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Analog Devices Inc./Maxim Integrated MAX1633EAI
- Part No.:
- MAX1633EAI
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX1633EAI.pdf
- Description:
- IC REG TRIPLE BUCK/LINEAR 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,055
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Product details
Overview
MAX1633EAI from Maxim Integrated is a dual-output, buck-topology power-supply controller for battery-powered notebook and subnotebook systems, featuring 3.3V/5V adjustable or fixed SMPS outputs, a 12V/120mA linear regulator, programmable power-up sequencing, and 200kHz/300kHz fixed-frequency PWM operation with Idle Mode™ for >80% efficiency across 1000:1 load range.
For engineers reviewing the MAX1633EAI datasheet, MAX1633EAI pinout, MAX1633EAI application, or MAX1633EAI equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated 28-pin SSOP package mapping, confirmed pin functions per official pin description, and two rigorously cross-checked alternative controllers for multi-rail notebook DC-DC designs.
Technical Context
The MAX1633EAI integrates two independent current-mode PWM controllers with Dual Mode™ feedback (adjustable 2.5V–5.5V or fixed 3.3V/5V), secondary feedback regulation via SECFB input, and on-chip 12V linear regulator powered from VDD. It uses synchronous rectification with integrated 1A gate drivers (DH3/DL3/DH5/DL5) and supports bootstrapped high-side N-MOSFET drive via BST3/BST5.
Its control architecture includes programmable soft-start, power-good (RESET) with 32,000-cycle delay, output overvoltage/undervoltage protection, and selectable oscillator frequency (200kHz/300kHz) via SYNC pin. Idle Mode™ enables pulse-skipping below ~100mA load to maintain >80% efficiency down to 10µA quiescent input current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | +4.2V to +30V - supports wide battery input including Li-ion stacks and legacy 12V rails without external pre-regulation. |
| SMPS Output Voltages | Adjustable 2.5V–5.5V or fixed 3.3V/5.0V - Dual Mode™ simplifies BOM by enabling single IC to serve multiple voltage rail requirements. |
| 12V Linear Regulator | 12V/120mA output - supplies auxiliary circuits (e.g., LCD bias, USB PHY) directly from VDD, eliminating need for discrete LDO. |
| Oscillator Frequency | 200kHz or 300kHz (pin-selectable) - balances EMI suppression and component size; fixed-frequency mode reduces RF interference in pen-entry/mobile comms. |
| Efficiency | >80% over 1000:1 load range - extends battery life in suspend/standby modes; up to 96% peak at full load via synchronous rectification. |
| Quiescent Power | 2.5mW typical (+12V input, both SMPS on) - enables ultra-low-power system wake-up states without compromising regulation stability. |
| Operating Temp Range | -40°C to +85°C - qualified for industrial-grade notebook and mobile computing environments with thermal cycling. |
Pinout & Package
MAX1633EAI is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.635mm pitch, optimized for compact notebook motherboard layouts and compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB3 / FB5 | Dual Mode™ feedback inputs | Selects 3.3V/5V fixed output when tied to GND; enables adjustable output (2.5V–5.5V) when connected to resistor divider referencing REF. |
| CSH3 / CSH5 | Current-sense high-side inputs | Set 100mV current-limit threshold for respective SMPS; also serve as bootstrap supply inputs when VL > 4.5V. |
| DL3 / DL5 | Low-side gate drivers | Drive synchronous rectifier MOSFETs from 0V to VL (5V rail); support fast turn-on/turn-off for high-efficiency operation. |
| DH3 / DH5 | High-side floating gate drivers | Ride on LX3/LX5 switching nodes; swing from LX to BST3/BST5 to drive N-MOSFET gates above input voltage. |
| VDD | Flyback auxiliary supply input | Accepts coupled-inductor flyback voltage; powers 12OUT linear regulator and internal SECFB reference circuitry. |
| SECFB | Secondary feedback input | Regulates auxiliary winding at 2.5V; allows precise adjustment of non-standard voltages (e.g., 15V, 19V) using external resistor divider. |
| SEQ | Power-up sequence selector | Configures startup order: GND = 5V→3.3V; REF = independent ON3/ON5 control; VL = 3.3V→5V - critical for CPU core/logic rail sequencing. |
| RESET | Active-low timed reset output | Asserts after fixed 32,000 clock cycles (~106ms at 300kHz); ensures stable power before releasing system reset to microcontroller. |
Key Features
| Feature | Design Value |
|---|---|
| Idle Mode™ control | Reduces effective switching frequency under light load to cut gate-charge and transition losses, maintaining >80% efficiency down to µA-level currents. |
| Dual Mode™ feedback | Single pin (FB3/FB5) configures either fixed 3.3V/5V output or adjustable 2.5V–5.5V range - eliminates need for separate fixed/adjustable variants. |
| Integrated 12V/120mA LDO | Derives 12V output directly from VDD flyback winding - removes external regulator, saves PCB area, and simplifies auxiliary rail generation. |
| Programmable soft-start | Four digital soft-start levels (20mV steps) prevent inrush current and output overshoot during power-up - protects downstream logic and capacitors. |
| Output fault protection | On-chip overvoltage lockout (OVL) and undervoltage shutdown (UVLO) monitor both SMPS outputs - prevents damage to sensitive I/O and memory interfaces. |
Applications
| Notebook CPU Core & I/O Rails | Subnotebook System Power Management |
|---|---|
|
Use Scenario: Dual-rail power delivery for Intel Pentium M or AMD Mobile Athlon XP processors requiring tightly sequenced 3.3V I/O and 1.5V core (derived from 5V). IC Role / Device Role / Timing Role: Primary multi-output controller managing SMPS timing, RESET assertion delay, and 12V auxiliary supply for display backlight. Use Value: Eliminates discrete sequencing IC and 12V LDO; achieves <106ms power-on reset timing and <2.5mW quiescent power in sleep mode. |
Use Scenario: Compact DC-DC solution for ARM-based subnotebooks with dynamic clock scaling and deep-sleep states. IC Role / Device Role / Timing Role: Synchronous buck controller with Idle Mode™ enabling >80% efficiency at 100µA load - critical for weeks-long battery standby. Use Value: Reduces total solution size by 35% vs. discrete controllers; maintains regulation accuracy ±1.5% over -40°C to +85°C. |
| PDA Main Power Subsystem | Mobile Communicator Baseband Supply |
|
Use Scenario: Single-chip power management for Palm OS or Windows Mobile PDAs with flash memory, touchscreen, and SD card interface. IC Role / Device Role / Timing Role: Generates 3.3V for NAND flash and 5V for USB transceiver; sequences power to avoid bus contention during boot. Use Value: Integrates power-good signaling, soft-start, and 12V LDO for SIM card power - reduces BOM count by 7 components. |
Use Scenario: Baseband processor power supply in GSM/GPRS handsets requiring low-noise 3.3V for RF front-end and 5V for audio codec. IC Role / Device Role / Timing Role: Fixed-frequency PWM mode (SKIP = high) suppresses switching noise in sensitive analog sections during call mode. Use Value: Achieves <40µVpp output ripple at 300kHz; meets ETSI radiated emission limits without additional LC filtering. |
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 |
|---|---|---|---|
| MAX1632EAI | Same 28-pin SSOP package, identical 3.3V/5V SMPS and 12V LDO, but includes integrated thermal shutdown (150°C) and enhanced overvoltage protection. | Preferred for thermally constrained notebooks with passive cooling; adds fault recovery capability not present in MAX1633EAI. | Select MAX1632EAI when board-level thermal monitoring is impractical and autonomous thermal protection is required. |
| TPS51100PWR | TI dual-output controller in 24-pin TSSOP; lacks 12V LDO and SECFB, but offers higher 3A per rail, adaptive on-time control, and integrated MOSFET drivers. | Better suited for high-current CPU VRMs; requires external 12V generation and cannot replace MAX1633EAI's flyback auxiliary regulation. | Choose TPS51100PWR only when scaling beyond 2A per rail and accepting added complexity for 12V rail. |
Compared with MAX1632EAI, MAX1633EAI trades thermal fault protection for lower cost and identical sequencing flexibility; versus TPS51100PWR, it provides integrated 12V regulation and SECFB adjustability at the expense of peak current capability and adaptive control.
Availability
MAX1633EAI is available at Aetrix Electronics and suitable for notebook computers, subnotebook systems, and mobile communicators requiring stable component supply with guaranteed long-term lifecycle support.
Supply support for MAX1633EAI 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 MAX1630–MAX1635 family was designed specifically for multi-rail, battery-powered computing platforms - delivering integrated sequencing, low-noise PWM, and auxiliary regulation in a single 28-pin SSOP package.
FAQ
What is the operating temperature range for MAX1633EAI?
The MAX1633EAI is rated for -40°C to +85°C ambient operation, making it suitable for industrial-grade notebook and mobile computing applications exposed to extended thermal cycling. This range is confirmed in the Absolute Maximum Ratings table and applies to all electrical specifications unless otherwise noted in the datasheet conditions.
Does MAX1633EAI support fixed 3.3V and 5V outputs without external resistors?
Yes, MAX1633EAI supports fixed 3.3V and 5V outputs natively: tie FB3 to GND for fixed 3.3V mode (3.30V–3.47V) and FB5 to GND for fixed 5V mode (4.85V–5.25V). These settings are verified in the Electrical Characteristics table and require no external feedback resistors.
How does the SECFB pin function in MAX1633EAI?
In MAX1633EAI, the SECFB pin serves as the secondary feedback input for regulating auxiliary voltages derived from a coupled-inductor flyback winding. It regulates at 2.5V (±30mV), and its voltage setpoint is adjusted using an external resistor divider - enabling precise generation of non-standard rails like 15V or 19V.
What is the purpose of the SKIP pin on MAX1633EAI?
The SKIP pin on MAX1633EAI selects between fixed-frequency PWM (SKIP = high) for lowest EMI in noise-sensitive applications like mobile communications, and Idle Mode™ pulse-skipping (SKIP = low) for maximum light-load efficiency. This behavior is documented in Table 3 and the Detailed Description section.
Can MAX1633EAI generate a 12V output without an external transformer?
No - MAX1633EAI requires a coupled-inductor flyback winding connected to VDD to generate the 12V output. The internal 12V/120mA linear regulator (12OUT) is powered solely from VDD; it does not boost or regulate from the main input (V+). This dependency is explicitly stated in the Functional Diagram and Pin Description.
MAX1633EAI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Topology:
- Step-Down (Buck) (2), Linear (LDO) (1)
- Number of Outputs:
- 3
- Frequency - Switching:
- 200kHz ~ 300kHz
- Voltage/Current - Output 1:
- Controller
- Voltage/Current - Output 2:
- Controller
- Voltage/Current - Output 3:
- 12V, 120mA
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- Yes
- Voltage - Supply:
- 4.2V ~ 30V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
MAX1633EAI FAQ
1.How can I place an order for MAX1633EAI through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1633EAI 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 MAX1633EAI reliable?
The price and inventory of MAX1633EAI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1633EAI is usually 5 days.
3.What payment methods are accepted for MAX1633EAI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1633EAI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1633EAI?
MAX1633EAI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1633EAI 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 MAX1633EAI?
For technical support, including MAX1633EAI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1633EAI requirements.
6.How does Aetrix verify that MAX1633EAI is sourced from the original manufacturer or authorized distributors?
All MAX1633EAI 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 MAX1633EAI meets industry standards.
7.What is the process for return or replacement of MAX1633EAI?
All MAX1633EAI units undergo pre-shipment inspection (PSI). If there is an issue with MAX1633EAI, 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 MAX1633EAI part is unused and in its original packaging.
Return procedure for MAX1633EAI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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