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Analog Devices Inc./Maxim Integrated MAX1904ETJ+T
- Part No.:
- MAX1904ETJ+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
MAX1904ETJ+T.pdf
- Description:
- IC REG CTRLR NOTEBK 2OUT 32TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,799
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Product details
Overview
MAX1904ETJ+T from Maxim Integrated is a dual-output, buck-topology, synchronous PWM power-supply controller for notebook and subnotebook computers. It delivers independently adjustable 3.3V and 5V logic supplies from a 4.2V–30V input, features 500kHz fixed-frequency operation, integrated 1A gate drivers, and secondary feedback control via SECFB/STEER pins for auxiliary winding regulation. It enables high-efficiency (up to 97%) battery-powered DC-DC conversion with programmable power-up sequencing and power-good signaling.
For engineers reviewing the MAX1904ETJ+T datasheet, MAX1904ETJ+T pinout, MAX1904ETJ+T application, or MAX1904ETJ+T equivalent, key selection considerations include its dual adjustable/fixed output modes, 32-pin Thin QFN package with exposed thermal pad, secondary feedback flexibility, Idle Mode™ efficiency optimization, and compatibility with N-channel MOSFETs in synchronous buck topologies.
Technical Context
The MAX1904ETJ+T integrates two independent BiCMOS PWM controllers with Dual Mode™ feedback-supporting both fixed (3.3V/5V) and adjustable (2.5V–5.5V) outputs via FB3/FB5 and REF. Its oscillator operates at 500kHz when SYNC = VL, or 333kHz when SYNC = GND, and supports external synchronization from 400kHz to 583kHz.
It implements secondary feedback regulation using SECFB (threshold 2.44V–2.60V) and STEER to select which PWM channel (3.3V or 5V) receives transformer-coupled feedback-enabling quasi-regulated auxiliary voltages beyond fixed 12V. The device includes on-chip 1A gate drivers (DH3/DH5, DL3/DL5), internal frequency compensation, low-dropout operation up to 98% duty cycle, and digital soft-start with 512-clock ramp time.
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 rails. |
| Output Voltage Options | 3.3V/5V fixed mode or 2.5V–5.5V adjustable mode per channel - selectable via FBx grounding or resistor divider. |
| Oscillator Frequency | 500kHz (SYNC = VL) or 333kHz (SYNC = GND) - reduces EMI in noise-sensitive mobile applications. |
| SECFB Regulation Threshold | 2.44V to 2.60V - sets precision point for auxiliary flyback winding voltage regulation. |
| Gate Drive Capability | 1A sink/source per driver (DH3/DH5/DL3/DL5) - ensures fast switching of external N-channel MOSFETs. |
| Quiescent Power (both SMPS on) | 1.5mW to 4mW at 12V input - extends battery life during light-load suspend/standby states. |
| Shutdown Current | 4µA to 10µA - minimizes leakage during system off-state. |
Pinout & Package
MAX1904ETJ+T is housed in a 32-pin Thin QFN package (5mm × 5mm, 0.5mm pitch) with exposed thermal pad (EP) for enhanced thermal performance. Pin numbering follows standard QFN convention, with EP electrically connected to PGND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CSH3 / CSL3 | 3.3V SMPS current-sense inputs | CSH3–CSL3 = 100mV threshold triggers overcurrent shutdown; CSL3 doubles as fixed-mode feedback node. |
| FB3 | 3.3V SMPS feedback input | Regulates at ≈2.5V (REF); grounded for fixed 3.3V mode; resistor-divider for adjustable mode. |
| STEER | Secondary feedback selector | GND → 3.3V SMPS uses SECFB; VL → 5V SMPS uses SECFB - enables flexible auxiliary winding control. |
| SECFB | Secondary winding feedback input | Regulates auxiliary output at 2.44V–2.60V; connect to resistor divider from flyback winding. |
| DH3 / DH5 | High-side gate drivers | Floating outputs swinging LXx to BSTx; drive external N-MOS high-side switches in buck topology. |
| DL3 / DL5 | Low-side gate drivers | 0–VL referenced outputs; drive synchronous rectifier N-MOSFETs for high-efficiency conduction. |
| PGND | Power ground | Separate from analog GND; must be low-inductance connection to minimize switching noise coupling. |
| EP | Exposed thermal pad | Internally connected to PGND; requires soldered thermal land for reliable power dissipation (1702mW max). |
Key Features
| Feature | Design Value |
|---|---|
| Dual Mode™ Output Configuration | Each SMPS supports either fixed 3.3V/5V or adjustable 2.5V–5.5V output - simplifies design reuse across multiple voltage rail requirements. |
| Idle Mode™ Control | Variable-frequency pulse-skipping below ~100mA load - maintains >80% efficiency across 1000:1 load range without audible noise. |
| Programmable Power-Up Sequencing | SEQ pin selects 3.3V-first, 5V-first, or independent ON3/ON5 control - meets strict CPU/core logic boot timing requirements. |
| Secondary Feedback Flexibility | SECFB + STEER enable transformer-coupled regulation of non-standard auxiliary voltages - eliminates need for separate flyback controller IC. |
| Integrated 1A Gate Drivers | On-die drivers eliminate external driver ICs and reduce layout complexity - supports fast turn-on/turn-off of discrete N-MOSFETs. |
Applications
| Notebook Power Management | Subnotebook DC-DC Conversion |
|---|---|
|
Use Scenario: Main logic supply generation in ultra-thin notebooks with dual-core CPUs and DDR memory. IC Role / Device Role / Timing Role: Dual-output buck controller delivering synchronized 3.3V I/O and 5V core rails with precise power-up sequencing and RESET assertion. Use Value: Enables single-chip solution for multi-rail battery-powered systems, reducing BOM count and PCB area versus discrete controllers. |
Use Scenario: Compact portable computing devices requiring high-density, low-noise power conversion under tight thermal constraints. IC Role / Device Role / Timing Role: Primary power controller managing 3.3V/5V rails plus auxiliary winding feedback for USB or display bias supplies. Use Value: 500kHz fixed-frequency operation minimizes EMI in RF-sensitive pen-entry and cellular-integrated platforms. |
| Mobile Communicator Power System | Embedded Industrial Controller Supply |
|
Use Scenario: Power architecture for handheld PDAs with GSM/Wi-Fi radios and touch-screen interfaces. IC Role / Device Role / Timing Role: Synchronous buck controller providing regulated 3.3V (RF section) and 5V (processor) with low quiescent current in standby. Use Value: 4µA shutdown current and Idle Mode™ extend battery runtime during idle/suspend cycles without compromising transient response. |
Use Scenario: Ruggedized embedded controller in factory automation equipment requiring stable dual-rail supplies from wide-input industrial batteries. IC Role / Device Role / Timing Role: Robust power controller supporting 4.2V–30V input, overvoltage/undervoltage fault detection, and thermal shutdown protection. Use Value: Built-in OVP/UVP (on MAX1901/MAX1902 variants) and 150°C thermal shutdown ensure reliability in unattended industrial deployments. |
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 |
|---|---|---|---|
| MAX1901ETJ+T | Identical pinout, package, and feature set; differs only in internal configuration - lacks 12V linear regulator (MAX1902-specific) and shares same SECFB/STEER functionality. | Same dual-buck + secondary feedback use cases; suitable where no 12V LDO is required. | Select MAX1901ETJ+T if secondary feedback is needed but 12V LDO is unnecessary - identical layout and firmware compatibility. |
| TPS51116PWR | TI dual-output controller with integrated MOSFET drivers; supports 3.3V/5V outputs but no SECFB/STEER; uses different sequencing logic and lacks Idle Mode™. | Targeted at mainstream notebooks; not suited for auxiliary winding regulation or ultra-low-IQ standby. | Choose TPS51116PWR for cost-sensitive designs without flyback auxiliary needs and where TI ecosystem support is preferred. |
Compared with MAX1901ETJ+T, the MAX1904ETJ+T offers identical secondary feedback capability and package compatibility but is optimized for broader design reuse across MAX1901/MAX1904 families; versus TPS51116PWR, it provides unique SECFB-based auxiliary regulation and superior light-load efficiency via Idle Mode™.
Availability
MAX1904ETJ+T is available at Aetrix Electronics and suitable for notebook computers, subnotebook power systems, and mobile communicator DC-DC converters requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX1904ETJ+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
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for demanding applications in computing, communications, and industrial systems.
The MAX1901/MAX1902/MAX1904 product line was designed specifically for multi-rail, battery-powered computing platforms-delivering high efficiency, low noise, and flexible sequencing in minimal footprint packages.
FAQ
What is the function of the STEER pin on the MAX1904ETJ+T?
The STEER pin on the MAX1904ETJ+T selects which PWM channel (3.3V or 5V) receives secondary feedback via the SECFB input. When STEER = GND, the 3.3V SMPS uses SECFB; when STEER = VL, the 5V SMPS uses SECFB. This enables precise regulation of auxiliary voltages derived from transformer-coupled windings - a key capability distinguishing MAX1904ETJ+T from single-feedback controllers.
Does the MAX1904ETJ+T include overvoltage or undervoltage protection?
No, the MAX1904ETJ+T does not include output overvoltage or undervoltage protection circuitry. That feature is present only in the MAX1901 and MAX1902 variants (as noted in the datasheet's "FAULT DETECTION" section). The MAX1904ETJ+T shares the same pinout and core control architecture but omits those protection blocks - making it suitable for systems where external monitoring or simplified fault handling is acceptable.
What is the purpose of the SECFB pin on the MAX1904ETJ+T?
The SECFB (Secondary Feedback) pin on the MAX1904ETJ+T accepts a resistor-divider voltage from an auxiliary transformer winding to regulate non-standard output voltages (e.g., 7V, 9V, or 15V) with ±1.5% accuracy. It operates at a 2.44V–2.60V threshold and works in conjunction with the STEER pin to inject feedback into either the 3.3V or 5V PWM loop - enabling quasi-regulated flyback-derived rails without a dedicated controller.
Can the MAX1904ETJ+T operate with a 3.3V input supply?
No, the MAX1904ETJ+T requires a minimum input voltage of 4.2V as specified in its Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 4.2V violates the device's operational specification and may result in failure to start, unstable regulation, or undefined behavior - particularly because the internal VL regulator and gate-drive bootstrap circuits depend on sufficient headroom above output voltages.
How does the MAX1904ETJ+T achieve high efficiency at light loads?
The MAX1904ETJ+T achieves high light-load efficiency (≥80% across 1000:1 load range) through its proprietary Idle Mode™ - a variable-frequency pulse-skipping scheme that reduces switching and gate-charge losses when output current falls below ~100mA. Unlike forced-PWM controllers, MAX1904ETJ+T dynamically lowers frequency and skips pulses while maintaining regulation, significantly cutting quiescent power to 1.5–4mW under full operation.
MAX1904ETJ+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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+T FAQ
1.How can I place an order for MAX1904ETJ+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1904ETJ+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 MAX1904ETJ+T reliable?
The price and inventory of MAX1904ETJ+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1904ETJ+T is usually 5 days.
3.What payment methods are accepted for MAX1904ETJ+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1904ETJ+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1904ETJ+T?
MAX1904ETJ+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1904ETJ+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 MAX1904ETJ+T?
For technical support, including MAX1904ETJ+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1904ETJ+T requirements.
6.How does Aetrix verify that MAX1904ETJ+T is sourced from the original manufacturer or authorized distributors?
All MAX1904ETJ+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 MAX1904ETJ+T meets industry standards.
7.What is the process for return or replacement of MAX1904ETJ+T?
All MAX1904ETJ+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1904ETJ+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 MAX1904ETJ+T part is unused and in its original packaging.
Return procedure for MAX1904ETJ+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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