Datasheet NE5521D, NE5521N, SA5521D, SA5521N Datasheet (Philips)

Philips Semiconductors Linear Products Product specification

NE/SA/SE5521LVDT signal conditioner

901

August 31, 1994 853-0043 13721

DESCRIPTION

The NE/SA/SE5521 is a signal conditioning circuit for use with
Linear Variable Differential Transformers (LVDTs) and Rotary
Variable Differential Transformers (RVDTs). The chip includes a low
distortion, amplitude-stable sine wave oscillator with programmable
frequency to drive the primary of the LVDT/RVDT, a synchronous
demodulator to convert the LVDT/RVDT output amplitude and phase
to position information, and an output amplifier to provide
amplification and filtering of the demodulated signal.

FEATURES

•Low distortion

•Single supply 5V to 20V, or dual supply ±2.5V to ±10V

•Oscillator frequency 1kHz to 20kHz

•Capable of ratiometric operation

•Low power consumption (182mV typ)

APPLICATIONS

•LVDT signal conditioning

•RVDT signal conditioning

•LPDT signal conditioning

•Bridge circuits

PIN CONFIGURATIONS

1
2
3
4
5
6
7
8

9

10

11

12

13

14

16
15

1
2
3
4
5
6
7
8

11

12

13

14

15

16

18
17

9

10

AMP OUT

+IN
–IN

LVDT IN

DEMOD OUT

SYNC

GND

N.C.
N.C.

V+
C

T

V

REF

FEEDBACK
OSC
OSC

V

REF/2

R

T

N.C.

AMP OUT

+IN
–IN

LVDT IN

DEMOD OUT

SYNC

GND

N.C.

V+
C

T

V

REF

FEEDBACK
OSC
OSC

V

REF/2

R

T

F, N Packages

TOP VIEW

D1 Package

TOP VIEW

NOTE:

1. SOL — released in large SO package only.

ORDERING INFORMATION

DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG #

18-Pin Plastic Dual In-Line Package (DIP) 0 to +70°C NE5521N 0407A
16-Pin Small Outline Large (SOL) Package 0 to +70°C NE5521D 0171B
18-Pin Plastic Dual In-Line Package (DIP) –40 to +85°C SA5521N 0407A
18-Pin Ceramic Dual In-Line Package (CERDIP) –55 to +125°C SE5521F 0583A
16-Pin Ceramic Dual In-Line Package (CERDIP) –40 to +85°C SA5521D 0582B

ABSOLUTE MAXIMUM RATINGS

SYMBOL PARAMETER RATING UNIT

V

CC

Supply voltage +20 V
Split supply voltage ±10 V

T

A

Operating temperature range
NE5521
SA5521
SE5521

0 to 70

–40 to +85

–55 to +125

°C
°C
°C

T

STG

Storage temperature range –65 to +125 °C

P

D

Power dissipation

1

910 mW

NOTES:

1. For derating, see typical power dissipation versus load curves (Figure 1).

Philips Semiconductors Linear Products Product specification

NE/SA/SE5521LVDT 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

–
+

–
+

V

REF

V

REF

/2

OSC

C

T

R

T

V+

–IN

+IN

AMP

OUT

SYNCHRONOUS
DEMODULATOR

PIN DEFINITIONS FOR D, F AND N PACKAGES

PIN NO.
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

OSC

output. Sync is referenced to V

REF

/2.
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 R

T

A temperature stable 18kΩ resistor should be connected between this pin and Pin 7.

10 12 V

REF

/2 A high impedance source of one half the potential applied to V

REF

. The LVDT/RVDT secondary return
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 V

REF

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

15 17 C

T

Oscillator frequency-determining capacitor. The capacitor connected between this pin and ground should
be a temperature-stable type.

16 18 +V Positive supply connection.

Philips Semiconductors Linear Products Product specification

NE/SA/SE5521LVDT signal conditioner

August 31, 1994

903

DC ELECTRICAL CHARACTERISTICS

V+ = V

REF

= 10V, TA = 0 to 70°C for NE5521, TA = –55 to +125°C for SE5521, TA = –40 to 85°C for SA5521, Frequency = 1kHz, unless

otherwise noted.

NE5521 SA/SE5521

SYMBOL

PARAMETER

TEST CONDITIONS

Min Typ Max Min Typ Max

UNIT

V

CC

Supply current 12.9 20 12.9 18 mA

I

REF

Reference current 5.3 8 5.3 8 mA

V

REF

Reference voltage range 5 V+ 5 V+ V

P

D

Power dissipation 182 280 182 260 mW

Oscillator Section

Oscillator output RL = 10kΩ

V

REF

8.8

V

REF

8.8

V

RMS

THD Sine wave distortion No load 1.5 1.5 %

Initial amplitude error TA = 25°C 0.4 ±3 0.4 ±3 %
Tempco of amplitude 0.005 0.01 0.005 0.01 %/°C
Init. accuracy of oscillator freq. TA = 25°C ±0.9 ±5 ±0.9 ±5 %
Temperature coeff. of frequency

1

0.05 0.05 %/°C

Voltage coeff. of frequency 2.5 3.3 %/V(V

REF

)

Min OSC (OSC) Load

2

300 170 300 170 Ω

Demodulator Section

∈

r

Linearity error 5V

P-P

input ±0.05 ±0.1 ±0.05 ±0.1 %FS

Maximum demodulator input

V

REF

2

V

REF

2

V

P-P

V

OS

Demodulator offset voltage ±1.4 ±5 ±1.4 ±5 mV

TCV

OS

Demodulator offset voltage drift 5 25 5 25 µV/5C

I

BIAS

Demodulator input current –600 –234 –500 –234 nA
V

R/2

accuracy ±0.1 ±1 ±0.1 ±1 %

Auxiliary Output Amplifier

V

OS

Input offset voltage ±0.5 ±5 ±0.5 ±5 mV

I

BIAS

Input bias current –600 –210 –500 –210 nA

I

OS

Input offset current 10 50 10 50 nA

A

V

Gain 100 385 100 385 V/mV

SR Slew rate 1.3 1.3 V/µs

GBW Unity gain bandwidth product AV = 1 1.6 1.6 MHz

Output voltage swing RL = 10kΩ 7 8.2 7 8.2 V
Output short circuit current to

ground or to V

CC

TA = 25°C 42 100 42 100 mA

NOTES:

1. This is temperature coefficient of frequency for the device only. It is assumed that C

T

and RT are fixed in value and CT leakage is fixed over

the operating temperature range.

2. Minimum load impedance for which distortion is guaranteed to be less than 5%.

Philips Semiconductors Linear Products Product specification

NE/SA/SE5521LVDT signal conditioner

August 31, 1994

904

DEFINITION OF TERMS

Oscillator Output RMS value of the AC voltage at the oscillator output pin. This output is referenced to V

REF/2

and is a function of V

REF

.

Sine Wave Distortion The Total Harmonic Distortion (THD) of the oscillator output with no load. This is not a

critical specification in LVDT/RVDT systems. This figure could be 15% or more without
affecting system performance.

Initial Amplitude Error A measure of the interchangeability of NE/SA/SE5521 parts, not a characteristic of any one

part. It is the degree to which the oscillator output of a number of NE/SA/SE5521 samples
will vary from the median of that sample.

Initial Accuracy of Oscillator Frequency Another measure of the interchangeability of individual NE/SA/SE5521 parts. This is the

degree to which the oscillator frequency of a number of NE/SA/SE5521 samples will vary
from the median of that sample with a given timing capacitor.

Tempco of Oscillator Amplitude A measure of how the oscillator amplitude varies with ambient temperature as that

temperature deviates from a 25°C ambient.

Tempco of Oscillator Frequency A measure of how the oscillator frequency varies with ambient temperature as that

temperature deviates from a 25°C ambient.

Voltage Coefficient of Oscillator Frequency The degree to which the oscillator frequency will vary as the reference voltage (V

REF

)

deviates from +10V.

Min OSC (OSC) Load Minimum load impedance for which distortion is guaranteed to be less than 5%.
Linearity Error The degree to which the DC output of the demodulator/amplifier combination matches a

change in the AC signal at the demodulator input. It is measured as the worst case
nonlinearity from a straight line drawn between positive and negative fullscale end points.

Maximum Demodulator Input The maximum signal that can be applied to the demodulator input without exceeding the

specified linearity error.

APPLICATION INFORMATION

OSC frequency 

V

REF

 1.3V

V

REF(RT

 1.5k) C

T

Figure 1. Device Power Dissipation vs OSC – OSC Load at +25°C

2000
1000

800
700
600
500
400
300
200
100

0.2 0.4 0.6 0.8 1 2 3

DEVICE POWER DISSIPATION (mW)

OSC–OSC LOAD (kΩ)

5V

15V

10V

V

REF

= V+ = 20V

PD

MAX

(SO PACKAGE)

PD

MAX

(N PACKAGE)

AT TA = 70°C, T

J(MAX)

= +150°C

AT TA = +85°C, T

J(MAX)

= +150°C

PD

MAX

(F PACKAGE)

PD

MAX

(F PACKAGE)

AT T

A

= +125°C, T

J(MAX)

= +165°C

AT T

A

= +125°C, T

J(MAX)

= +150°C

Philips Semiconductors Linear Products Product specification

NE/SA/SE5521LVDT signal conditioner

August 31, 1994

905

Figure 2. Oscillator Frequency Variation With Voltage

(Normalized to V

REF

= VCC = 10V) TA = +25°C

16

8

0

–8

–16

5 8 10 12 14 16 18 20

V

CC

= V

REF

(V)

∆f

OSC

(%)

I(mA)

Figure 3. I

REF

and ICC vs Voltage (TA = +25°C)

20

15

10

5

0 5 10 15 20 25

V

CC

= V

REF

(V)

I

REF

I

CC

I(mA)

Figure 4. I

REF

and ICC vs Temperature

(V

REF

= VCC = 10V)

16

14

12

10

8

6

4
–55 –40 0 25 70 85 125

T

A

(°C)

I

REF

I

CC