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Analog Devices Inc./Maxim Integrated MAX1644EAE+T
- Part No.:
- MAX1644EAE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX1644EAE+T.pdf
- Description:
- IC REG BUCK ADJ 2A 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,685
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Product details
Overview
The MAX1644EAE+T from Maxim Integrated is a constant-off-time, current-mode PWM synchronous step-down DC-DC regulator delivering up to 2A continuous output current. It integrates 0.10Ω PMOS and 0.10Ω NMOS power switches, operates from +3V to +5.5V input, and supports pin-selectable +3.3V/+2.5V or adjustable +1.1V to VIN outputs-ideal for CPU I/O supply and PC Card bus-termination boards.
For engineers reviewing the MAX1644EAE+T datasheet, MAX1644EAE+T pinout, MAX1644EAE+T application, or MAX1644EAE+T equivalent, key selection considerations include its 95% peak efficiency, Idle Mode™ light-load optimization, programmable off-time (up to 350kHz), 100% duty-cycle low-dropout operation, and integrated soft-start with <1µA shutdown current.
Technical Context
The MAX1644EAE+T employs a proprietary current-mode, constant-off-time PWM architecture that dynamically shifts between continuous-conduction mode (>0.2A load) and pulse-skipping Idle Mode™ (<0.2A load) to maintain high efficiency across wide load ranges. Regulation is achieved by modulating PMOS on-time while holding off-time fixed via external RTOFF.
It features internal synchronous rectification eliminating external Schottky diodes, a transconductance integrator amplifier at COMP for precise DC regulation, and dual-mode feedback control (FBSEL-selectable 1% or 2% AC load regulation). Thermal shutdown and output short-circuit protection are built-in.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | +3.0V to +5.5V - supports standard 3.3V and 5V system rails without external level-shifting. |
| Output Current | 2A continuous - sufficient for CPU I/O, PC Card logic, and bus-termination loads. |
| Efficiency | Up to 95% - enabled by synchronous rectification and low-RON internal switches (70mΩ/100mΩ at VIN = 4.5V/3V). |
| Switching Frequency | Up to 350kHz - programmable via RTOFF to balance EMI, inductor size, and efficiency. |
| Shutdown Current | <1µA - ensures ultra-low quiescent power during system sleep or standby states. |
| Output Accuracy | ±1% - guaranteed over temperature and line/load, critical for stable digital supply rails. |
| Dropout Behavior | 100% duty cycle - maintains regulation when VIN approaches VOUT, minimizing dropout voltage to IOUT × RON,P. |
Pinout & Package
Package: 16-pin SSOP (5.3 mm width), lead-free, RoHS-compliant, with θJA = 60°C/W on 0.5 in² copper (no airflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SHDN | Logic-level shutdown control | Drives internal circuitry and MOSFETs into ultra-low-power state (<1µA ICC) when pulled low. |
| IN (Pins 2,4) | Main power input | Supplies the internal PMOS switch; accepts +3V to +5.5V with UVLO at 2.6V. |
| LX (Pins 3,14,16) | Switch node | Connects drains of internal PMOS/NMOS; requires low-inductance path to inductor and output capacitor. |
| PGND (Pins 13,15) | Power ground return | Internally tied to NMOS source; must be connected directly to input/output capacitor grounds to minimize noise. |
| FB | Voltage feedback input | Senses output directly (fixed mode) or via resistor divider (adjustable mode); regulates to 1.1V reference. |
| FBSEL | Feedback configuration select | Chooses preset (3.3V/2.5V) or adjustable mode, and sets AC load-regulation error (1% or 2%). |
| SS | Soft-start timing node | Accepts external capacitor to linearly ramp current limit from 0A to 2.9A, limiting inrush during startup. |
| TOFF | Off-time programming input | Resistor-to-ground sets fixed off-time (0.4–4µs), determining switching frequency up to 350kHz. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous switches | 0.10Ω PMOS + 0.10Ω NMOS eliminate external Schottky diode, reducing BOM count and conduction losses. |
| Idle Mode™ operation | Skips switching cycles below 0.2A load, preserving >85% efficiency at light loads without external control. |
| Programmable constant-off-time | RTOFF-set architecture enables precise trade-off between efficiency, EMI, and passive component size. |
| Adjustable soft-start | External capacitor on SS pin controls inrush current ramp rate, preventing input rail collapse during power-up. |
| 100% duty-cycle low-dropout | PMOS remains fully on when VIN ≈ VOUT, enabling regulation down to VOUT + (IOUT × 0.1Ω). |
Applications
| +5V to +3.3V/+2.5V Conversion | CPU I/O Supply |
|---|---|
Use Scenario: Converting main system +5V rail to clean +3.3V or +2.5V for microprocessor address/data buffers and peripheral interfaces. IC Role / Device Role / Timing Role: Primary point-of-load (POL) regulator delivering tightly regulated, low-noise DC power with fast transient response. Use Value: ±1% output accuracy and 95% efficiency ensure stable I/O signaling margins and reduced thermal load on dense CPU daughter cards. | Use Scenario: Powering core logic, cache, and memory interface circuits on CPU daughter cards requiring stable sub-3.3V supplies. IC Role / Device Role / Timing Role: Synchronous buck controller with integrated power switches, operating in constant-off-time mode for rapid line/load regulation. Use Value: Internal 70mΩ/100mΩ switches and Idle Mode™ sustain >90% efficiency from 10mA to 2A, minimizing board-level heat generation. |
| +3.3V PC Card and CardBus Applications | Desktop Bus-Termination Boards |
Use Scenario: Providing compliant +3.3V power to PCMCIA/CardBus slots in portable and embedded systems with strict power envelope limits. IC Role / Device Role / Timing Role: Compact, high-efficiency step-down regulator meeting JEDEC PC Card power sequencing and ripple requirements. Use Value: 16-pin SSOP footprint and <1µA shutdown current enable space-constrained designs with zero-quiescent-power sleep modes. | Use Scenario: Generating termination voltages (e.g., +2.5V, +3.3V) for parallel bus standards like PCI or ISA on desktop motherboard add-in cards. IC Role / Device Role / Timing Role: Fixed-output or resistor-programmable buck regulator with thermal shutdown and short-circuit protection for robust field operation. Use Value: Built-in output short-circuit protection and 150°C thermal shutdown prevent damage during hot-plug or bus fault events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54202DRCT | 4.5–17V input range; 2A output; uses voltage-mode control; no Idle Mode™; 500kHz max fSW | Better suited for higher-input industrial rails; lacks light-load efficiency optimization for battery-powered PC Cards. | Select only if input exceeds +5.5V or higher switching frequency is required; verify loop stability with external compensation. |
| RT8205AZSP | 2.7–5.5V input; 2A output; constant-on-time control; 1.2% output accuracy; no FBSEL pin | Fixed 1.2V reference; no pin-selectable presets; simpler layout but less flexible output configuration. | Prefer when fixed 1.2V output suffices and design prioritizes minimal external components over multi-voltage flexibility. |
Compared with TPS54202DRCT and RT8205AZSP, the MAX1644EAE+T uniquely combines pin-selectable +2.5V/+3.3V outputs, Idle Mode™ for sub-100µA light-load operation, and integrated soft-start-making it optimal for legacy PC Card and CPU daughter card designs where input is strictly 3–5.5V and output flexibility is essential.
Availability
MAX1644EAE+T is available at Aetrix Electronics and suitable for CPU I/O supply, PC Card power conversion, and desktop bus-termination boards requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX1644EAE+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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.
The MAX1644EAE+T belongs to Maxim's legacy high-efficiency DC-DC converter product line, designed specifically for low-voltage, high-current point-of-load regulation in space-constrained computing peripherals and embedded systems.
FAQ
What output voltages does the MAX1644EAE+T support?
The MAX1644EAE+T supports three output configurations: pin-selectable +3.3V (FBSEL unconnected), +2.5V (FBSEL = VCC), or adjustable +1.1V to VIN (FBSEL = GND or REF with external resistor divider). All modes regulate to the internal 1.1V reference with ±1% DC accuracy over temperature and line/load conditions.
How does the MAX1644EAE+T achieve 95% efficiency?
The MAX1644EAE+T achieves up to 95% efficiency through synchronous rectification using integrated 0.10Ω PMOS and 0.10Ω NMOS switches, eliminating Schottky diode conduction losses. Its constant-off-time PWM architecture minimizes gate-charge and transition losses, and Idle Mode™ reduces switching losses at light loads-verified in typical +5V-to-+3.3V, 2A applications.
What is the function of the TOFF pin on the MAX1644EAE+T?
The TOFF pin on the MAX1644EAE+T sets the constant off-time period via an external resistor to ground (RTOFF). This directly determines the switching frequency-ranging from ~100kHz to 350kHz-and allows designers to optimize for efficiency, EMI, inductor size, and cost. Typical RTOFF values range from 39kΩ to 470kΩ.
Does the MAX1644EAE+T require an external Schottky diode?
No, the MAX1644EAE+T does not require an external Schottky diode. It integrates both a 0.10Ω PMOS high-side switch and a 0.10Ω NMOS synchronous rectifier, enabling full synchronous operation that replaces the external diode and improves efficiency by reducing conduction losses.
What protection features are built into the MAX1644EAE+T?
The MAX1644EAE+T includes thermal shutdown (150°C trip), output short-circuit protection, undervoltage lockout (2.6V threshold), and current-limit protection (2.5–3.3A threshold). During shutdown, all internal circuitry and MOSFETs disable, and the LX node becomes high-impedance-ensuring safe operation under fault conditions.
MAX1644EAE+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.1V (2.525V, 3.33V)
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 2A
- Frequency - Switching:
- Up to 350kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
MAX1644EAE+T FAQ
1.How can I place an order for MAX1644EAE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1644EAE+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 MAX1644EAE+T reliable?
The price and inventory of MAX1644EAE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1644EAE+T is usually 5 days.
3.What payment methods are accepted for MAX1644EAE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1644EAE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1644EAE+T?
MAX1644EAE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1644EAE+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 MAX1644EAE+T?
For technical support, including MAX1644EAE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1644EAE+T requirements.
6.How does Aetrix verify that MAX1644EAE+T is sourced from the original manufacturer or authorized distributors?
All MAX1644EAE+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 MAX1644EAE+T meets industry standards.
7.What is the process for return or replacement of MAX1644EAE+T?
All MAX1644EAE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1644EAE+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 MAX1644EAE+T part is unused and in its original packaging.
Return procedure for MAX1644EAE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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