Overview
The AD598AD, produced by Analog Devices Inc., is a complete, monolithic Linear Variable Differential Transformer (LVDT) signal conditioning subsystem. This device is designed to work in conjunction with LVDTs and RVDTs to convert mechanical position into a unipolar or bipolar DC voltage with high accuracy and repeatability. The AD598AD integrates all necessary circuit functions, including a low distortion sine wave oscillator, a decoder, a filter, and an output amplifier, making it a comprehensive solution for LVDT and RVDT signal conditioning.
Key Specifications
| Parameter | Description |
|---|---|
| Temperature Range | –40°C to +85°C |
| Package | 20-Pin Ceramic DIP |
| LVDT Excitation Frequency | 20 Hz to 20 kHz (determined by a single external capacitor) |
| Primary Drive Voltage | Up to 24 V rms |
| Secondary Input Levels | As low as 100 mV rms |
| Gain Error | ±1% full scale at +25°C |
| Gain Drift | 50 ppm/°C of FS |
| Offset Drift | 50 ppm/°C of FS |
| Nonlinearity | Defined as the maximum measured deviation from a straight line, in units of ppm of full scale |
Key Features
- Single Chip Solution: Contains internal oscillator and voltage reference.
- No Adjustments Required: Eliminates the need for adjustments, improving ease of use.
- Insensitive to Transducer Null Voltage and Phase Shifts: Ensures high accuracy and stability.
- Temperature Stability: Improved temperature stability enhances reliability.
- Transducer Interchangeability: Supports a wide range of LVDTs and RVDTs.
- Multiple LVDTs Support: Can drive multiple LVDTs in series or parallel, within power dissipation limits.
- Thermally Protected Excitation Output: Ensures safe operation in various environments.
- Long Cable Drive Capability: Can drive LVDTs at the end of 300 feet of cable and position output up to 1000 feet.
Applications
- Telemetry Applications: Suitable for remote sensing and data transmission.
- Hostile Environments: Can operate in harsh environments where interface electronics may be remote from the LVDT.
- Electromechanical Servo Loops: Can be used as a loop integrator in simple electromechanical servo loop designs.
- Industrial Automation: Ideal for position sensing and control in industrial automation systems.
- Aerospace and Defense: Available in military-grade packaging, processed to MIL-STD-883B standards.
Q & A
- What is the AD598AD used for?
The AD598AD is used as a signal conditioning subsystem for Linear Variable Differential Transformers (LVDTs) and Rotary Variable Differential Transformers (RVDTs) to convert mechanical position into a DC voltage.
- What are the key components of the AD598AD?
The AD598AD includes a sine wave oscillator, a decoder, a filter, and an output amplifier.
- What is the temperature range of the AD598AD?
The AD598AD operates within a temperature range of –40°C to +85°C.
- How is the LVDT excitation frequency determined?
The LVDT excitation frequency is determined by a single external capacitor and can range from 20 Hz to 20 kHz.
- Can the AD598AD drive multiple LVDTs?
Yes, the AD598AD can drive multiple LVDTs in series or parallel, provided power dissipation limits are not exceeded.
- What are the benefits of the ratiometric decoding scheme used in the AD598AD?
The ratiometric decoding scheme eliminates the effects of transducer null voltage and primary to secondary phase shifts, improving system accuracy and stability.
- How does the AD598AD handle long cable lengths?
The AD598AD can drive an LVDT at the end of 300 feet of cable and the position output can drive up to 1000 feet of cable.
- Is the AD598AD suitable for military applications?
Yes, the AD598AD is available in military-grade packaging, processed to MIL-STD-883B standards.
- What are some common applications of the AD598AD?
The AD598AD is commonly used in telemetry applications, hostile environments, electromechanical servo loops, industrial automation, and aerospace and defense.
- Does the AD598AD require any adjustments?
No, the AD598AD does not require any adjustments, making it easier to use and integrate into systems.
