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Analog Devices Inc. LT8638SJV#TRMPBF
- Part No.:
- LT8638SJV#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TFQFN Exposed Pad
- Datasheet:
-
LT8638SJV#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 10A 28LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,862
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Product details
Overview
LT8638SJV#TRMPBF from Analog Devices is a 42V, 10A continuous/12A peak synchronous step-down Silent Switcher 2 regulator in a 28-lead 5mm × 4mm LQFN package. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT), features 25ns minimum on-time, ±1% reference accuracy, and AEC-Q100 qualification for automotive power supplies.
For engineers reviewing the LT8638SJV#TRMPBF datasheet, LT8638SJV#TRMPBF pinout, LT8638SJV#TRMPBF application, or LT8638SJV#TRMPBF equivalent, key selection criteria include ultralow EMI performance (CISPR 25 Class 5 compliant), PolyPhase® operation support up to 12 phases, spread spectrum modulation, and -40°C to 150°C junction temperature rating.
Technical Context
The LT8638SJV#TRMPBF implements peak current mode control with integrated input bypass capacitors inside the LQFN package to minimize fast-current-loop area and reduce PCB layout sensitivity. Its second-generation Silent Switcher architecture achieves <10mVP-P output ripple and radiated EMI below CISPR 25 Class 5 limits without external filters.
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 synchronization. The VC pin enables external loop compensation for optimized transient response across 200kHz–3MHz switching frequencies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 42V - supports wide automotive battery transients including cold-crank and load-dump conditions. |
| Output Current | 10A continuous / 12A peak - sustains high transient loads without thermal shutdown in properly heatsinked layouts. |
| Switching Frequency | 200kHz to 3MHz - programmable via RT resistor; enables compact magnetics and high-density power designs. |
| Reference Accuracy | ±1% over temperature - ensures stable output regulation across automotive and industrial ambient ranges. |
| Min On-Time | 25ns - enables high step-down ratios (e.g., 42V→3.3V) at 2MHz without pulse-skipping artifacts. |
| Quiescent Current | 90µA at 12VIN→5VOUT in Burst Mode - extends battery life in always-on automotive modules. |
| EMI Performance | CISPR 25 Class 5 compliant - eliminates need for external EMI filters in automotive infotainment and ADAS systems. |
Pinout & Package
Package: 28-lead 5mm × 4mm × 0.94mm LQFN with exposed thermal pad (Pins 29–32 = GND). JEDEC-compliant footprint; θJC(PAD) = 3.2°C/W enables high-power operation with minimal board-level thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PHMODE (1) | Phase configuration select | Determines CLKOUT phase shift: GND = 2-phase, float = 3-phase, INTVCC = 4-phase for multiphase interleaving. |
| BIAS (2) | Internal regulator supply | Reduces VIN current draw when tied to VOUT ≥3.3V; improves light-load efficiency and thermal performance. |
| INTVCC (3) | Internal 3.4V rail bypass | Requires ≥1µF low-ESR ceramic capacitor to ground; powers control circuitry and gate drivers. |
| BST (4) | Bootstrap supply | Drives high-side NMOS gate; requires 0.1µF ceramic capacitor between BST and SW pins. |
| SW (5–8) | Power switch node | Four paralleled switch outputs - must be shorted together and connected to inductor with minimal trace area. |
| GND (9–14, 20, 29–32) | Power and signal return | Multiple GND pins + exposed thermal pad - solder pad to large copper pour for thermal management and EMI reduction. |
| VIN (15–18) | Main input supply | Four dedicated input pins - require local 4.7µF+ ceramic capacitor with shortest possible path to GND pins. |
| EN/UV (21) | Enable & input UVLO | Hysteretic threshold (0.98V rise / 0.94V fall); enables programmable input undervoltage lockout via resistor divider. |
| RT (22) | Frequency set | Resistor to GND sets switching frequency from 200kHz to 3MHz; tolerance directly impacts fSW accuracy. |
| CLKOUT (23) | Multiphase clock output | 50% duty cycle square wave synchronized to internal clock; phase determined by PHMODE state. |
| SYNC/MODE (24) | Operating mode control | GND = Burst Mode, float = FCM, INTVCC = spread spectrum + FCM, external clock = sync mode. |
| PG (25) | Power good indicator | Open-drain output asserts high when FB is within ±7.75% of 0.6V reference and no fault conditions exist. |
| VC (26) | Error amplifier output | External RC network sets loop compensation; enables fast transient response across full load and frequency range. |
| SS (27) | Soft-start & tracking | 2µA internal current source charges external capacitor; controls output voltage ramp rate and enables output tracking. |
| FB (28) | Feedback reference | Regulates to 0.6V ±1%; 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-di/dt loop area, enabling CISPR 25 Class 5 compliance on standard 2-layer PCBs. |
| PolyPhase® Operation Support | Up to 12-phase interleaving via CLKOUT and PHMODE pins - reduces input/output ripple and capacitor count in high-current systems. |
| Spread Spectrum Modulation | ±24% triangular frequency dithering - lowers peak EMI by spreading energy across bandwidth without affecting regulation performance. |
| AEC-Q100 Qualified | Rated for -40°C to 150°C junction temperature - validated for automotive engine control, ADAS, and infotainment power rails. |
| Low Dropout Operation | 45mV dropout at 1A - maintains regulation during low-input-voltage conditions such as automotive cold-crank (≤4.5V). |
Applications
| Automotive Engine Control Unit (ECU) | Industrial Motor Drive Controller |
|---|---|
Use Scenario: Powering microcontrollers, CAN transceivers, and sensor interfaces in under-hood ECUs exposed to 125°C ambient and 42V load-dump transients. IC Role / Device Role / Timing Role: Primary 5V/3.3V point-of-load regulator delivering 10A peak current with ultralow EMI to avoid interference with crankshaft position sensors. Use Value: AEC-Q100 qualification and 150°C junction rating ensure reliability; integrated capacitors eliminate layout-sensitive filtering components. | Use Scenario: Supplying FPGA I/O banks and gate drivers in servo motor controllers requiring clean, stable 3.3V/5V rails amid high dv/dt noise from PWM inverters. IC Role / Device Role / Timing Role: High-efficiency synchronous buck converter with forced continuous mode for fast load-step response during torque transients. Use Value: 25ns min on-time enables 24V→3.3V conversion at 2MHz; spread spectrum reduces conducted EMI coupling into encoder feedback lines. |
| ADAS Camera Module Power | Telecom Remote Radio Head (RRH) |
Use Scenario: Providing regulated 1.8V/3.3V power to image sensors and ISP processors in automotive surround-view cameras mounted near heat sources. IC Role / Device Role / Timing Role: Low-noise DC/DC regulator with Burst Mode® for standby power and FCM for active imaging, minimizing thermal dissipation in sealed enclosures. Use Value: 90µA quiescent current extends battery backup time; <10mVP-P ripple prevents image sensor pattern noise. | Use Scenario: Generating 5V/12V bias rails for RF power amplifiers and analog front-end ICs in outdoor 5G RRH units operating from -40°C to 85°C ambient. IC Role / Device Role / Timing Role: High-reliability step-down regulator supporting wide input range (24–48V DC) and delivering 10A with thermal foldback protection. Use Value: 42V absolute max input withstands telecom power surges; exposed thermal pad enables direct mounting to aluminum heatsink. |
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, 42V/8A, but rated for -40°C to 125°C (not 150°C); lacks PHMODE pin for multiphase control. | Not qualified for under-hood automotive use above 125°C; suitable for cabin electronics or industrial control where lower temp grade suffices. | Select LT8640SIV#PBF only if 8A output and 125°C rating meet requirements and PolyPhase® is unnecessary. |
| MPQ4436AGL-AEC1-Z | 45V/10A AEC-Q100 automotive buck; no integrated input caps, higher EMI, no spread spectrum; 120ns min on-time vs 25ns. | Requires larger external input filter for CISPR 25 compliance; cannot achieve same high-frequency step-down ratio (e.g., 42V→1.2V @ 2MHz). | Choose MPQ4436AGL-AEC1-Z only if cost sensitivity outweighs EMI and layout simplicity requirements. |
Compared with LT8640SIV#PBF and MPQ4436AGL-AEC1-Z, the LT8638SJV#TRMPBF uniquely combines AEC-Q100 150°C operation, integrated EMI-reduction capacitors, 25ns min on-time, and PolyPhase® support - making it the only option for high-density, high-temperature automotive power designs demanding ultralow EMI without external filtering.
Availability
LT8638SJV#TRMPBF is available at Aetrix Electronics and suitable for automotive engine control units, industrial motor drive controllers, ADAS camera modules, and telecom remote radio heads requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT8638SJV#TRMPBF 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 LT8638SJV#TRMPBF belongs to the Silent Switcher® 2 family of high-efficiency, ultralow-EMI DC/DC regulators designed specifically for noise-sensitive automotive, industrial, and communications applications where layout simplicity and regulatory compliance are critical.
FAQ
What is the maximum junction temperature rating for the LT8638SJV#TRMPBF?
The LT8638SJV#TRMPBF is qualified for operation up to 150°C junction temperature and carries AEC-Q100 Grade 1 certification. This rating is confirmed in the Absolute Maximum Ratings table (page 2) and Operating Junction Temperature Range specification for the "J" grade variant. Thermal derating applies above 125°C per Note 2 in the datasheet.
Does the LT8638SJV#TRMPBF require external input capacitors despite its integrated VIN bypass capacitors?
Yes, the LT8638SJV#TRMPBF requires external input capacitors in addition to its internal ones. The datasheet specifies two small (<1µF) ceramic capacitors placed as close as possible to the IC (COPT1/COPT2), plus a larger 4.7µF or greater bulk capacitor nearby (CIN3). These external capacitors handle low-frequency ripple and ensure stability under high-current transients.
Can the LT8638SJV#TRMPBF synchronize to an external clock while operating in spread spectrum mode?
No, the LT8638SJV#TRMPBF cannot operate in both spread spectrum and external synchronization modes simultaneously. When an external clock is applied to the SYNC/MODE pin, the part enters synchronization mode and disables spread spectrum modulation. Spread spectrum is only active when SYNC/MODE is tied high to INTVCC (or >3V) with no external clock present.
What is the purpose of the PHMODE pin on the LT8638SJV#TRMPBF, and how does it affect multiphase operation?
The PHMODE pin on the LT8638SJV#TRMPBF selects the phase relationship between the internal oscillator and the CLKOUT signal for PolyPhase® operation. Tying PHMODE to GND configures 2-phase interleaving, floating enables 3-phase, and connecting to INTVCC selects 4-phase. This allows up to 12 phases using three LT8638SJV#TRMPBF devices, reducing input/output capacitor requirements and ripple current stress.
How does the LT8638SJV#TRMPBF achieve ultralow EMI without requiring complex PCB layout techniques?
The LT8638SJV#TRMPBF achieves ultralow EMI through second-generation Silent Switcher architecture, which integrates ceramic bypass capacitors inside the LQFN package to minimize high-di/dt loop area. This eliminates sensitivity to PCB layout parasitics and enables CISPR 25 Class 5 compliance on simple 2-layer boards - verified on the DC2929A demo board with EMI filter installed (Figures G38–G40).
LT8638SJV#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 28-TFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- 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#TRMPBF FAQ
1.How can I place an order for LT8638SJV#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8638SJV#TRMPBF 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#TRMPBF reliable?
The price and inventory of LT8638SJV#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8638SJV#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT8638SJV#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8638SJV#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8638SJV#TRMPBF?
LT8638SJV#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8638SJV#TRMPBF 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#TRMPBF?
For technical support, including LT8638SJV#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8638SJV#TRMPBF requirements.
6.How does Aetrix verify that LT8638SJV#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT8638SJV#TRMPBF 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#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT8638SJV#TRMPBF?
All LT8638SJV#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8638SJV#TRMPBF, 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#TRMPBF part is unused and in its original packaging.
Return procedure for LT8638SJV#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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