The **AD736KRZ-R7** is a high-precision, low-power, monolithic true RMS-to-DC converter manufactured by Analog Devices. It is widely used for measuring the complex AC signals found in multimeters and industrial instrumentation. --- ### 1. General Specifications Below are the primary technical parameters for the AD736KRZ-R7: | Feature | Specification | | :--- | :--- | | **Function** | True RMS-to-DC Converter | | **Input Voltage Range** | 0 to 200 mV RMS | | **Supply Voltage** | ±2.8 V to ±16.5 V (Dual) or +5.6 V to +33 V (Single) | | **Supply Current** | 160 µA (Typical) | | **Bandwidth (3dB)** | 190 kHz (at 200 mV input) | | **Package Type** | 8-Lead SOIC (N-Suffix) | | **Operating Temp** | -40°C to +85°C | --- ### 2. Key Internal Components The AD736 achieves its conversion through several internal stages: 1. **Input Amplifier:** A high-impedance (10¹² Ω) buffer that allows for easy interfacing with high-impedance sensors or attenuators. 2. **Full-Wave Rectifier:** Converts the AC input signal into an absolute value signal. 3. **RMS Core:** Uses a "log-antilog" circuit to perform the mathematical operation: $V_{out} = \text{Avg}[V_{in}^2 / V_{out}]$. 4. **Output Buffer:** Provides a low-impedance DC output, making it compatible with ADCs or display drivers. --- ### 3. Part Number Breakdown The suffixing on this part provides specific information regarding its packaging and performance grade: * **AD736**: The base model number. * **K**: Indicates the performance grade (higher accuracy/lower error compared to the 'J' grade). * **R**: Denotes the package type (SOIC - Small Outline Integrated Circuit). * **Z**: Indicates a RoHS-compliant (Lead-Free) part. * **R7**: Specifies the shipping method (7-inch Tape and Reel, typically containing 1,000 units). --- ### 4. Application Circuit Example To use the AD736 in a standard configuration, external capacitors ($C_{AV}$ and $C_B$) are required to set the averaging time constant and the low-frequency cutoff. ```c // Concept of Operation (Pseudocode logic) Input_Signal = AC_Waveform; RMS_Value = sqrt(mean(Input_Signal^2)); Output_DC = RMS_Value; // Analog DC level proportional to RMS ``` --- ### 5. Common Use Cases * **Precision Digital Multimeters (DMMs):** For measuring non-sinusoidal AC voltages. * **Power Monitors:** Calculating effective power consumption in AC lines. * **Communication Equipment:** Measuring signal strength and noise levels. * **Industrial Sensors:** Processing vibration or acoustic data where RMS values are critical.