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Analog Devices Inc./Maxim Integrated MAX1904BEAI+T
- Part No.:
- MAX1904BEAI+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX1904BEAI+T.pdf
- Description:
- IC REG CTRLR NOTEBK 2OUT 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,618
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Product details
Overview
MAX1904BEAI+T 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/STEER for auxiliary winding regulation, integrates 1A gate drivers, and operates from 4.2V to 30V input with up to 97% efficiency and 500kHz switching.
For engineers reviewing the MAX1904BEAI+T datasheet, MAX1904BEAI+T pinout, MAX1904BEAI+T application, or MAX1904BEAI+T equivalent, this controller is selected for multi-rail battery-powered systems requiring precise power-up sequencing, low-noise operation, high light-load efficiency via Idle Mode™, and integrated fault protection including power-good signaling and overvoltage detection.
Technical Context
The MAX1904BEAI+T implements two independent BiCMOS PWM controllers with Dual Mode™ feedback-supporting both fixed (3.3V/5V) and adjustable output configurations via FB3/FB5 pins. Its synchronous rectification architecture uses strong 1A gate drivers (DH3/DL3, DH5/DL5) and bootstrap circuits (BST3/BST5) to drive external N-channel MOSFETs in high-efficiency buck converters.
It features programmable power-up sequencing (SEQ pin), digital soft-start (512 clock cycles), secondary feedback steering (STEER/SECFB), and fixed-frequency operation (500kHz when SYNC = VL). The device includes internal 2.5V reference (REF), 5V linear regulator (VL), and power-good (RESET) with 32,000-cycle delay-optimized for logic-supply generation in portable computing platforms.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 30V - supports wide battery input including Li-ion stacks and adapter rails. |
| Output Voltages | 3.3V and 5V (fixed modes); adjustable 2.5V–5.5V per rail using REF - enables flexible logic supply design. |
| Oscillator Frequency | 500kHz (SYNC = VL) - reduces EMI and enables compact magnetics in space-constrained notebooks. |
| Gate-Drive Capability | 1A sink/source per driver (DH3/DL3/DH5/DL5) - ensures fast switching of external N-MOSFETs for high efficiency. |
| Efficiency | Up to 97% at full load; >80% across 1000:1 load range - extends battery life in suspend/standby modes. |
| Quiescent Power | 2.5mW typical (12V input, both SMPS on) - minimizes no-load power loss in always-on subsystems. |
| Shutdown Current | 4µA typical - critical for ultra-low-power system-level sleep states. |
Pinout & Package
MAX1904BEAI+T is housed in a 28-pin SSOP (shrink small-outline package) with exposed pad for thermal performance. Pin functions are validated per Maxim's official datasheet Rev 3 (12/03).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CSH3 / CSL3 | 3.3V SMPS current-sense inputs | Detect inductor current for cycle-by-cycle limiting (100mV threshold referred to CSL3). |
| FB3 | 3.3V feedback input | Regulates output to REF (2.5V) in adjustable mode; grounded for fixed 3.3V output. |
| STEER | Secondary feedback selector | Directs SECFB signal to 3.3V (GND) or 5V (VL) SMPS - enables auxiliary voltage regulation via transformer winding. |
| SECFB | Secondary feedback input | Accepts resistor-divider voltage from flyback winding; regulates at 2.44V–2.60V threshold for quasi-regulated auxiliary outputs. |
| SYNC | Oscillator sync/frequency select | Set to VL for 500kHz; GND for 333kHz - enables noise-sensitive mobile applications and external synchronization. |
| RESET | Active-low timed reset output | Asserts after 32,000 oscillator cycles - provides reliable system initialization timing for CPU and peripherals. |
| V+ | Main input supply | 4.2V–30V battery/adapter input; powers internal regulators and gate drivers via integrated LDO. |
| VL | Internal 5V linear regulator output | Supplies chip core logic and external loads ≤50mA; auto-switches to 5V SMPS output above 4.5V for bootstrapping. |
Key Features
| Feature | Design Value |
|---|---|
| Idle Mode™ control | Variable-frequency pulse-skipping at light loads - reduces gate-charge and transition losses to sustain >80% efficiency down to 1mA output current. |
| Dual Mode™ feedback | Single-pin (FB3/FB5) selection between fixed 3.3V/5V and adjustable 2.5V–5.5V outputs - simplifies BOM and layout across product variants. |
| Programmable sequencing | SEQ pin selects 3.3V-first, 5V-first, or independent ON3/ON5 control - meets strict CPU/core logic power-up timing requirements. |
| Integrated 2.5V reference | REF pin provides ±2% accuracy (2.45V–2.55V), <12.5mV load regulation - serves as precision feedback reference for both SMPS rails. |
| Power-good signaling | RESET output with 32,000-cycle delay and ±5.5% trip threshold - ensures stable rail establishment before releasing processor reset. |
Applications
| Mobile Computing Power Management | Notebook CPU Core Supply |
|---|---|
|
Use Scenario: Dual-rail DC-DC conversion in ultraportable notebooks with Li-ion battery input (7V–24V) and strict EMI limits. IC Role / Device Role / Timing Role: Primary controller for synchronized 3.3V I/O and 5V peripheral rails, with SEQ-driven startup and RESET coordination. Use Value: 500kHz fixed-frequency operation minimizes conducted noise in RF-sensitive pen-entry and cellular modules. |
Use Scenario: Local DC-DC regulation near CPU socket requiring tight transient response and sequencing compliance. IC Role / Device Role / Timing Role: Generates 3.3V/5V logic supplies with <5-cycle load transient correction and programmable ON3/ON5 timing. Use Value: Strong 1A gate drivers and low-duty-cycle dropout support enable rapid load steps without rail collapse. |
| Auxiliary Winding Regulation | Battery-Powered System Standby |
|
Use Scenario: Generating quasi-regulated 12V auxiliary output from coupled inductor flyback winding in compact designs. IC Role / Device Role / Timing Role: Uses SECFB/STEER to steer secondary feedback to selected SMPS, enabling adjustable auxiliary voltage via external resistor divider. Use Value: Eliminates need for separate flyback controller IC - reduces component count and board area in multi-output systems. |
Use Scenario: Maintaining always-on 3.3V/5V rails during deep-sleep states in PDAs and subnotebooks. IC Role / Device Role / Timing Role: Delivers 4µA shutdown current and 2.5mW quiescent power while sustaining regulated outputs. Use Value: Extends battery runtime by >30% in suspend mode compared to non-Idle Mode controllers. |
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 |
|---|---|---|---|
| MAX1901EAI+T | Identical pinout, same 28-pin SSOP package, identical feature set except lacks 12V linear regulator (MAX1902 only has it); shares same SECFB/STEER functionality. | Used where auxiliary 12V rail is not required; otherwise functionally interchangeable in 3.3V/5V-only designs. | Select when secondary feedback and dual SMPS control are needed but 12V LDO is unnecessary - reduces cost and complexity. |
| TPS51116PWR | TI dual-output controller with integrated MOSFET drivers, 3.3V/5V fixed outputs, but no SECFB/STEER or Idle Mode™; higher quiescent current (15µA vs 4µA). | Targeted at mainstream notebooks with simpler sequencing; lacks transformer-coupled auxiliary regulation capability. | Choose for cost-sensitive, non-auxiliary designs where Maxim's low-IQ and flyback flexibility are not required. |
Compared with MAX1901EAI+T, MAX1904BEAI+T offers identical dual-SMPS control and SECFB/STEER functionality but is specified for extended temperature range (−40°C to +85°C) and includes enhanced production screening; versus TPS51116PWR, it delivers superior light-load efficiency and auxiliary winding support at the expense of vendor-specific feature alignment.
Availability
MAX1904BEAI+T is available at Aetrix Electronics and suitable for notebook computers, subnotebook power management, and battery-powered embedded systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for MAX1904BEAI+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 portable, industrial, and communications applications.
The MAX190x family was designed specifically for multi-output, high-efficiency DC-DC conversion in battery-powered computing platforms-emphasizing low-noise PWM, intelligent sequencing, and ultra-low quiescent power.
FAQ
What is the operating temperature range for MAX1904BEAI+T?
The MAX1904BEAI+T is rated for −40°C to +85°C ambient operation, matching the industrial temperature grade specified in the ordering information table. This range is validated across all electrical parameters including oscillator frequency, gate-drive strength, and feedback accuracy - making MAX1904BEAI+T suitable for ruggedized portable computing environments where thermal margins are constrained.
How does the STEER pin function in MAX1904BEAI+T?
In MAX1904BEAI+T, the STEER pin selects which SMPS (3.3V or 5V) receives the secondary feedback signal from SECFB. When STEER = GND, the 3.3V SMPS uses the SECFB input for auxiliary winding regulation; when STEER = VL, the 5V SMPS uses it. This allows designers to regulate an auxiliary voltage derived from either winding without adding external circuitry - a key differentiator of MAX1904BEAI+T versus single-feedback controllers.
Does MAX1904BEAI+T support power-up sequencing, and how is it configured?
Yes, MAX1904BEAI+T supports programmable power-up sequencing via the SEQ pin. Strapping SEQ to GND sequences 5V before 3.3V; strapping to REF enables independent ON3/ON5 control; strapping to VL sequences 3.3V before 5V. This configuration directly determines RESET assertion timing and fault monitoring behavior - ensuring MAX1904BEAI+T complies with Intel Mobile Voltage Positioning (MVP) and other platform-specific sequencing requirements.
What is the purpose of the SKIP pin on MAX1904BEAI+T?
The SKIP pin on MAX1904BEAI+T disables Idle Mode™ when driven high, forcing fixed-frequency PWM operation under all load conditions. This eliminates low-frequency ripple and audible noise in sensitive applications like touchscreens and audio subsystems. For normal operation - maximizing light-load efficiency - SKIP is tied to GND, enabling automatic pulse-skipping below ~100mA load.
Can MAX1904BEAI+T regulate a 12V auxiliary output?
MAX1904BEAI+T does not include an integrated 12V linear regulator (unlike MAX1902), but it supports quasi-regulated 12V auxiliary outputs via its SECFB/STEER interface. By connecting SECFB to a resistor divider from a transformer secondary winding and configuring STEER appropriately, MAX1904BEAI+T adjusts the selected SMPS duty cycle to maintain SECFB ≈ 2.5V - enabling accurate, low-component-count 12V generation without a dedicated flyback controller IC.
MAX1904BEAI+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- 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:
- 28-SSOP
MAX1904BEAI+T FAQ
1.How can I place an order for MAX1904BEAI+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1904BEAI+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 MAX1904BEAI+T reliable?
The price and inventory of MAX1904BEAI+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1904BEAI+T is usually 5 days.
3.What payment methods are accepted for MAX1904BEAI+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1904BEAI+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1904BEAI+T?
MAX1904BEAI+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1904BEAI+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 MAX1904BEAI+T?
For technical support, including MAX1904BEAI+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1904BEAI+T requirements.
6.How does Aetrix verify that MAX1904BEAI+T is sourced from the original manufacturer or authorized distributors?
All MAX1904BEAI+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 MAX1904BEAI+T meets industry standards.
7.What is the process for return or replacement of MAX1904BEAI+T?
All MAX1904BEAI+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1904BEAI+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 MAX1904BEAI+T part is unused and in its original packaging.
Return procedure for MAX1904BEAI+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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