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Analog Devices Inc. LT8638SJV#PBF
- Part No.:
- LT8638SJV#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TFQFN Exposed Pad
- Datasheet:
-
LT8638SJV#PBF.pdf
- Description:
- IC REG BUCK ADJ 10A 28LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,308
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Product details
Overview
LT8638SJV#PBF from Analog Devices is a 42V, 10A continuous / 12A peak synchronous step-down Silent Switcher 2 regulator with integrated input bypass capacitors, 25ns minimum on-time, and AEC-Q100 qualification for automotive junction temperatures up to 150°C. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT) and supports PolyPhase® operation across up to 12 phases in noise-sensitive power systems.
For engineers reviewing the LT8638SJV#PBF datasheet, LT8638SJV#PBF pinout, LT8638SJV#PBF application, or LT8638SJV#PBF equivalent, key selection considerations include its ultralow EMI performance per CISPR 25 Class 5, spread spectrum modulation, external VC-loop compensation for fast transient response, and 2.8V–42V input range with 0.6V ±1% reference accuracy.
Technical Context
The LT8638SJV#PBF implements peak current mode control with a 25ns minimum on-time and frequency programmability from 200kHz to 3MHz via the RT pin. Its second-generation Silent Switcher 2 architecture integrates internal VIN bypass capacitors to minimize high-di/dt loop area and reduce radiated EMI without requiring complex PCB layout mitigation.
It supports four operating modes via the SYNC/MODE pin: Burst Mode® (90µA IQ), forced continuous mode (FCM), spread spectrum (±24% frequency modulation), and external clock synchronization. PolyPhase® interleaving is enabled through CLKOUT and PHMODE pins, allowing phase-shifted operation across multiple units to reduce input/output ripple and capacitor stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 42V - supports wide automotive battery transients and industrial 24/36V rails. |
| Output Current | 10A continuous, 12A peak - enables single-chip 5V/10A or 3.3V/10A supplies without parallel devices. |
| Switching Frequency | 200kHz to 3MHz - adjustable via RT resistor; allows optimization of size vs. efficiency vs. EMI. |
| Feedback Reference | 0.6V ±1% over temperature - ensures tight output regulation across –40°C to 150°C junction range. |
| Min On-Time | 25ns - enables high step-down ratios (e.g., 42V→3.3V) at 2MHz without pulse-skipping. |
| Quiescent Current | 90µA in Burst Mode (12VIN→5VOUT) - extends battery life in always-on automotive modules. |
| EMI Performance | CISPR 25 Class 5 compliant - meets stringent automotive radiated/conducted emission limits without shielding. |
Pinout & Package
LT8638SJV#PBF is housed in a 28-lead 5mm × 4mm LQFN package with exposed thermal pad (pins 29–32). The package is RoHS-compliant, moisture sensitivity level (MSL) 3, and rated for –40°C to 150°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PHMODE (1) | Phase configuration selector | Determines CLKOUT phase shift: GND = 2-phase, float = 3-phase, INTVCC = 4-phase for PolyPhase® interleaving. |
| BIAS (2) | Internal regulator bias supply | Reduces VIN current draw when tied to VOUT ≥3.3V; improves light-load efficiency and thermal performance. |
| INTVCC (3) | Internal 3.4V regulator output | Bypass with ≥1µF ceramic capacitor; powers control circuitry and drivers; not for external loading. |
| BST (4) | Bootstrap supply for top MOSFET gate | Requires 0.1µF ceramic capacitor between BST and SW to sustain high-side drive voltage. |
| SW (5–8) | Power switch node | Connects directly to inductor; must be minimized in PCB area to suppress EMI and switching losses. |
| VIN (15–18) | Main input power supply | Multiple pins reduce impedance; requires local ≥4.7µF ceramic bypass close to pins. |
| EN/UV (21) | Enable and input UVLO control | Hysteretic threshold (0.98V rise / 0.94V fall); enables programmable input undervoltage lockout. |
| RT (22) | Frequency programming | Resistor to GND sets fSW: 38.3kΩ = 1MHz, 16.9kΩ = 2MHz, 226kΩ = 200kHz. |
| SYNC/MODE (24) | Operating mode selection | GND = Burst Mode, float = FCM, INTVCC = FCM + spread spectrum, external clock = sync mode. |
| PG (25) | Power good open-drain output | Asserts high when FB is within ±7.75% of 0.6V and no fault (UVLO, thermal, overcurrent) is present. |
| VC (26) | Error amplifier output | External RC network from VC to GND sets loop compensation for optimal transient response. |
| SS (27) | Soft-start and tracking | 2µA internal current source enables capacitor-based ramp rate control; supports output voltage tracking. |
| FB (28) | Feedback input | Regulated to 0.6V; connects to resistor divider tap; requires 4.7–47pF phase-lead capacitor to VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 Architecture | Integrated VIN bypass capacitors minimize high-frequency loop area, enabling CISPR 25 Class 5 compliance on standard 2-layer PCBs without shielding. |
| PolyPhase® Interleaving Support | CLKOUT and PHMODE pins allow up to 12-phase interleaving across multiple LT8638S units, reducing input/output ripple and capacitor RMS current by >70%. |
| Spread Spectrum Modulation | ±24% triangular frequency dithering (e.g., 2MHz → 1.52–2.48MHz) lowers peak EMI by >10dB without affecting regulation or transient response. |
| Ultrafast Transient Response | External VC compensation enables <10µs recovery from 50% load steps (e.g., 100mA→5.1A) with <100mV undershoot at 5VOUT. |
| AEC-Q100 Automotive Grade | Qualified for –40°C to 150°C junction operation with full electrical characterization and reliability testing per automotive standards. |
Applications
| Automotive ADAS Power Supply | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering radar sensor SoCs and image signal processors in forward collision warning systems requiring low-noise, high-reliability 5V/3.3V rails. IC Role / Device Role / Timing Role: Primary 42V-input synchronous buck converter delivering regulated 5V/10A with ultralow EMI to avoid RF interference with 77GHz radar front-ends. Use Value: Eliminates need for ferrite beads or metal shields while meeting CISPR 25 Class 5 limits-reducing BOM cost and board area by >30%. |
Use Scenario: Generating isolated 3.3V/5A and 5V/5A outputs for microcontroller, FPGA, and analog I/O in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: High-efficiency, thermally robust DC/DC stage converting 24V industrial bus to stable low-voltage rails under full load and ambient temperatures up to 85°C. Use Value: 94% efficiency at 2MHz (12VIN→5VOUT) enables compact 12mm × 12mm solution size with no heatsink required. |
| Medical Imaging Sensor Hub | EV Battery Management System |
|
Use Scenario: Powering low-noise ADCs, precision amplifiers, and timing ICs in portable ultrasound transducer modules where EMI must not corrupt µV-level analog signals. IC Role / Device Role / Timing Role: Silent Switcher 2 buck regulator supplying clean 3.3V/3A with <10mVP-P ripple and sub-100ns switching edges to preserve signal integrity. Use Value: Integrated bypass caps and optimized layout reduce conducted emissions below 150MHz by 20dB compared to discrete solutions. |
Use Scenario: Providing auxiliary 5V/10A power for MCU, CAN transceivers, and cell monitoring ICs in high-voltage battery packs (up to 400V nominal). IC Role / Device Role / Timing Role: Input-transient-hardened buck converter accepting 8–42V input (from DC-DC pre-regulator) with AEC-Q100 reliability and thermal shutdown at 150°C. Use Value: 12A peak capability handles cold-cranking surges; 45mV dropout at 1A ensures stable operation during deep discharge events. |
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#PBF | Same Silent Switcher 2 architecture, but 6A continuous / 8A peak; smaller 4mm × 4mm LQFN; max 40V input. | Lower current capacity suits compact 3.3V/5A applications; less suitable for 10A automotive ECUs. | Select LT8640SIV#PBF when board space is constrained and peak load ≤8A; verify thermal margin at 150°C ambient. |
| MPQ4436AGL-AEC1-Z | Monolithic 3.5A buck with AEC-Q100 grade; 3.8–60V input; no integrated VIN caps; lower EMI performance (CISPR 25 Class 4 only). | Lacks PolyPhase® support and spread spectrum; requires external EMI filters for Class 5 compliance. | Choose MPQ4436AGL-AEC1-Z for cost-sensitive 3.5A designs where full Silent Switcher 2 EMI advantages are not required. |
Compared with LT8640SIV#PBF and MPQ4436AGL-AEC1-Z, the LT8638SJV#PBF uniquely combines 10A continuous output, integrated VIN bypass capacitors, and PolyPhase® scalability-making it the only option capable of single-chip 5V/10A CISPR 25 Class 5 compliance in automotive ADAS power rails.
Availability
LT8638SJV#PBF is available at Aetrix Electronics and suitable for automotive ADAS systems, industrial PLCs, medical imaging sensor hubs, and EV battery management systems requiring stable component supply with AEC-Q100 qualification and long-term production support.
Supply support for LT8638SJV#PBF 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 LT8638SJV#PBF belongs to Analog Devices' Silent Switcher® 2 power management product line, engineered specifically for ultra-low EMI, high-efficiency DC/DC conversion in safety-critical automotive and industrial applications demanding AEC-Q100 reliability.
FAQ
What is the maximum junction temperature rating for LT8638SJV#PBF?
The LT8638SJV#PBF is qualified for operation up to 150°C junction temperature and is AEC-Q100 grade 1 certified. This rating is confirmed in the Absolute Maximum Ratings table and supported by thermal characterization data showing θJC(PAD) = 3.2°C/W, enabling reliable operation in under-hood automotive environments without derating below 150°C.
Does LT8638SJV#PBF support synchronization to an external clock?
Yes, the LT8638SJV#PBF supports external clock synchronization via the SYNC/MODE pin. When driven with a TTL/CMOS-compatible clock signal, the device locks its internal oscillator to the external frequency and operates in forced continuous mode, maintaining precise phase alignment for multi-rail timing-critical systems.
How does the LT8638SJV#PBF achieve CISPR 25 Class 5 compliance without external EMI filters?
The LT8638SJV#PBF achieves CISPR 25 Class 5 compliance through its Silent Switcher 2 architecture, which integrates ceramic bypass capacitors inside the LQFN package to minimize high-di/dt loop area. Combined with symmetrical SW pin layout and optimized internal power switches, this reduces radiated emissions by >20dB compared to conventional buck regulators-even on 2-layer PCBs without ferrites or metal shields.
Can LT8638SJV#PBF operate with input voltage below 3V?
Yes, the LT8638SJV#PBF supports a minimum input voltage of 2.8V (typical) across temperature, as specified in the Electrical Characteristics table. This enables operation from single-cell Li-ion (2.7–4.2V) or supercapacitor backup sources, provided the output voltage is set appropriately and minimum on-time constraints are met for the desired VOUT/VIN ratio.
What is the purpose of the PHMODE pin on LT8638SJV#PBF?
The PHMODE pin on LT8638SJV#PBF selects the phase relationship between the internal clock and the CLKOUT signal for PolyPhase® operation: grounded for 2-phase, floating for 3-phase, or tied to INTVCC for 4-phase interleaving. This enables precise phase offset control across multiple LT8638SJV#PBF units to reduce input/output capacitor RMS current and improve dynamic response.
LT8638SJV#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 28-TFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.8V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 10A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-LQFN (5x4)
LT8638SJV#PBF FAQ
1.How can I place an order for LT8638SJV#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8638SJV#PBF 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 LT8638SJV#PBF reliable?
The price and inventory of LT8638SJV#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8638SJV#PBF is usually 5 days.
3.What payment methods are accepted for LT8638SJV#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8638SJV#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8638SJV#PBF?
LT8638SJV#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8638SJV#PBF 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 LT8638SJV#PBF?
For technical support, including LT8638SJV#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8638SJV#PBF requirements.
6.How does Aetrix verify that LT8638SJV#PBF is sourced from the original manufacturer or authorized distributors?
All LT8638SJV#PBF 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 LT8638SJV#PBF meets industry standards.
7.What is the process for return or replacement of LT8638SJV#PBF?
All LT8638SJV#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8638SJV#PBF, 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 LT8638SJV#PBF part is unused and in its original packaging.
Return procedure for LT8638SJV#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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