Cirrus Logic CS3002 User Manual
CS3002
Hz
Out A
-In A
+In A
V-
V+
Out B
-In B
+In B
A
B
-
-
+
+
1
2
3
4
8
7
6
5
CS3002
8-lead SOIC
Noise vs. Frequency (Measured)
1
10
100
0.001 0.01 0.1 1 10
Freque ncy (Hz)
nV/√Hz
CS3002
R1
100
R2
64.9k
C2
0.015F
Dexter Research
Thermophile 1M
Precision Low-voltage Amplifier; DC to 2kHz
Features & Description
• Low Offset: 10V Max
• Low Drift: 0.05V/°C Max
• Low Noise
- 6nV/ @ 0.5Hz
- 0.1 to 10Hz = 125 nVpp
- 1/f corner @ 0.08Hz
• Open-loop Voltage Gain
- 300dB Typical
- 200dB Minimum
• Rail-to-rail Output Swing
• Slew Rate: 5V/s
Applications
• Thermocouple/Thermopile Amplifiers
• Load Cell and Bridge Transducer Amplifiers
• Precision Instrumentation
• Battery-powered Systems
Description
The CS3002 dual amplifier is designed for precision amplification of low-level signals and is ideally suited for
applications that require very high closed-loop gains.
These amplifiers achieve excellent offset stability, superhigh open-loop gain, and low noise over time and temperature. The devices also exhibit excellent CMRR and
PSRR. The common mode input range includes the negative supply rail. The amplifiers operate with any total
supply voltage from 2.7V to 6.7V (±1.35 V to ±3.35 V).
Pin Configuration
Cirrus Logic, Inc.
http://www.cirrus.com
Copyright Cirrus Logic, Inc. 2012
(All Rights Reserved)
DEC ‘12
DS490F10
CS3002
TABLE OF CONTENTS
1. Characteristics and Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Typical Performance Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 Open-loop Gain and Phase Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Open-loop Gain and Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.1 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.2 Gain Calculation Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . 11
Calculate the Compensation Capacitor Value: . . . . . . . . . . . . . . . . . 11
Verify the Op Amp Compensation: . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4. Package Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Environmental, Manufacturing, & Handling Information . . . . . . . . . . . . . . . . . . 13
7. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
LIST OF FIGURES
Figure 1. Noise vs. Frequency (Measured)................................................................................... 4
Figure 2. Noise vs. Frequency ...................................................................................................... 4
Figure 3. 0.01Hz to 10Hz Noise ................................................................................................... 4
Figure 4. Offset Voltage Stability (DC to 3.2Hz) ........................................................................... 4
Figure 5. Supply Current vs. Temperature.................................................................................... 4
Figure 6. Supply Current vs. Supply Voltage ................................................................................ 4
Figure 7. Open-loop Gain and Phase vs. Frequency.................................................................... 5
Figure 8. Open-loop Gain and Phase vs. Frequency (Expanded) ................................................ 5
Figure 9. Input Bias Current vs. Supply Voltage ........................................................................... 6
Figure 10. Input Bias Current vs. Common Mode Voltage ........................................................... 6
Figure 11. Voltage Swing vs. Output Current ............................................................................... 7
Figure 12. Voltage Swing vs. Output Current (5V) ....................................................................... 7
Figure 13. Open-loop Gain and Phase Response ........................................................................ 8
Figure 14. Non-inverting Gain Configuration ................................................................................ 9
Figure 15. Non-inverting Gain Configuration with Compensation................................................. 9
Figure 16. Loop Gain Plot: Unity Gain and with Pole-zero Compensation ................................. 10
Figure 17. Thermopile Amplifier with a Gain of 650V/ V ............................................................. 12
Figure 18. Load Cell Bridge Amplifier and A/D Converter .......................................................... 12
2 DS490F10
1. CHARACTERISTICS AND SPECIFICATIONS
nV/ Hz
nV/ Hz
fA/ Hz
1.1 Electrical Characteristics
Typical characteristics conditions:
=25°C, V+=+5V, V-=0V, VCM=2.5V
•T
A
• All voltages are measured with respect to V-
CS3002
Minimum/Maximum characteristics conditions:
•TJ=-40°Cto+125°C, V+=+5V, V-=0V, VCM=2.5V
Parameter
Condition
Min Typ Max Unit
Input Offset Voltage (Note 1)--±10µV
Average Input Offset Drift (Note 1) - ±0.01 ±0.05 µV/ºC
Long Term Input Offset Voltage Stability (Note 2)
Input Bias Current T
Input Offset Current
R
= 100, f0 = 1Hz
Input Noise Voltage Density
Input Noise Voltage
S
R
= 100, f0 = 1kHz
S
0.1 to 10Hz - 125 nV
Input Noise Current Density
Input Noise Current
0.1 to 10Hz - 1.9 pA
= 25ºC
A
T
= 25ºC
A
-
-
-
-
-
-
= 1Hz - 100
f
0
±100
-
±200
-
6
6
-
±1000
-
±2000
pA
pA
pA
pA
pp
p-p
Input Common Mode Voltage Range -0.1 - (V+)-1.25 V
Common Mode Rejection Ratio (DC) (Note 3) 115 120 - dB
Power Supply Rejection Ratio 120 136 - dB
Large Signal Voltage Gain (Note 4)R
Output Voltage Swing
= 2k to V+/2 200 300 - dB
L
= 2k to V+/2
R
L
R
= 100k to V+/2
L
+4.7 -
+4.99
-
V
V
= 2k, 100pF 5 - V/µs
Slew Rate
R
L
Overload Recovery Time - 100 - µs
PWDN
Threshold (Note 5) (V+) -1.0 - - V
Start-up Time (Note 5)-912ms
Notes: 1. This parameter is guaranteed by design and laboratory characterization. Thermocouple effects prohibit accurate
measurement of these parameters in automatic test systems.
2. 1000-hour life test data @ 125 °C indicates randomly distributed variation approximately equal to measurement
repeatability of 1µV.
3. Measured within the specified common mode range limits.
4. Guaranteed within the output limits of (V+ - 0.3V) to (V- + 0.3V). Tested with proprietary production test method.
5. The device has a controlled start-up behavior due to its complex open-loop gain characteristics. Start-up time
applies when supply voltage is applied or when PDWN
is released.
1.2 Absolute Maximum Ratings
Parameter Min Typ Max Unit
Supply Voltage [(V+) - (V-)] 6.8 V
Input Voltage (V-) - 0.3 (V+) + 0.3 V
Storage Temperature Range -65 +150 ºC
DS490F10 3
2. TYPICAL PERFORMANCE PLOTS
Noise vs. Frequency (Measured)
1
10
100
0.001 0.01 0.1 1 10
Frequency (Hz)
nV/√Hz
1
10
100
1000
10 100 1K 10K 100K 1M 10M
Frequency (Hz)
-100
-50
0
50
100
TIM E (Se c)
0
1
2
34 5
6
78
9
10
Time (1 Hour)
-100
-75
-50
-25
0
25
50
75
100
nV
= 13 nVσ
Tempe rature (°C)
Supply Current (mA)
2.7 V
6.7 V
2.0
2.5
3.0
3.5
4.0
4.5
-40 -20 0 20 40 60 80
1.5
1.6
1.7
1.8
1.9
2
234567
Supply Voltage (V)
Supply Current (mA)
CS3002
Figure 1. Noise vs. Frequency (Measured)
nV
Figure 3. 0.01Hz to 10Hz Noise
Figure 2. Noise vs. Frequency
Figure 4. Offset Voltage Stability (DC to 3.2Hz)
Figure 5. Supply Current vs. Temperature
4 DS490F10
Figure 6. Supply Current vs. Supply Voltage
CS3002
-500
-400
-300
-200
-100
0
100
200
300
400
500
Figure 7. Open-loop Gain and Phase vs. Frequency
1 10 100 1k 10k 1M 10M
Frequency (Hz)
100k
GAIN
PHASE
1M
M
Gain (dB)
100
Figure 8. Open-loop Gain and Phase vs. Frequency (Expanded)
80
60
40
20
0
-45
-90
-135
-180
-225
-270
Phase (Degrees)
-315
-360
10K
100K
10
DS490F10 5
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