The **ADM1023ARQZ-R7** is a precision dual-channel digital thermometer and environmental monitor, primarily designed for thermal management in computers and embedded systems. It is manufactured by Analog Devices (formerly ON Semiconductor/ADI). --- ## 1. Core Technical Specifications The device acts as a remote and local temperature sensor, communicating over a 2-wire serial interface. | Feature | Specification | | :--- | :--- | | **Interface** | SMBus (System Management Bus) / I2C | | **Supply Voltage** | 3.0V to 5.5V | | **Temperature Accuracy** | ±1°C (Remote), ±3°C (Local) | | **Resolution** | 0.125°C (Remote channel) | | **Package Type** | QSOP-16 | | **Operating Current** | 500 µA (Max) | | **Measurement Range** | 0°C to +127°C | --- ## 2. Key Internal Components & Functions The IC integrates several electronic blocks to ensure accurate thermal reporting: ### A. Dual Sensing Channels * **Internal Sensor:** An on-chip bandgap temperature sensor used to monitor the ambient temperature where the IC is mounted. * **Remote Sensor:** Uses a "Thermal Diode" (typically a substrate PNP transistor found inside CPUs or GPUs) to measure the temperature of a high-power component directly. ### B. Delta-Vbe Measurement The device operates by injecting two different currents into the remote diode and measuring the change in base-emitter voltage ($\Delta V_{be}$). This allows the chip to calculate temperature while canceling out parasitic resistances. ### C. Digital Interface * **SMBus Logic:** Allows the host (CPU/Microcontroller) to read temperature data and write configuration registers. * **ALERT Output:** An interrupt pin that triggers if the temperature exceeds a pre-programmed threshold, allowing for emergency system shutdowns or fan speed increases. --- ## 3. Pin Configuration (QSOP-16) Below is a simplified layout of the critical pins: | Pin Name | Function | | :--- | :--- | | **VDD** | Positive Supply Voltage | | **GND** | Ground Reference | | **D+ / D-** | Connections to the remote thermal diode | | **SCLK** | SMBus Clock Input | | **SDATA** | SMBus Bidirectional Data Line | | **ALERT** | Interrupt output for over/under temperature | --- ## 4. Typical Application Circuit In a standard design, the ADM1023 is placed near the CPU: 1. **D+ and D-** pins are routed to the CPU's thermal diode pins using differential traces to minimize noise. 2. **Pull-up resistors** (typically 4.7kΩ to 10kΩ) are required on the SCLK, SDATA, and ALERT lines. 3. A **bypass capacitor** (0.1µF) is placed close to the VDD pin to filter power supply noise. ---