQFN thermal performance with exposed GND pads.
Technical Context
The LT8643SIV-2#TRPBF implements peak current mode control with a dedicated VC error amplifier output for external compensation-enabling precise current sharing across parallel converters and optimized transient response at 2–3MHz switching frequencies. Its Silent Switcher architecture integrates dual independent input paths and symmetrical power switch layout to suppress common-mode EMI.
It supports four distinct operating modes via the SYNC/MODE pin: Burst Mode (ground), Forced Continuous (floating), Spread Spectrum (3–4V), and External Synchronization (clock input). The VC pin provides direct access to the error amplifier output (1.7mS transconductance, ±350µA sink/source), allowing custom loop shaping with RC networks.
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 without pre-regulation. |
| Output Current | 6A continuous, 7A peak - sustains full load under 125°C junction temperature with proper PCB copper and thermal pad soldering. |
| Quiescent Current (Burst) | 230µA at VBIAS = 0V - enables >1-year battery life in always-on automotive modules (e.g., telematics, ADAS sensors). |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics (e.g., 1µH at 3MHz) and avoids AM band interference. |
| Min On-Time | 30ns - enables high step-down ratios (e.g., 42VIN → 3.3VOUT at 2MHz) without pulse-skipping instability. |
| Feedback Reference | 0.970V ±6mV - tight tolerance reduces output voltage error across temperature and line/load variations. |
| Thermal Rating | –40°C to 125°C junction - qualified per AEC-Q100 Grade I, suitable for under-hood and infotainment systems. |
Pinout & Package
LT8643SIV-2#TRPBF uses a 24-lead 4mm × 4mm × 0.94mm LQFN package with exposed GND pads (Pins 25–28) requiring PCB soldering for thermal integrity (θJC = 7°C/W). Pin functions are validated per Analog Devices' Rev. D datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST (7) | Bootstrap supply | Drives high-side NMOS gate above VIN; requires 0.1µF ceramic capacitor placed adjacent to IC. |
| SW (8–12) | Power switch node | Common drain of internal top/bottom FETs; must be routed as minimal-area copper pour to reduce EMI radiation. |
| VC (22) | Error amplifier output | Direct access to transconductance stage (1.7mS); connects to external RC network for loop compensation and current sharing. |
| SYNC/MODE (20) | Operating mode control | Selects Burst Mode (GND), FCM (open), Spread Spectrum (3–4V), or external sync (clock input); no pull-up/pull-down required in FCM. |
| TR/SS (21) | Soft-start & tracking | 1.9µA internal current source enables programmable ramp rate; below 1.6V enables output tracking of external reference. |
| PG (23) | Power good indicator | Open-drain output asserts high when FB is within ±7.5% of 0.97V and no fault (UVLO, thermal, EN/UV low) is present. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Reduces radiated EMI by >30dB vs conventional buck regulators-meets CISPR 25 Class 5 limits without shielding or ferrites. |
| External compensation (VC pin) | Enables fast transient response (<50µs recovery for 2A step) and precise current sharing across paralleled LT8643S-2 units. |
| Spread spectrum modulation | 22% frequency dithering centered on RT-set frequency lowers peak EMI by 10dB and simplifies compliance testing. |
| Ultralow dropout | 100mV at 1A load - maintains regulation during cold-crank (4.5V battery) with 3.3V output. |
| AEC-Q100 Grade I | Qualified for automotive applications including infotainment, ADAS cameras, and body control modules. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering 5V/3.3V rails for SoC, DDR memory, and display controllers in head units with strict EMI limits. IC Role / Device Role / Timing Role: Primary 42V-input synchronous buck converter with spread spectrum enabled to pass CISPR 25 Class 5 radiated emissions. Use Value: Eliminates need for external EMI filters and metal shielding, reducing BOM cost and board area by >30%. |
Use Scenario: Generating isolated 5V/6A supply for fieldbus communication (CAN, RS-485) and sensor interfaces in harsh factory environments. IC Role / Device Role / Timing Role: High-reliability DC/DC regulator with AEC-Q100 qualification and 125°C operation for extended thermal margin. Use Value: Maintains regulation during 40V load-dump transients and operates continuously at 85°C ambient without derating. |
| ADAS Camera Module | Medical Portable Monitor |
|
Use Scenario: Powering image sensor and ISP in rear-view camera with always-on capability and ultra-low standby power. IC Role / Device Role / Timing Role: Low-IQ (230µA) step-down regulator in Burst Mode, enabling >2-year battery backup during vehicle sleep. Use Value: Meets ISO 16750-2 cold-crank (4.5V min) while delivering clean 3.3V at <10mVP-P ripple for noise-sensitive analog front-ends. |
Use Scenario: Providing regulated 5V/6A for LCD backlight, touch controller, and wireless comms in battery-powered patient monitors. IC Role / Device Role / Timing Role: Compact, thermally robust power stage using 4mm × 4mm LQFN with soldered exposed pad for passive cooling. Use Value: Achieves 95% efficiency at 2MHz, minimizing heat rise in sealed enclosures and extending single-charge runtime. |
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 |
|---|---|---|---|
| LT8640SIV-2#TRPBF | Internal compensation, 2.5µA IQ (vs 230µA), no VC pin - simpler layout but slower transient response and no current sharing. | Preferred for cost-sensitive, single-rail designs where loop stability is fixed and paralleling is unnecessary. | Select when design prioritizes lowest standby power over dynamic performance or multi-phase scalability. |
| MPQ4433AGL-A-Z | 36V max input, 6A, 1.5µA IQ, no spread spectrum or SYNC - lower voltage rating and fewer EMI mitigation features. | Suitable for non-automotive industrial or consumer applications with less stringent EMI or transient requirements. | Choose for 24V systems where 42V capability and CISPR 25 compliance are not required. |
Compared with LT8640SIV-2#TRPBF, the LT8643SIV-2#TRPBF trades slightly higher light-load IQ for external loop control and current sharing; versus MPQ4433AGL-A-Z, it adds 42V operation, spread spectrum, and AEC-Q100 qualification at the cost of higher BOM complexity.
Availability
LT8643SIV-2#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and ADAS camera systems requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.
Supply support for LT8643SIV-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 automotive, industrial, communications, and healthcare markets.
The LT8643S-2 belongs to the Silent Switcher® family of high-efficiency, low-EMI DC/DC regulators designed specifically for noise-sensitive automotive and industrial applications demanding robust transient response and compact size.
FAQ
What is the maximum input voltage rating for LT8643SIV-2#TRPBF?
The LT8643SIV-2#TRPBF has an absolute maximum input voltage rating of 42V on VIN pins, with guaranteed operation from 3.4V to 42V. This enables direct connection to 24V/36V industrial rails and withstands automotive load-dump transients up to ISO 16750-2 Level V (40V for 400ms).
How does the VC pin on LT8643SIV-2#TRPBF enable current sharing between multiple converters?
The VC pin on LT8643SIV-2#TRPBF outputs the error amplifier's transconductance node (1.7mS, ±350µA). When VC pins of paralleled LT8643SIV-2#TRPBF units are tied together with small resistors, the shared voltage forces identical peak inductor currents, achieving precise current balancing without master-slave control circuitry.
Can LT8643SIV-2#TRPBF operate in forced continuous mode without external synchronization?
Yes - LT8643SIV-2#TRPBF enters forced continuous mode (FCM) when the SYNC/MODE pin is left floating (high-impedance). In this state, the internal oscillator runs continuously at the RT-set frequency, ensuring consistent switching and optimal transient response across all load conditions.
What thermal performance can be expected from LT8643SIV-2#TRPBF in a standard 4-layer PCB layout?
With the exposed GND pads (Pins 25–28) fully soldered to a 2oz internal ground plane, LT8643SIV-2#TRPBF achieves θJA ≈ 24°C/W on demo boards. At 6A/12VIN→5VOUT, this yields ~35°C case rise above ambient - well within the 125°C junction limit even at 85°C ambient temperature.
Is LT8643SIV-2#TRPBF pin-compatible with LT8640SIV-2#TRPBF?
No - although both use the same 24-lead LQFN package, LT8643SIV-2#TRPBF repurposes Pin 22 as VC (error amp output), whereas LT8640SIV-2#TRPBF uses Pin 22 as GND. Swapping them without PCB revision will cause functional failure due to incorrect grounding and missing compensation path.
LT8643SIV-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)
LT8643SIV-2#TRPBF FAQ
1.How can I place an order for LT8643SIV-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8643SIV-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 LT8643SIV-2#TRPBF reliable?
The price and inventory of LT8643SIV-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 LT8643SIV-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8643SIV-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8643SIV-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8643SIV-2#TRPBF?
LT8643SIV-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8643SIV-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 LT8643SIV-2#TRPBF?
For technical support, including LT8643SIV-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8643SIV-2#TRPBF requirements.
6.How does Aetrix verify that LT8643SIV-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8643SIV-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 LT8643SIV-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8643SIV-2#TRPBF?
All LT8643SIV-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8643SIV-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 LT8643SIV-2#TRPBF part is unused and in its original packaging.
Return procedure for LT8643SIV-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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