### Technical Overview of the REF02CPZ The **REF02CPZ** is a precision voltage reference integrated circuit manufactured by Analog Devices (formerly Precision Monolithics/Maxim). It is widely recognized for its stability and is a staple in high-precision analog design. --- ### 1. Key Technical Specifications The "CPZ" suffix indicates a Plastic Dual-In-Line Package (PDIP) with a lead-free finish and a commercial temperature range. | Parameter | Specification | | :--- | :--- | | **Output Voltage ($V_{OUT}$)** | +5.0V | | **Input Voltage Range** | 7.0V to 40V | | **Output Adjustment Range** | $\pm$3% minimum | | **Temperature Coefficient** | 8.5 ppm/°C (Typical) | | **Supply Current** | 1.4 mA (Typical) | | **Line Regulation** | 0.01 %/V | | **Package Type** | 8-Lead PDIP (Plastic) | --- ### 2. Functional Pins The REF02 series typically utilizes the following pin configuration in an 8-pin package: 1. **NC / TEMP**: No connection or Temperature output (depending on specific revision). 2. **$V_{IN}$**: Input voltage supply. 3. **TEMP**: Provides a voltage output proportional to the absolute temperature (approx. 2.1mV/°C). 4. **GND**: Ground reference. 5. **TRIM**: Allows for fine-tuning the 5V output using a potentiometer. 6. **$V_{OUT}$**: The precision +5V output. 7. **NC**: No internal connection. 8. **NC**: No internal connection. --- ### 3. Core Features * **Low Noise:** It produces very low high-frequency noise, making it ideal for high-resolution Data Converters (ADCs/DACs). * **Built-in Temperature Transducer:** Unique to the REF02 is the **TEMP pin**, which outputs a voltage that varies linearly with temperature. This allows the chip to act as a temperature sensor while simultaneously providing a voltage reference. * **High Input Range:** With an input capability up to 40V, it can be powered directly from high-voltage industrial rails. * **Trim Capability:** The output voltage can be adjusted (trimmed) via an external potentiometer without affecting the temperature coefficient. --- ### 4. Common Applications The REF02CPZ is typically found in: * **Precision ADCs:** Providing the reference for 12-bit to 16-bit analog-to-digital converters. * **Digital Voltmeters:** Acting as the "yardstick" for measurement accuracy. * **Industrial Controls:** Used in 4-20mA loop transmitters. * **Calibration Standards:** Used in portable equipment that requires a stable voltage over time. --- ### 5. Application Circuit (Example) To achieve a standard 5.0V output with minimal noise, a simple bypass capacitor setup is used: ```markdown [Input 15V] ----+---- [Pin 2: Vin] | [0.1uF Cap] | [GND] --------- [Pin 4: GND] | [Pin 6: Vout] ----> [5.0V Output] | [1uF Cap] | [GND] ```