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Analog Devices Inc./Maxim Integrated MAX8643ETG+
- Part No.:
- MAX8643ETG+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
MAX8643ETG+.pdf
- Description:
- IC REG BUCK ADJ 3A 24TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,175
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Product details
Overview
The MAX8643ETG+ from Maxim Integrated is a high-efficiency, voltage-mode synchronous step-down DC-DC regulator delivering up to 3A continuous output current with ±1% output voltage accuracy over load, line, and temperature. It operates from a 2.35V–3.6V input, supports adjustable output from 0.6V to 0.9×VIN, and features programmable switching frequency (500kHz–2MHz) for compact all-ceramic capacitor designs-ideal for point-of-load regulation in ASIC/CPU core supplies.
For engineers reviewing the MAX8643ETG+ datasheet, MAX8643ETG+ pinout, MAX8643ETG+ application, or MAX8643ETG+ equivalent, this page delivers verified technical context, validated pin functions, confirmed VID-selectable output voltages (0.6V–2.5V), real-world thermal shutdown behavior (+165°C), and precise soft-start timing control via external capacitor-enabling first-pass layout success in DDR, telecom, and embedded power systems.
Technical Context
The MAX8643ETG+ employs voltage-mode control architecture with a >14MHz bandwidth error amplifier and type III compensation support, enabling loop bandwidth up to 20% of switching frequency for fast transient response. Its integrated 37mΩ high-side and 34mΩ low-side nMOS switches eliminate external FETs and reduce critical inductance sensitivity.
It uses tri-state logic inputs (CTL1/CTL2) to select one of nine preset output voltages without precision resistors, while also supporting full analog feedback (0.6V reference) or external reference injection at REFIN-making it suitable for both fixed-voltage POLs and tracking DDR supply rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Continuous 3A - sufficient for CPU core, ASIC I/O, and DDR memory rail loads without derating at +85°C ambient. |
| Input Voltage Range | 2.35V to 3.6V - matches single-cell Li-ion, 3.3V system rails, and post-regulated intermediate bus architectures. |
| Output Voltage Accuracy | ±1% over load/line/temperature - eliminates need for post-production trimming in volume production. |
| Switching Frequency | 500kHz to 2MHz (resistor-programmable) - enables use of sub-1µH inductors and all-ceramic 22µF output capacitors. |
| On-Resistance (HS/LS) | 37mΩ / 34mΩ (typ @ 3.3V) - minimizes conduction loss and thermal rise under full 3A load. |
| Soft-Start Control | Capacitor-adjustable via SS pin - limits inrush current during power-up to protect upstream converters and input caps. |
| Thermal Protection | 165°C shutdown with 20°C hysteresis - prevents permanent damage during sustained overload or poor PCB heatsinking. |
| Power-Good Output | Open-drain PWRGD asserts high-impedance when VFB ≥ 90% of regulation point - provides reliable sequencing signal for FPGA/CPU reset logic. |
Pinout & Package
MAX8643ETG+ is housed in a lead-free, 24-pin, 4mm × 4mm thin QFN package with exposed thermal pad (EP) for enhanced heat dissipation. Pin assignments are validated per Maxim's official datasheet Rev 3 (9/07).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1,7) | Analog ground reference | Separate from PGND; must be tied to quiet analog ground plane to avoid noise coupling into FB/COMP. |
| VDD (Pin 2) | Bias supply input | Requires local 1µF ceramic bypass; connected to IN via 10Ω resistor to isolate switching noise. |
| CTL1/CTL2 (Pins 3,4) | VID voltage selection inputs | Tri-state logic (GND/VDD/unconnected) selects one of nine preset outputs - must be set before EN assertion. |
| REFIN (Pin 5) | External reference input | Accepts 0.6V internal ref (when tied to SS) or external voltage; forces FB regulation to applied value - enables tracking applications. |
| SS (Pin 6) | Soft-start timing node | 8µA internal current source charges external cap; sets ramp time for controlled VOUT rise - disables when REFIN is externally driven. |
| COMP (Pin 8) | Error amplifier output | Connects to type III compensation network (R1/C1/C2); pulled low during shutdown - requires external pull-up if used in active feedback. |
| FB (Pin 9) | Feedback sense input | Regulates output via resistor divider (for 0.6V ref) or direct connection (for VID mode); bias current < ±200nA ensures high-accuracy sensing. |
| OUT (Pin 10) | Output voltage sense | Direct connection to power rail for remote sensing - left floating when using external resistor divider. |
| FREQ (Pin 11) | Frequency programming | Resistor to GND sets fSW: 50kΩ = ~1MHz, 23.2kΩ = ~2MHz - tolerance directly impacts loop stability margin. |
| PWRGD (Pin 12) | Power-good status flag | Open-drain output signals valid regulation (≥90% of target); pulled low during UVLO, thermal shutdown, or EN=low. |
| BST (Pin 13) | Bootstrap supply | Requires 0.1µF ceramic cap to LX - sustains high-side gate drive above VIN during HS conduction. |
| LX (Pins 14–16) | Switch node | Internally paralleled; connects to inductor - carries full AC switching current; clamped internally to GND/IN. |
| PGND (Pins 17–20) | Power ground return | Must connect to low-impedance power ground plane - separates high di/dt return path from analog GND. |
| IN (Pins 21–23) | Main power input | 22µF ceramic bypass required to PGND; accepts 2.35–3.6V - shared with VDD but filtered separately. |
| EN (Pin 24) | Enable control | Logic-high (>1.4V) enables regulation; logic-low (<0.7V) shuts down IC drawing <13µA - supports power sequencing. |
| EP | Exposed thermal pad | Must be soldered to large copper pour - primary thermal path; improves θJA by >30% vs. non-connected pad. |
Key Features
| Feature | Design Value |
|---|---|
| Voltage-mode control with >14MHz error amp | Enables stable 2MHz operation and fast transient recovery (<10µs) with minimal output capacitance. |
| Nine VID-selectable output voltages | 0.6V, 0.7V, 0.8V, 1.0V, 1.2V, 1.5V, 1.8V, 2.0V, 2.5V - eliminates 0.1% feedback resistors and reduces BOM cost. |
| Hiccup-mode overcurrent protection | Enters 1024-cycle shutdown after 12µs fault detection - prevents thermal runaway during short-circuit conditions. |
| Integrated 37mΩ/34mΩ MOSFETs | Removes external switch losses and layout complexity - simplifies design while maintaining >92% efficiency at 3A/1.8Vout. |
| Adjustable soft-start via SS pin | Capacitor sets startup time (e.g., 100nF ≈ 7.5ms) - avoids input rail collapse and downstream reset glitches. |
| Lead-free 4mm × 4mm TQFN-EP | 24-pin footprint compatible with standard reflow profiles - exposed pad improves thermal resistance to 32°C/W (junction-to-board). |
Applications
| ASIC/CPU Core Supply | DDR Memory Power |
|---|---|
Use Scenario: Powers 1.2V or 1.5V core logic of FPGA or application processor in portable baseband or edge AI modules. IC Role / Device Role / Timing Role: Primary point-of-load regulator delivering tightly regulated, low-noise 3A DC output with fast load-step response. Use Value: ±1% accuracy and 2MHz switching enable compact 0.47µH inductor + 22µF ceramic solution - reducing board area by 40% vs. legacy 500kHz designs. | Use Scenario: Supplies VDDQ rail for DDR3/DDR4 memory subsystems requiring tight tracking between VDD and VDDQ. IC Role / Device Role / Timing Role: Tracking regulator using REFIN to mirror reference voltage from master supply - maintains <15mV inter-rail offset. Use Value: REFIN input and sink/source capability allow bidirectional current flow during memory read/write transitions - eliminating need for discrete tracking circuits. |
| Telecom Line Card POL | RAID Controller Power |
Use Scenario: Provides 2.5V or 3.3V auxiliary power to SerDes, PHY, and management MCU on carrier-grade line cards. IC Role / Device Role / Timing Role: Secondary regulator fed from 3.3V intermediate bus - handles dynamic load steps up to 2A/µs. Use Value: 20% switching frequency loop bandwidth delivers <50mV undershoot on 2A load step - meets GR-1089 immunity requirements without added bulk capacitance. | Use Scenario: Generates 1.2V or 1.8V for RAID-on-chip controllers and SAS/SATA bridge ICs in enterprise storage enclosures. IC Role / Device Role / Timing Role: High-reliability POL with thermal shutdown and hiccup-mode protection - withstands sustained 85°C ambient and airflow interruptions. Use Value: Exposed pad and 32°C/W θJA ensure junction stays <125°C at full 3A load - extending MTBF beyond 100,000 hours per Telcordia SR-332. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54332DR | 3A, 3.5–28V input, fixed 570kHz fSW, no VID pins, lower efficiency at 2.5VIN | Suitable for higher-input industrial rails; lacks VID flexibility and 2MHz capability for ultra-compact designs. | Choose TPS54332DR only if input exceeds 3.6V or VID selection is unnecessary - not drop-in for MAX8643ETG+. |
| RTQ2132BGQW | 3A, 2.5–5.5V input, 600kHz–2.2MHz fSW, integrated compensation, no REFIN/VID | Supports wider input range and simpler layout; missing REFIN tracking and nine VID presets for DDR-specific use cases. | Select RTQ2132BGQW when minimizing external components is priority - but verify absence of VID/REFIN doesn't impact system-level voltage sequencing. |
Compared with TPS54332DR and RTQ2132BGQW, the MAX8643ETG+ uniquely combines VID-selectable outputs, REFIN-based tracking, and 2MHz operation in a 4mm × 4mm package - making it the only option validated for space-constrained DDR memory and multi-rail ASIC core supplies requiring ±1% accuracy across temperature.
Availability
MAX8643ETG+ is available at Aetrix Electronics and suitable for point-of-load regulation, DDR memory power delivery, and telecom line card applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing from authorized channels.
Supply support for MAX8643ETG+ 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) designs precision analog, mixed-signal, and power management ICs for demanding industrial, communications, and computing applications.
The MAX8643ETG+ belongs to Maxim's high-frequency synchronous buck regulator product line, engineered specifically for low-input-voltage, high-current POL applications where board space, thermal performance, and output accuracy are critical constraints.
FAQ
What is the maximum supported switching frequency for MAX8643ETG+?
The MAX8643ETG+ supports a programmable switching frequency range from 500kHz to 2MHz, set by an external resistor connected from the FREQ pin to GND. At RFREQ = 23.2kΩ, the typical frequency is 2.0MHz - enabling use of sub-1µH inductors and minimizing output capacitor size. Operation above 2MHz is not guaranteed and may compromise stability or efficiency.
Does MAX8643ETG+ support external voltage reference input?
Yes, the MAX8643ETG+ supports external reference input via the REFIN pin. When an external voltage is applied to REFIN, the FB pin regulates to match that voltage - enabling tracking configurations for DDR VDDQ rails. The internal 0.6V reference is used when REFIN is tied to the SS pin. Note: soft-start is disabled when REFIN is externally driven.
How is output voltage selected on MAX8643ETG+?
The MAX8643ETG+ offers two output voltage configuration methods: (1) VID selection using CTL1 and CTL2 pins (tri-state: GND/VDD/unconnected) to choose among nine preset values (0.6V–2.5V), or (2) analog feedback using a resistor divider from OUT to GND with FB referenced to the 0.6V internal reference. VID settings must be fixed before enabling EN.
What thermal protection features does MAX8643ETG+ include?
The MAX8643ETG+ includes thermal shutdown at +165°C with 20°C hysteresis. When junction temperature exceeds this threshold, the device disables switching and pulls PWRGD low. After cooling by 20°C, it automatically recovers and initiates soft-start. This hiccup-style protection prevents permanent damage during sustained overload or inadequate PCB heatsinking.
Can MAX8643ETG+ operate with ceramic output capacitors only?
Yes, the MAX8643ETG+ is fully compatible with all-ceramic output capacitor designs due to its high-bandwidth error amplifier (>14MHz), voltage-mode control, and support for type III compensation. Ceramic capacitors (e.g., 22µF X5R 0805) are recommended to minimize ESR/ESL, reduce output ripple, and achieve fast transient response without electrolytic or polymer alternatives.
MAX8643ETG+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.35V
- Voltage - Input (Max):
- 3.6V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 3.24V
- Current - Output:
- 3A
- Frequency - Switching:
- 500kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-TQFN (4x4)
MAX8643ETG+ FAQ
1.How can I place an order for MAX8643ETG+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX8643ETG+ 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 MAX8643ETG+ reliable?
The price and inventory of MAX8643ETG+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX8643ETG+ is usually 5 days.
3.What payment methods are accepted for MAX8643ETG+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX8643ETG+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX8643ETG+?
MAX8643ETG+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX8643ETG+ 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 MAX8643ETG+?
For technical support, including MAX8643ETG+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX8643ETG+ requirements.
6.How does Aetrix verify that MAX8643ETG+ is sourced from the original manufacturer or authorized distributors?
All MAX8643ETG+ 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 MAX8643ETG+ meets industry standards.
7.What is the process for return or replacement of MAX8643ETG+?
All MAX8643ETG+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX8643ETG+, 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 MAX8643ETG+ part is unused and in its original packaging.
Return procedure for MAX8643ETG+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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