Philips Semiconductors Linear Products

Product specification

NE/SA/SE5521

LVDT signal conditioner

August 31, 1994

902

BLOCK DIAGRAM

NOTE:

Pin numbers are for F, N packages.

16

17

11

18

3

2

1

5

15

13

14

12

7

4

6

OSC

AUX AMP

DOMOD OUT

SINE

CONV

10k

10k

10k

10k

–

+

FEEDBACK

OSC

GND/V–

LVDT IN

SYNC

–

+

–

+

VREF

VREF/2

OSC

CT

RT

V+

–IN

+IN

AMP

OUT

SYNCHRONOUS

DEMODULATOR

PIN DEFINITIONS FOR D, F AND N PACKAGES

PIN NO.

SYMBOL

DEFINITION

D

F, N

SYMBOL

DEFINITION

1

1

Amp Out

Auxiliary Amplifier Out.

2

2

+IN

Auxiliary Amplifier non-inverting input.

3

3

–IN

Auxiliary Amplifier inverting input.

4

4

LVDT IN

Input to Synchronous Demodulator from the LVDT/RVDT secondary.

5

5

DEMOD OUT

Pulsating DC output from the Synchronous Demodulator output. This voltage should be filtered before

use.

6

6

SYNC

Synchronizing input for the Synchronizing Demodulator. This input should be connected to the OSC or

7

7

GND

Device return. Should be connected to system ground or to the negative supply.

8

8

NC

No internal connection.

--

9

NC

No internal connection.

--

10

NC

No internal connection.

9

11

A temperature stable 18k

Ω resistor should be connected between this pin and Pin 7.

10

12

should be to this point. A bypass capacitor with low impedance at the oscillator frequency should also be

connected between this pin and ground.

11

13

OSC

Oscillator sine wave output that is 180

° out of phase with the OSC signal. The LVDT/RVDT primary is

usually connected between OSC and OSC pins.

12

14

OSC

Oscillator sine wave output. The LVDT/RVDT primaries are usually connected between OSC and OSC

pins.

13

15

FEEDBACK

Usually connected to the OSC output for unity gain, a resistor between this pin and OSC, and one be-

tween this pin and ground can provide for a change in the oscillator output pin amplitudes.

14

16

Reference voltage input for the oscillator and sine converter. This voltage MUST be stable and must not

exceed +V supply voltage.

15

17

Oscillator frequency-determining capacitor. The capacitor connected between this pin and ground should

be a temperature-stable type.

16

18

+V

Positive supply connection.