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Analog Devices Inc./Maxim Integrated MAX42405AFOB+
- Part No.:
- MAX42405AFOB+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 17-PowerWFQFN
- Datasheet:
-
MAX42405AFOB+.pdf
- Description:
- IC REG BUCK ADJ 6A 17FC2QFN
- Quantity:
- Payment:
- Shipping:
Inventory:687
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Product details
Overview
MAX42405AFOB+ from Analog Devices is a fully integrated 36V, 5A synchronous buck converter with internal high-side and low-side MOSFETs, fixed 400kHz switching frequency, programmable 0.8V–12V output voltage, and PGOOD monitoring - designed for industrial point-of-load regulation in space-constrained 24V/36V systems.
For engineers reviewing the MAX42405AFOB+ datasheet, MAX42405AFOB+ pinout, MAX42405AFOB+ application, or MAX42405AFOB+ equivalent, key selection criteria include dropout operation at >96% duty cycle, 20μA no-load quiescent current in skip mode, FC2QFN thermal performance, dual-phase current-sharing via VEA, and 17-pin symmetrical layout for EMI control.
Technical Context
The MAX42405AFOB+ implements average current-mode control with internal slope compensation, enabling stable operation across wide input (4.5V–36V) and output (0.8V–12V) ranges while rejecting noise on the current-sense path. Its 36ns minimum on-time supports high step-down ratios without cycle skipping.
It integrates a 1.8V BIAS linear regulator with automatic switchover from SUP to OUT, a 2.5ms internal soft-start, and hiccup-mode short-circuit protection triggered when VOUT drops below 25% of target during current limit. Thermal shutdown activates at 175°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 36V - supports direct connection to 24V industrial rails and 36V battery systems without pre-regulation. |
| Output Current | 5A continuous - rated for sustained load delivery with thermal derating per θJA = 38.41°C/W on JEDEC board. |
| Switching Frequency | Fixed 400kHz - enables compact external components (e.g., 3.3µH inductor, 3×47µF output caps) and reduced output ripple. |
| Quiescent Current | 20μA in skip mode - extends battery life in always-on industrial sensors and remote I/O modules. |
| Feedback Accuracy | ±1.6% (0.787V–0.813V) - ensures tight output regulation across temperature and line/load conditions. |
| High-Side RDS(on) | 46mΩ typical - minimizes conduction loss at 5A, contributing to >92% peak efficiency at 12VIN/3.3VOUT. |
| Duty Cycle Max | 96% - enables operation in dropout (e.g., 36VIN → 34.5VOUT) with minimal voltage headroom. |
Pinout & Package
MAX42405AFOB+ is housed in a 3.5mm × 3.75mm, 17-pin flip-chip quad flat no-lead (FC2QFN) package with symmetrical VIN/PGND layout optimized for EMI suppression and thermal dissipation (θJC = 10.35°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN | Enable input | High-voltage-compatible logic input; pulls device into 4μA shutdown when low. |
| 2 BST | Bootstrap supply | Connects 0.1µF capacitor between BST and LX to drive high-side FET gate above SUP. |
| 3,9 SUP | Main power input | Dual pins reduce IR drop and improve EMI; requires parallel 1µF + 4.7µF ceramic input capacitors. |
| 4,5,7,8 PGND | Power ground | Four dedicated low-impedance ground returns for high-current LX switching node paths. |
| 6 LX | Switch node | Connection to inductor; carries full AC switching current; must be minimized in loop area. |
| 10 GND | Analog ground | Separate AGND reference for feedback and error amplifier; tied to PGND at single point. |
| 11 BIAS | Internal 1.8V LDO output | Powers internal circuitry; requires ≥2.2µF ceramic cap to PGND for stability. |
| 12 FB | Voltage feedback input | Senses resistor-divider ratio; leakage <100nA preserves accuracy at high divider impedances. |
| 13 OUT | Output voltage sense | Direct connection to regulated rail; used with FB to close voltage control loop. |
| 14 VEA | Error amplifier output/input | Controller: EA output; Target: EA input - enables precise dynamic current sharing in dual-phase setups. |
| 15 PGOOD | Open-drain power-good | Active-low signal indicating VOUT within ±4% of target; requires external pull-up. |
| 16 SYNC | Mode selection | Tied to GND = skip mode; tied to BIAS = forced PWM; also accepts external clock for synchronization. |
| 17 SYNCOUT | 180° out-of-phase clock | Drives second phase in dual-phase configuration; inactive in skip mode. |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Enables robust noise immunity in electrically noisy industrial environments without external compensation. |
| Symmetrical FC2QFN pinout | Reduces common-mode EMI by balancing high-di/dt PGND return paths across package centerline. |
| Dual-phase current sharing | VEA pin coupling achieves <±3% current mismatch between phases under transient load steps. |
| Ultra-low IQ skip mode | 20μA no-load consumption enables multi-year battery operation in wireless sensor nodes. |
| Integrated 1.8V BIAS regulator | Eliminates need for external bias supply; auto-switches from SUP to OUT after startup if VOUT > 2.5V. |
| Hiccup-mode short-circuit protection | Disables output for 25ms (400kHz) or 35ms (1.5MHz), then retries - prevents thermal runaway during sustained faults. |
Applications
| Industrial PLC I/O Modules | Factory Automation Sensors |
|---|---|
Use Scenario: Powering isolated analog input/output channels in DIN-rail mounted programmable logic controllers operating from 24V DC bus. IC Role / Device Role / Timing Role: Primary 5A buck regulator delivering stable 3.3V/5V to ADCs, DACs, and digital isolators. Use Value: 96% max duty cycle maintains regulation during brownout events on aging 24V supplies; PGOOD enables system-level fault logging. | Use Scenario: Compact, sealed environmental sensors deployed on production lines requiring long-life operation from 3.6V LiSOCl₂ batteries. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter supplying 1.8V to ultra-low-power microcontrollers and MEMS transducers. Use Value: 20μA skip-mode IQ extends operational lifetime beyond 10 years; FC2QFN footprint fits sub-100mm² PCB area constraints. |
| Ruggedized Motor Drive Boards | Distributed Power Architectures |
Use Scenario: Auxiliary power supply on servo drive boards where EMI from high-current motor switching must not disrupt control logic. IC Role / Device Role / Timing Role: Noise-immune 5A buck stage powering FPGA configuration, gate drivers, and position feedback ICs. Use Value: Symmetrical FC2QFN layout and average current-mode control suppress conducted EMI by >10dB vs. peak-mode alternatives. | Use Scenario: Scalable 12A power rail generated from two synchronized MAX42405AFOB+ devices in dual-phase configuration on modular industrial compute cards. IC Role / Device Role / Timing Role: One device as controller, one as target, sharing VEA for precise current balance across phases. Use Value: Dual-phase operation delivers 12A with <±2% current mismatch and 30% lower output ripple vs. single-phase 5A solution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX42406AFOB+ | Higher 7.5A–10A current limit; identical pinout, package, and feature set. | Required for designs needing >5A continuous output with same layout and control interface. | Select MAX42406AFOB+ when peak load exceeds 5A but thermal margin allows higher ILIM threshold. |
| LM61480RQR | 4.5V–36V input, 8A, 2.1MHz fixed frequency, different pinout (16-pin QFN), no VEA dual-phase support. | Used where higher switching frequency reduces inductor size but dual-phase coordination is unnecessary. | Choose LM61480RQR only if board redesign is acceptable and dual-phase operation is not required. |
Compared with MAX42406AFOB+, the MAX42405AFOB+ offers tighter current-limit threshold (6.5A–8.5A) for improved overcurrent safety margin at 5A loads; versus LM61480RQR, it provides native dual-phase capability and superior EMI performance via symmetrical FC2QFN layout - critical for industrial noise-sensitive applications.
Availability
MAX42405AFOB+ is available at Aetrix Electronics and suitable for industrial automation, point-of-load regulation, and distributed DC power systems requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for MAX42405AFOB+ 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 MAX42405/MAX42406 family was engineered specifically for rugged, space-constrained industrial power conversion - emphasizing EMI resilience, wide-input operation, and seamless dual-phase scalability without external controllers.
FAQ
What is the maximum output voltage supported by the MAX42405AFOB+?
The MAX42405AFOB+ supports an adjustable output voltage range of 0.8V to 12V when configured for 400kHz operation. This range is defined by the internal 0.8V feedback reference and the external resistor-divider network connected between OUT, FB, and GND. The upper limit is constrained by the 400kHz frequency option - the 1.5MHz variant limits output to 10V.
Does the MAX42405AFOB+ require an external bootstrap capacitor?
Yes, the MAX42405AFOB+ requires a 0.1µF ceramic capacitor connected between the BST and LX pins to properly drive the high-side MOSFET gate. This capacitor must be placed as close as possible to the IC with low-inductance traces; failure to install it results in insufficient gate drive and converter malfunction.
Can the MAX42405AFOB+ operate in dropout mode, and what is its maximum duty cycle?
Yes, the MAX42405AFOB+ supports dropout operation with a maximum duty cycle of 96%. This allows regulation even when input voltage approaches the output voltage - for example, maintaining 12V output from a sagging 12.5V supply - by extending the high-side switch on-time to near-continuous conduction.
How does the MAX42405AFOB+ achieve dual-phase current sharing?
The MAX42405AFOB+ achieves precise dual-phase current sharing through its VEA pin: in controller-target configuration, the controller's VEA (voltage error amplifier output) connects directly to the target's VEA (current error amplifier input), forcing both phases to regulate to the same voltage loop setpoint and dynamically balance current within ±3% under load transients.
What thermal protection features are built into the MAX42405AFOB+?
The MAX42405AFOB+ includes thermal shutdown that disables the converter when junction temperature exceeds 175°C, with 20°C hysteresis to prevent oscillation. It also features overtemperature derating support via its thermal resistance specs: θJA = 38.41°C/W on JEDEC board and 29°C/W on four-layer EV kit, enabling accurate thermal design for industrial ambient conditions up to +125°C.
MAX42405AFOB+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 17-PowerWFQFN
- Packaging:
- Tray
- 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):
- 10V
- Current - Output:
- 6A
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 17-FC2QFN (3.5x3.75)
MAX42405AFOB+ FAQ
1.How can I place an order for MAX42405AFOB+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX42405AFOB+ 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 MAX42405AFOB+ reliable?
The price and inventory of MAX42405AFOB+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX42405AFOB+ is usually 5 days.
3.What payment methods are accepted for MAX42405AFOB+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX42405AFOB+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX42405AFOB+?
MAX42405AFOB+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX42405AFOB+ 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 MAX42405AFOB+?
For technical support, including MAX42405AFOB+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX42405AFOB+ requirements.
6.How does Aetrix verify that MAX42405AFOB+ is sourced from the original manufacturer or authorized distributors?
All MAX42405AFOB+ 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 MAX42405AFOB+ meets industry standards.
7.What is the process for return or replacement of MAX42405AFOB+?
All MAX42405AFOB+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX42405AFOB+, 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 MAX42405AFOB+ part is unused and in its original packaging.
Return procedure for MAX42405AFOB+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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