Overview
The AD2S44-TM18B, manufactured by Analog Devices Inc., is a 14-bit dual channel, continuous tracking synchro/resolver-to-digital converter. This device is specifically designed for applications where space, weight, and cost are critical factors. It features two independent Type II servo loop tracking converters, utilizing a ratiometric conversion technique that provides excellent noise immunity and tolerance of long lead lengths. The converter is built using Analog Devices' proprietary BiMOS II process, combining low power CMOS digital logic with bipolar linear circuits to ensure high reliability and low internal component count.
Key Specifications
| Parameter | Min | Typ | Max | Unit | Test Conditions/Comments |
|---|---|---|---|---|---|
| Accuracy | −4.0 | +4.0 | Arc minutes | −55°C to +125°C | |
| Tracking Rate | 20 | Rev/sec | |||
| Resolution | 14 Bits (1 LSB = 1.3 Arc Minutes) | ||||
| Output Coding | Parallel Natural Binary | ||||
| Signal/Reference Frequency | 400 | 2600 | Hz | ||
| Bandwidth | 100 | Hz | |||
| Signal Voltage | 11.8 or 90 V rms | See the Ordering Information section | |||
| Input Impedance | 200 kΩ (90 V Signal), 26 kΩ (11.8 V Signal) | Resistive tolerance ±2% | |||
| Common-Mode Rejection | 74 dB | V dc IIL = 1.2 mA | |||
| Time to Data Stable | 640 ns | After Negative Edge of OE or Change of Level of A/B | |||
| Time to Data in High Impedance State | 200 ns | After Positive Edge of OE |
Key Features
- Dual Channel Capability: The AD2S44-TM18B features two independent Type II servo loop tracking converters, allowing for simultaneous processing of two input signals.
- Ratiometric Conversion Technique: This technique provides excellent noise immunity and tolerance of long lead lengths, ensuring reliable operation in various environments.
- High Accuracy Differential Conditioning: Each channel includes a high accuracy differential conditioning circuit for signal inputs, providing more than 74 dB of common-mode rejection.
- Built-In Test (BIT) Facility: The device includes a built-in test facility that can be used in failsafe systems to indicate whether the converter is tracking accurately.
- Independent Reference Inputs: Different reference frequencies can be used for each channel, enhancing flexibility in different applications.
- Three-State Output Latch: The converter output is via a three-state transparent latch, allowing data to be read without interrupting the converter operation.
- High Reliability: Devices are 100% tested at −55°C, +25°C, and +125°C and processed to high reliability screening standards.
Applications
- Avionic Systems: The AD2S44-TM18B is suitable for use in avionic systems due to its high reliability and performance in harsh environments.
- Antenna Monitoring: It can be used for precise monitoring and control of antenna systems, ensuring accurate positioning and tracking.
- CNC Machine Tooling: The converter is also applicable in CNC machine tooling where precise angular measurement and control are essential.
- Other Industrial Applications: Its robust design and high accuracy make it suitable for various industrial applications requiring precise angular measurement and control.
Q & A
- What is the resolution of the AD2S44-TM18B?
The AD2S44-TM18B has a resolution of 14 bits, with 1 LSB equal to 1.3 arc minutes.
- What are the input voltage options for the AD2S44-TM18B?
The device supports input voltages of 11.8 V rms or 90 V rms.
- What is the common-mode rejection ratio of the AD2S44-TM18B?
The common-mode rejection ratio is more than 74 dB.
- Does the AD2S44-TM18B have built-in test capabilities?
Yes, the device includes a built-in test (BIT) facility to indicate whether the converter is tracking accurately.
- What is the operating temperature range of the AD2S44-TM18B?
The operating temperature range is from −55°C to +125°C.
- How many channels does the AD2S44-TM18B support?
The device supports two independent channels.
- What is the tracking rate of the AD2S44-TM18B?
The tracking rate is up to 20 revolutions per second.
- Does the AD2S44-TM18B support different reference frequencies for each channel?
Yes, the device allows different reference frequencies for each channel.
- What is the output coding format of the AD2S44-TM18B?
The output coding is in parallel natural binary format.
- How long does it take for the data to become stable after the negative edge of OE or change of level of A/B?
The time to data stable is 640 ns.
- What is the time for repetitive strobing of the selected channel?
The time for repetitive strobing is 200 ns.
