Analog Devices Inc./Maxim Integrated MAX6650EUB+TG002

Overview

MAX6650EUB+TG002 from Maxim Integrated is a single-fan SMBus/I2C-compatible fan-speed regulator and monitor IC for 5V/12V brushless DC fans with open-collector tachometers. It linearly regulates fan voltage via external MOSFET/bipolar transistor, maintains tachometer frequency to match programmable Fan-Speed Register values, and operates across –40°C to +85°C in a 10-pin µMAX package. Used in server thermal management for acoustic noise reduction and power-efficient cooling.

For engineers reviewing the MAX6650EUB+TG002 datasheet, MAX6650EUB+TG002 pinout, MAX6650EUB+TG002 application, or MAX6650EUB+TG002 equivalent, key selection criteria include closed-loop tachometer feedback accuracy, GPIO0 alert output configuration, 3V–5.5V supply compatibility, and 10-pin µMAX footprint constraints in dense PCB layouts.

Technical Context

The MAX6650EUB+TG002 implements dual control loops: an analog feedback loop using an internal 8-bit DAC (1.5V reference) and op-amp to regulate FB voltage and drive OUT, and a digital tachometer loop that compares measured tach pulse period against a scaled register value to adjust DAC output. It supports only single-tachometer input (TACH0), unlike the MAX6651's four-channel capability.

It uses a fixed 254kHz ±10% internal oscillator (no external clock option), supports four SMBus slave addresses via ADD pin strapping, and provides three GPIOs (GPIO0 as alert output, GPIO1 as hardware full-on override, GPIO2 not present). All registers are volatile and reset on POR at VCC > 1.6V.

Key Specifications

Pinout & Package

MAX6650EUB+TG002 is housed in a 10-pin µMAX® package (3mm × 3mm, 0.5mm pitch), RoHS-compliant and lead(Pb)-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fan-speed regulation applications.

Compared with MAX6651EEE+, MAX6650EUB+TG002 offers lower cost and smaller footprint for single-fan use but lacks multi-tach support; compared with ADM1032ARMZ-REEL, it delivers superior tach accuracy and deterministic hardware fault response at the expense of integrated temperature sensing.

Availability

MAX6650EUB+TG002 is available at Aetrix Electronics and suitable for RAID enclosures, desktop computers, telecommunications equipment, and industrial embedded servers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX6650EUB+TG002 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 industrial, computing, and communications markets.

The MAX6650/MAX6651 product line was engineered specifically for SMBus-based thermal management in space-constrained, reliability-critical systems-emphasizing deterministic closed-loop fan control, hardware fail-safes, and minimal external component count.

FAQ

What is the function of the ADD pin on the MAX6650EUB+TG002?

The ADD pin on the MAX6650EUB+TG002 selects one of four SMBus slave addresses (36h, 3Eh, 90h, or 96h) by connecting it to GND via a 10kΩ resistor or leaving it floating. This enables multiple MAX6650EUB+TG002 devices to share the same SMBus without address collision. The pin has ±1µA leakage and accepts 0.1V–VCC–0.05V logic levels; it is not used for clock or data functions.

Can the MAX6650EUB+TG002 control a 12V fan with closed-loop tachometer feedback?

Yes, the MAX6650EUB+TG002 supports both 5V and 12V fans in closed-loop mode. Configuration Register bit 3 must be set to '1' to enable 12V operation, which adjusts tachometer threshold voltage and prescaler scaling. The TACH0 input tolerates up to 13.2V, and the FB pin feedback range accommodates 12V fan drive when paired with appropriate external MOSFET RDS(ON) and layout.

How does the GPIO1 pin provide hardware full-on override in the MAX6650EUB+TG002?

In the MAX6650EUB+TG002, GPIO1 is configured as a FULL-ON input by setting bits 3:2 of the GPIO Definition Register to '01'. When GPIO1 is pulled low externally, it forces the fan to 100% speed regardless of SMBus commands, Fan-Speed Register contents, or DAC state-providing fail-safe operation during microcontroller lockup or firmware crash. The pin sinks ≤10mA at 0.4V.

What is the maximum tachometer input frequency supported by the MAX6650EUB+TG002?

The MAX6650EUB+TG002 supports a maximum tachometer input frequency of 1kHz. This corresponds to a minimum tachometer period of 1ms, consistent with its internal timing resolution and overflow handling in the Tachometer Count Register. At 2 pulses per revolution, this supports fans up to 30,000 RPM (500 RPS) when using the shortest 0.25s count time.

Does the MAX6650EUB+TG002 require an external clock source for operation?

No, the MAX6650EUB+TG002 uses an internal 254kHz ±10% oscillator and does not require an external clock. Unlike the MAX6651, it lacks GPIO2 and cannot accept or generate synchronization clocks. All timing-including tach period calculation, DAC settling, and SMBus communication-is derived from this internal oscillator, simplifying board design and reducing component count.