Overview
The AD736BQ, produced by Analog Devices Inc., is a low power, precision, monolithic true rms-to-dc converter. It is designed to compute the rms value of both ac and dc input voltages with high accuracy. The device is laser trimmed to ensure a maximum error of ±0.3 mV ± 0.3% of reading with sine wave inputs. It maintains high accuracy across a wide range of input waveforms, including variable duty-cycle pulses and triac (phase)-controlled sine waves. The AD736BQ is optimized for use in battery-powered applications due to its low power consumption of 1 mW and a supply current of only 200 µA.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Range | - | - | 200 mV rms | - |
| High Input Impedance | - | - | 10^12 Ω | - |
| Low Input Impedance | - | - | 8 kΩ | - |
| Input Bias Current | - | - | 25 pA | - |
| Accuracy | - | - | ±0.3 mV ± 0.3% of reading | - |
| Power Supply Range | +2.8 V, -3.2 V | - | ±16.5 V | - |
| Quiescent Current | 160 µA | 200 µA | - | - |
| Operating Temperature Range | -40°C | - | +85°C | - |
| Package Types | - | - | PDIP, SOIC, CERDIP | - |
Key Features
- Computes the true rms value, average rectified value, or absolute value of various input signals.
- Requires only one external component, an averaging capacitor, for true rms measurement.
- Low power consumption of 1 mW, making it suitable for battery-powered applications.
- High input impedance of 10^12 Ω eliminates the need for an external buffer when interfacing with input attenuators.
- Low impedance input available for measuring input signals up to 300 mV rms from low power supply voltages.
- Buffered voltage output with no external trims needed for specified accuracy.
- Operates as an ac-coupled device with the addition of one external capacitor, resolving input signal levels of 100 µV rms or less.
- Maintains high accuracy for input waveforms with crest factors up to 5.
Applications
- Portable multimeters and other battery-powered measurement devices.
- Upgrading the performance of non-rms precision rectifiers in various applications.
- Measuring a wide range of input waveforms, including variable duty-cycle pulses and triac (phase)-controlled sine waves.
- Applications requiring high accuracy and low power consumption.
Q & A
- What is the primary function of the AD736BQ?
The AD736BQ is a true rms-to-dc converter that computes the rms value of both ac and dc input voltages.
- What is the input impedance of the AD736BQ?
The AD736BQ has a high input impedance of 10^12 Ω and a low input impedance of 8 kΩ.
- What is the power consumption of the AD736BQ?
The AD736BQ consumes a maximum of 1 mW and has a supply current of 200 µA.
- What are the operating temperature ranges for the AD736BQ?
The AD736BQ operates over the industrial temperature range of -40°C to +85°C.
- What types of packages are available for the AD736BQ?
The AD736BQ is available in PDIP, SOIC, and CERDIP packages.
- Can the AD736BQ measure input signals with high crest factors?
Yes, the AD736BQ can measure input waveforms with crest factors up to 5, introducing only 2.5% additional error at the 200 mV full-scale input level.
- Does the AD736BQ require external trims for accuracy?
No, the AD736BQ does not require external trims for specified accuracy.
- How can the AD736BQ be operated as an ac-coupled device?
The AD736BQ can be operated as an ac-coupled device by adding one external capacitor.
- What is the bandwidth of the AD736BQ for a 1% reading error?
The AD736BQ has a 1% reading error bandwidth that exceeds 10 kHz for input amplitudes from 20 mV rms to 200 mV rms.
- Can the AD736BQ be used in battery-powered applications?
Yes, the AD736BQ is optimized for use in battery-powered applications due to its low power consumption.
