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Analog Devices Inc./Maxim Integrated MAX6651EEE+TG05
- Part No.:
- MAX6651EEE+TG05
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Motor Drivers, Controllers
- Package:
- -
- Datasheet:
-
MAX6651EEE+TG05.pdf
- Description:
- INTEGRATED CIRCUIT
- Quantity:
- Payment:
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Product details
Overview
MAX6651EEE+TG05 from Maxim Integrated is a 16-pin QSOP SMBus/I2C-compatible fan-speed regulator and monitor for single 5V/12V brushless fans, supporting up to four tachometer inputs for parallel fan control, with programmable closed-loop speed regulation, GPIO0 alert output, GPIO1 hardware full-on override, and internal oscillator frequency of 254kHz ±10% - deployed in server rack cooling and telecom chassis thermal management.
For engineers reviewing the MAX6651EEE+TG05 datasheet, MAX6651EEE+TG05 pinout, MAX6651EEE+TG05 application, or MAX6651EEE+TG05 equivalent, key selection considerations include tachometer input count (4), SMBus slave address configurability (4 options), GPIO2 clock synchronization capability, DAC resolution (8-bit), and feedback voltage range (VFB + 0.5V to VFB + 3V).
Technical Context
The MAX6651EEE+TG05 implements dual control loops: an analog feedback loop using an 8-bit DAC (±5 LSB DNL) and internal op-amp to regulate fan voltage via external N-MOSFET/bipolar transistor, and a digital tachometer loop that forces tachometer frequency to match a reference derived from the Fan-Speed Register, prescaler (÷1/÷2/÷4/÷8/÷16), and internal 254kHz oscillator. It supports both closed-loop (auto-regulation) and open-loop (µC-driven DAC) operation modes.
Its GPIO structure includes three open-drain pins (GPIO0–GPIO2) with configurable roles: GPIO0 as active-low ALERT output on fault detection, GPIO1 as hardware FULL-ON override input, and GPIO2 (MAX6651-specific) as internal clock output or external clock input for multi-device synchronization - all sinking up to 10mA with 100kΩ internal pullup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.0V to 5.5V - powers logic and interface; supports 3.3V and 5V systems without level shifters. |
| Fan Voltage Support | 5VDC or 12VDC - enables direct control of common server/telecom cooling fans without external voltage translation. |
| Tachometer Inputs | 4 independent inputs (TACH0–TACH3) - allows monitoring and synchronized regulation of up to four parallel fans. |
| DAC Resolution | 8 bits with guaranteed monotonicity - provides 256 discrete fan voltage steps for fine-grained open-loop control. |
| SMBus Address Options | 4 slave addresses (0x36, 0x3E, 0x90, 0x96) - enables multiple MAX6651EEE+TG05 devices on same bus via ADD pin strapping. |
| Internal Oscillator | 254kHz ±10% - sets base timing for tachometer period calculation; stable enough for RPS accuracy within ±2% at 25°C. |
| GPIO Sink Current | 10mA per GPIO - sufficient to drive LEDs directly or interface with standard logic inputs without external buffers. |
Pinout & Package
MAX6651EEE+TG05 is housed in a 16-pin QSOP package (5.3mm × 10.2mm, 1.0mm height), RoHS-compliant and lead(Pb)-free (+ suffix), rated for -40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TACH0 | Primary tachometer input | Closes speed control loop; used for closed-loop regulation of main fan. |
| TACH1–TACH3 | Secondary tachometer inputs | Monitor additional fans; enable synchronized control when used in parallel configurations. |
| OUT | Analog output driver | Drives gate/base of external N-MOSFET or bipolar transistor to regulate fan voltage on low side. |
| FB | Feedback input | Connects to source/emitter node of external transistor; closes analog control loop with internal op-amp. |
| GPIO0 | Configurable I/O | Default: active-low ALERT output signaling fault conditions (e.g., tach overflow, min/max output alarm). |
| GPIO1 | Configurable I/O | Default: FULL-ON hardware override input - forces fan to maximum speed on logic-low assertion, bypassing software. |
| GPIO2 | Configurable I/O (MAX6651 only) | Configurable as internal clock output (254kHz) or external clock input - synchronizes multiple MAX6651 devices. |
| ADD | Slave address select | Pin-strapped to GND/VCC/10kΩ-to-GND/high-Z to select one of four SMBus addresses (0x36/0x3E/0x90/0x96). |
| SDA/SCL | SMBus/I2C interface | Open-drain bidirectional data/clock lines compliant with SMBus v1.1 and I2C fast-mode (400kHz max). |
| VCC/GND | Power supply | 3.0V–5.5V logic supply; internal POR activates at VCC > 1.6V; 100mA max continuous current draw. |
Key Features
| Feature | Design Value |
|---|---|
| Closed-loop fan speed regulation | Automatically adjusts OUT voltage to force tachometer frequency to match programmed value - eliminates manual µC polling and PID tuning. |
| Hardware full-on override | GPIO1 acts as fail-safe input: logic-low assertion overrides all software commands and drives fan at 100% speed - critical for thermal safety in µC lockup scenarios. |
| Multi-fan synchronization | GPIO2 enables clock sharing across multiple MAX6651EEE+TG05 units - ensures identical tachometer timing references for consistent parallel fan behavior. |
| Four SMBus slave addresses | ADD pin configuration supports up to four devices on same bus without address conflict - simplifies thermal management in multi-zone chassis designs. |
| Programmable tachometer threshold | Configuration-byte bit 4 selects 5V or 12V tachometer input range - avoids signal clipping and false pulse detection across fan voltage variants. |
Applications
| RAID Storage Enclosures | Telecom Line Cards |
|---|---|
|
Use Scenario: High-density 2U/4U RAID chassis with 12–24 hot-swap fans requiring coordinated speed control based on disk temperature zones. IC Role / Device Role / Timing Role: MAX6651EEE+TG05 monitors up to four fans per controller, regulates speed via closed-loop tachometer matching, and reports status via SMBus to host BMC. Use Value: Reduces acoustic noise by 8–12dB(A) vs fixed-speed operation while maintaining <±2°C disk temperature uniformity across zones. |
Use Scenario: Carrier-grade line cards with ASICs generating 15–25W heat, requiring dynamic fan response to inlet air temperature shifts. IC Role / Device Role / Timing Role: MAX6651EEE+TG05 acts as local thermal manager - reads ambient sensor via SMBus, adjusts fan speed, and asserts GPIO0 ALERT on thermal runaway. Use Value: Enables sub-second fan ramp-up from idle (20% speed) to full (100%) within 1.2s of 10°C inlet rise - prevents ASIC throttling during burst traffic. |
| Enterprise Servers | Network Switch Chassis |
|
Use Scenario: Dual-socket Xeon servers with redundant 40mm/60mm fans per power domain, needing fault-tolerant speed control and hot-swap awareness. IC Role / Device Role / Timing Role: MAX6651EEE+TG05 uses TACH1–TACH3 to monitor backup fans; GPIO1 FULL-ON ensures cooling continuity if primary fan fails or µC hangs. Use Value: Achieves 99.999% thermal uptime via hardware-level failover - no firmware intervention required for fan redundancy activation. |
Use Scenario: 1RU/2RU Ethernet switches with 8–16 fans distributed across front/rear airflow paths, requiring zone-specific speed profiles. IC Role / Device Role / Timing Role: MAX6651EEE+TG05 configures GPIO2 as clock output to synchronize tachometer sampling across adjacent controllers - eliminates beat-frequency vibration. Use Value: Reduces mechanical resonance-induced fan wear by 35% and eliminates audible 2–5Hz pulsing noise in stacked chassis deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fan-speed regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6650EUB+ | 10-pin µMAX package; single tachometer input (TACH0 only); no GPIO2 or TACH1–TACH3; identical SMBus interface and DAC specs. | Suitable only for single-fan systems; lacks multi-fan monitoring/synchronization capability required for server/RAID use cases. | Select MAX6650EUB+ only when cost-sensitive single-fan control suffices and PCB space is constrained. |
| LM7805CV/NOPB | Fixed 5V linear regulator; no SMBus interface, tachometer input, DAC, or GPIOs; no fan control functionality. | Cannot perform closed-loop speed regulation or tachometer monitoring - serves only as power supply, not thermal management IC. | Not functionally equivalent; LM7805CV/NOPB is incompatible for fan control - included only as common mis-selection reference. |
Compared with MAX6650EUB+, MAX6651EEE+TG05 adds three tachometer inputs and GPIO2 clock sync for multi-fan coordination; compared with LM7805CV/NOPB, it delivers full SMBus-managed thermal control rather than passive voltage regulation - making it the sole viable choice for intelligent cooling systems.
Availability
MAX6651EEE+TG05 is available at Aetrix Electronics and suitable for enterprise servers, telecom line cards, and RAID storage enclosures requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for MAX6651EEE+TG05 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 and mixed-signal ICs for industrial, communications, and computing applications, with emphasis on power efficiency and system integration.
The MAX6651EEE+TG05 belongs to Maxim's thermal management product line, engineered specifically for SMBus-based intelligent fan control in high-reliability computing infrastructure where hardware fail-safes and multi-device synchronization are mandatory.
FAQ
What is the function of GPIO2 on the MAX6651EEE+TG05?
GPIO2 on the MAX6651EEE+TG05 is a multifunction pin configurable as an internal 254kHz clock output or an external clock input - enabling precise synchronization of tachometer sampling and speed regulation across multiple MAX6651EEE+TG05 devices in a chassis. This capability is absent in the MAX6650 and exclusive to the MAX6651EEE+TG05 variant.
Does the MAX6651EEE+TG05 support 12V fans?
Yes, the MAX6651EEE+TG05 supports both 5VDC and 12VDC brushless fans with built-in open-collector tachometers. Its tachometer inputs tolerate up to 13.2V, and the feedback input (FB) operates with VFB + 0.5V to VFB + 3V thresholds - allowing reliable detection across 12V fan tach signals without external attenuation.
How many tachometer inputs does the MAX6651EEE+TG05 have?
The MAX6651EEE+TG05 has four tachometer inputs: TACH0 (primary control loop), and TACH1, TACH2, TACH3 (monitor-only). All four accept open-collector/drain tachometer outputs and share the same 70–150kΩ input impedance - enabling coordinated monitoring of up to four parallel fans for synchronized speed regulation.
What is the SMBus clock frequency limit for the MAX6651EEE+TG05?
The MAX6651EEE+TG05 supports SMBus/I2C fast-mode operation up to 400kHz, with guaranteed timing compliance including tLOW ≥ 1.3µs, tHIGH ≥ 0.6µs, and tBUF ≥ 1.3µs. Its SDA/SCL pins are open-drain with ±1µA leakage and 6mA sink capability - compatible with standard 4.7kΩ pullups on 3.3V or 5V buses.
Can the MAX6651EEE+TG05 operate without an external microcontroller?
No - the MAX6651EEE+TG05 requires an external SMBus/I2C master (e.g., BMC, baseboard management controller, or host µC) to configure registers, set fan speed targets, read tachometer counts, and enable alarms. It has no autonomous startup behavior beyond power-on defaults (full-on mode, prescaler ÷4, all alarms disabled).
MAX6651EEE+TG05 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- -
- Function:
- -
- Output Configuration:
- -
- Interface:
- -
- Technology:
- -
- Step Resolution:
- -
- Applications:
- -
- Current - Output:
- -
- Voltage - Supply:
- -
- Voltage - Load:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX6651EEE+TG05 FAQ
1.How can I place an order for MAX6651EEE+TG05 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6651EEE+TG05 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 MAX6651EEE+TG05 reliable?
The price and inventory of MAX6651EEE+TG05 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6651EEE+TG05 is usually 5 days.
3.What payment methods are accepted for MAX6651EEE+TG05?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6651EEE+TG05 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6651EEE+TG05?
MAX6651EEE+TG05 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6651EEE+TG05 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 MAX6651EEE+TG05?
For technical support, including MAX6651EEE+TG05 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6651EEE+TG05 requirements.
6.How does Aetrix verify that MAX6651EEE+TG05 is sourced from the original manufacturer or authorized distributors?
All MAX6651EEE+TG05 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 MAX6651EEE+TG05 meets industry standards.
7.What is the process for return or replacement of MAX6651EEE+TG05?
All MAX6651EEE+TG05 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6651EEE+TG05, 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 MAX6651EEE+TG05 part is unused and in its original packaging.
Return procedure for MAX6651EEE+TG05:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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