The **AD1585CRT-R2** is a low-power, precision shunt mode voltage reference produced by Analog Devices. It is part of the AD158x family, specifically designed for high-accuracy applications where space and power consumption are critical. --- ### 1. Key Technical Specifications The AD1585 is categorized as a **Shunt Voltage Reference**, meaning it operates similarly to a Zener diode but with much higher precision and stability. | Parameter | Specification | | :--- | :--- | | **Output Voltage ($V_{out}$)** | 5.0 V | | **Initial Accuracy** | ±5.0 mV (for C-grade) | | **Temperature Coefficient** | 50 ppm/°C | | **Operating Current Range** | 65 µA to 10 mA | | **Package Type** | SOT-23 (3-lead) | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Functional Characteristics The "CRT" suffix in the part number provides specific information about its grading and packaging: * **A/B/C Grade:** The "C" denotes the highest precision grade within this series regarding initial error and drift. * **RT:** Indicates the **SOT-23** surface-mount package. * **R2:** Refers to the tape and reel packaging size (usually a 7-inch reel containing 2,000 units). ### 3. Pin Configuration The device is housed in a small 3-pin SOT-23 package, though only two pins are functionally required for operation as a shunt reference. | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **+V** | Positive terminal (Output/Feedback) | | 2 | **-V** | Negative terminal (Ground) | | 3 | **NC** | No internal connection | --- ### 4. Typical Application Circuit Because it is a shunt reference, it requires an external resistor ($R_s$) to limit the current. The resistor value is calculated based on the input voltage ($V_{in}$) and the desired operating current ($I_q$). ```text Vin (Input Voltage) | [Rs] <-- Series Resistor | +----o Vout (5.0V Reference) | [AD1585] | GND ``` ### 5. Common Use Cases 1. **Analog-to-Digital Converters (ADCs):** Providing a stable 5V reference for high-resolution data acquisition. 2. **Battery Powered Portables:** Due to its ultra-low minimum current (65 µA), it extends battery life. 3. **Precision Instrumentation:** Used in sensors where voltage stability over temperature changes is required. 4. **Power Supplies:** Serving as a reference for feedback loops in linear regulators. ---