AD2S44-TM12B

Overview

The AD2S44-TM12B is a low-cost, 14-bit dual-channel synchro/resolver-to-digital converter housed in a 32-lead DIL hybrid package. It provides independent Type II servo loop tracking for two channels with 2.6 arc minute accuracy within the -25°C to +85°C range and ±4.0 arc minutes from -55°C to +125°C. The device supports signal frequencies of 400 Hz to 2600 Hz, utilizing a ratiometric conversion technique for noise immunity. Key electrical parameters include a tracking rate of 20 rev/sec, 100 Hz bandwidth, and an acceleration constant of 62,000 sec⁻². It features built-in test capabilities and three-state output latches for seamless digital data access.

Feature Summary

• Dual-channel architecture with independent reference inputs and high-speed SIN/COS multipliers
• 14-bit parallel natural binary output with three-state transparent latches
• Built-in test (BIT) facility for fault detection with hysteresis to prevent flickering
• High common-mode rejection exceeding 74 dB via differential conditioning circuits

Applications

• Gimbal and gyro control systems
• Robotics positioning
• Engine controllers
• Military servo control systems
• CNC machine tooling

Procurement Notes

Verify the specific voltage configuration required for your application, as the TM12B suffix denotes 90 V signal and 115 V reference synchro format inputs. Confirm that the system environment falls within the specified operating temperature ranges for the desired accuracy grade. Ensure power supplies are strictly maintained at ±15 V to meet performance specifications. Check for availability of high-reliability screened units if mission-critical operation is required.

Selection Notes

Select this component when space, weight, and cost are critical constraints requiring dual-channel resolution. Choose the TM12B variant specifically for standard 90 V/115 V synchro interfaces. Consider the 20 rev/sec tracking rate limit for dynamic applications; higher acceleration may induce position errors defined by the 62,000 sec⁻² constant. Ensure external scaling resistors are matched to 0.1% tolerance if nonstandard voltages are used to maintain accuracy.

Part Context

The AD2S44 series utilizes Analog Devices' proprietary BiMOS II process, combining CMOS digital logic with bipolar linear circuits to minimize internal component count and enhance reliability. The TM12B model is part of the high-reliability screening group, undergoing processes such as temperature cycling and burn-in. It serves as a direct replacement for older single-channel converters where dual-axis monitoring is needed without increasing board footprint significantly.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the datasheet. The document references the SDC/RDC1740 series for hybrid solutions with isolation and the AD2S80A series for monolithic 16-bit resolver-to-digital conversion. These alternatives differ in resolution, channel count, or packaging technology and require circuit redesign.