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Analog Devices Inc./Maxim Integrated MAX1904ETJ+
- Part No.:
- MAX1904ETJ+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
MAX1904ETJ+.pdf
- Description:
- IC REG CTRLR NOTEBK 2OUT 32TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,589
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Product details
Overview
MAX1904ETJ+ from Maxim Integrated is a dual-output, buck-topology, fixed-frequency PWM power-supply controller for notebook and subnotebook computers. It delivers independently regulated 3.3V and 5V outputs (adjustable or fixed), supports secondary feedback via SECFB pin, integrates 1A gate drivers, and operates from 4.2V to 30V input with up to 97% efficiency in synchronous rectification mode.
For engineers reviewing the MAX1904ETJ+ datasheet, MAX1904ETJ+ pinout, MAX1904ETJ+ application, or MAX1904ETJ+ equivalent, this page provides verified technical context, confirmed pin functions, real-world sequencing behavior, secondary feedback configuration details, and validated alternative options for multi-rail battery-powered DC-DC designs.
Technical Context
The MAX1904ETJ+ implements two independent BiCMOS PWM controllers with Dual Mode™ feedback-supporting both fixed (3.3V/5V) and adjustable (2.5V–5.5V) output configurations. Each channel features current-mode control, programmable soft-start (512 clock cycles), and Idle Mode™ pulse-skipping at light load.
It includes dedicated high-side (DH3/DH5) and low-side (DL3/DL5) gate drivers capable of 1A sink/source, BST3/BST5 bootstrap circuits for N-channel MOSFETs, and a configurable secondary feedback path (SECFB + STEER) enabling auxiliary voltage regulation from a flyback winding-distinct from the MAX1902's integrated 12V linear regulator.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 30V - supports wide battery input including Li-ion stacks and industrial 24V rails. |
| Output Voltages | 3.3V & 5V fixed modes; adjustable 2.5V–5.5V - selectable per channel via FB3/FB5 grounding or resistor dividers. |
| Oscillator Frequency | 500kHz (SYNC = VL) or 333kHz (SYNC = GND) - fixed-frequency operation reduces EMI in mobile comms. |
| Gate Drive Capability | 1A sink/source per driver (DH3/DH5/DL3/DL5) - enables fast switching of external N-MOSFETs up to 6A load. |
| Secondary Feedback | SECFB input with 2.44V–2.60V regulation threshold - allows precise auxiliary voltage tuning using external resistor divider. |
| Quiescent Power | 2.5mW typical (12V input, both SMPS on) - extends battery life in suspend/standby states. |
| Shutdown Current | 4µA typical - ensures ultra-low leakage during system sleep. |
Pinout & Package
MAX1904ETJ+ uses a 32-pin Thin QFN package (5mm × 5mm, 0.5mm pitch), thermally enhanced with exposed pad (EP). Pin numbering follows standard QFN layout; EP must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CSH3 / CSL3 | 3.3V SMPS current-sense inputs | CSH3–CSL3 = 100mV current-limit threshold; CSL3 doubles as fixed-mode feedback node. |
| FB3 | 3.3V SMPS feedback input | Regulates at REF (~2.5V) in adjustable mode; grounded for fixed 3.3V output. |
| STEER | Secondary feedback selector | GND → 3.3V SMPS receives SECFB; VL → 5V SMPS receives SECFB. |
| SECFB | Secondary winding feedback input | Regulates auxiliary flyback output at 2.5V reference; connect to VL if unused. |
| DH3 / DL3 / LX3 / BST3 | 3.3V SMPS gate-drive & switching nodes | DH3 drives high-side N-MOSFET; DL3 drives low-side sync rectifier; LX3 is switch-node; BST3 powers DH3 bootstrap. |
| DH5 / DL5 / LX5 / BST5 | 5V SMPS gate-drive & switching nodes | Identical function to 3.3V channel, independent timing and regulation. |
| SEQ | Power-up sequence strap | GND → 5V before 3.3V; VL → 3.3V before 5V; REF → independent ON3/ON5 control. |
| RESET | Active-low timed reset output | Asserts low for 32,000 oscillator cycles after valid output regulation - ensures clean system boot. |
Key Features
| Feature | Design Value |
|---|---|
| Dual Mode™ Output Configuration | Each SMPS supports either fixed (3.3V/5V) or adjustable (2.5V–5.5V) output without external components beyond resistive dividers. |
| Programmable Power-Up Sequencing | Three SEQ strap options define startup order (3.3V-first, 5V-first, or independent) and RESET assertion logic - eliminates need for external sequencers. |
| Secondary Feedback Flexibility | SECFB + STEER pins enable transformer-coupled auxiliary regulation (e.g., 12V, ±15V) without dedicated linear regulator - saves board space vs. MAX1902. |
| Low-Noise Fixed-Frequency PWM | 500kHz operation (SYNC = VL) minimizes RF interference in pen-entry and wireless subsystems - avoids variable-frequency noise spread. |
| High-Efficiency Idle Mode™ | Automatic pulse-skipping below ~100mA load maintains >80% efficiency across 1000:1 current range - critical for battery standby longevity. |
Applications
| Mobile Computing Power Rail | Notebook CPU Core Supply |
|---|---|
|
Use Scenario: Dual-rail power for Intel Pentium M or AMD Mobile Athlon processors requiring tightly sequenced 3.3V I/O and 5V peripheral rails. IC Role / Device Role / Timing Role: Primary multi-output controller managing independent enable timing, fault monitoring, and RESET generation. Use Value: Eliminates discrete sequencing ICs and external voltage monitors - reduces BOM count by ≥4 components. |
Use Scenario: Local DC-DC conversion near CPU socket for core logic supply, where low-noise and fast transient response are mandatory. IC Role / Device Role / Timing Role: High-bandwidth PWM controller with five-cycle load transient correction and synchronous rectification. Use Value: Maintains ±1% output regulation during 1A–5A load steps - prevents CPU brownouts during burst activity. |
| Subnotebook System Power | PDAs with Auxiliary Flyback Rails |
|
Use Scenario: Compact 3.3V/5V generation in subnotebooks with strict height constraints and thermal limits. IC Role / Device Role / Timing Role: Thermally optimized QFN controller delivering 97% peak efficiency at 4A load with minimal heatsinking. Use Value: Enables 5mm × 5mm footprint for full dual-output capability - reduces PCB area by 35% vs. SSOP alternatives. |
Use Scenario: PDA with main 3.3V/5V rails plus isolated 12V for backlight or RS-232 transceiver. IC Role / Device Role / Timing Role: SECFB-regulated flyback controller using transformer-coupled winding - no extra LDO required. Use Value: Achieves ±3% auxiliary voltage accuracy over line/load/temperature - replaces discrete 12V LDO and feedback optocoupler. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-output buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1901ETJ+ | Identical pinout, package, and feature set; differs only in SEQ/RESET logic mapping (SEQ = VL → 3.3V-first, RESET tied to both outputs). | No functional difference in dual-rail notebook use; same SECFB/STEER operation and efficiency profile. | Select MAX1901ETJ+ when 3.3V-first sequencing with joint RESET is required; otherwise MAX1904ETJ+ offers identical performance. |
| RT8205AZSP | Single 5V/3.3V dual-output controller with integrated MOSFETs; no SECFB, no STEER, lower gate drive (0.8A), 600kHz fixed frequency. | Lacks secondary feedback capability and independent channel control - unsuitable for flyback-auxiliary or asymmetric sequencing. | Choose RT8205AZSP only for cost-sensitive, space-constrained designs where auxiliary rails and flexible sequencing are unnecessary. |
Compared with MAX1901ETJ+, MAX1904ETJ+ provides identical hardware functionality but guarantees 3.3V-first sequencing with joint RESET assertion; versus RT8205AZSP, MAX1904ETJ+ trades integrated FETs for design flexibility, higher drive strength, and SECFB-based auxiliary regulation - essential for systems requiring isolated or adjustable auxiliary voltages.
Availability
MAX1904ETJ+ is available at Aetrix Electronics and suitable for notebook computers, subnotebook power management, and portable industrial controllers requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX1904ETJ+ 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) designs high-performance analog and mixed-signal ICs for power, interface, sensing, and RF applications - with emphasis on energy efficiency and integration for portable electronics.
The MAX190x family targets battery-powered computing platforms, delivering multi-rail, low-quiescent-power DC-DC control with built-in sequencing, protection, and noise-reduction features - specifically engineered for notebook/subnotebook power architecture.
FAQ
What is the function of the STEER pin on the MAX1904ETJ+?
The STEER pin on the MAX1904ETJ+ selects which PWM channel (3.3V or 5V) receives the secondary feedback signal from the SECFB pin. When STEER = GND, the 3.3V SMPS uses SECFB for regulation; when STEER = VL, the 5V SMPS uses SECFB. This enables flexible auxiliary voltage derivation from either output winding without hardware changes.
Does the MAX1904ETJ+ include overvoltage or undervoltage protection?
No - unlike the MAX1901/MAX1902, the MAX1904ETJ+ omits output overvoltage and undervoltage protection circuitry. Its datasheet confirms these features are present only in MAX1901/MAX1902. Designers must implement external monitoring or rely on downstream load protection for fault safety.
Can the MAX1904ETJ+ generate a 12V output?
Yes - the MAX1904ETJ+ supports 12V (or other auxiliary voltages) via its SECFB pin and an external flyback winding. By connecting SECFB to a resistor divider from a coupled inductor, the device regulates the auxiliary output at 2.5V reference level - enabling precise 12V, ±15V, or custom voltages without adding a separate linear regulator.
What is the purpose of the TIME/ON5 pin on the MAX1904ETJ+?
The TIME/ON5 pin on the MAX1904ETJ+ serves dual roles: as a timing capacitor connection for power-up delay (when SEQ = REF), and as an ON/OFF control input for the 5V SMPS. When used as ON5, it accepts logic-level signals to enable/disable the 5V output independently - supporting dynamic rail management in advanced power architectures.
How does the MAX1904ETJ+ achieve 97% efficiency?
The MAX1904ETJ+ achieves 97% peak efficiency through synchronous rectification (using external N-MOSFETs driven by 1A gate drivers) and Maxim's Idle Mode™ control scheme, which reduces switching losses at light loads. Efficiency remains above 80% across a 1000:1 load-current range - directly extending battery runtime in suspend and active modes.
MAX1904ETJ+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- 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)
MAX1904ETJ+ FAQ
1.How can I place an order for MAX1904ETJ+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1904ETJ+ 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 MAX1904ETJ+ reliable?
The price and inventory of MAX1904ETJ+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1904ETJ+ is usually 5 days.
3.What payment methods are accepted for MAX1904ETJ+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1904ETJ+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1904ETJ+?
MAX1904ETJ+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1904ETJ+ 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 MAX1904ETJ+?
For technical support, including MAX1904ETJ+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1904ETJ+ requirements.
6.How does Aetrix verify that MAX1904ETJ+ is sourced from the original manufacturer or authorized distributors?
All MAX1904ETJ+ 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 MAX1904ETJ+ meets industry standards.
7.What is the process for return or replacement of MAX1904ETJ+?
All MAX1904ETJ+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1904ETJ+, 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 MAX1904ETJ+ part is unused and in its original packaging.
Return procedure for MAX1904ETJ+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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