STMICROELECTRONICS TSH330

TSH330
1.1 GHz Low-Noise Operational Amplifier
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Bandwidth: 1.1GHz (Gain=+2)
Quiescent current: 16.6 mA
Slew rate: 1800V/µs
Input noise: 1.3nV/√Hz
Distortion: SFDR = -78dBc (10MHz, 2Vp-p)
Output stage optimized for driving 100Ω
loads
Tested on 5V power supply
Pin Connections (top view)
D
SO-8
(Plastic Micropackage)
Description
The TSH330 is a current feedback operational
amplifier using a very high-speed complementary
technology to provide a large bandwidth of
1.1GHz in gain of 2 while drawing only 16.6mA of
quiescent current. In addition, the TSH330 offers
0.1dB gain flatness up to 160MHz with a gain of 2.
With a slew rate of 1800V/µs and an output stage
optimized for driving a standard 100Ω load, this
device is highly suitable for applications where
speed and low-distortion are the main
requirements.
8 NC
NC 1
-IN 2
_
7 +VCC
+IN 3
+
6 Output
5 NC
-VCC 4
SO8
The TSH330 is a single operator available in the
SO8 plastic package, saving board space as well
as providing excellent thermal and dynamic
performances.
Applications
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Communication & video test equipment
Medical instrumentation
ADC drivers
Order Codes
Part Number
Temperature Range
Package
Conditioning
Marking
TSH330ID
TSH330IDT
-40°C to +85°C
SO8
SO8
Tube
Tape&Reel
TSH330I
TSH330I
June 2005
Revision 3
1/19
TSH330
Absolute Maximum Ratings
1 Absolute Maximum Ratings
Table 1. Key parameters and their absolute maximum ratings
Symbol
VCC
Vid
Vin
Parameter
Supply Voltage
1
Differential Input
Voltage2
Range3
Value
Unit
6
V
+/-0.5
V
+/-2.5
V
Toper
Input Voltage
Operating Free Air Temperature Range
-40 to + 85
°C
Tstg
Storage Temperature
-65 to +150
°C
Maximum Junction Temperature
150
°C
Rthja
SO8 Thermal Resistance Junction to Ambient
60
°C/W
Rthjc
SO8 Thermal Resistance Junction to Case
28
°C/W
Tj
Pmax
4
830
mW
5
2
kV
0.6
kV
MM: Machine Model 6 (pins 1, 4, 5, 6, 7 and 8)
MM: Machine Model (pins 2 and 3)
CDM: Charged Device Model (pins 1, 4, 5, 6, 7 and 8)
CDM: Charged Device Model (pins 2 and 3)
Latch-up Immunity
200
V
80
1.5
1
200
V
kV
kV
mA
SO8 Maximum Power Dissipation (@Ta=25°C) for Tj=150°C
HBM: Human Body Model (pins 1, 4, 5, 6, 7 and 8)
HBM: Human Body Model (pins 2 and 3)
ESD
1) All voltages values are measured with respect to the ground pin.
2) Differential voltage are non-inverting input terminal with respect to the inverting input terminal.
3) The magnitude of input and output voltage must never exceed VCC +0.3V.
4) Short-circuits can cause excessive heating. Destructive dissipation can result from short circuit on amplifiers.
5) Human body model, 100pF discharged through a 1.5kΩ resistor into pMin of device.
6) This is a minimum Value. Machine model ESD, a 200pF cap is charged to the specified voltage, then discharged directly into the IC with
no external series resistor (internal resistor < 5Ω), into pin to pin of device.
Table 2. Operating conditions
Symbol
VCC
Vicm
Parameter
Supply Voltage 1
Common Mode Input Voltage
1) Tested in full production at 5V (±2.5V) supply voltage.
2/19
Value
Unit
4.5 to 5.5
V
-Vcc+1.5V, +Vcc-1.5V
V
Electrical Characteristics
TSH330
2 Electrical Characteristics
Table 3. Electrical characteristics for VCC= ±2.5Volts, Tamb=+25°C (unless otherwise specified)
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
-3.1
0.18
+3.1
Unit
DC performance
Vio
Input Offset Voltage
Offset Voltage between both inputs
∆Vio
Vio drift vs. Temperature
Tamb
Tmin. < Tamb < Tmax.
0.8
Tmin. < Tamb < Tmax.
1.6
Iib+
Non Inverting Input Bias Current
Tamb
DC current necessary to bias the input +
Tmin. < Tamb < Tmax.
26
Iib-
Inverting Input Bias Current
Tamb
DC current necessary to bias the input Tmin. < Tamb < Tmax.
7
CMR
SVR
PSR
ICC
mV
µV/°C
55
21
22
13
µA
µA
Common Mode Rejection Ratio
∆Vic = ±1V
20 log (∆Vic/∆Vio)
Tmin. < Tamb < Tmax.
Supply Voltage Rejection Ratio
∆Vcc= 3.5V to 5V
20 log (∆Vcc/∆Vout)
Tmin. < Tamb < Tmax.
Power Supply Rejection Ratio
∆Vcc=200mVp-p@1kHz
56
20 log (∆Vcc/∆Vout)
Tmin. < Tamb < Tmax.
52
Supply Current
DC consumption with no input signal
No load
16.6
Tmin. < Tamb < Tmax.
16.6
mA
153
kΩ
152
kΩ
1500
1100
630
600
MHz
50
54
dB
54
63
74
dB
67
dB
20.2
mA
Dynamic performance and output characteristics
ROL
Bw
Transimpedance
Output Voltage/Input Current Gain in
open loop of a CFA.
For a VFA, the analog of this feature is
the Open Loop Gain (AVD)
-3dB Bandwidth
Frequency where the gain is 3dB below
the DC gain AV
Note: Gain Bandwidth Product criterion is
not applicable for Current-FeedbackAmplifiers
∆Vout= ±1V, RL = 100Ω
104
Tmin. < Tamb < Tmax.
Vout=20mVp-p, RL = 100Ω
AV = +1
AV = +2
AV = -4
AV = -4, Tmin. < Tamb < Tmax.
550
Gain Flatness @ 0.1dB
Small Signal Vout=20mVp-p
Band of frequency where the gain varia- AV = +2, RL = 100Ω
tion does not exceed 0.1dB
SR
VOH
VOL
Slew Rate
Maximum output speed of sweep in
large signal
Vout = 2Vp-p, AV = +2,
RL = 100Ω
High Level Output Voltage
RL = 100Ω
Low Level Output Voltage
160
1.5
1800
V/µs
1.64
V
Tmin. < Tamb < Tmax.
1.54
RL = 100Ω
-1.55
Tmin. < Tamb < Tmax.
-1.5
-1.5
V
3/19
TSH330
Electrical Characteristics
Table 3. Electrical characteristics for VCC= ±2.5Volts, Tamb=+25°C (unless otherwise specified)
Symbol
Iout
Parameter
Isink
Short-circuit Output current coming in
the op-amp.
See fig-17 for more details
Isource
Output current coming out from the opamp.
See fig-18 for more details
Test Condition
Output to GND
Min.
Typ.
360
453
Tmin. < Tamb < Tmax.
Max.
Unit
427
Output to GND
-340
Tmin. < Tamb < Tmax.
mA
-400
-350
Noise and distortion
eN
iN
SFDR
Equivalent Input Noise Voltage
see application note on page 13
F = 100kHz
Equivalent Input Noise Current (+)
see application note on page 13
F = 100kHz
Equivalent Input Noise Current (-)
see application note on page 13
F = 100kHz
Spurious Free Dynamic Range
The highest harmonic of the output
spectrum when injecting a filtered sine
wave
AV = +2, Vout = 2Vp-p,
RL = 100Ω
F = 10MHz
F = 20MHz
F = 100MHz
F = 150MHz
1.3
nV/√Hz
22
pA/√Hz
16
pA/√Hz
-78
-73
-48
-37
dBc
Table 4. Closed-loop gain and feedback components
VCC (V)
Gain
Rfb (Ω)
-3dB Bw (MHz)
0.1dB Bw (MHz)
+10
200
280
50
-10
200
270
45
+2
300
1000
160
-2
270
530
180
+1
300
1500
38
-1
260
600
280
±2.5
4/19
Electrical Characteristics
TSH330
24
22
20
18
16
14
12
10
8
6
4
2
0
-2
-4 Small Signal
-6 Vcc=5V
-8
Load=100 Ω
-10
1M
Figure 4. Frequency response, negative gain
Gain=+10
Gain=+4
Gain (dB)
Gain (dB)
Figure 1. Frequency response, positive gain
Gain=+2
Gain=+1
10M
100M
1G
24
22
20
18
16
14
12
10
8
6
4
2
0
-2
-4 Small Signal
-6 Vcc=5V
-8
Load=100Ω
-10
1M
Gain=-10
Gain=-4
Gain=-2
Gain=-1
10M
Frequency (Hz)
100M
1G
Frequency (Hz)
Figure 2. Gain flatness, gain=+4
Figure 5. Gain flatness, gain=+2
12,2
6,2
Gain Flatness (dB)
Gain Flatness (dB)
12,0
11,8
Vin
Vout
+
-
11,6
8k2
22pF
300R
100R
6,0
Vin
Vout
+
5,8
-
8k2
1pF
300R
300R
5,6
11,4
Gain=+4, Vcc=5V,
Small Signal
1M
Gain=+2, Vcc=5V,
Small Signal
10M
5,4
1M
100M
10M
10
16
8
14
6
12
4
10
2
8
0
6
-2
4
-4
Vin
-8
-
-10
-12
-14
Vout
+
8k2
1pF
-20
-22
1M
2
0
Vin
Vout
+
-2
-
-4
-6
300R
300R
-8
8k2
22pF
300R
100R
-10
-16
-18
1G
Figure 6. Compensation, gain=+4
Gain (dB)
Gain (dB)
Figure 3. Compensation, gain=+2
-6
100M
Frequency (Hz)
Frequency (Hz)
-12
Gain=+2, Vcc=5V,
Small Signal
10M
-14
100M
Frequency (Hz)
1G
-16
1M
Gain=+4, Vcc=5V,
Small Signal
10M
100M
1G
Frequency (Hz)
5/19
TSH330
Electrical Characteristics
Figure 7. Compensation, gain=+10
Figure 10. Quiescent current vs. Vcc
24
20
22
15
20
18
Icc(+)
10
16
5
12
10
Vin
8
+
6
-
4
15pF
2
Icc (mA)
Gain (dB)
14
Vout
200R
22R
0
-5
-10
-15
0
-20
-2
Gain=+10, Vcc=5V,
Small Signal
-4
-6
-8
1M
-25
10M
100M
-30
1,25
1G
Icc(-)
Gain=+2
Vcc=5V
Input to ground, no load
1,50
1,75
Frequency (Hz)
2,00
2,25
2,50
+/-Vcc (V)
Figure 8. Input current noise vs. frequency
Figure 11. Input voltage noise vs. frequency
150
4.0
140
130
120
110
3.5
Neg. Current
Noise
90
80
3.0
en (nV/VHz)
in (pA/VHz)
100
Pos. Current
Noise
70
60
50
2.5
2.0
40
30
1.5
20
10
1k
10k
100k
1M
1.0
1k
10M
10k
Frequency (Hz)
100k
1M
10M
Frequency (Hz)
Figure 9. Output amplitude vs. load
Figure 12. Noise figure
40
4,0
35
30
25
NF (dB)
Vout max. (Vp-p)
3,5
3,0
20
15
10
2,5
Freq=?
Gain=+2
Vcc=5V
2,0
10
100
1k
Load (ohms)
6/19
10k
100k
5
Vcc=5V
0
1
10
100
1k
Rsource (ohms)
10k
100k
Electrical Characteristics
TSH330
Figure 13. Output amplitude vs. frequency
Figure 16. Distortion vs. amplitude
5
-20
-25
-30
-35
4
HD2 & HD3 (dBc)
Vout max. (Vp-p)
-40
3
2
1
-45
HD2
-50
-55
-60
-65
-70
-75
-80
Gain=+2
Vcc=5V
F=30MHz
Load=100 Ω
-85
Gain=+2
Vcc=5V
Load=100Ω
-90
HD3
-95
-100
0
1M
10M
100M
0
1G
1
Figure 14. Distortion vs. amplitude
600
-25
550
-30
500
-35
4
-0,5
0,0
+2.5V
VOL
-45
400
Isink (mA)
-50
-55
-60
HD2
-70
350
withou t load
+
-1V
Isink
_
450
-40
HD2 & HD3 (dBc)
3
Figure 17. Isink
-20
-65
2
Output Amplitude (Vp-p)
Frequency (Hz)
V
- 2.5V
RG
Amplifier in open
loop without load
300
250
200
-75
-80
HD3
-90
150
Gain=+2
Vcc=5V
F=10MHz
Load=100Ω
-85
-95
100
50
0
-2,0
-100
0
1
2
3
4
-1,5
-1,0
V (V)
Output Amplitude (Vp-p)
Figure 15. Distortion vs. amplitude
Figure 18. Isource
-20
0
-25
-50
-30
-100
-35
-150
-45
Isource (mA)
HD2 & HD3 (dBc)
-40
-50
HD2
-55
-60
-65
-70
-75
-80
HD3
-90
-95
1
2
Output Amplitude (Vp-p)
3
-300
+2.5V
VOH
-350
without load
+
+1V
-400
Isource
_
V
- 2.5V
RG
-500
Amplifier in open
loop without load
-550
-100
0
-250
-450
Gain=+2
Vcc=5V
F=20MHz
Load=100Ω
-85
-200
4
-600
0,0
0,5
1,0
1,5
2,0
V (V)
7/19
TSH330
Electrical Characteristics
Figure 19. Slew rate
Figure 22. CMR vs. temperature
64
2,0
Output Response (V)
62
60
1,5
CMR (dB)
58
1,0
0,5
56
54
52
50
Gain=+2
Vcc=5V
Load=100Ω
0,0
-2ns
-1ns
0s
1ns
2ns
48
46
Gain=+1
Vcc=5V
Load=100Ω
3ns
-40
Time (ns)
-20
0
20
40
60
80
100
120
80
100
120
80
100
120
Temperature (°C)
Figure 20. Reverse isolation vs. frequency
Figure 23. SVR vs. temperature
85
0
80
-20
SVR (dB)
75
Gain (dB)
-40
-60
70
65
60
-80
Small Signal
Vcc=5V
Load=100Ω
-100
1M
55
Gain=+1
Vcc=5V
Load=100Ω
50
10M
100M
1G
-40
-20
0
Frequency (Hz)
20
40
60
Temperature (°C)
Figure 21. Bandwidth vs. temperature
Figure 24. ROL vs. temperature
1,3
200
1,2
180
1,0
ROL (MΩ )
Bw (GHz)
1,1
0,9
0,8
160
140
0,7
0,6
120
Gain=+2
Vcc=5V
Load=100Ω
Open Loop
Vcc=5V
0,5
100
-40
-20
0
20
40
60
Temperature (°C)
8/19
80
100
120
-40
-20
0
20
40
60
Temperature (°C)
Electrical Characteristics
TSH330
Figure 25. I-bias vs. temperature
Figure 28. Icc vs. temperature
20
24
15
Ib(+)
22
Icc(+)
10
20
5
0
ICC (mA)
IBIAS (µA)
18
16
14
Ib(-)
Icc(-)
-20
10
6
-10
-15
12
8
-5
Gain=+1
Vcc=5V
no Load
-30
In+/In- to GND
-25
Gain=+1
Vcc=5V
Load=100 Ω
-35
-40
-20
0
20
40
60
80
100
120
-40
-20
0
Temperature (°C)
20
40
60
80
100
120
80
100
120
Temperature (°C)
Figure 26. Vio vs. temperature
Figure 29. Iout vs. temperature
1000
600
400
Isource
800
Iout (mA)
VIO (micro V)
200
600
400
0
-200
Isink
-400
200
Open Loop
Vcc=5V
Load=100Ω
-600
0
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
Output: short-circuit
Gain=+1
Vcc=5V
-800
-40
-20
0
20
40
60
Temperature (°C)
Figure 27. VOH & VOL vs. temperature
2
V OH
VOH & OL (V)
1
0
-1
VOL
-2
-3
Gain=+1
Vcc=5V
Load=100Ω
-4
-40
-20
0
20
40
60
80
Temperature (°C)
9/19
TSH330
Evaluation Boards
3 Evaluation Boards
An evaluation board kit optimized for high-speed operational amplifiers is available (order code:
KITHSEVAL/STDL). The kit includes the following evaluation boards, as well as a CD-ROM containing
datasheets, articles, application notes and a user manual:
z
SOT23_SINGLE_HF BOARD: Board for the evaluation of a single high-speed op-amp in SOT23-5
package.
z
SO8_SINGLE_HF: Board for the evaluation of a single high-speed op-amp in SO8 package.
z
SO8_DUAL_HF: Board for the evaluation of a dual high-speed op-amp in SO8 package.
z
SO8_S_MULTI: Board for the evaluation of a single high-speed op-amp in SO8 package in inverting
and non-inverting configuration, dual and single supply.
z
SO14_TRIPLE: Board for the evaluation of a triple high-speed op-amp in SO14 package with video
application considerations.
Board material:
z
2 layers
z
FR4 (εr=4.6)
z
epoxy 1.6mm
z
copper thickness: 35µm
Figure 30. Evaluation kit for high-speed op-amps
10/19
Power Supply Considerations
TSH330
4 Power Supply Considerations
Correct power supply bypassing is very important for optimizing performance in high-frequency ranges.
Bypass capacitors should be placed as close as possible to the IC pins to improve high-frequency
bypassing. A capacitor greater than 1µF is necessary to minimize the distortion. For better quality
bypassing, a capacitor of 10nF can be added using the same implementation conditions. Bypass
capacitors must be incorporated for both the negative and the positive supply.
For example, on the SO8_SINGLE_HF board, these capacitors are C6, C7, C8, C9.
Figure 31. Circuit for power supply bypassing
+VCC
10microF
+
10nF
+
-
10nF
10microF
+
-VCC
Single power supply
In the event that a single supply system is used, new biasing is necessary to assume a positive output
dynamic range between 0V and +VCC supply rails. Considering the values of VOH and VOL, the amplifier
will provide an output dynamic from +0.9V to +4.1V on 100Ω load.
The amplifier must be biased with a mid-supply (nominally +VCC/2), in order to maintain the DC
component of the signal at this value. Several options are possible to provide this bias supply, such as a
virtual ground using an operational amplifier or a two-resistance divider (which is the cheapest solution).
A high resistance value is required to limit the current consumption. On the other hand, the current must
be high enough to bias the non-inverting input of the amplifier. If we consider this bias current (55µA
max.) as the 1% of the current through the resistance divider to keep a stable mid-supply, two resistances
of 470Ω can be used.
The input provides a high pass filter with a break frequency below 10Hz which is necessary to remove the
original 0 volt DC component of the input signal, and to fix it at +VCC/2.
Figure 32 illustrates a 5V single power supply configuration for the SO8_SINGLE evaluation board (see
Evaluation Boards on page 10).
11/19
TSH330
Power Supply Considerations
A capacitor CG is added in the gain network to ensure a unity gain in low-frequency to keep the right DC
component at the output. CG contributes to a high-pass filter with Rfb//RG and its value is calculated with
a consideration of the cut off frequency of this low-pass filter.
Figure 32. Circuit for +5V single supply
+5V
10µF
+
IN
+5V
Rin
1kΩ
100µF
_
100Ω
R1
470Ω
Rfb
R2
470Ω
12/19
+ 1µF
RG
10nF
+
CG
OUT
Noise Measurements
TSH330
5 Noise Measurements
The noise model is shown in Figure 33, where:
z
eN: input voltage noise of the amplifier
z
iNn: negative input current noise of the amplifier
z
iNp: positive input current noise of the amplifier
Figure 33. Noise model
+
iN+
R3
output
HP3577
Input noise:
8nV/√Hz
_
N3
iN-
eN
R2
N2
R1
N1
The thermal noise of a resistance R is:
4kTR ∆ F
where ∆F is the specified bandwidth.
On a 1Hz bandwidth the thermal noise is reduced to
4kTR
where k is the Boltzmann's constant, equal to 1,374.10-23J/°K. T is the temperature (°K).
The output noise eNo is calculated using the Superposition Theorem. However eNo is not the simple sum
of all noise sources, but rather the square root of the sum of the square of each noise source, as shown
in Equation 1:
eNo =
eN o
2
2
2
2
2
2
2
V1 + V2 + V3 + V 4 + V5 + V6
2
2
2
2
2
2
2 R2 2
R2- 2 × 4kTR3
= e N × g + iNn × R 2 + iNp × R3 × g + -------- × 4kTR1 + 4kTR2 + 1 + ------R1
R1
Equation 1
Equation 2
13/19
TSH330
Noise Measurements
The input noise of the instrumentation must be extracted from the measured noise value. The real output
noise value of the driver is:
eNo =
2
2
( Measured ) – ( instrumentation )
Equation 3
The input noise is called the Equivalent Input Noise as it is not directly measured but is evaluated from the
measurement of the output divided by the closed loop gain (eNo/g).
After simplification of the fourth and the fifth term of Equation 2 we obtain:
eNo
2
2
2
2
2
2
2
2
R2 2
= eN × g + iNn × R2 + iNp × R3 × g + g × 4kTR2 + 1 + -------- × 4kTR3
R1
Equation 4
Measurement of the Input Voltage Noise eN
If we assume a short-circuit on the non-inverting input (R3=0), from Equation 4 we can derive:
eNo =
2
2
2
2
eN × g + iNn × R2 + g × 4kTR2
Equation 5
In order to easily extract the value of eN, the resistance R2 will be chosen to be as low as possible. In the
other hand, the gain must be large enough:
R3=0, gain: g=100
Measurement of the Negative Input Current Noise iNn
To measure the negative input current noise iNn, we set R3=0 and use Equation 5. This time the gain
must be lower in order to decrease the thermal noise contribution:
R3=0, gain: g=10
Measurement of the Positive Input Current Noise iNp
To extract iNp from Equation 3, a resistance R3 is connected to the non-inverting input. The value of R3
must be chosen in order to keep its thermal noise contribution as low as possible against the iNp
contribution:
R3=100W, gain: g=10
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Intermodulation Distortion Product
TSH330
6 Intermodulation Distortion Product
The non-ideal output of the amplifier can be described by the following series:
2
n
Vout = C 0 + C 1 Vin + C 2 V in + … Cn V in
due to non-linearity in the input-output amplitude transfer, where the input is Vin=Asinωt, C0 is the DC
component, C1(Vin) is the fundamental and Cn is the amplitude of the harmonics of the output signal Vout.
A one-frequency (one-tone) input signal contributes to harmonic distortion. A two-tone input signal
contributes to harmonic distortion and to the intermodulation product.
The study of the intermodulation and distortion for a two-tone input signal is the first step in characterizing
the driving capability of multi-tone input signals.
In this case:
Vin = A sin ω 1 t + A sin ω 2 t
then:
2
n
V out = C 0 + C1 ( A sin ω 1 t + A sin ω 2 t ) + C 2 ( A sin ω 1 t + A sin ω 2 t ) … + C n ( A sin ω 1 t + A sin ω 2 t )
From this expression, we can extract the distortion terms, and the intermodulation terms form a single
sine wave: second-order intermodulation terms IM2 by the frequencies (ω1-ω2) and (ω1+ω2) with an
amplitude of C2A2 and third-order intermodulation terms IM3 by the frequencies (2ω1-ω2), (2ω1+ω2), (−
ω1+2ω2) and (ω1+2ω2) with an amplitude of (3/4)C3A3.
The measurement of the intermodulation product of the driver is achieved by using the driver as a mixer
by a summing amplifier configuration (see Figure 34). In this way, the non-linearity problem of an external
mixing device is avoided.
Figure 34. Inverting summing amplifier (using evaluation board SO8_S_MULTI)
Vin1
R1
Vin2
R2
R fb
_
Vout
+
100Ω
R
15/19
TSH330
The Bias of an Inverting Amplifier
7 The Bias of an Inverting Amplifier
A resistance is necessary to achieve a good input biasing, such as resistance R shown in Figure 35.
The magnitude of this resistance is calculated by assuming the negative and positive input bias current.
The aim is to compensate for the offset bias current, which could affect the input offset voltage and the
output DC component. Assuming Ib-, Ib+, Rin, Rfb and a zero volt output, the resistance R will be:
R in × R fb
R = ---------------------R in + R fb
Figure 35. Compensation of the input bias current
Rfb
Ib-
Rin
_
Vcc+
Output
+
Vcc-
Ib+
R
16/19
Load
Active Filtering
TSH330
8 Active Filtering
Figure 36. Low-pass active filtering, Sallen-Key
C1
R1
R2
+
IN
OUT
C2
_
100Ω
Rfb
RG
From the resistors Rfb and RG we can directly calculate the gain of the filter in a classical non-inverting
amplification configuration:
R fb
A V = g = 1 + ---------Rg
We assume the following expression as the response of the system:
Voutj ω
g
T j ω = ------------------- = --------------------------------------------Vin j ω
2
jω ( jω)
1 + 2 ζ ------- + -------------ω
c ω 2
c
The cut-off frequency is not gain-dependent and so becomes:
ω
1
c = ------------------------------------R1R2C 1C2
The damping factor is calculated by the following expression:
1
ζ = --- ω c ( C 1 R1 + C 1 R2 + C 2 R 1 – C 1 R 1 g )
2
The higher the gain, the more sensitive the damping factor is. When the gain is higher than 1, it is
preferable to use some very stable resistor and capacitor values. In the case of R1=R2=R:
R fb
2 C 2 – C1 ---------Rg
ζ = -----------------------------------2 C1 C2
Due to a limited selection of values of capacitors in comparison with resistors, we can fix C1=C2=C, so
that:
R fb
2 R 2 – R1 ---------Rg
ζ = -----------------------------------2 R1 R2
17/19
TSH330
Package Mechanical Data
9 Package Mechanical Data
SO-8 MECHANICAL DATA
DIM.
mm.
MIN.
TYP
inch
MAX.
MIN.
TYP.
MAX.
A
1.35
1.75
0.053
0.069
A1
0.10
0.25
0.04
0.010
A2
1.10
1.65
0.043
0.065
B
0.33
0.51
0.013
0.020
C
0.19
0.25
0.007
0.010
D
4.80
5.00
0.189
0.197
E
3.80
4.00
0.150
0.157
e
1.27
0.050
H
5.80
6.20
0.228
0.244
h
0.25
0.50
0.010
0.020
L
0.40
1.27
0.016
0.050
k
ddd
8˚ (max.)
0.1
0.04
0016023/C
18/19
Revision History
TSH330
10 Revision History
Date
Revision
Description of Changes
Oct. 2004
1
First release corresponding to Preliminary Data version of datasheet.
Dec. 2004
2
Release of mature product datasheet.
June 2005
3
Table 1 on page 2
- Rthjc: Thermal Resistance Junction to Ambient replaced by Thermal
Resistance Junction to Case
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