The **ADM1029ARQZ-R7** is a specialized dual-channel remote thermal controller and fan speed monitor manufactured by **onsemi** (formerly Analog Devices). It is designed specifically for system cooling management in computers and industrial hardware. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Supply Voltage (Vcc)** | 3.0V to 5.5V | | **Interface** | SMBus (I2C Compatible) | | **Temperature Channels** | 1 Internal, 1 Remote (External Diode) | | **Fan Channels** | 2 Tachometer inputs / 2 PWM/DAC outputs | | **Package** | 24-Lead QSOP (Quarter Size Outline Package) | | **Operating Temperature** | 0°C to +100°C | --- ### 2. Core Functional Blocks #### A. Thermal Monitoring The device features an internal temperature sensor and a "Remote" channel. The remote channel connects to a discrete transistor (e.g., 2N3904) or a thermal diode embedded inside a CPU or FPGA to monitor localized heat. * **Accuracy:** Typically $\pm 1^\circ C$. * **Resolution:** 8-bit digital output. #### B. Fan Control Mechanism The ADM1029 allows for two methods of fan speed control: 1. **PWM Control:** Sends a pulse-width modulated signal to the fan's control pin. 2. **DAC Control:** Provides an analog voltage output for controlling linear fan drivers. #### C. Fault Detection and Safety The chip includes dedicated logic for system protection: * **C_T (Critical Temperature):** A hardware-based output that triggers if temperatures exceed a hard-coded limit, even if the software crashes. * **Fault Pins:** Alerts the system to fan failure or stalled rotors. --- ### 3. Pinout Description (Selection) | Pin Name | Function | | :--- | :--- | | **VCC/GND** | Power supply pins. | | **SDA/SCL** | SMBus data and clock lines for communication with the CPU. | | **TACH1/2** | Inputs for fan speed feedback signals. | | **PWM/DAC1/2** | Control outputs to set fan speeds. | | **D+/D-** | Connection pins for the external remote temperature diode. | | **INT** | Interrupt output to notify the host of a fault condition. | --- ### 4. Typical Application Circuit The ADM1029 is usually placed between a microprocessor and the cooling fans. ```mermaid graph LR CPU[Host CPU] -- SMBus --> ADM1029 Remote_Diode -- Sense --> ADM1029 ADM1029 -- PWM Output --> Fan_Driver Fan_Driver --> Fan[Cooling Fan] Fan -- Tach Signal --> ADM1029 ``` --- ### 5. Part Number Breakdown: ADM1029ARQZ-R7 * **ADM1029:** Base part number. * **A:** Performance grade. * **RQ:** Package type (QSOP). * **Z:** RoHS compliant (Lead-free). * **-R7:** Tape and Reel packaging (7-inch reel).