## Overview of AD7680BRJZ-R2 The **AD7680BRJZ-R2** is a high-performance, 16-bit, successive-approximation (SAR) Analog-to-Digital Converter (ADC). Manufactured by Analog Devices, it is known for its extremely compact size and low power consumption, making it ideal for battery-powered and space-constrained applications. --- ### Key Technical Specifications | Feature | Specification | |:---|:---| | **Resolution** | 16-Bit | | **Throughput Rate** | Up to 100 kSPS (kilo-samples per second) | | **Interface** | Serial SPI / QSPI / MICROWIRE / DSP Compatible | | **Input Voltage Range** | 0V to $V_{DD}$ (Unipolar) | | **Power Supply** | 2.5V to 5.5V | | **Power Consumption** | ~3 mW (at 100 kSPS, 3V supply) | | **Package Type** | SOT-23-6 (Tiny 6-lead surface mount) | | **Operating Temp** | -40°C to +85°C | --- ### Core Functional Blocks 1. **SAR ADC Core:** The heart of the device uses Successive Approximation Register logic to convert analog signals to digital values without the latency issues found in pipeline ADCs. 2. **Sample-and-Hold (T/H):** It features a track-and-hold circuit that ensures the input signal remains stable during the conversion process. 3. **Serial Interface:** It utilizes a 3-wire high-speed serial interface. The data is clocked out on the falling edge of the serial clock (SCLK), allowing for easy integration with microcontrollers. 4. **Reference:** The reference for the device is taken internally from the $V_{DD}$ supply, which simplifies the design but requires a stable and clean power supply for high accuracy. --- ### Pin Configuration (SOT-23-6) | Pin No. | Name | Description | |:---:|:---|:---| | 1 | **$V_{DD}$** | Power supply and Reference input. | | 2 | **GND** | Ground reference. | | 3 | **$V_{IN}$** | Analog input channel. | | 4 | **SCLK** | Serial Clock input for data synchronization. | | 5 | **SDAT** | Serial Data output (the converted 16-bit word). | | 6 | **$\overline{CS}$** | Chip Select (Active Low) / Initiates conversion. | --- ### Typical Application Circuit The AD7680 requires minimal external components. A typical implementation involves decoupling capacitors on the supply line and a simple RC filter on the analog input to reduce noise. ```c // Pseudocode for reading AD7680 via SPI uint16_t readADC() { uint16_t result = 0; digitalWrite(CS_PIN, LOW); // Start conversion result = SPI.transfer16(0x0000); // Clock in 16 bits of data digitalWrite(CS_PIN, HIGH); // End communication return result; } ``` --- ### Common Use Cases * **Battery-Powered Systems:** Due to its low power draw and "Power-Down" mode between conversions. * **Medical Instrumentation:** Portable ECGs or glucose meters. * **Remote Data Acquisition:** Ideal for isolated sensors where space is at a premium. * **Process Control:** Monitoring transducer outputs in industrial environments.