Philips Semiconductors Linear Products
Product specification
LVDT signal conditioner
NE/SA/SE5521
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.
PIN CONFIGURATIONS
F, N Packages
AMP OUT 1
+IN 2
–IN 3
LVDT IN 4
DEMOD OUT 5
SYNC 6
18 V+
17 C
T
16 V
REF
15 FEEDBACK
14 OSC
13 OSC
12 V
REF/2
11 R
T
10 N.C.
TOP VIEW
FEATURES
GND 7
N.C. 8
N.C. 9
•
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
D
1
Package
AMP OUT 1
+IN 2
–IN 3
LVDT IN 4
DEMOD OUT 5
SYNC 6
GND 7
N.C. 8
TOP VIEW
NOTE:
1. SOL — released in large SO package only.
16 V+
15 C
T
14 V
REF
13 FEEDBACK
12 OSC
11 OSC
10 V
REF/2
9 R
T
•
LVDT signal conditioning
•
RVDT signal conditioning
•
LPDT signal conditioning
•
Bridge circuits
ORDERING INFORMATION
DESCRIPTION
18-Pin Plastic Dual In-Line Package (DIP)
16-Pin Small Outline Large (SOL) Package
18-Pin Plastic Dual In-Line Package (DIP)
18-Pin Ceramic Dual In-Line Package (CERDIP)
16-Pin Ceramic Dual In-Line Package (CERDIP)
TEMPERATURE RANGE
0 to +70°C
0 to +70°C
–40 to +85°C
–55 to +125°C
–40 to +85°C
ORDER CODE
NE5521N
NE5521D
SA5521N
SE5521F
SA5521D
DWG #
0407A
0171B
0407A
0583A
0582B
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
CC
Supply voltage
Split supply voltage
Operating temperature range
NE5521
SA5521
SE5521
Storage temperature range
Power dissipation
1
PARAMETER
RATING
+20
±10
0 to 70
–40 to +85
–55 to +125
–65 to +125
910
UNIT
V
V
°C
°C
°C
°C
mW
T
A
T
STG
P
D
NOTES:
1. For derating, see typical power dissipation versus load curves (Figure 1).
August 31, 1994
901
853-0043 13721
Philips Semiconductors Linear Products
Product specification
LVDT signal conditioner
NE/SA/SE5521
BLOCK DIAGRAM
V
REF
16
15
FEEDBACK
10k
10k
17
C
T
R
T
V+
11
10k
18
10k
–IN
+IN
AMP
OUT
3
–
2
1
+
SYNCHRONOUS
DEMODULATOR
AUX AMP
4
6
7
OSC
SINE
CONV
–
+
–
+
14
12
V
REF
/2
GND/V–
LVDT IN
SYNC
OSC
13
OSC
5
DOMOD OUT
NOTE:
Pin numbers are for F, N packages.
PIN DEFINITIONS FOR D, F AND N PACKAGES
PIN NO.
D
1
2
3
4
5
6
7
8
--
--
9
10
F, N
1
2
3
4
5
6
7
8
9
10
11
12
SYMBOL
Amp Out
+IN
–IN
LVDT IN
DEMOD OUT
SYNC
GND
NC
NC
NC
R
T
V
REF
/2
Auxiliary Amplifier Out.
Auxiliary Amplifier non-inverting input.
Auxiliary Amplifier inverting input.
Input to Synchronous Demodulator from the LVDT/RVDT secondary.
Pulsating DC output from the Synchronous Demodulator output. This voltage should be filtered before
use.
Synchronizing input for the Synchronizing Demodulator. This input should be connected to the OSC or
OSC output. Sync is referenced to V
REF
/2.
Device return. Should be connected to system ground or to the negative supply.
No internal connection.
No internal connection.
No internal connection.
A temperature stable 18kΩ resistor should be connected between this pin and Pin 7.
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.
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.
Oscillator sine wave output. The LVDT/RVDT primaries are usually connected between OSC and OSC
pins.
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.
Reference voltage input for the oscillator and sine converter. This voltage MUST be stable and must not
exceed +V supply voltage.
Oscillator frequency-determining capacitor. The capacitor connected between this pin and ground should
be a temperature-stable type.
Positive supply connection.
DEFINITION
11
12
13
14
15
16
13
14
15
16
17
18
OSC
OSC
FEEDBACK
V
REF
C
T
+V
August 31, 1994
902
Philips Semiconductors Linear Products
Product specification
LVDT signal conditioner
NE/SA/SE5521
DC ELECTRICAL CHARACTERISTICS
V+ = V
REF
= 10V, T
A
= 0 to 70°C for NE5521, T
A
= –55 to +125°C for SE5521, T
A
= –40 to 85°C for SA5521, Frequency = 1kHz, unless
otherwise noted.
SYMBOL
V
CC
I
REF
V
REF
P
D
PARAMETER
Supply current
Reference current
Reference voltage range
Power dissipation
V
REF
8.8
1.5
0.4
0.005
T
A
= 25°C
±0.9
0.05
2.5
300
5V
P-P
input
170
±0.05
V
REF
2
±1.4
5
–600
–234
±0.1
±0.5
–600
100
A
V
= 1
R
L
= 10kΩ
T
A
= 25°C
7
–210
10
385
1.3
1.6
8.2
42
100
7
50
100
±1
±5
–500
±0.1
300
±3
0.01
±5
5
182
TEST CONDITIONS
NE5521
Min
Typ
12.9
5.3
Max
20
8
V+
280
5
182
V
REF
8.8
1.5
0.4
0.005
±0.9
0.05
3.3
170
±0.05
V
REF
2
±1.4
5
–500
–234
±0.1
±0.5
–210
10
385
1.3
1.6
8.2
42
100
50
±1
±5
±0.1
±3
0.01
±5
Min
SA/SE5521
Typ
12.9
5.3
Max
18
8
V+
260
UNIT
mA
mA
V
mW
Oscillator Section
Oscillator output
THD
Sine wave distortion
Initial amplitude error
Tempco of amplitude
Init. accuracy of oscillator freq.
Temperature coeff. of frequency
1
Voltage coeff. of frequency
Min OSC (OSC) Load
2
R
L
= 10kΩ
No load
T
A
= 25°C
V
RMS
%
%
%/°C
%
%/°C
%/V(V
REF
)
Ω
%FS
V
P-P
±5
25
mV
µV/
5
C
nA
%
mV
nA
nA
V/mV
V/µs
MHz
V
mA
Demodulator Section
∈
r
Linearity error
Maximum demodulator input
V
OS
TCV
OS
I
BIAS
Demodulator offset voltage
Demodulator offset voltage drift
Demodulator input current
V
R/2
accuracy
±5
25
Auxiliary Output Amplifier
V
OS
I
BIAS
I
OS
A
V
SR
GBW
Input offset voltage
Input bias current
Input offset current
Gain
Slew rate
Unity gain bandwidth product
Output voltage swing
Output short circuit current to
ground or to V
CC
NOTES:
1. This is temperature coefficient of frequency for the device only. It is assumed that C
T
and R
T
are fixed in value and C
T
leakage is fixed over
the operating temperature range.
2. Minimum load impedance for which distortion is guaranteed to be less than 5%.
August 31, 1994
903
Philips Semiconductors Linear Products
Product specification
LVDT signal conditioner
NE/SA/SE5521
DEFINITION OF TERMS
Oscillator Output
Sine Wave Distortion
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
.
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.
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.
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.
A measure of how the oscillator amplitude varies with ambient temperature as that
temperature deviates from a 25°C ambient.
A measure of how the oscillator frequency varies with ambient temperature as that
temperature deviates from a 25°C ambient.
The degree to which the oscillator frequency will vary as the reference voltage (V
REF
)
deviates from +10V.
Minimum load impedance for which distortion is guaranteed to be less than 5%.
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.
The maximum signal that can be applied to the demodulator input without exceeding the
specified linearity error.
Initial Amplitude Error
Initial Accuracy of Oscillator Frequency
Tempco of Oscillator Amplitude
Tempco of Oscillator Frequency
Voltage Coefficient of Oscillator Frequency
Min OSC (OSC) Load
Linearity Error
Maximum Demodulator Input
APPLICATION INFORMATION
OSC frequency
+
V
REF
*
1.3V
V
REF
(R
T
)
1.5k) C
T
2000
DEVICE POWER DISSIPATION (mW)
1000
800
700
600
500
400
300
200
100
0.2
10V
5V
0.4
0.6
0.8
1 2
3
15V
V
REF
= V+ = 20V
PD
MAX
(N PACKAGE)
AT T
A
= 70°C, T
J(MAX)
= +150°C
PD
MAX
(SO PACKAGE)
AT T
A
= +85°C, T
J(MAX)
= +150°C
PD
MAX
(F PACKAGE)
AT T
A
= +125°C, T
J(MAX)
= +165°C
PD
MAX
(F PACKAGE)
AT T
A
= +125°C, T
J(MAX)
= +150°C
OSC–OSC LOAD (kΩ)
Figure 1. Device Power Dissipation vs OSC – OSC Load at +25°C
August 31, 1994
904
Philips Semiconductors Linear Products
Product specification
LVDT signal conditioner
NE/SA/SE5521
16
16
14
12
I(mA)
10
8
6
I
CC
8
∆f
OSC
(%) 0
–8
I
REF
–16
5
8
10
12
14
16
18
20
V
CC
= V
REF
(V)
4
–55
–40
0
T
A
(°C)
25
70 85 125
Figure 2. Oscillator Frequency Variation With Voltage
(Normalized to V
REF
= V
CC
= 10V) T
A
= +25°C
Figure 4. I
REF
and I
CC
vs Temperature
(V
REF
= V
CC
= 10V)
20
15
I(mA)
I
CC
10
I
REF
5
0
5
10
15
20
25
V
CC
= V
REF
(V)
Figure 3. I
REF
and I
CC
vs Voltage (T
A
= +25°C)
August 31, 1994
905
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