CIRRUS SWR200_10

SWR200
SWR200
®
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Precision Sine Wave Reference
FEATURES
DESCRIPTION
SWR200 is a Precision Sine Wave Reference providing an ultra stable sine wave output of +7.071 V at
±0.5% initial accuracy and temperature coefficient as
low as 20 ppm/°C over the full military temperature
range. The extreme accuracy is made possible by a
chopper-based AGC circuit. The temperature characteristic of the chopper circuit compensates the typical
nonlinearity of the internal DC zener reference, resulting in a nearly linear amplitude-temperature characteristic. Frequency of the SWR200 is programmable with
two external capacitors.
♦ Very High Accuracy: +7.071 Vrms ±0.5%
♦ Extremely Low Drift: 20 ppm/°C
(-55°C to +125°C)
♦ Excellent Stability: 10 ppm/1000 Hrs. Typical
♦ Low Distortion: 0.1% Thd @ f = 3300 Hz
♦ Hermetic 14-pin Ceramic DIP
♦ Military Processing Option
APPLICATIONS
♦ Transducer Excitation
♦ High Resolution Servo Systems
♦ High Precision Test and Measurement Instruments
♦ AC Voltage Standard
♦ LVDT Or RVDT Reference
♦ Multiplying D/A Reference
The SWR200 is available in a 14-pin bottom braze
package. They are hermetically sealed and “M” versions are screened for high reliability and quality.
SWR200 is well suited for any application requiring a
stable sine wave source. The SWR200 can be used as
a reference source in precision sensing systems based
on LVDT or RVDT position sensors. A programmable AC
reference can be constructed using the SWR200 as
a reference for a high accuracy multiplying Digital to
Analog Converter.
Figure 1. BLOCK DIAGRAM
+15V
+15V
+15V
-15V
-15V
+15V
-15V
3
SWR200DS
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Copyright © Cirrus Logic, Inc. 2010
(All Rights Reserved)
MAY 20101
APEX − SWR200DSREVH
SWR200
Product Innovation From
SELECTION GUIDE
Temperature
Operating Range
Package
+7.071V
-25°C to +85°C
DIP
+7.071V
-55°C to +125°C
DIP
Type
Output (Typ.)
SWR200C
SWR200M
1. CHARACTERISTICS AND SPECIFICATIONS
Hermetic 14-pin Ceramic DIP
Package Style HC
ELECTRICAL SPECIFICATIONS
VPS =±15V, T = +25°C, RL = 10KΩ UNLESS OTHERWISE NOTED.
Model
Parameter
SWR200C
SWR200M
Min
Typ
Max
Min
Typ
Max
Units
±13.5
±15
±22
*
*
*
V
ABSOLUTE MAXIMUM RATINGS
Power Supply
Operating Temperature
-25
+85
-55
+125
ºC
Storage Temperature
-65
+85
*
*
ºC
Short Circuit Protection
OUTPUT VOLTAGE
Continuous
*
Vrms
7.071
*
V
OUTPUT VOLTAGE ERRORS
Initial Error
±0.5
Warmup Drift
*
100
DC Offset
*
3
DC Offset Over Temp.
3
TMIN - TMAX
*
18
*
20.0
Long-Term Stability
10
%
µV
mV
*
µV/ ºC
30.0
ppm/ ºC
*
ppm/ ºC
OUTPUT CURRENT
Range
±10
*
mA
REGULATION
Line
10
*
ppm/V
Load
3
*
ppm/mA
POWER SUPPLY CURRENTS
+PS
10.5
13
*
*
mA
-PS
9.5
13
*
*
mA
*
%
*
Hz
*
Hz
*
ppm/ºC
DISTORTION
0.5
FREQUENCY
10-5
Range (f) f = C C
1
2
∆f vs. temperature
f
2
.98
400
1
1.02
*
10K
*
15
*
SWR200DS
SWR200
Product Innovation From
NOTES:
* Same as C Models.
1. Using the box method, the specified value is the maximum deviation from the output voltage at
+25°C over the specified operating temperature range.
2. The specified values are unloaded.
3. Pin 8 is internally connected to Pin 7 and can be used as Ref. GND.
4. The frequency range can be extended to any desired lower value by using 2 external AGC capacitors
(see AN-3).
5. The increase in distrotion at lower frequencies can be eliminated by using external AGC capacitors
(see AN-3).
2. TYPICAL PERFORMANCE GRAPHS
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
20
% ∆ FREQ. vs. TEMP.
% ∆ FREQ. vs. TEMP.
50
35
15.6
0
0
-15.6
-35
-50
-20
Temperature oC
SWR200C
Temperature oC
SWR200M
DISTORTION VS. TEMP
Temperature oC
POWER SUPPLY CURRENT vs. TEMP.
Temperature oC
SWR200DS
Temperature oC
SWR200C
DISTORTION vs. FREQUENCY
Frequency (Hz)
CASE TEMP. RISE ABOVE AMBIENT
vs. OUTPUT CURRENT
Output Current (mA)
Temperature oC
SWR200M
NORMALIZED DISTORTION vs. C2/C1
C2/C1
JUNCTION TEMP. RISE
ABOVE CASE TEMP. vs
OUTPUT CURRENT
Output Current (mA)
3
SWR200
Product Innovation From
3. THEORY OF OPERATION
The following refers to the schematic in Figure 1. A1 and A2 are connected as a phase-shift oscillator circuit with
the frequency set by the external capacitors C1 and C2. Q4 is included in the feedback loop of A1 as a gain control
element.
The oscillator output is fed to the chopper amplifier which develops an absolute value representation of the oscillator
output. The chopper output is compared to a precision DC reference in integrator amplifier A3. This DC error signal
is used ot control the gain setting FET Q4.
As in all precision zener based DC references, the drift of the zener becomes nonlinear at temperature extremes.
The chopper amplifier drift characteristic is complementary to this nonlinearity and compensates for the reference
drift.
4. APPLICATION INFORMATION
Figure 1 shows the connections for the SWR200 including the two frequency setting capacitors. The frequency is:
f=
10-5
C1 C2
The frequency stability is directly related to the stability of the capacitors, therefore stable capacitors like NPO ceramic, or polycarbonate or polystyrene film should be used.
Two separate ground pins are provided for accurate ground sensing. This minimizes errors due to drops in the
ground pin which can become a significant source of error in sockets.
The offset of the SWR200 is fully specified for initial offset and drift and is low enough that it can normally be neglected. In applications which are especially sensitive to offset the output can be AC coupled. Proper capacitor sizing and high impedance sensing will minimize errors due to capacitive coupling.
EXTERNAL CONNECTIONS
PIN CONFIGURATION
TOP VIEW
C1
C2
C1
C2
+PS
-PS
NC
NC
NC
NC
NC
OUTPUT
GND
4
SWR200
GND SENSE
SWR200DS
Product Innovation From
SWR200
CONTACTING CIRRUS LOGIC SUPPORT
For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America.
For inquiries via email, please contact [email protected]
International customers can also request support by contacting their local Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com
IMPORTANT NOTICE
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to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
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SWR200DS
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