The **ADR1581ARTZ-R2** is a high-precision, low-power shunt mode voltage reference produced by Analog Devices. It is designed to provide a stable 1.25V output for data acquisition systems and high-resolution converters. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Output Voltage** | 1.25 V | | **Tolerance (Initial Accuracy)** | ±0.1% (Grade A) | | **Temperature Coefficient** | 50 ppm/°C | | **Operating Current Range** | 60 μA to 10 mA | | **Package Type** | SOT-23-3 (ARTZ) | | **Operating Temperature** | -40°C to +85°C | | **Output Noise** | 4 μV p-p (0.1 Hz to 10 Hz) | --- ### 2. Functional Characteristics The ADR1581 is a **Shunt Reference**, which means it operates similarly to a Zener diode but with much higher precision. * **Low Operating Current:** It can maintain regulation with as little as 60 μA, making it ideal for battery-powered applications. * **No Output Capacitor Required:** Unlike many linear regulators, it is stable without an external output capacitor, though one can be added to reduce noise. * **High Stability:** It offers excellent long-term drift characteristics and resistance to thermal hysteresis. --- ### 3. Pin Configuration (SOT-23) | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **+V** | Positive terminal (Output/Input) | | 2 | **-V** | Negative terminal (Ground) | | 3 | **NC** | No internal connection (should be left floating) | --- ### 4. Typical Application Circuit To use the ADR1581, a current-limiting resistor ($R_S$) is required to set the operating current based on the input voltage ($V_{IN}$). ```text V_IN ----[ R_S ]----+---- V_OUT (1.25V) | [ADR1581] | GND ``` **Formula for $R_S$ Selection:** $R_S = \frac{V_{IN} - V_{OUT}}{I_L + I_Q}$ *Where:* * $V_{IN}$ = Input Supply Voltage * $V_{OUT}$ = 1.25V * $I_L$ = Load Current * $I_Q$ = Operating current of the ADR1581 (typically 100 μA for stability) --- ### 5. Common Use Cases * **Precision Data Converters:** Providing the reference voltage for 12-bit to 16-bit ADCs/DACs. * **Portable Instrumentation:** Handheld meters where power consumption is critical. * **Power Supplies:** Serving as a reference for switching regulator control loops. ---