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Analog Devices Inc./Maxim Integrated MAX42408AFOB+T
- Part No.:
- MAX42408AFOB+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 17-PowerWFQFN
- Datasheet:
-
MAX42408AFOB+T.pdf
- Description:
- IC REG BUCK ADJ 8A 17FC2QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,887
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Product details
Overview
MAX42408AFOB+T from Analog Devices is a fully integrated 36V, 8A synchronous buck converter with internal high-side and low-side MOSFETs, 1.5MHz fixed switching frequency, 0.8V–6V programmable output voltage, and dual-phase capability for up to 16A in single-IC configuration-designed for industrial point-of-load power delivery.
For engineers reviewing the MAX42408AFOB+T datasheet, MAX42408AFOB+T pinout, MAX42408AFOB+T application, or MAX42408AFOB+T equivalent, key selection considerations include its 36ns minimum on-time for high VIN/VOUT ratios, 10μA quiescent current in skip mode, thermally enhanced 3.5mm × 3.75mm FC2QFN package, and 180° out-of-phase synchronization support for dual-phase operation.
Technical Context
The MAX42408AFOB+T implements average current-mode control with a 36ns minimum on-time, enabling stable operation across wide input-to-output voltage ratios (e.g., 36V → 3.3V). Its internal 1.5MHz oscillator supports forced PWM or skip-mode operation via the SYNC pin, and it features an integrated 1.8V BIAS linear regulator with 2.2μF output capacitance requirement.
Dual-phase operation is enabled by connecting one IC as controller (SYNC tied high) and another as target (SYNCOUT tied to BIAS), sharing VEA for dynamic current balancing and operating 180° out-of-phase. The device includes cycle-by-cycle overcurrent protection, hiccup-mode short-circuit response, and thermal shutdown at 175°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 36V - supports wide industrial supply rails including 24V and 36V battery/bus systems. |
| Max Output Current | 8A - continuous RMS current rating at junction temperature ≤125°C with proper PCB thermal design. |
| Switching Frequency | 1.5MHz (fixed) - enables compact magnetics and low output ripple; compatible with external sync up to 1.845MHz. |
| Output Voltage Range | 0.8V to 6V - set via external resistor divider; limited to 6V at 1.5MHz due to control loop stability constraints. |
| Quiescent Current | 10μA in skip mode - extends battery life in always-on industrial sensors and IoT edge nodes. |
| Min On-Time | 36ns - allows high step-down ratios (e.g., 36V→3.3V at ~9% duty cycle) without pulse-skipping instability. |
| Thermal Resistance θJA | 38.6°C/W (JEDEC board) - requires ≥4 thermal vias under PGND pads and ≥200mm² copper pour for full 8A operation. |
Pinout & Package
Package: 3.5mm × 3.75mm, 17-pin FC2QFN with exposed thermal pad (PGND-connected); RoHS-compliant, lead-free, tape-and-reel (T suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN | Enable input | High-voltage compatible (up to 42V); drives internal bias circuitry and initiates soft-start when pulled high. |
| BST | Bootstrap supply | Supplies gate driver for high-side FET; requires 0.1μF ceramic capacitor between BST and LX. |
| SUP (pins 3, 9) | Main IC supply | Input rail for internal logic and high-side switch; must be bypassed with 0.1μF + 4.7μF ceramics per pin. |
| PGND (pins 4, 5, 7, 8) | Power ground | Low-impedance return path for high-current switching loops; all four pins must be connected to solid thermal plane. |
| LX | Switch node | Connection to buck inductor; high dv/dt node requiring minimized trace length and guard ring isolation. |
| BIAS | Internal LDO output | 1.8V regulated supply for analog blocks; requires ≥2.2μF ceramic capacitor to GND for stability. |
| FB | Voltage feedback input | Monitors output via resistor divider; reference = 0.8V ±1.5%; leakage <100nA ensures accuracy at high-divider impedances. |
| OUT | Output sense | Direct connection to output rail for accurate regulation sensing; used with PGOOD and internal error amplifier. |
| VEA | Error amplifier output | Exposed for dual-phase current sharing; connects controller and target VEA nodes to balance load dynamically. |
| PGOOD | Open-drain status indicator | Asserts low during soft-start or if VOUT drops below 93% of regulation; requires external pull-up to BIAS or ≤5.5V rail. |
| SYNC | Mode control/sync input | Low = skip mode; high = forced PWM; external clock = sync mode; determines operating efficiency vs. EMI trade-off. |
| SYNCOUT | 180° phase clock output | Drives target IC's SYNC in dual-phase; disabled in skip mode; must tie to BIAS to configure as target. |
| GND | Analog ground | Reference for FB/VEA; star-connected to PGND at single point to avoid noise coupling into feedback path. |
Key Features
| Feature | Design Value |
|---|---|
| Symmetric SUP/PGND pinout | Reduces high-current loop area and magnetic field coupling, lowering conducted EMI by >6dB compared to asymmetric layouts. |
| Dual-phase scalability | Two MAX42408AFOB+T ICs deliver up to 16A with matched current sharing (±5%) and 180° interleaving to halve input/output ripple. |
| Low dropout operation | Supports >96% duty cycle, enabling regulation down to VOUT ≈ VIN − 0.5V - critical for 24V→23.5V bias rail applications. |
| Integrated protection suite | Includes cycle-by-cycle current limit, hiccup-mode short-circuit response (35ms off-time), and thermal shutdown with 20°C hysteresis. |
| Thermally enhanced FC2QFN | θJC = 7.7°C/W enables 8A operation with ≤25°C rise above ambient using 4-layer board with 2oz copper and thermal vias. |
Applications
| Industrial PLC I/O Module Power | Factory Automation Sensor Hub |
|---|---|
Use Scenario: Powers isolated analog input/output channels and microcontroller subsystems in DIN-rail mounted PLCs with 24V DC input. IC Role / Device Role / Timing Role: Primary 3.3V/5V POL regulator delivering 8A peak to FPGA, ADCs, and isolated RS-485 transceivers. Use Value: 36ns min-on-time maintains regulation during 24V brownouts; dual-phase option scales to 16A for multi-channel high-speed DAQ modules. | Use Scenario: Supplies power to distributed wireless sensor nodes (vibration, temp, pressure) in predictive maintenance gateways. IC Role / Device Role / Timing Role: High-efficiency 1.5MHz buck converting 12V bus to 3.3V for ultra-low-power MCU and BLE radio subsystems. Use Value: 10μA quiescent current in skip mode extends battery life >10 years in sleep-wake cycles; small 3.5×3.75mm footprint fits dense sensor PCBs. |
| Programmable Logic Controller (PLC) Backplane | Industrial Motor Drive Auxiliary Supply |
Use Scenario: Generates 5V/3.3V rails for backplane communication (CAN, EtherCAT) and FPGA configuration in modular PLC chassis. IC Role / Device Role / Timing Role: Dual-phase configured MAX42408AFOB+T pair delivers 16A at 5V with <15mVpp ripple for noise-sensitive SERDES links. Use Value: 180° interleaving reduces input capacitor RMS current by 30%, allowing smaller 1210-case MLCCs instead of bulk electrolytics. | Use Scenario: Provides isolated 15V gate drive and 5V logic supply for IGBT/SiC half-bridge drivers in servo inverters. IC Role / Device Role / Timing Role: Secondary buck stage stepping down 24V auxiliary rail to 15V/5V with fast transient response for gate driver timing integrity. Use Value: 2.5ms soft-start prevents inrush into downstream capacitive loads; PGOOD enables safe enable sequencing before motor startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX42410AFOB+T | 10A rated (vs. 8A), identical 1.5MHz/0.8–6V spec, same package and pinout. | Higher current headroom for future-proofing or margin-critical 8A+ designs with elevated ambient temps. | Select MAX42410AFOB+T when full 8A load persists >60s or ambient exceeds +85°C with limited airflow. |
| MPQ4436GL-AEC1-P | Automotive-grade (AEC-Q100), 10A, 2.2MHz, 3.3–36V input, but no dual-phase or VEA sharing capability. | Targeted at automotive ADAS camera modules; lacks industrial-grade thermal shutdown hysteresis and PGOOD accuracy specs. | Choose MPQ4436GL-AEC1-P only for automotive-qualified designs requiring 2.2MHz switching and AEC-Q100 compliance. |
Compared with MAX42410AFOB+T, the MAX42408AFOB+T offers tighter cost control for 8A-limited applications while retaining identical feature set and layout compatibility; versus MPQ4436GL-AEC1-P, it provides superior dual-phase scalability and industrial thermal robustness but lacks automotive qualification.
Availability
MAX42408AFOB+T is available at Aetrix Electronics and suitable for industrial automation, distributed DC power systems, and point-of-load applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for MAX42408AFOB+T 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 industrial, automotive, communications, and healthcare markets since 1965.
The MAX42408/MAX42410 product line was designed specifically for high-density, high-reliability industrial DC/DC conversion - emphasizing low IQ, dual-phase scalability, and robust operation across -40°C to +125°C ambient.
FAQ
What is the maximum output current supported by the MAX42408AFOB+T?
The MAX42408AFOB+T is rated for 8A continuous output current under typical thermal conditions (TA ≤ +70°C, 4-layer JEDEC board). At higher ambient temperatures or with reduced copper area, derating applies: e.g., 6.5A at TA = +85°C. Peak current capability remains 8A, but sustained operation requires adherence to θJA = 38.6°C/W and proper thermal via placement under PGND pads.
Does the MAX42408AFOB+T support dual-phase operation, and how is it configured?
Yes, the MAX42408AFOB+T supports dual-phase operation for up to 16A total output. Configure one IC as controller (SYNC tied high) and the other as target (SYNCOUT tied to BIAS). Connect VEA pins together for dynamic current sharing and route SYNCOUT of controller to SYNC of target to enforce 180° interleaving. Use separate FB dividers per phase; do not parallel FB nodes.
What is the purpose of the VEA pin on the MAX42408AFOB+T, and how should it be used?
The VEA pin on the MAX42408AFOB+T is the internal voltage-loop error amplifier output. In single-phase operation, leave VEA unconnected. In dual-phase, connect VEA of controller and target together to share the error signal and achieve balanced current distribution. This avoids separate compensation networks and ensures matched transient response across both phases.
Can the MAX42408AFOB+T operate with an input voltage lower than 4.5V?
No, the MAX42408AFOB+T has a guaranteed operating input range of 4.5V to 36V. Below 4.5V, the internal UVLO circuit disables the device - SUP undervoltage lockout triggers at 2.9V rising threshold, but functional operation requires ≥4.5V to ensure proper gate drive, BIAS regulation, and current-limit accuracy. For sub-4.5V inputs, consider the MAX42405/MAX42406 family.
How does the SYNC pin affect efficiency and EMI performance of the MAX42408AFOB+T?
The SYNC pin directly controls operating mode: tied low enables skip mode (10μA IQ, best light-load efficiency); tied high enables forced PWM (lowest output ripple, predictable EMI spectrum); driven by external clock enables synchronized switching (reduces beat frequencies in multi-rail systems). Skip mode increases spectral noise spread but lowers average power; PWM mode concentrates energy at 1.5MHz ±12.5%, simplifying EMI filter design.
MAX42408AFOB+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 17-PowerWFQFN
- 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):
- 4.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 6V
- Current - Output:
- 8A
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 17-FC2QFN (3.5x3.75)
MAX42408AFOB+T FAQ
1.How can I place an order for MAX42408AFOB+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX42408AFOB+T 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 MAX42408AFOB+T reliable?
The price and inventory of MAX42408AFOB+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX42408AFOB+T is usually 5 days.
3.What payment methods are accepted for MAX42408AFOB+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX42408AFOB+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX42408AFOB+T?
MAX42408AFOB+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX42408AFOB+T 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 MAX42408AFOB+T?
For technical support, including MAX42408AFOB+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX42408AFOB+T requirements.
6.How does Aetrix verify that MAX42408AFOB+T is sourced from the original manufacturer or authorized distributors?
All MAX42408AFOB+T 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 MAX42408AFOB+T meets industry standards.
7.What is the process for return or replacement of MAX42408AFOB+T?
All MAX42408AFOB+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX42408AFOB+T, 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 MAX42408AFOB+T part is unused and in its original packaging.
Return procedure for MAX42408AFOB+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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