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Analog Devices Inc. LT8638SJV#TRPBF
- Part No.:
- LT8638SJV#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TFQFN Exposed Pad
- Datasheet:
-
LT8638SJV#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 10A 28LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,862
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Product details
Overview
LT8638SJV#TRPBF from Analog Devices is a 42V, 10A continuous / 12A peak synchronous step-down regulator featuring second-generation Silent Switcher 2 architecture for ultralow EMI emissions. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT), supports 200kHz–3MHz switching frequency via RT resistor, and operates across –40°C to +150°C junction temperature. It is used in automotive ADAS power supplies requiring high reliability and low radiated noise.
For engineers reviewing the LT8638SJV#TRPBF datasheet, LT8638SJV#TRPBF pinout, LT8638SJV#TRPBF application, or LT8638SJV#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, integrated input bypass capacitors, 25ns minimum on-time for high step-down ratios, PolyPhase® capability up to 12 phases, and spread spectrum modulation for CISPR 25 Class 5 compliance.
Technical Context
The LT8638SJV#TRPBF employs peak current mode control with internal 0.6V reference and external VC-loop compensation for fast transient response. Its Silent Switcher 2 architecture integrates ceramic input capacitors inside the LQFN package to minimize high-di/dt loop area and reduce PCB layout sensitivity to EMI performance.
It supports four operating modes via SYNC/MODE pin: Burst Mode® (low IQ), forced continuous mode (FCM), spread spectrum (±24% frequency dither), and external synchronization. PHMODE pin configures 2-/3-/4-phase PolyPhase® operation, while EN/UV enables programmable input UVLO and shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 42V - supports wide automotive battery transients including cold-crank (≥4.5V) and load-dump (≤42V). |
| Output Current | 10A continuous, 12A peak - sustains short-term overloads without thermal shutdown in properly heatsinked layouts. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - enables compact magnetics; 2MHz operation allows ≤0.68µH inductors. |
| Quiescent Current | 90µA at 12VIN→5VOUT in Burst Mode - extends battery life in always-on automotive modules. |
| Reference Accuracy | ±1% over temperature - ensures stable output voltage across –40°C to +150°C junction range. |
| EMI Performance | CISPR 25 Class 5 compliant (radiated/conducted) with spread spectrum - eliminates need for external EMI filters in most automotive designs. |
| Minimum On-Time | 25ns - enables 12VIN→1.0VOUT conversion at 2MHz without pulse-skipping. |
Pinout & Package
LT8638SJV#TRPBF is housed in a thermally enhanced 28-lead 5mm × 4mm × 0.94mm LQFN package with exposed GND pad (pins 29–32). The package is RoHS-compliant, moisture-sensitive level 3, and qualified per AEC-Q100 Grade 1 (–40°C to +150°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (5–8) | Power switch node | Connects directly to inductor; must be minimized in PCB area to reduce EMI radiation and switching losses. |
| VIN (15–18) | Main input supply | Requires local ≥4.7µF ceramic bypass; multiple pins reduce IR drop and improve high-frequency current delivery. |
| GND (9–14, 20, 29–32) | Power and signal ground | Exposed pad must be soldered to PCB thermal plane; provides θJC(PAD) = 3.2°C/W for thermal management. |
| EN/UV (21) | Enable & input UVLO control | Hysteretic threshold (0.98V rise / 0.94V fall); resistor divider sets precise VIN turn-on/off points. |
| SYNC/MODE (24) | Operating mode selector | GND = Burst Mode; float = FCM; INTVCC = spread spectrum + FCM; external clock = sync mode. |
| VC (26) | Error amplifier output | External RC network sets loop bandwidth and phase margin; enables optimization for specific fSW and output capacitor. |
| PHMODE (1) | PolyPhase phase configuration | GND = 2-phase; float = 3-phase; INTVCC = 4-phase - enables interleaving of multiple LT8638S units. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher 2 architecture | Integrated VIN bypass capacitors reduce high-frequency loop area by >90%, enabling CISPR 25 Class 5 compliance without ferrite beads or shielded inductors. |
| 25ns minimum on-time | Supports high step-down ratios (e.g., 24V→1.2V at 2MHz) without pulse-skipping, maintaining regulation under light loads. |
| AEC-Q100 Grade 1 qualification | Guaranteed operation from –40°C to +150°C junction temperature with full electrical specs validated - suitable for engine bay and ADAS ECU applications. |
| Spread spectrum modulation | ±24% triangular frequency dither reduces peak EMI amplitude by up to 10dB, easing EMC certification in noisy automotive environments. |
| PolyPhase® support (up to 12 phases) | CLKOUT and PHMODE enable precise interleaving across multiple LT8638S units, reducing input/output ripple and capacitor count by √N. |
Applications
| Automotive ADAS Power Supply | Industrial Motor Drive Bias Rail |
|---|---|
|
Use Scenario: Powering radar sensor SoCs (e.g., TI AWR2944) requiring clean, low-noise 1.0V/1.8V/3.3V rails in front-bumper-mounted modules. IC Role / Device Role / Timing Role: Primary 12VIN→3.3V/1.8V synchronous buck converter with integrated EMI suppression and thermal robustness. Use Value: Eliminates external EMI filters and reduces board area by 35% vs. legacy solutions; meets ISO 11452-2/ISO 11452-4 immunity requirements. |
Use Scenario: Generating isolated gate driver bias supplies (e.g., 15V/–5V) for IGBT/SiC half-bridges in servo drives. IC Role / Device Role / Timing Role: High-efficiency intermediate bus converter delivering 10A at 15V from 48V DC-link, supporting fast load transients during PWM switching. Use Value: 94% efficiency at 2MHz reduces heat sink size; 12A peak current handles motor startup surges without derating. |
| Telecom Remote Radio Unit (RRU) | Medical Imaging Detector Bias |
|
Use Scenario: Providing regulated 5V/3.3V power to FPGA, ADCs, and RF transceivers in outdoor 5G base station RRUs exposed to wide ambient temperatures. IC Role / Device Role / Timing Role: Main point-of-load regulator with AEC-Q100-grade reliability and extended temperature operation. Use Value: Guaranteed –40°C to +150°C operation avoids thermal throttling; spread spectrum ensures FCC Part 15B compliance in dense RF environments. |
Use Scenario: Supplying ultra-low-noise ±5V bias to photodiode arrays and analog front-ends in portable X-ray detectors. IC Role / Device Role / Timing Role: Low-ripple, low-EMI primary buck stage feeding downstream LDOs; operates in forced continuous mode for flat PSRR. Use Value: <10mVP-P output ripple and <90µA IQ preserve signal integrity and battery runtime; Silent Switcher 2 prevents image artifacts from switching noise. |
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 |
|---|---|---|---|
| LT8643SIV#TRPBF | Same Silent Switcher 2 architecture, but rated for 40V max input and 8A continuous (10A peak); smaller 4mm × 4mm LQFN package. | Better suited for space-constrained industrial IoT nodes where 40V input suffices and 8A output is adequate. | Select when board area is critical and input voltage never exceeds 40V; not AEC-Q100 qualified. |
| MPQ4433AGL-AEC1-Z | Monolithic 36V, 10A buck with AEC-Q100 Grade 1, but lacks integrated input caps, spread spectrum, and PolyPhase support. | Requires external EMI filtering and larger layout; lower EMI performance than LT8638SJV#TRPBF in unshielded enclosures. | Choose for cost-sensitive automotive infotainment systems where full Silent Switcher 2 benefits are not required. |
Compared with LT8638SJV#TRPBF, LT8643SIV#TRPBF offers smaller footprint but reduced voltage headroom and no AEC-Q100 rating, while MPQ4433AGL-AEC1-Z provides automotive qualification at the expense of higher EMI design effort and no multi-phase coordination.
Availability
LT8638SJV#TRPBF is available at Aetrix Electronics and suitable for automotive ADAS, industrial motor control, telecom RRU, and medical imaging applications requiring stable component supply, long lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT8638SJV#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.
The LT8638S product line delivers high-current, ultralow-EMI power conversion for safety-critical automotive and industrial systems where electromagnetic compatibility and thermal reliability are non-negotiable.
FAQ
What is the maximum junction temperature specification for LT8638SJV#TRPBF?
The LT8638SJV#TRPBF is specified for operation from –40°C to +150°C junction temperature and is AEC-Q100 Grade 1 qualified. This rating is guaranteed across all electrical parameters, unlike the LT8638SEV variant (–40°C to +125°C). Thermal derating begins above 125°C, and the device includes internal overtemperature protection that activates above 150°C.
Does LT8638SJV#TRPBF require external input capacitors despite its integrated Silent Switcher 2 capacitors?
Yes, LT8638SJV#TRPBF requires external input capacitors: two small ceramic capacitors (<1µF) placed immediately adjacent to the IC (COPT1/COPT2), plus a bulk ≥4.7µF ceramic capacitor near the VIN pins. The integrated capacitors reduce high-frequency loop area but do not replace bulk energy storage or low-frequency decoupling needed for transient response and stability.
How does the PHMODE pin configure PolyPhase operation in LT8638SJV#TRPBF?
The PHMODE pin on LT8638SJV#TRPBF selects CLKOUT phase offset: tied to GND enables 2-phase interleaving (180° shift), left floating enables 3-phase (120° shift), and tied to INTVCC enables 4-phase (90° shift). This allows up to 12-phase operation when cascading three LT8638SJV#TRPBF units, reducing input/output ripple and capacitor stress proportionally.
Can LT8638SJV#TRPBF operate with a 2.5V input voltage?
No, LT8638SJV#TRPBF has a minimum input voltage of 2.8V (typical) across temperature, as confirmed in the Electrical Characteristics table. At 2.5V input, the device will not regulate - the internal UVLO circuit prevents startup, and the top MOSFET cannot sustain conduction due to insufficient gate drive headroom relative to the 0.6V reference and control logic thresholds.
What is the purpose of the VC pin on LT8638SJV#TRPBF, and how is it used?
The VC pin on LT8638SJV#TRPBF is the error amplifier output node, controlling peak inductor current via voltage-to-current gain (12A/V). An external RC network from VC to GND sets loop compensation - selecting values based on switching frequency, inductor value, and output capacitance ensures optimal phase margin (>45°) and fast transient response without oscillation or excessive overshoot.
LT8638SJV#TRPBF 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:
- Active
- 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#TRPBF FAQ
1.How can I place an order for LT8638SJV#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8638SJV#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 LT8638SJV#TRPBF reliable?
The price and inventory of LT8638SJV#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8638SJV#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8638SJV#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8638SJV#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8638SJV#TRPBF?
LT8638SJV#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8638SJV#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 LT8638SJV#TRPBF?
For technical support, including LT8638SJV#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8638SJV#TRPBF requirements.
6.How does Aetrix verify that LT8638SJV#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8638SJV#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 LT8638SJV#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8638SJV#TRPBF?
All LT8638SJV#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8638SJV#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 LT8638SJV#TRPBF part is unused and in its original packaging.
Return procedure for LT8638SJV#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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