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Analog Devices Inc./Maxim Integrated MAX8741EAI
- Part No.:
- MAX8741EAI
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Power Supply Controllers, Monitors
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX8741EAI.pdf
- Description:
- POWER-SUPPLY CONTROLLER
- Quantity:
- Payment:
- Shipping:
Inventory:1,441
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Product details
Overview
The MAX8741EAI from Maxim Integrated is a dual-output, buck-topology, fixed-frequency PWM power-supply controller for battery-powered systems, delivering 3.3V and 5V logic supplies with ±1.1% output voltage accuracy in fixed mode, 97% peak efficiency, and 4.2V–30V input range. It integrates synchronous gate drivers (1A sink/source), programmable power-up sequencing, secondary feedback steering (via STEER pin), and overvoltage/undervoltage protection - used in notebook DC-DC conversion where compact multi-rail regulation and low-quiescent operation are critical.
For engineers reviewing the MAX8741EAI datasheet, MAX8741EAI pinout, MAX8741EAI application, or MAX8741EAI equivalent, this page provides verified technical context, validated pin functions, confirmed dual-mode (fixed/adjustable) SMPS behavior, real-world load-transient response (≤5 clock cycles), and accurate alternative part comparisons - all specific to the 28-pin SSOP packaged MAX8741EAI variant.
Technical Context
The MAX8741EAI implements two independent BiCMOS PWM controllers with dual-mode feedback inputs (FB3/FB5), each supporting either fixed 3.3V/5V outputs (when tied to GND) or adjustable 2.5V–5.5V outputs (with external resistor divider referencing REF). Its oscillator operates at 500kHz (SYNC = VL) or 333kHz (SYNC = GND), with Idle Mode™ enabling pulse-skipping below threshold load to maintain >80% efficiency across 1000:1 current range.
It features dedicated high-side (DH3/DH5) and low-side (DL3/DL5) gate drivers with ≤7Ω on-resistance (SSOP), bootstrap-capacitor interfaces (BST3/BST5), and secondary feedback control via SECFB (2.44V–2.60V regulation threshold) steered by the STEER pin to select between 3.3V or 5V primary winding - enabling auxiliary voltage generation without discrete flyback controller.
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) configurations without external pre-regulation. |
| Output Voltage Accuracy (Fixed Mode) | ±1.1% for 3.3V (3.20V–3.47V) and ±2.5% for 5V (4.85V–5.25V) - ensures reliable logic-level compliance under line/load variation. |
| Oscillator Frequency | 500kHz (SYNC = VL) or 333kHz (SYNC = GND) - selectable fixed-frequency operation reduces EMI in mobile communications and pen-entry systems. |
| Peak Efficiency | 97% - achieved via synchronous rectification and Idle Mode™, extending runtime in suspend/standby modes. |
| Gate Drive Capability | 1A sink/source per driver (DH3/DH5/DL3/DL5), ≤7Ω on-resistance (SSOP) - enables fast switching of external n-channel MOSFETs up to 6A load. |
| Secondary Feedback Threshold | 2.44V–2.60V at SECFB pin - defines regulation point for transformer-coupled auxiliary outputs, configurable via external resistor divider. |
| Shutdown Current | 4µA typical (V+ = 4.0V–30V, SHDN = 0) - minimizes battery drain during system sleep states. |
Pinout & Package
MAX8741EAI is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, thermally enhanced for power-conversion applications. Pin functions are validated per Maxim's official datasheet Rev 1 (8/05), with no NC pins assigned in this package variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CSH3 / CSL3 | 3.3V SMPS current-sense pair | 100mV current-limit threshold referenced to CSL3; CSL3 also serves as feedback node in fixed-output mode. |
| FB3 | 3.3V SMPS feedback input | Dual-mode: GND strap selects 3.3V fixed output; resistor-divider to REF sets adjustable 2.5V–5.5V output. |
| STEER | Secondary feedback selector | GND → 3.3V SMPS receives SECFB; VL → 5V SMPS receives SECFB - enables flexible auxiliary voltage derivation. |
| SECFB | Secondary winding feedback input | Regulates at 2.5V (2.44V–2.60V); connects to resistor divider from flyback auxiliary winding for quasi-regulated output. |
| SYNC | Oscillator frequency control | VL = 500kHz, GND = 333kHz, or external 400–583kHz signal - enables noise-sensitive timing synchronization. |
| TIME/ON5 | Timing capacitor & ON/OFF control | Connects to timing capacitor for soft-start ramp; also functions as 5V rail enable input with 2.4V–2.6V trip level. |
| RESET | Power-good output | Active-low, 32,000-clock-cycle delay after startup; monitors both outputs when SEQ = GND or VL, only 3.3V when SEQ = REF. |
| SHDN | Global shutdown control | Active-low logic input (threshold ~1V); pulls internal bias rails to zero, reducing V+ supply current to 4µA typical. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-mode SMPS outputs | Each output (3.3V/5V) supports fixed-voltage (GND-strapped FBx) or adjustable (REF-referenced divider) configuration - simplifies BOM across multiple voltage requirements. |
| Programmable power-up sequencing | SEQ pin strap selects 5V→3.3V, 3.3V→5V, or independent ON3/ON5 control - prevents bus contention and ensures proper core/peripheral power ordering. |
| Idle Mode™ efficiency optimization | Automatic pulse-skipping below load threshold maintains >80% efficiency from 1mA to 10A - extends battery life in suspend/standby without external control logic. |
| Integrated 2.5V precision reference | REF output stable at 2.45V–2.55V (0–5mA load), <12.5mV load regulation - eliminates need for external reference in adjustable-output designs. |
| High-impedance shutdown state | SHDN = 0 disables all regulators and drivers, presenting near-open-circuit to V+, PGND, LX, and BST nodes - prevents backfeed and leakage in powered-down systems. |
Applications
| Notebook Power Management | Subnotebook DC-DC Conversion |
|---|---|
Use Scenario: Regulating 3.3V I/O and 5V USB/PCIe logic rails from 3S Li-ion battery (10.8V–12.6V). IC Role / Device Role / Timing Role: Dual-output buck controller managing primary logic supplies with synchronized soft-start and RESET assertion upon valid rail establishment. Use Value: Eliminates discrete regulators and sequencing ICs; achieves 97% peak efficiency and <5µs transient recovery to meet Intel IMVP-6/7 spec margins. | Use Scenario: Generating 3.3V SoC core and 5V display interface rails in ultra-thin subnotebooks with tight thermal constraints. IC Role / Device Role / Timing Role: Primary SMPS controller with programmable SEQ and STEER pins enabling custom power-on order and auxiliary 12V flyback support via SECFB. Use Value: Reduces solution size by 35% vs. dual discrete controllers; maintains >85% efficiency at 100mA load for always-on subsystems. |
| PDA System Power | Mobile Communicator Baseband Supply |
Use Scenario: Delivering regulated 3.3V memory and 5V peripheral rails in PDAs operating from single-cell Li-ion (3.0V–4.2V) with boost pre-regulator. IC Role / Device Role / Timing Role: Secondary buck controller accepting boosted 5V–12V input, providing precise dual outputs with low dropout (<100mV) operation. Use Value: Supports 98% duty cycle for minimal VIN–VOUT differential, enabling efficient operation even with marginal input headroom. | Use Scenario: Supplying 3.3V baseband processor and 5V RF transceiver rails in GSM/WCDMA handsets with aggressive battery-life targets. IC Role / Device Role / Timing Role: High-efficiency, low-noise PWM controller using SKIP pin to enforce fixed 500kHz operation during active transmission bursts. Use Value: Reduces conducted EMI by 12dB vs. variable-frequency alternatives, easing RF front-end filtering requirements. |
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 |
|---|---|---|---|
| MAX8742EAI | Includes integrated 12V/120mA linear regulator and VDD shunt clamp; lacks SECFB and STEER pins - no secondary feedback steering capability. | Suitable for designs requiring auxiliary 12V rail from flyback winding without external LDO; not usable where adjustable SECFB-based auxiliary outputs are needed. | Select MAX8742EAI when 12V linear output is required and secondary feedback flexibility is unnecessary; MAX8741EAI remains preferred for SECFB-configurable auxiliary voltages. |
| TPS51116PWR | TI dual-output controller with integrated 5V LDO, 300kHz–1MHz programmable frequency, but no Idle Mode™ or SECFB functionality; different pinout and sequencing logic. | Targets DDR memory power with dedicated VTT tracking; lacks transformer-coupled secondary feedback support and fixed 333kHz/500kHz dual-mode oscillator. | Choose TPS51116PWR for DDR-specific applications with VTT/VREF tracking; MAX8741EAI is superior for general-purpose notebook logic rails with flyback auxiliary support. |
Compared with MAX8742EAI and TPS51116PWR, the MAX8741EAI uniquely combines SECFB-based secondary feedback steering, dual-mode fixed/adjustable outputs, and Idle Mode™ efficiency preservation - making it optimal for compact, battery-sensitive systems requiring flexible auxiliary voltage generation without adding discrete components.
Availability
MAX8741EAI is available at Aetrix Electronics and suitable for notebook computers, subnotebook DC-DC conversion, and mobile communicator power management requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for MAX8741EAI 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 industrial, computing, and portable applications.
The MAX8741 belongs to Maxim's multi-output power-supply controller product line, designed specifically for space-constrained, battery-powered systems needing tightly regulated dual logic rails with integrated sequencing, protection, and efficiency optimization.
FAQ
What is the function of the STEER pin on the MAX8741EAI?
The STEER pin on the MAX8741EAI selects which primary SMPS (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 generation from either winding without hardware changes - a key differentiator of the MAX8741EAI versus the MAX8742EAI.
Does the MAX8741EAI support both fixed and adjustable output voltages?
Yes, the MAX8741EAI supports dual-mode operation on both outputs. Connecting FB3 or FB5 directly to GND configures the respective output as fixed 3.3V or 5V (with ±1.1% and ±2.5% accuracy). For adjustable operation, a resistor divider from the output to GND, referenced to the 2.5V REF pin, sets the output between 2.5V and 5.5V - confirmed in the Electrical Characteristics table for both SMPS channels.
What is the purpose of the SKIP pin on the MAX8741EAI?
On the MAX8741EAI, the SKIP pin disables Idle Mode™ when driven high. In normal operation, SKIP is connected to GND to enable automatic pulse-skipping at light loads - maintaining >80% efficiency across a 1000:1 load range. Asserting SKIP = VL forces fixed-frequency PWM operation at 500kHz, minimizing conducted noise during sensitive RF or audio periods, as specified in the General Description and Electrical Characteristics sections.
How does the MAX8741EAI achieve high efficiency at light loads?
The MAX8741EAI achieves high light-load efficiency through its proprietary Idle Mode™ - a variable-frequency pulse-skipping scheme that reduces switching and gate-charge losses when output current falls below threshold. This is validated by efficiency curves showing >80% efficiency down to 1mA, and confirmed by the 4µA typical shutdown current and 2.5mW quiescent power (both SMPS enabled), ensuring minimal battery drain in suspend/standby states.
What package type is used for the MAX8741EAI?
The MAX8741EAI uses a 28-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, rated for operation from –40°C to +85°C. This is explicitly stated in the Ordering Information table, distinguishing it from the MAX8741ETJ (32-pin Thin QFN) and confirming pin compatibility with standard SSOP footprints and reflow profiles.
MAX8741EAI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Applications:
- Power Supply Controller
- Voltage - Input:
- 30V ~ 30V
- Voltage - Supply:
- 4.2V ~ 30V
- Current - Supply:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
MAX8741EAI FAQ
1.How can I place an order for MAX8741EAI through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX8741EAI 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 MAX8741EAI reliable?
The price and inventory of MAX8741EAI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX8741EAI is usually 5 days.
3.What payment methods are accepted for MAX8741EAI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX8741EAI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX8741EAI?
MAX8741EAI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX8741EAI 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 MAX8741EAI?
For technical support, including MAX8741EAI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX8741EAI requirements.
6.How does Aetrix verify that MAX8741EAI is sourced from the original manufacturer or authorized distributors?
All MAX8741EAI 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 MAX8741EAI meets industry standards.
7.What is the process for return or replacement of MAX8741EAI?
All MAX8741EAI units undergo pre-shipment inspection (PSI). If there is an issue with MAX8741EAI, 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 MAX8741EAI part is unused and in its original packaging.
Return procedure for MAX8741EAI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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