LMV821M5X [TI]
Single/ LMV822 Dual/ LMV824 Quad Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps; 单/双LMV822 / LMV824四路低电压，低功耗，R到R输出， 5 MHz的运算放大器
| 型号： | LMV821M5X |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | Single/ LMV822 Dual/ LMV824 Quad Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps |
| 文件： | 总26页 (文件大小：1061K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LMV821,LMV822,LMV824
LMV821 Single/ LMV822 Dual/ LMV824 Quad Low Voltage, Low Power, R-to-R
Output, 5 MHz Op Amps
Literature Number: SNOS032D
November 2003
LMV821 Single/ LMV822 Dual/ LMV824 Quad
Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps
n Maximum VOS
n VOS Temp. Drift
3.5 mV (Guaranteed)
1 uV/˚ C
General Description
The LMV821/LMV822/LMV824 bring performance and
economy to low voltage / low power systems. With a 5 MHz
unity-gain frequency and a guaranteed 1.4 V/µs slew rate,
the quiescent current is only 220 µA/amplifier (2.7 V). They
provide rail-to-rail (R-to-R) output swing into heavy loads
(600 Ω Guarantees). The input common-mode voltage range
includes ground, and the maximum input offset voltage is
3.5mV (Guaranteed). They are also capable of comfortably
driving large capacitive loads (refer to the application notes
section).
@
n GBW product 2.7 V
5 MHz
@
n ISupply 2.7 V
220 µA/Amplifier
1.4 V/us (Guaranteed)
90 dB
n Minimum SR
n CMRR
n PSRR
85 dB
-0.3V to 4.3V
@
n VCM 5V
n Rail-to-Rail (R-to-R) Output Swing
@
@
—
—
600 Ω Load
10 kΩ Load
160 mV from rail
55 mV from rail
The LMV821 (single) is available in the ultra tiny SC70-5
package, which is about half the size of the previous title
holder, the SOT23-5.
n Stable with High Capacitive Loads (Refer to Application
Section)
Overall, the LMV821/LMV822/LMV824 (Single/Dual/Quad)
are low voltage, low power, performance op amps, that can
be designed into a wide range of applications, at an eco-
nomical price.
Applications
n Cordless Phones
n Cellular Phones
n Laptops
n PDAs
n PCMCIA
Features
(For Typical, 5 V Supply Values; Unless Otherwise Noted)
n Ultra Tiny, SC70-5 Package
2.0 x 2.0 x 1.0 mm
n Guaranteed 2.5 V, 2.7 V and 5 V Performance
Telephone-line Transceiver for a
PCMCIA Modem Card
10012833
© 2003 National Semiconductor Corporation
DS100128
www.national.com
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 1)
Supply Voltage
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
2.5V to 5.5V
Temperature Range
LMV821, LMV822, LMV824
−40˚C ≤T ≤85˚C
J
ESD Tolerance (Note 2)
Thermal Resistance (θ
)
JA
Machine Model
Human Body Model
LMV822/824
100V
Ultra Tiny SC70-5 Package, 5-Pin
Surface Mount
440 ˚C/W
2000V
1500V
Tiny SOT23-5 Package, 5-Pin
Surface Mount
LMV821
265 ˚C/W
190 ˚C/W
Differential Input Voltage
Supply Voltage
5.5V
SO Package, 8-Pin Surface Mount
MSOP Package, 8-Pin Mini
Surface Mount
Supply Voltage (V+–V
)
−
Output Short Circuit to V+ (Note 3)
Output Short Circuit to V− (Note 3)
Soldering Information
235 ˚C/W
SO Package, 14-Pin Surface
Mount
145 ˚C/W
155 ˚C/W
Infrared or Convection (20 sec)
Storage Temperature Range
Junction Temperature (Note 4)
235˚C
−65˚C to 150˚C
150˚C
TSSOP Package, 14-Pin
2.7V DC Electrical Characteristics
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V = 0V, VCM = 1.0V, VO = 1.35V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
1
LMV821/822/824
Limit (Note 6)
Symbol
VOS
Parameter
Condition
Units
Input Offset Voltage
3.5
mV
max
4
TCVOS
IB
Input Offset Voltage Average
Drift
1
µV/˚C
Input Bias Current
30
90
140
30
nA
max
nA
IOS
Input Offset Current
0.5
85
50
max
dB
CMRR
+PSRR
−PSRR
VCM
Common Mode Rejection Ratio 0V ≤ VCM ≤ 1.7V
70
68
min
dB
Positive Power Supply Rejection 1.7V ≤ V+ ≤ 4V, V- = 1V, VO
Ratio
=
85
75
0V, VCM = 0V
70
min
dB
Negative Power Supply
Rejection Ratio
-1.0V ≤ V- ≤ -3.3V, V+ = 1.7V,
85
73
VO = 0V, VCM = 0V
70
min
V
Input Common-Mode Voltage
Range
For CMRR ≥ 50dB
-0.3
2.0
100
90
-0.2
max
V
1.9
min
dB
AV
Large Signal Voltage Gain
Sourcing, RL = 600Ω to 1.35V,
90
85
85
80
95
90
90
85
VO = 1.35V to 2.2V
min
dB
Sinking, RL = 600Ω to 1.35V,
VO = 1.35V to 0.5V
min
dB
Sourcing, RL = 2kΩ to 1.35V,
100
95
VO = 1.35V to 2.2V
min
dB
Sinking, RL = 2kΩ to 1.35, VO
=
1.35 to 0.5V
min
www.national.com
2
2.7V DC Electrical Characteristics (Continued)
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V = 0V, VCM = 1.0V, VO = 1.35V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
2.58
LMV821/822/824
Limit (Note 6)
2.50
Symbol
V O
Parameter
Output Swing
Condition
Units
V+ = 2.7V, RL= 600Ω to 1.35V
V
2.40
min
V
0.13
2.66
0.08
16
0.20
0.30
max
V
V+ = 2.7V, RL= 2kΩ to 1.35V
2.60
2.50
min
V
0.120
0.200
12
max
mA
min
mA
min
mA
max
mA
max
mA
max
IO
Output Current
Supply Current
Sourcing, VO = 0V
Sinking, VO = 2.7V
LMV821 (Single)
LMV822 (Dual)
26
12
IS
0.22
0.45
0.72
0.3
0.5
0.6
0.8
1.0
1.2
LMV824 (Quad)
2.5V DC Electrical Characteristics
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.5V, V = 0V, VCM = 1.0V, VO = 1.25V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
1
LMV821/822/824
Limit (Note 6)
3.5
Symbol
VOS
Parameter
Condition
Units
Input Offset Voltage
mV
max
V
4
V O
Output Swing
V+ = 2.5V, RL = 600Ω to 1.25V
2.37
0.13
2.46
0.08
2.30
2.20
min
V
0.20
0.30
max
V
V+ = 2.5V, RL = 2kΩ to 1.25V
2.40
2.30
min
V
0.12
0.20
max
2.7V AC Electrical Characteristics
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V = 0V, VCM = 1.0V, VO = 1.35V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
1.5
LMV821/822/824 Limit
Symbol
SR
Parameter
Conditions
Units
(Note 6)
Slew Rate
(Note 7)
V/µs
MHz
Deg.
dB
GBW
Φm
Gain-Bandwdth Product
Phase Margin
5
61
Gm
Gain Margin
10
Amp-to-Amp Isolation
Input-Related Voltage Noise
(Note 8)
135
28
dB
en
f = 1 kHz, VCM = 1V
3
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2.7V AC Electrical Characteristics (Continued)
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 2.7V, V = 0V, VCM = 1.0V, VO = 1.35V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
0.1
LMV821/822/824 Limit
Symbol
in
Parameter
Conditions
Units
(Note 6)
Input-Referred Current Noise
f = 1 kHz
THD
Total Harmonic Distortion
f = 1 kHz, AV = −2,
0.01
%
RL = 10 kΩ, VO = 4.1 V
PP
5V DC Electrical Characteristics
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V = 0V, VCM = 2.0V, VO = 2.5V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
1
LMV821/822/824
Limit (Note 6)
Symbol
VOS
Parameter
Condition
Units
Input Offset Voltage
3.5
mV
max
4.0
TCVOS
IB
Input Offset Voltage Average
Drift
1
µV/˚C
Input Bias Current
40
100
150
30
nA
max
nA
IOS
Input Offset Current
0.5
50
max
dB
CMRR
+PSRR
−PSRR
VCM
Common Mode Rejection Ratio 0V ≤ VCM ≤ 4.0V
90
72
70
min
dB
Positive Power Supply Rejection 1.7V ≤ V+ ≤ 4V, V- = 1V, VO
=
85
75
Ratio
0V, VCM = 0V
70
min
dB
Negative Power Supply
Rejection Ratio
-1.0V ≤ V- ≤ -3.3V, V+ = 1.7V,
VO = 0V, VCM = 0V
85
73
70
min
V
Input Common-Mode Voltage
Range
For CMRR ≥ 50dB
-0.3
4.3
-0.2
max
V
4.2
min
dB
AV
Large Signal Voltage Gain
Sourcing, RL = 600Ω to 2.5V,
VO = 2.5 to 4.5V
105
105
105
105
4.84
0.17
4.90
0.10
95
90
min
dB
Sinking, RL = 600Ω to 2.5V, VO
= 2.5 to 0.5V
95
90
min
dB
Sourcing, RL = 2kΩ to 2.5V, VO
= 2.5 to 4.5V
95
90
min
dB
Sinking, RL = 2kΩ to 2.5, VO
=
95
2.5 to 0.5V
90
min
V
V O
Output Swing
V+ = 5V,RL = 600Ω to 2.5V
V+ = 5V, RL = 2kΩ to 2.5V
4.75
4.70
0.250
.30
min
V
max
V
4.85
4.80
0.15
0.20
min
V
max
www.national.com
4
5V DC Electrical Characteristics (Continued)
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V = 0V, VCM = 2.0V, VO = 2.5V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
45
LMV821/822/824
Limit (Note 6)
Symbol
IO
Parameter
Output Current
Condition
Sourcing, VO = 0V
Units
20
15
mA
min
mA
Sinking, VO = 5V
LMV821 (Single)
LMV822 (Dual)
LMV824 (Quad)
40
0.30
0.5
20
15
min
mA
IS
Supply Current
0.4
0.6
0.7
0.9
1.3
1.5
max
mA
max
mA
1.0
max
5V AC Electrical Characteristics
−
Unless otherwise specified, all limits guaranteed for TJ = 25˚C. V+ = 5V, V = 0V, VCM = 2V, VO = 2.5V and R
1 MΩ.
>
L
Boldface limits apply at the temperature extremes.
Typ
(Note 5)
2.0
LMV821/822/824 Limit
Symbol
Parameter
Conditions
Units
(Note 6)
1.4
SR
Slew Rate
(Note 7)
V/µs min
MHz
Deg.
dB
GBW
Φm
Gain-Bandwdth Product
Phase Margin
5.6
67
Gm
Gain Margin
15
Amp-to-Amp Isolation
Input-Related Voltage Noise
(Note 8)
135
24
dB
en
f = 1 kHz, VCM = 1V
f = 1 kHz
in
Input-Referred Current Noise
Total Harmonic Distortion
0.25
0.01
THD
f = 1 kHz, AV = −2,
%
RL = 10 kΩ, VO = 4.1 V
PP
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: Human body model, 1.5 kΩ in series wth 100 pF. Machine model, 200Ω in series with 100 pF.
Note 3: Applies to both single-supply and split-supply operation. Continuous short circuit operation at elevated ambient temperature can result in exceeding the
maximum allowed junction temperature of 150˚C. Output currents in excess of 45 mA over long term may adversely affect reliability.
Note 4: The maximum power dissipation is a function of T
, θ , and T . The maximum allowable power dissipation at any ambient temperature is P =
JA A D
J(max)
(T
–T )/θ . All numbers apply for packages soldered directly into a PC board.
A JA
J(max)
Note 5: Typical Values represent the most likely parametric norm.
Note 6: All limits are guaranteed by testing or statistical analysis.
+
Note 7: V = 5V. Connected as voltage follower with 3V step input. Number specified is the slower of the positive and negative slew rates.
+
Note 8: Input referred, V = 5V and R = 100kΩ connected to 2.5V. Each amp excited in turn with 1 kHz to produce V = 3 V
.
L
O
PP
5
www.national.com
Typical Performance Characteristics
Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C.
Supply Current vs. Supply Voltage (LMV821)
Input Current vs. Temperature
10012802
10012801
Sourcing Current vs. Output Voltage (VS = 2.7V)
Sourcing Current vs Output Voltage (VS = 5V)
10012803
10012804
Sinking Current vs. Output Voltage (VS = 2.7V)
Sinking Current vs. Output Voltage (VS = 5V)
10012805
10012806
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6
Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C. (Continued)
Output Voltage Swing vs. Supply Voltage (RL = 10kΩ)
Output Voltage Swing vs. Supply Voltage (RL = 2kΩ)
10012807
10012886
Output Voltage Swing vs. Supply Voltage (RL = 600Ω)
Output Voltage Swing vs. Load Resistance
10012808
10012887
Input Voltage Noise vs. Frequency
Input Current Noise vs. Frequency
10012818
10012817
7
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Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C. (Continued)
Crosstalk Rejection vs. Frequency
+PSRR vs. Frequency
10012893
10012809
-PSRR vs. Frequency
CMRR vs. Frequency
10012847
10012810
Gain and Phase Margin vs. Frequency
Input Voltage vs. Output Voltage
(RL = 100kΩ, 2kΩ, 600Ω) 2.7V
10012888
10012811
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8
Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C. (Continued)
Gain and Phase Margin vs. Frequency
Gain and Phase Margin vs. Frequency
(RL = 100kΩ, 2kΩ, 600Ω) 5V
(Temp.= 25, -40, 85˚C, RL = 10kΩ) 2.7V
10012812
10012813
Gain and Phase Margin vs. Frequency
Gain and Phase Margin vs. Frequency
(Temp.= 25, -40, 85 ˚C, RL = 10kΩ) 5V
(CL = 100pF, 200pF, 0pF, RL = 10kΩ)2.7V
10012814
10012815
Gain and Phase Margin vs. Frequency
Gain and Phase Margin vs. Frequency
(CL = 100pF, 200pF, 0pF RL = 10kΩ) 5V
(CL = 100pF, 200pF, 0pF RL = 600Ω) 2.7V
10012816
10012819
9
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Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C. (Continued)
Gain and Phase Margin vs. Frequency
(CL = 100pF, 200pF, 0pF RL = 600Ω) 5V
Slew Rate vs. Supply Voltage
10012862
10012820
Non-Inverting Large Signal Pulse Response
Non-Inverting Small Signal Pulse Response
10012821
10012824
Inverting Large Signal Pulse Response
Inverting Small Signal Pulse Response
10012827
10012830
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10
Typical Performance Characteristics Unless otherwise specified, VS = +5V, single supply,
TA = 25˚C. (Continued)
THD vs. Frequency
10012882
added in parallel with 220 picofarads capacitance, to in-
crease the φm 20˚(approx.), but at the price of about a 100
kHz of bandwidth.
Application Note
This application note is divided into two sections: design
considerations and Application Circuits.
Overall, the LMV821/822/824 family provides good stability
for loaded condition.
DESIGN CONSIDERATIONS
This section covers the following design considerations:
1. Frequency and Phase Response Considerations
2. Unity-Gain Pulse Response Considerations
3. Input Bias Current Considerations
FREQUENCY AND PHASE RESPONSE
CONSIDERATIONS
The relationship between open-loop frequency response
and open-loop phase response determines the closed-loop
stability performance (negative feedback). The open-loop
phase response causes the feedback signal to shift towards
becoming positive feedback, thus becoming unstable. The
further the output phase angle is from the input phase angle,
the more stable the negative feedback will operate. Phase
Margin (φm) specifies this output-to-input phase relationship
at the unity-gain crossover point. Zero degrees of phase-
10012860
margin means that the input and output are completely in
phase with each other and will sustain oscillation at the
unity-gain frequency.
FIGURE 1. Phase Margin vs Common Mode Voltage for
Various Loads
The AC tables show φm for a no load condition. But φm
changes with load. The Gain and Phase margin vs Fre-
quency plots in the curve section can be used to graphically
determine the φm for various loaded conditions. To do this,
examine the phase angle portion of the plot, find the phase
margin point at the unity-gain frequency, and determine how
far this point is from zero degree of phase-margin. The larger
the phase-margin, the more stable the circuit operation.
The bandwidth is also affected by load. The graphs of Figure
1 and Figure 2 provide a quick look at how various loads
affect the φm and the bandwidth of the LMV821/822/824
family. These graphs show capacitive loads reducing both
φm and bandwidth, while resistive loads reduce the band-
width but increase the φm. Notice how a 600Ω resistor can be
11
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Application Note (Continued)
10012854
FIGURE 5. Pulse Response per Figure 4
10012861
INPUT BIAS CURRENT CONSIDERATION
Input bias current (IB) can develop a somewhat significant
offset voltage. This offset is primarily due to IB flowing
through the negative feedback resistor, RF. For example, if IB
FIGURE 2. Unity-Gain Frequency vs Common Mode
Voltage for Various Loads
@
is 90 nA (max room) and RF is 100 kΩ, then an offset of 9
UNITY GAIN PULSE RESPONSE CONSIDERATION
mV will be developed (VOS=IBx RF).Using a compensation
resistor (RC), as shown in Figure 6, cancels out this affect.
But the input offset current (IOS) will still contribute to an
offset voltage in the same manner - typically 0.05 mV at
room temp.
A pull-up resistor is well suited for increasing unity-gain,
pulse response stability. For example, a 600 Ω pull-up resis-
tor reduces the overshoot voltage by about 50%, when
driving a 220 pF load. Figure 3 shows how to implement the
pull-up resistor for more pulse response stability.
10012841
FIGURE 3. Using a Pull-up Resistor at the Output for
Stabilizing Capacitive Loads
Higher capacitances can be driven by decreasing the value
of the pull-up resistor, but its value shouldn’t be reduced
beyond the sinking capability of the part. An alternate ap-
proach is to use an isolation resistor as illustrated in Figure 4
.
Figure 5 shows the resulting pulse response from a LMV824,
while driving a 10,000 pF load through a 20Ω isolation
resistor.
10012859
FIGURE 6. Canceling the Voltage Offset Effect of Input
Bias Current
APPLICATION CIRCUITS
10012843
This section covers the following application circuits:
1. Telephone-Line Transceiver
FIGURE 4. Using an Isolation Resistor to Drive Heavy
Capacitive Loads
2. “Simple” Mixer (Amplitude Modulator)
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12
Application Note (Continued)
3. Dual Amplifier Active Filters (DAAFs)
•
•
a. Low-Pass Filter (LPF)
b. High-Pass Filter (HPF)
4. Tri-level Voltage Detector
TELEPHONE-LINE TRANSCEIVER
The telephone-line transceiver of Figure 7 provides a full-
duplexed connection through a PCMCIA, miniature trans-
former. The differential configuration of receiver portion
(UR), cancels reception from the transmitter portion (UT).
Note that the input signals for the differential configuration of
UR, are the transmit voltage (VT) and VT/2. This is because
Rmatch is chosen to match the coupled telephone-line imped-
10012839
>>
ance; therefore dividing VT by two (assuming R1
Rmatch). The differential configuration of UR has its resistors
chosen to cancel the VT and VT/2 inputs according to the
following equation:
FIGURE 8. Amplitude Modulator Circuit
f
mod
f
carrier
10012840
FIGURE 9. Output signal per the Circuit of Figure 8
DUAL AMPLIFIER ACTIVE FILTERS (DAAFs)
10012833
The LMV822/24 bring economy and performance to DAAFs.
The low-pass and the high-pass filters of Figure 10 and
Figure 11 (respectively), offer one key feature: excellent
sensitivity performance. Good sensitivity is when deviations
in component values cause relatively small deviations in a
filter’s parameter such as cutoff frequency (Fc). Single am-
plifier active filters like the Sallen-Key provide relatively poor
sensitivity performance that sometimes cause problems for
high production runs; their parameters are much more likely
to deviate out of specification than a DAAF would. The
DAAFs of Figure 10 and Figure 11 are well suited for high
volume production.
FIGURE 7. Telephone-line Transceiver for a PCMCIA
Modem Card
Note that Cr is included for canceling out the inadequacies of
the lossy, miniature transformer. Refer to application note
AN-397 for detailed explanation.
“SIMPLE” MIXER (AMPLITUDE MODULATOR)
The mixer of Figure 8 is simple and provides a unique form
of amplitude modulation. Vi is the modulation frequency
(FM), while a +3V square-wave at the gate of Q1, induces a
carrier frequency (FC). Q1 switches (toggles) U1 between
inverting and non-inverting unity gain configurations. Offset-
ting a sine wave above ground at Vi results in the oscillo-
scope photo of Figure 9.
The simple mixer can be applied to applications that utilize
the Doppler Effect to measure the velocity of an object. The
difference frequency is one of its output frequency compo-
nents. This difference frequency magnitude (/FM-FC/) is the
key factor for determining an object’s velocity per the Dop-
pler Effect. If a signal is transmitted to a moving object, the
reflected frequency will be a different frequency. This differ-
ence in transmit and receive frequency is directly propor-
tional to an object’s velocity.
13
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Note that this information provides insight on how to fine
tune the cutoff frequency, if necessary. It should be also
noted that R4 and R5 of each circuit also caused variations in
the pass band gain. Increasing R4 by ten percent, increased
the gain by 0.4 dB, while increasing R5 by ten percent,
decreased the gain by 0.4 dB.
Application Note (Continued)
TABLE 1.
Component Sensitivity Component Sensitivity
(LPF)
Ra
(LPF)
-1.2
-0.1
-1.1
+0.7
-1.5
-0.6
+0.6
(HPF)
Ca
(HPF)
-0.7
C1
Rb
-1.0
R2
R1
+0.1
-0.1
R3
C2
C3
R3
+0.1
-0.1
R4
R4
R5
R5
+0.1
10012836
Active filters are also sensitive to an op amp’s parameters
-Gain and Bandwidth, in particular. The LMV822/24 provide
a large gain and wide bandwidth. And DAAFs make excel-
lent use of these feature specifications.
FIGURE 10. Dual Amplifier, 3 kHz Low-Pass Active
Filter with a Butterworth Response and a Pass Band
Gain of Times Two
Single Amplifier versions require a large open-loop to
closed-loop gain ratio - approximately 50 to 1, at the Fc of
the filter response. Figure 12 shows an impressive photo-
graph of a network analyzer measurement (hp3577A). The
measurement was taken from a 300 kHz version of Figure
@
10. At 300 kHz, the open-loop to closed-loop gain ratio Fc
is about 5 to 1. This is 10 times lower than the 50 to 1 “rule
of thumb” for Single Amplifier Active Filters.
10012837
FIGURE 11. Dual Amplifier, 300 Hz High-Pass Active
Filter with a Butterworth Response and a Pass Band
Gain of Times Two
10012892
FIGURE 12. 300 kHz, Low-Pass Filter, Butterworth
Response as Measured by the HP3577A Network
Analyzer
Table 1 provides sensitivity measurements for a 10 MΩ load
condition. The left column shows the passive components
for the 3 kHz low-pass DAAF. The third column shows the
components for the 300 Hz high-pass DAAF. Their respec-
tive sensitivity measurements are shown to the right of each
component column. Their values consists of the percent
change in cutoff frequency (Fc) divided by the percent
change in component value. The lower the sensitivity value,
the better the performance.
In addition to performance, DAAFs are relatively easy to
design and implement. The design equations for the low-
pass and high-pass DAAFs are shown below. The first two
equation calculate the Fc and the circuit Quality Factor (Q)
for the LPF (Figure 10). The second two equations calculate
the Fc and Q for the HPF (Figure 11).
Each resistor value was changed by about 10 percent, and
this measured change was divided into the measured
change in Fc. A positive or negative sign in front of the
measured value, represents the direction Fc changes rela-
tive to components’ direction of change. For example, a
sensitivity value of negative 1.2, means that for a 1 percent
increase in component value, Fc decreases by 1.2 percent.
www.national.com
14
Application Note (Continued)
Notice that R3 could also be calculated as 0.707 of Ra or R2.
The circuit was implemented and its cutoff frequency mea-
sured. The cutoff frequency measured at 2.92 kHz.
The circuit also showed good repeatability. Ten different
LMV822 samples were placed in the circuit. The correspond-
ing change in the cutoff frequency was less than a percent.
To simplify the design process, certain components are set
equal to each other. Refer to Figure 10 and Figure 11. These
equal component values help to simplify the design equa-
tions as follows:
TRI-LEVEL VOLTAGE DETECTOR
The tri-level voltage detector of Figure 13 provides a type of
window comparator function. It detects three different input
voltage ranges: Min-range, Mid-range, and Max-range. The
output voltage (VO) is at VCC for the Min-range. VO is
clamped at GND for the Mid-range. For the Max-range, VO is
at Vee. Figure 14 shows a VO vs. VI oscilloscope photo per
the circuit of Figure 13.
Its operation is as follows: VI deviating from GND, causes
the diode bridge to absorb IIN to maintain a clamped condi-
tion (VO= 0V). Eventually, IIN reaches the bias limit of the
diode bridge. When this limit is reached, the clamping effect
stops and the op amp responds open loop. The design
equation directly preceding Figure 14, shows how to deter-
mine the clamping range. The equation solves for the input
voltage band on each side GND. The mid-range is twice this
voltage band.
To illustrate the design process/implementation, a 3 kHz,
Butterworth response, low-pass filter DAAF (Figure 10) is
designed as follows:
1. Choose C1 = C3 = C = 1 nF
2. Choose R4 = R5 = 1 kΩ
3. Calculate Ra and R2 for the desired Fc as follows:
10012889
4. Calculate R3 for the desired Q. The desired Q for a
Butterworth (Maximally Flat) response is 0.707 (45 degrees
into the s-plane). R3 calculates as follows:
15
www.national.com
Application Note (Continued)
10012834
FIGURE 13. Tri-level Voltage Detector
|
∆v
|
∆v
|
OV
+V
IN
-V
IN
OV
10012835
FIGURE 14. X, Y Oscilloscope Trace showing VOUT vs VIN per the Circuit of Figure 13
www.national.com
16
Connection Diagrams
5-Pin SC70-5/SOT23-5
8-Pin SO/MSOP
14-Pin SO/TSSOP
10012884
10012863
Top View
10012885
Top View
Top View
Ordering Information
Temperature Range
Package
5-Pin SC-70-5
Industrial
−40˚C to +85˚C
LMV821M7
LMV821M7X
LMV821M5
LMV821M5X
LMV822M
Packaging Marking
Transport Media
NSC Drawing
MAA05
A15
A14
1k Units Tape and Reel
3k Units Tape and Reel
1k UnitsTape and Reel
3k Units Tape and Reel
Rails
5-Pin SOT23-5
8-Pin SOIC
MF05A
LMV822M
M08A
LMV822MX
2.5k Units Tape and
Reel
8-Pin MSOP
14-Pin SOIC
14-Pin TSSOP
LMV822MM
LMV822
LMV824M
LMV824MT
1k Units Tape and Reel
3.5k Units Tape and
Reel
MUA08A
M14A
LMV822MMX
LMV824M
Rails
LMV824MX
2.5k Units Tape and
Reel
LMV824MT
Rails
MTC14
LMV824MTX
2.5k Units Tape and
Reel
17
www.national.com
SC70-5 Tape and Reel
Specification
10012896
SOT-23-5 Tape and Reel
Specification
Tape Format
#
Tape Section
Leader
Cavities
Cavity Status
Empty
Cover Tape Status
Sealed
0 (min)
(Start End)
Carrier
75 (min)
3000
Empty
Sealed
Filled
Sealed
250
Filled
Sealed
Trailer
125 (min)
0 (min)
Empty
Sealed
(Hub End)
Empty
Sealed
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18
Tape Dimensions
10012897
8 mm
0.130
(3.3)
0.124
(3.15)
0.130
(3.3)
0.126
(3.2)
0.138 0.002
(3.5 0.05)
DIM F
0.055 0.004
(1.4 0.11)
DIM Ko
0.157
(4)
0.315 0.012
(8 0.3)
Tape Size
DIM A
DIM Ao
DIM B
DIM Bo
DIM P1
DIM W
19
www.national.com
Reel Dimensions
10012898
8 mm
7.00 0.059 0.512 0.795 2.165 0.331 + 0.059/−0.000 0.567
W1+ 0.078/−0.039
W1 + 2.00/−1.00
W3
330.00 1.50 13.00 20.20 55.00
8.40 + 1.50/−0.00
14.40
Tape Size
A
B
C
D
N
W1
W2
www.national.com
20
Physical Dimensions inches (millimeters) unless otherwise noted
SC70-5
NS Package Number MAA05
SOT 23-5
NS Package Number MF05A
21
www.national.com
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
8-Pin Small Outline
NS Package Number M08A
14-Pin Small Outline
NS Package Number M14A
www.national.com
22
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
8-Pin MSOP
NS Package Number MUA08A
14-Pin TSSOP
NS Package Number MTC14
23
www.national.com
Notes
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
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National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification
(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
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Support Center
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Fax: +49 (0) 180-530 85 86
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Email: new.feedback@nsc.com
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www.national.com
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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相关型号：
LMV821M7/NOPB
IC OP-AMP, 3500 uV OFFSET-MAX, 5 MHz BAND WIDTH, PDSO5, SC-70, 5 PIN, Operational Amplifier
NSC
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