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Analog Devices Inc./Maxim Integrated MAX1901ETJ+
- Part No.:
- MAX1901ETJ+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
MAX1901ETJ+.pdf
- Description:
- IC REG CTRLR NOTEBK 2OUT 32TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,045
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Product details
Overview
MAX1901ETJ+ from Maxim Integrated is a dual-output, buck-topology, synchronous PWM power-supply controller for battery-powered systems. It delivers adjustable 3.3V and 5V logic supplies (2.5V–5.5V range), supports 4.2V–30V input, achieves up to 97% efficiency via Idle Mode™ and synchronous rectification, and integrates 1A gate drivers, programmable sequencing, and power-good signaling - used in notebook subnotebook DC-DC conversion.
For engineers reviewing the MAX1901ETJ+ datasheet, MAX1901ETJ+ pinout, MAX1901ETJ+ application, or MAX1901ETJ+ equivalent, key selection criteria include dual adjustable/fixed output modes, secondary feedback control (SECFB/STEER), 500kHz fixed-frequency PWM with SKIP pin noise reduction, overvoltage/undervoltage protection, and QFN-32 thermal performance for compact portable power designs.
Technical Context
The MAX1901ETJ+ implements two independent BiCMOS PWM controllers with Dual Mode™ feedback-each configurable as fixed (3.3V/5V) or adjustable via external resistor dividers referenced to its 2.5V internal REF. It uses synchronous N-channel MOSFET drive (DH3/DL3, DH5/DL5) with bootstrap circuits (BST3/BST5) and supports secondary winding regulation via SECFB input and STEER-selectable transformer coupling.
Its control architecture includes digital soft-start (512 clock cycles), programmable power-up sequencing (SEQ strap), timed RESET output (32,000-cycle delay), and fault detection with 4–10% overvoltage trip and 60–80% undervoltage lockout thresholds. Idle Mode™ enables pulse-skipping below threshold load current (10–40mV), while SKIP pin forces fixed-frequency operation for EMI-sensitive applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 30V - supports wide battery input including 3-cell Li-ion (12.6V) and 4-cell (16.8V) packs with headroom for transients. |
| Output Voltage Options | 3.3V/5V fixed mode or 2.5V–5.5V adjustable mode per channel - enables flexible logic rail generation without external DACs. |
| Oscillator Frequency | 500kHz (SYNC = VL) or 333kHz (SYNC = GND); externally synchronizable 400–583kHz - reduces EMI and allows system-level clock alignment. |
| Gate Drive Capability | 1A sink/source per driver (DH3/DL3/DH5/DL5); 1.5Ω typical on-resistance (QFN package) - drives low-Rds(on) MOSFETs for high-efficiency switching at 6A loads. |
| Efficiency Performance | Up to 97% peak; >80% across 1000:1 load range - extends battery life in suspend/standby by minimizing quiescent loss (4µA shutdown current). |
| Protection Features | Output overvoltage (4–10% trip), undervoltage lockout (60–80% of nominal), thermal shutdown (150°C) - ensures safe operation during fault conditions without external circuitry. |
| Reference Accuracy | 2.45V–2.55V REF output (±2%); 12.5mV load regulation (0–50µA) - provides stable feedback reference for precision output regulation. |
Pinout & Package
MAX1901ETJ+ is housed in a 32-pin Thin QFN package (5mm × 5mm, 0.5mm pitch), thermally enhanced with exposed pad for PCB heat sinking. The package supports high-density portable layouts and meets JEDEC MO-220 standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CSH3 / CSL3 | 3.3V SMPS current-sense pair | 100mV current-limit threshold; CSL3 doubles as fixed-mode feedback node - enables accurate cycle-by-cycle current limiting and mode selection. |
| FB3 / FB5 | Dual-mode feedback inputs | Connect to GND for fixed 3.3V/5V; connect to resistor divider for adjustable output - simplifies design reuse across voltage variants. |
| STEER / SECFB | Secondary feedback selector & input | STEER selects which SMPS receives SECFB signal; SECFB regulates auxiliary flyback outputs at 2.44–2.60V - enables quasi-regulated 12V or custom auxiliary rails. |
| DH3 / DH5 / DL3 / DL5 | High-side & low-side gate drivers | Floating high-side drivers (DH3/DH5) ride on LX nodes; low-side drivers (DL3/DL5) swing 0–VL - supports synchronous rectification without external drivers. |
| SEQ / SKIP / RUN/ON3 / TIME/ON5 | Sequencing & control logic inputs | SEQ sets startup order (3.3V-first/5V-first/separate ON); SKIP disables Idle Mode; RUN/ON3 enables 3.3V SMPS - enables robust system-level power management. |
| RESET / REF / VL / V+ | Power-good, reference, bias, and input rails | RESET is active-low with 32k-cycle delay; REF = 2.5V ±2%; VL = 5V internal LDO (50mA); V+ = main 4.2–30V supply - integrates essential support functions in one IC. |
Key Features
| Feature | Design Value |
|---|---|
| Dual Mode™ Output Configuration | Single pin (FBx) selects fixed 3.3V/5V or adjustable 2.5–5.5V output - eliminates BOM variants and simplifies firmware-independent hardware configuration. |
| Idle Mode™ Pulse-Skipping Control | Reduces switching losses at light load by skipping cycles below ~10–40mV current-sense threshold - maintains >80% efficiency down to µA-level loads. |
| Programmable Power-Up Sequencing | SEQ pin strapping defines 3.3V-before-5V, 5V-before-3.3V, or independent ON/OFF control - prevents bus contention and meets Intel VRD/CPU power sequencing requirements. |
| Integrated 1A Gate Drivers | Low on-resistance (≤8Ω QFN) and fast slew enable direct drive of <20nC gate charge MOSFETs - eliminates external drivers and reduces layout complexity. |
| Secondary Feedback Flexibility | SECFB + STEER pins allow selectable transformer-coupled regulation for auxiliary outputs - supports cost-effective multi-rail flyback topologies without dedicated controllers. |
Applications
| Notebook CPU Core Logic Supply | Subnotebook I/O Rail Generation |
|---|---|
Use Scenario: Generating tightly regulated 3.3V and 5V rails for CPU core logic, chipset, and memory interfaces in ultra-thin notebooks with 3–4 cell Li-ion batteries. IC Role / Device Role / Timing Role: Dual-output synchronous buck controller providing sequenced, low-noise, high-efficiency DC-DC conversion with integrated power-good signaling and fault protection. Use Value: Enables 97% peak efficiency and <4µA shutdown current to maximize runtime; 500kHz fixed-frequency operation minimizes EMI near RF sections and touchscreens. |
Use Scenario: Powering display interface (LVDS/TTL), USB PHY, and card reader in subnotebooks where board space and thermal density are constrained. IC Role / Device Role / Timing Role: Compact dual-buck controller delivering independently controllable 3.3V/5V rails with programmable ON/OFF timing and soft-start ramp control. Use Value: Reduces component count vs. discrete solutions; integrated 1A drivers eliminate external FET drivers; QFN-32 footprint fits tight 8mm × 8mm power module zones. |
| Mobile Communicator Baseband Power | Embedded Industrial Controller Local DC-DC |
Use Scenario: Supplying clean, low-noise 3.3V and 5V rails to baseband processors and analog front-ends in PDAs and mobile communicators operating from 7.2–12.6V battery packs. IC Role / Device Role / Timing Role: Low-EMI PWM controller with SKIP pin enabling fixed-frequency mode during RF transmission to avoid spectral interference with cellular bands. Use Value: Achieves >80% efficiency across 1000:1 load range - sustains long standby time; 333/500kHz selectable frequency avoids harmonics in sensitive 800MHz–2.4GHz bands. |
Use Scenario: Providing isolated, sequenced logic supplies in fanless industrial controllers using wide-input 12–24V DC power with strict thermal limits. IC Role / Device Role / Timing Role: Robust dual-output controller with overvoltage/undervoltage protection, thermal shutdown, and 150°C trip point - suited for unattended operation in harsh environments. Use Value: Eliminates need for external supervisors; integrated REF and VL reduce external components; QFN thermal pad improves reliability under continuous 1.7W dissipation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1904ETJ+ | Identical pinout, package, and feature set; differs only in internal sequencing logic - SEQ = VL forces 3.3V-first startup, no separate ON3/ON5 control. | Best for designs requiring fixed 3.3V-before-5V sequencing without software intervention; lacks independent RUN/ON3 control of MAX1901ETJ+. | Select MAX1901ETJ+ when independent 3.3V/5V enable control or SEQ = REF (separate ON3/ON5) is required. |
| TPS51116PWR | TI dual-output controller with integrated MOSFET drivers; 5–24V input; fixed 3.3V/5V only; no adjustable mode or SECFB/STEER functionality. | Suitable for cost-sensitive notebooks without auxiliary flyback needs; lacks secondary feedback flexibility and Dual Mode™ adjustability. | Choose MAX1901ETJ+ when adjustable outputs, transformer-coupled auxiliary rails, or precise sequencing control are mandatory. |
Compared with MAX1904ETJ+, MAX1901ETJ+ offers independent RUN/ON3 control and SEQ = REF mode for flexible sequencing; versus TPS51116PWR, it adds SECFB-based flyback regulation and 2.5–5.5V adjustability - critical for custom auxiliary rail generation and design reuse across voltage variants.
Availability
MAX1901ETJ+ is available at Aetrix Electronics and suitable for notebook computers, subnotebook I/O subsystems, and mobile communicator baseband power supplies requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX1901ETJ+ 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
Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for portable, industrial, and communications applications.
The MAX1901ETJ+ belongs to Maxim's notebook power-controller product line, designed specifically for high-efficiency, low-noise, multi-rail DC-DC conversion in space-constrained battery-powered systems with stringent EMI and thermal requirements.
FAQ
What is the function of the STEER pin on the MAX1901ETJ+?
The STEER pin on the MAX1901ETJ+ selects which PWM output (3.3V or 5V) receives the secondary feedback signal from the SECFB pin. When STEER = GND, the 3.3V SMPS uses transformer-coupled regulation; when STEER = VL, the 5V SMPS uses it. This enables flexible auxiliary voltage generation without redesigning the feedback network - a key capability distinguishing MAX1901ETJ+ from single-feedback controllers.
Does the MAX1901ETJ+ support both fixed and adjustable output voltages on the same device?
Yes, the MAX1901ETJ+ supports Dual Mode™ operation on both outputs: connecting FB3 or FB5 to GND configures fixed 3.3V or 5V output, while connecting them to a resistor divider referencing the 2.5V REF enables adjustable 2.5V–5.5V output. This eliminates the need for multiple SKUs and simplifies design across varying system voltage requirements - a verified capability confirmed in the MAX1901ETJ+ datasheet's Electrical Characteristics table.
What is the purpose of the SKIP pin on the MAX1901ETJ+?
The SKIP pin on the MAX1901ETJ+ disables Idle Mode™ pulse-skipping when driven high, forcing fixed-frequency PWM operation at 333kHz or 500kHz. This reduces conducted and radiated EMI in noise-sensitive applications like pen-entry tablets or RF modules - a documented feature used to meet FCC Class B emissions limits without additional filtering components.
How does the MAX1901ETJ+ handle power-up sequencing between its 3.3V and 5V outputs?
The MAX1901ETJ+ uses the SEQ pin to configure power-up order: SEQ = GND sequences 5V before 3.3V; SEQ = VL sequences 3.3V before 5V; SEQ = REF enables independent RUN/ON3 and TIME/ON5 controls. This hardware-strapped sequencing meets Intel VRD and mobile platform requirements without firmware dependency - confirmed in the Pin Description and Functional Diagram sections of the MAX1901ETJ+ datasheet.
What protection features are integrated into the MAX1901ETJ+?
The MAX1901ETJ+ integrates output overvoltage protection (trip at 4–10% above nominal), output undervoltage lockout (60–80% of nominal), thermal shutdown (150°C), and current-limit sensing (100mV threshold). These protections operate autonomously without external components - verified in the Fault Detection section of the MAX1901ETJ+ datasheet and applied identically across all operating conditions.
MAX1901ETJ+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Applications:
- Controller, Notebook Power System
- Voltage - Input:
- 4.2V ~ 30V
- Number of Outputs:
- 2
- Voltage - Output:
- 2.5V ~ 5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-TQFN (5x5)
MAX1901ETJ+ FAQ
1.How can I place an order for MAX1901ETJ+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1901ETJ+ 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 MAX1901ETJ+ reliable?
The price and inventory of MAX1901ETJ+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1901ETJ+ is usually 5 days.
3.What payment methods are accepted for MAX1901ETJ+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1901ETJ+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1901ETJ+?
MAX1901ETJ+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1901ETJ+ 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 MAX1901ETJ+?
For technical support, including MAX1901ETJ+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1901ETJ+ requirements.
6.How does Aetrix verify that MAX1901ETJ+ is sourced from the original manufacturer or authorized distributors?
All MAX1901ETJ+ 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 MAX1901ETJ+ meets industry standards.
7.What is the process for return or replacement of MAX1901ETJ+?
All MAX1901ETJ+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1901ETJ+, 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 MAX1901ETJ+ part is unused and in its original packaging.
Return procedure for MAX1901ETJ+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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