AD694ARZ Circuit Board Chips Integrated Circuit Chip 4–20 mA Transmitter

STOCK LIST

Feature

PRODUCT HIGHLIGHTS

1. The AD698 offers a single chip solution to LVDT signal conditioning problems. All active circuits are on the monolithic chip with only passive components required to complete the conversion from mechanical position to dc voltage.

2. The AD698 can be used with many different types of position sensors. The circuit is optimized for use with any LVDT, including half-bridge and series opposed, (4 wire) configurations. The AD698 accommodates a wide range of input and output voltages and frequencies.

3. The 20 Hz to 20 kHz excitation frequency is determined by a single external capacitor. The AD698 provides up to 24 volts rms to differentially drive the LVDT primary, and the AD698 meets its specifications with input levels as low as 100 millivolts rms.

4. Changes in oscillator amplitude with temperature will not affect overall circuit performance. The AD698 computes the ratio of the secondary voltage to the primary voltage to determine position and direction. No adjustments are required.

5. Multiple LVDTs can be driven by a single AD698 either in series or parallel as long as power dissipation limits are not exceeded. The excitation output is thermally protected.

6. The AD698 may be used as a loop integrator in the design of simple electromechanical servo loops.

7. The sum of the transducer secondary voltages do not need to be constant.

ABSOLUTE MAXIMUM RATINGS

Total Supply Voltage (+VS to –VS) . . . . . . . . . . . . . . . . . 36 V

Storage Temperature Range P Package . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Q Package . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Operating Temperature Range AD698SQ . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C

AD698AP . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

Lead Temperature Range (Soldering 60 sec) . . . . . . . . +300°C

Power Dissipation Derates above +65°C

P Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mW/°C

Q Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mW/°C