Page 1
LMV321 Single/ LMV358 Dual/ LMV324 Quad
General Purpose, Low Voltage, Rail-to-Rail Output
Operational Amplifiers
August 1999
LMV321 Single/ LMV358 Dual/ LMV324 Quad General Purpose, Low Voltage, Rail-to-Rail Output
Operational Amplifiers
General Description
The LMV358/324 are low voltage (2.7–5.5V) versions of the
dual and quad commodity op amps, LM358/324, which currently operate at 5–30V. The LMV321 is the single version.
The LMV321/358/324 are the most cost effective solutions
for the applications where low voltage operation, space saving and low price are needed. They offer specifications that
meet or exceed the familiar LM358/324. The
LMV321/358/324 haverail-to-railoutput swing capability and
the input common-mode voltage range includes ground.
They all exhibit excellent speed-power ratio, achieving
1 MHz of bandwidth and 1 V/µs of slew rate with low supply
current.
The LMV321 is available in space saving SC70-5, which is
approximately half the size of SOT23-5. The small package
saves space on pc boards, and enables the design of small
portable electronic devices. It also allows the designer to
place the device closer to the signal source to reduce noise
pickup and increase signal integrity.
The chips are built with National’s advanced submicron
silicon-gate BiCMOS process. The LMV321/358/324 have
bipolar input and output stages for improved noise performance and higher output current drive.
Connection Diagrams
5-Pin SC70-5/SOT23-5
Features
+
=
(For V
n Guaranteed 2.7V and 5V Performance
n No Crossover Distortion
n Space Saving Package SC70-5 2.0x2.1x1.0mm
n Industrial Temp.Range −40˚C to +85˚C
n Gain-Bandwidth Product 1MHz
n Low Supply Current
LMV321 130µA
LMV358 210µA
LMV324 410µA
n Rail-to-Rail Output Swing
@
10kΩ Load V+−10mV
n V
CM
5V and V
−
=
0V,Typical Unless Otherwise Noted)
V
−0.2V to V+−0.8V
−
+65mV
Applications
n Active Filters
n General Purpose Low Voltage Applications
n General Purpose Portable Devices
14-Pin SO/TSSOP
DS100060-1
Top View
8-Pin SO/MSOP
DS100060-2
Top View
© 1999 National Semiconductor Corporation DS100060 www.national.com
Top View
DS100060-3
Page 2
Ordering Information
Temperature Range
Package
−40˚C to +85˚C
5-Pin SC70-5 LMV321M7 A12 1k Units Tape and Reel MAA05
LMV321M7X A12 3k Units Tape and Reel
5-Pin SOT23-5 LMV321M5 A13 1k Units Tape and Reel MA05B
LMV321M5X A13 3k Units Tape and Reel
8-Pin Small Outline LMV358M LMV358M Rails
LMV358MX LMV358M 2.5k Units Tape and Reel
8-Pin MSOP LMV358MM LMV358 1k Units Tape and Reel
LMV358MMX LMV358 3.5k Units Tape and Reel
14-Pin Small Outline LMV324M LMV324M Rails
LMV324MX LMV324M 2.5k Units Tape and Reel
14-Pin TSSOP LMV324MT LMV324MT Rails
LMV324MTX LMV324MT 2.5k Units Tape and Reel
Packaging Marking Transport Media NSC DrawingIndustrial
M08A
MUA08A
M14A
MTC14
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Page 3
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
ESD Tolerance (Note 2)
Machine Model 100V
Human Body Model
LMV358/324 2000V
LMV321 900V
Differential Input Voltage
Supply Voltage (V
Output Short Circuit to V
Output Short Circuit to V
+–V−
) 5.5V
+
−
Soldering Information
Infrared or Convection (20 sec) 235˚C
±
Supply Voltage
(Note 3)
(Note 4)
Storage Temp. Range −65˚C to 150˚C
Junction Temp. (T
, max) (Note 5) 150˚C
j
Operating Ratings (Note 1)
Supply Voltage 2.7V to 5.5V
Temperature Range
LMV321, LMV358, LMV324 −40˚C≤T
Thermal Resistance (θ
)(Note 10)
JA
5-pin SC70-5 478˚C/W
5-pin SOT23-5 265˚C/W
8-Pin SOIC 190˚C/W
8-Pin MSOP 235˚C/W
14-Pin SOIC 145˚C/W
14-Pin TSSOP 155˚C/W
≤85˚C
J
2.7V DC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C, V+= 2.7V, V−= 0V, VCM= 1.0V, VO=V+/2 and R
Symbol Parameter Conditions Typ
V
OS
TCV
I
B
I
OS
CMRR Common Mode Rejection Ratio 0V ≤ V
PSRR Power Supply Rejection Ratio 2.7V ≤ V
V
CM
Input Offset Voltage 1.7 7 mV
Input Offset Voltage Average
OS
Drift
Input Bias Current 11 250 nA
Input Offset Current 5 50 nA
≤ 1.7V 63 50 dB
CM
+
≤ 5V
=1V
V
Input Common-Mode Voltage
O
For CMRR≥50dB −0.2 0 V
Range
(Note 6)
1.9 1.7 V
V
O
I
S
Output Swing RL= 10kΩ to 1.35V V+-10 V+-100 mV
Supply Current LMV321 80 170 µA
LMV358
140 340 µA
Both amplifiers
LMV324
260 680 µA
All four amplifiers
5 µV/˚C
60 50 dB
60 180 mV
Limit
(Note 7)
L
>
1MΩ.
Units
max
max
max
min
min
min
max
min
max
max
max
max
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Page 4
2.7V AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C, V+= 2.7V, V−= 0V, VCM= 1.0V, VO=V+/2 and R
Symbol Parameter Conditions
GBWP Gain-Bandwidth Product C
Φ
m
G
m
e
n
Phase Margin 60 Deg
Gain Margin 10 dB
Input-Referred Voltage Noise f = 1 kHz 46
= 200 pF 1 MHz
L
Typ
(Note 6)
Limit
(Note 7)
L
>
1MΩ.
Units
i
n
Input-Referred Current Noise f = 1 kHz 0.17
5V DC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C, V+= 5V, V−= 0V, VCM= 2.0V, VO=V+/2 and R
Boldface limits apply at the temperature extremes.
Symbol Parameter Conditions Typ
V
OS
TCV
I
B
I
OS
CMRR Common Mode Rejection Ratio 0V ≤ V
PSRR Power Supply Rejection Ratio 2.7V ≤ V
V
CM
Input Offset Voltage 1.7 7
Input Offset Voltage Average
OS
Drift
Input Bias Current 15 250
Input Offset Current 5 50
≤ 4V 65 50 dB
CM
+
≤ 5V
=1VVCM=1V
V
Input Common-Mode Voltage
O
For CMRR≥50dB −0.2 0 V
Range
(Note 6)
4.2 4 V
A
V
V
O
Large Signal Voltage Gain
(Note 8)
Output Swing RL=2kΩto 2.5V V+-40 V+-300
RL=2kΩ 100 15
120 300
R
= 10kΩ to 2.5V V+-10 V+-100
L
I
O
I
S
Output Short Circuit Current Sourcing, VO=0V 60 5 mA
Sinking, V
= 5V 160 10 mA
O
Supply Current LMV321 130 250
LMV358
210 440
Both amplifiers
LMV324
410 830
All four amplifiers
5 µV/˚C
60 50 dB
65 180
Limit
(Note 7)
9
500
150
10
+
-400
V
400
+
-200
V
280
350
615
1160
L
>
1MΩ.
Units
mV
max
nA
max
nA
max
min
min
min
max
V/mV
min
mV
min
mV
max
mV
min
mV
max
min
min
µA
max
µA
max
µA
max
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Page 5
5V AC Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ= 25˚C, V+= 5V, V−= 0V, VCM= 2.0V, VO=V+/2 and R
Boldface limits apply at the temperature extremes.
Symbol Parameter Conditions
Typ
(Note 6)
Limit
(Note 7)
SR Slew Rate (Note 9) 1 V/µs
GBWP Gain-Bandwidth Product C
Φ
m
G
m
e
n
Phase Margin 60 Deg
Gain Margin 10 dB
Input-Referred Voltage Noise f = 1 kHz, 39
= 200 pF 1 MHz
L
L
>
1MΩ.
Units
i
n
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 with 100 pF. Machine model, 0Ω in series with 200 pF.
Note 3: Shorting output to V
Note 4: Shorting output to V
Note 5: The maximum power dissipation is a function of T
(T
Note 6: Typical values represent the most likely parametric norm.
Note 7: All limits are guaranteed by testing or statistical analysis.
Note 8: R
Note 9: Connected as voltage follower with 3V step input. Number specified is the slower of the positive and negative slew rates.
Note 10: All numbers are typical, and apply for packages soldered directly onto a PC board in still air.
Typical Performance Characteristics Unless otherwise specified, V
Supply Current vs Supply
Voltage (LMV321)
Input-Referred Current Noise f = 1 kHz 0.21
+
will adversely affect reliability.
-
will adversely affect reliability.
)/θJA. All numbers apply for packages soldered directly into a PC board.
J(max)–TA
is connected to V-. The output voltage is 0.5V ≤ VO≤ 4.5V.
L
, θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD=
J(max)
Input Current vs
Temperature
DS100060-73
DS100060-A9
= +5V, single supply, TA= 25˚C.
S
Sourcing Current vs
Output Voltage
DS100060-69
Sourcing Current vs
Output Voltage
DS100060-68
Sinking Current vs
Output Voltage
DS100060-70
Sinking Current vs
Output Voltage
DS100060-71
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Page 6
Typical Performance Characteristics Unless otherwise specified, V
T
= 25˚C. (Continued)
A
= +5V, single supply,
S
Output Voltage Swing
vs Supply Voltage
DS100060-67
Input Current Noise vs Frequency
DS100060-58
CMRR vs Frequency
Input Voltage Noise vs Frequency
DS100060-56
Crosstalk Rejection vs Frequency
DS100060-61
CMRR vs Input
Common Mode Voltage
Input Current Noise vs Frequency
DS100060-60
PSRR vs Frequency
DS100060-51
CMRR vs Input
Common Mode Voltage
DS100060-62
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DS100060-64
DS100060-63
Page 7
Typical Performance Characteristics Unless otherwise specified, V
T
= 25˚C. (Continued)
A
= +5V, single supply,
S
vs CMR
∆ V
OS
Input Voltage vs
Output Voltage
Open Loop Frequency
Response vs Temperature
DS100060-53
DS100060-52
∆ VOSvs CMR
Open Loop
Frequency Response
Gain and Phase vs
Capacitive Load
DS100060-50
DS100060-42
Input Voltage vs
Output Voltage
DS100060-54
Open Loop
Frequency Response
DS100060-41
Gain and Phase vs
Capacitive Load
DS100060-43
DS100060-45
DS100060-44
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Page 8
Typical Performance Characteristics Unless otherwise specified, V
T
= 25˚C. (Continued)
A
= +5V, single supply,
S
Slew Rate vs
Supply Voltage
Non-Inverting Large
Signal Pulse Response
Non-Inverting Small
Signal Pulse Response
DS100060-57
DS100060-A0
Non-Inverting Large
Signal Pulse Response
Non-Inverting Small
Signal Pulse Response
Inverting Large Signal
Pulse Response
DS100060-88
DS100060-89
Non-Inverting Large
Signal Pulse Response
DS100060-A1
Non-Inverting Small
Signal Pulse Response
DS100060-A2
Inverting Large Signal
Pulse Response
DS100060-A3
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DS100060-90
DS100060-A4
Page 9
Typical Performance Characteristics Unless otherwise specified, V
T
= 25˚C. (Continued)
A
= +5V, single supply,
S
Inverting Large Signal
Pulse Response
DS100060-A5
Inverting Small Signal
Pulse Response
DS100060-A7
Stability vs Capacitive Load
Inverting Small Signal
Pulse Response
DS100060-91
Stability vs Capacitive Load
Stability vs Capacitive Load
DS100060-46
Inverting Small Signal
Pulse Response
DS100060-A6
Stability vs Capacitive Load
DS100060-47
THD vs Frequency
DS100060-49
DS100060-48
DS100060-59
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Page 10
Typical Performance Characteristics Unless otherwise specified, V
T
= 25˚C. (Continued)
A
= +5V, single supply,
S
Open Loop Output
Impedance vs Frequency
DS100060-55
Short Circuit Current
vs Temperature (Sinking)
Application Notes
1.0 Benefits of the LMV321/358/324
Size. The small footprints of the LMV321/358/324 packages
save space on printed circuit boards, and enable the design
of smaller electronic products, such as cellular phones, pagers, or other portable systems. The low profile of the
LMV321/358/324 make them possible to use in PCMCIA
type III cards.
Signal Integrity.Signals can pick up noise between the signal source and the amplifier. By using a physically smaller
amplifier package, the LMV321/358/324 can be placed
closer to the signal source, reducing noise pickup and increasing signal integrity.
Simplified Board Layout. These products help you to avoid
using longpc traces inyour pc board layout. This meansthat
no additional components, such as capacitors and resistors,
are needed to filter out the unwanted signals due to the interference between the long pc traces.
Low Supply Current. These devices will help you to maximize battery life. They are ideal for battery powered systems.
Low Supply Voltage. National provides guaranteed performance at 2.7V and 5V. These guarantees ensure operation
throughout the battery lifetime.
Rail-to-Rail Output. Rail-to-rail output swing provides maximum possible dynamic range at the output. This is particularly important when operating on low supply voltages.
Input Includes Ground. Allows direct sensing near GND in
single supply operation.
The differential input voltage may be larger than V
damaging the device. Protection should be provided to prevent the input voltages from going negative more than −0.3V
(at 25˚C).An input clamp diode with a resistor to the IC input
terminal can be used.
Ease of Use & No Crossover Distortion. The LMV321/
358/324 offer specifications similar to the familiar LM324. In
addition, the new LMV321/358/324 effectively eliminate the
output crossover distortion. The scope photos in
and
Figure 2
compare the output swing of the LMV324 and
the LM324 in a voltage follower configuration, with V
2.5V and RL(=2kΩ) connected to GND. It is apparent that
the crossover distortion has been eliminated in the new
LMV324.
+
without
Figure 1
=
S
Short Circuit Current
vs Temperature (Sourcing)
DS100060-65
Output Voltage (500mV/div)
Time (50µs/div)
FIGURE 1. Output Swing of LMV324
Output Voltage (500mV/div)
Time (50µs/div)
FIGURE 2. Output Swing of LM324
2.0 Capacitive Load Tolerance
The LMV321/358/324 can directly drive 200 pF in unity-gain
without oscillation. The unity-gain follower is the most sensitive configuration to capacitive loading. Direct capacitive
loading reduces the phase margin of amplifiers. The combi-
±
nation of the amplifier’s outputimpedance and thecapacitive
load induces phase lag. This results in either an underdamped pulse response or oscillation. To drive a heavier capacitive load, circuit in
Figure 3
can be used.
DS100060-66
DS100060-97
DS100060-98
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Page 11
Application Notes (Continued)
DS100060-4
FIGURE 3. Indirectly Driving A Capacitive Load Using
Resistive Isolation
Figure 3
In
C
margin to the overall system. The desired performance depends on the value of R
value, the more stable Vout will be.
waveform of
C
, the isolation resistor R
form a pole to increase stability by adding more phase
L
ISO
Figure 3
.
L.
using 620Ω for R
and the load capacitor
ISO
. The bigger the R
Figure 4
and 510 pF for
ISO
resistor
ISO
is an output
(1v/div)
Output Signal Input Signal
Time (2µs/div)
DS100060-99
FIGURE 4. Pulse Response of the LMV324 Circuit in
Figure 3
Figure 5
The circuitin
3
because it provides DC accuracy as well as AC stability. If
there were a load resistor in
voltage divided by R
ure 5
,RFprovides the DC accuracy by using feed-forward
techniques to connect V
ing the value of R
LMV321/358/324. C
of phase margin by feeding the high frequency component of
is animprovement to the one in
Figure 3
and the load resistor. Instead, in
ISO
to RL. Caution is needed in choos-
IN
due to the input bias current of the
F
and R
F
ISO
, the output would be
serve to counteract the loss
Figure
Fig-
the output signal back to the amplifier’s inverting input,
thereby preserving phase margin in the overall feedback
loop. Increased capacitive drive is possible by increasing the
value of C
. This in turn will slow down the pulse response.
F
DS100060-5
FIGURE 5. Indirectly Driving A Capacitive Load with
DC Accuracy
3.0 Input Bias Current Cancellation
The LMV321/358/324 family has a bipolar input stage. The
typical input bias current of LMV321/358/324 is 15 nA with
5V supply.Thus a 100 kΩ input resistor will cause 1.5 mV of
error voltage. By balancing the resistor values at both inverting and non-inverting inputs, the error caused by the amplifier’s input bias current will be reduced. The circuit in
6
shows how to cancel the error caused by input bias
Figure
current.
DS100060-6
FIGURE 6. Cancelling the Error Caused by Input Bias
Current
4.0 Typical Single-Supply Application Circuits
4.1 Difference Amplifier
The difference amplifier allows the subtraction of two voltages or, as a special case, the cancellation of a signal common totwo inputs. It is useful as a computational amplifier,in
making a differential to single-ended conversion or in rejecting a common mode signal.
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Page 12
Application Notes (Continued)
DS100060-7
4.2.2 Two-op-amp Instrumentation Amplifier
A two-op-amp instrumentation amplifier can also be used to
make a high-input-impedance dc differential amplifier (
ure 9
) . As in the three-op-amp circuit, this instrumentation
Fig-
amplifier requires precise resistor matching for good CMRR.
R4 should equal to R1 and R3 should equal R2.
DS100060-11
DS100060-19
FIGURE 7. Difference Amplifier
4.2 Instrumentation Circuits
The input impedance of the previous difference amplifier is
set by the resistors R
problems of low input impedance, one way is to use a volt-
, and R4. To eliminate the
1,R2,R3
age follower ahead of each input as shown in the following
two instrumentation amplifiers.
4.2.1 Three-op-amp Instrumentation Amplifier
The quad LMV324 can be used to build a three-op-amp instrumentation amplifier as shown in
Figure 8
.
DS100060-85
FIGURE 8. Three-op-amp Instrumentation Amplifier
The first stage of this instrumentation amplifier is a
differential-input, differential-output amplifier, with two voltage followers. These two voltage followers assure that the
input impedance is over 100 MΩ. The gain of this instrumentation amplifier is set by the ratio of R
R
, and R4equal R2. Matching of R3to R1and R4to R2af-
1
fects the CMRR. For good CMRR over temperature, low drift
resistors should be used. Making R
2
and addinga trim pot equal to twice the difference between
R
and R4will allow the CMRR to be adjusted for optimum.
2
4
should equal
2/R1.R3
slightly smaller than R
DS100060-35
FIGURE 9. Two-Op-amp Instrumentation Amplifier
4.3 Single-Supply Inverting Amplifier
There may be cases where the input signal going into the
amplifier is negative. Because the amplifier is operating in
single supply voltage, a voltage divider using R
implemented to bias the amplifier so the input signal is within
and R4is
3
the input common-mode voltage range of the amplifier. The
capacitor C
tor R
V
. The values of R1and C1affect the cutoff frequency, fc
IN
= 1/2πR
As a result, the output signal is centered around mid-supply
(if the voltage divider provides V
is placed between the inverting input and resis-
1
to blockthe DC signal going into theAC signal source,
1
.
1C1
+
/2 at the non-inverting input). The output can swing to both rails, maximizing the
signal-to-noise ratio in a low voltage system.
DS100060-13
DS100060-20
FIGURE 10. Single-Supply Inverting Amplifier
4.4 Active Filter
4.4.1 Simple Low-Pass Active Filter
Figure 11
The simple low-pass filter is shown in
frequency gain (ω→0) is defined by -R
frequency gains other than unity to be obtained. The filter
3/R1
. Its low-
. This allows low-
has a -20dB/decade roll-off after its corner frequency fc. R
should be chosen equal to the parallel combination of R1and
R
to minimize errors due to bias current. The frequency re-
3
sponse of the filter is shown in
Figure 12
.
2
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Page 13
Application Notes (Continued)
DS100060-37
FIGURE 11. Simple Low-Pass Active Filter
DS100060-14
DS100060-16
FIGURE 13. Sallen-Key 2nd-Order Active Low-Pass
Filter
The following paragraphs explain how to select values for
R
1,R2,R3,R4,C1
as A
, Q, and fc.
LP
, and C2for given filter requirements, such
The standard form for a 2nd-order low pass filter is
(3)
where
Q: Pole Quality Factor
: Corner Frequency
ω
C
Comparison between the
Equation (2)
and
Equation (3)
yields
DS100060-15
FIGURE 12. Frequency Response of Simple Low-Pass
Active Filter in Figure 11
Note that the single-op-amp active filters are used in to the
applications that require low quality factor, Q( ≤ 10), low frequency (≤ 5 kHz), and low gain (≤ 10), or a small value for
the product of gain times Q (≤ 100).The op amp should have
an open loop voltage gain at the highest frequency of interest at least 50 times larger than the gain of the filter at this
frequency. In addition, the selected op amp should have a
slew rate that meets the following requirement:
SlewRate ≥ 0.5x(ω
where ω
output peak-to-peak voltage.
is thehighest frequency of interest, and V
H
)x10−6V/µsec
HVOPP
is the
opp
4.4.2 Sallen-Key 2nd-Order Active Low-Pass Filter
The Sallen-Key 2nd-order active low-pass filter is illustrated
in
Figure 13
. The dc gain of the filter is expressed as
(1)
Its transfer function is
(2)
(4)
(5)
To reduce the required calculations in filter design, it is convenient to introduce normalization into the components and
design parameters. To normalize, let ω
C
1=C2=Cn
(4)
and
= 1F, and substitute these values into
Equation (5)
. From
Equation (4)
= ωn= 1rad/s, and
C
Equation
, we obtain
(6)
From
Equation (5)
, we obtain
(7)
For minimum dc offset, V+ = V-, the resistor values at both
inverting and non-inverting inputs should be equal, which
means
(8)
From
Equation (1)
and
Equation (8)
, we obtain
(9)
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Page 14
Application Notes (Continued)
(10)
The values of C
As a design example:
Require: A
Start by selecting C1 and C2. Choose a standard value that
is close to
From
Equations (6), (7), (9), (10)
The above resistor values are normalized values with
ω
=1rad/s and C1=C2=Cn= 1F. To scale the normalized
n
cut-off frequency and resistances to the real values, two
scaling factors are introduced, frequency scaling factor (k
and impedance scaling factor (k
and C2are normally close to or equal to
1
=2,Q=1,fc=1KHz
LP
,
=1Ω
R
1
=1Ω
R
2
=4Ω
R
3
=4Ω
R
4
).
m
An adjustment to the scaling may be made in order to have
realistic values for resistors and capacitors. The actual value
used for each component is shown in the circuit.
4.4.3 2nd-order High Pass Filter
A 2nd-order high pass filter can be built by simply interchanging those frequency selective components (R
C
) in the Sallen-Key 2nd-order active low pass filter.As
1,C2
shown in
Figure 14
, resistors become capacitors, and capacitors become resistors. The resulted high pass filter has
the same corner frequency and the same maximum gain as
the previous 2nd-order low pass filter if the same components are chosen.
)
f
FIGURE 14. Sallen-Key 2nd-Order Active High-Pass
Filter
1,R2
DS100060-83
,
Scaled values:
= 15.9 kΩ
R
2=R1
= 63.6 kΩ
R
3=R4
= 0.01 µF
C
1=C2
FIGURE 15. State Variable Active Filter
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4.4.4 State Variable Filter
A state variable filter requires three op amps. One convenient way to build state variable filters is with a quad op amp,
Figure 15
such as the LMV324 (
).
This circuit can simultaneously represent a low-pass filter,
high-pass filter, and bandpassfilter at three different outputs.
The equations for these functions are listed below. It is also
called ″Bi-Quad″ active filter as it can produce a transfer
function which is quadratic in both numerator and
denominator.
DS100060-39
Page 15
Application Notes (Continued)
where for all three filters,
(11)
(12)
A design example for a bandpass filter is shown below:
Assume the system design requires a bandpass filter with f
= 1 kHz and Q = 50. What needs tobe calculated are capacitor and resistor values.
First choose convenient values for C
= 1200 pF
C
1
=30kΩ
1
,
Then from
2R2=R
Equation (11)
1,R1
and R2:
O
From
Equation (12)
,
From the above calculated values, the midband gain is H0=
R
= 100 (40dB). The nearest 5%standard values have
3/R2
been added to
Figure 15
.
4.5 Pulse Generators and Oscillators
A pulse generator is shown in
Figure 16
. Two diodes have
been used to separatethe charge and discharge pathsto capacitor C.
DS100060-81
FIGURE 16. Pulse Generator
When the output voltage V
pacitor C is charged toward V
across C rises exponentially with a time constant τ =R
and this voltage is applied to the inverting input of the op
is first at its high, VOH, the ca-
O
through R2. The voltage
OH
2
amp. Meanwhile, the voltage at the non-inverting input is set
at the positive threshold voltage (V
capacitor voltage continually increases until it reaches V
at which point the output of the generator will switch to its
low, V
(=0V in this case). The voltage at the non-inverting
OL
input is switched to the negative threshold voltage (V
the generator. The capacitor then starts to discharge toward
V
exponentially through R1, with a time constant τ =R1C.
OL
When the capacitor voltage reaches V
pulse generator switches to V
charge, and the cycle repeats itself.
) of the generator. The
TH+
, the output of the
TH-
. The capacitor starts to
OH
www.national.com15
TH+
)of
TH-
C,
,
Page 16
Application Notes (Continued)
DS100060-86
FIGURE 17. Waveforms of the Circuit in Figure 16
Figure 17
As shown in the waveformsin
is set by R
set by R
have different frequencies and pulse width by selecting dif-
, C and VOH, and the time between pulses (T2)is
2
, C and VOL. This pulse generator can be made to
1
ferent capacitor value and resistor values.
Figure 18
shows another pulse generator, with separate
charge and discharge paths. The capacitor is charged
through R1 and is discharged through R
, the pulse width (T1)
.
2
DS100060-76
FIGURE 19. Squarewave Generator
4.6 Current Source and Sink
The LMV321/358/324 can be used in feedback loops which
regulate the current in external PNP transistors to provide
current sources or in external NPN transistors to provide current sinks.
4.6.1 Fixed Current Source
A multiple fixed current source is show in
age (V
age divider (R
the voltage drop acrossR
the emitter current of transistor Q
current of Q
able out of the collector of Q
= 2V)is established acrossresistor R3by thevolt-
REF
and R4). Negative feedback is used to cause
3
and Q2, essentially this same current is avail-
1
to be equal toV
1
1
.
1
Figure 20
and if we neglect the base
.This controls
REF
. A volt-
Large input resistors can be used to reduce current loss and
a Darlington connection can be used to reduce errors due to
the β of Q
The resistor,R
Q
.
1
, can be used to scale the collector current of
either above or below the 1 mA reference value.
2
2
DS100060-77
FIGURE 18. Pulse Generator
Figure 19
is a squarewave generator with the same path for
charging and discharging the capacitor.
www.national.com 16
DS100060-80
FIGURE 20. Fixed Current Source
Page 17
Application Notes (Continued)
4.6.2 High Compliance Current Sink
A current sink circuit is shown in
quires only one resistor (R
which is directly proportional to this resistor value.
FIGURE 21. High Compliance Current Sink
4.7 Power Amplifier
A power amplifier is illustrated in
provide a higher output current because a transistor follower
is added to the output of the op amp.
Figure 21
) and supplies an output current
E
Figure 22
. The circuit re-
DS100060-82
. This circuit can
=
V
(V
H
OH−VOL
)/(1+R2/R1)
where
: Positive Threshold Voltage
V
TH+
: Negative Threshold Voltage
V
TH−
: Output Voltage at High
V
OH
: Output Voltage at Low
V
OL
: Hysteresis Voltage
V
H
Since LMV321/358/324 have rail-to-rail output, the
(V
) equals to VS, which is the supply voltage.
OH−VOL
V
H
=
V
S
/(1+R2/R1)
The differential voltage at the input of the op amp should not
exceed the specified absolute maximum ratings. For real
comparators that are much faster, we recommend you to use
National’s LMV331/393/339, which aresingle, dual and quad
general purpose comparators for low voltage operation.
DS100060-78
FIGURE 24. Comparator with Hysteresis
DS100060-79
FIGURE 22. Power Amplifier
4.8 LED Driver
The LMV321/358/324 can beused to drive an LEDas shown
Figure 23
in
.
DS100060-84
FIGURE 23. LED Driver
4.9 Comparator with Hysteresis
The LMV321/358/324 can be used as a low power comparator.
Figure 24
shows a comparator with hysteresis. The hys-
teresis is determined by the ratio of the two resistors.
=
V
TH+
V
TH−
/(1+R1/R2)+VOH/(1+R2/R1)
V
REF
=
/(1+R1/R2)+VOL/(1+R2/R1)
V
REF
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Page 18
SC70-5 Tape and Reel Specification
SOT-23-5 Tape and Reel Specification
TAPE FORMAT
Tape Section
Leader 0 (min) Empty Sealed
(Start End) 75 (min) Empty Sealed
Carrier 3000 Filled Sealed
Trailer 125 (min) Empty Sealed
(Hub End) 0 (min) Empty Sealed
www.national.com 18
#
Cavities Cavity Status Cover Tape Status
250 Filled Sealed
DS100060-B3
Page 19
SOT-23-5 Tape and Reel Specification (Continued)
TAPE DIMENSIONS
DS100060-B1
8 mm 0.130 0.124 0.130 0.126 0.138±0.002 0.055±0.004 0.157 0.315±0.012
(3.3) (3.15) (3.3) (3.2) (3.5
Tape Size DIM A DIM Ao DIM B DIM Bo DIM F DIM Ko DIM P1 DIM W
±
0.05) (1.4±0.11) (4) (8±0.3)
www.national.com19
Page 20
SOT-23-5 Tape and Reel Specification (Continued)
REEL DIMENSIONS
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
330.00 1.50 13.00 20.20 55.00 8.40 + 1.50/−0.00 14.40 W1 + 2.00/−1.00
Tape Size A B C D N W1 W2 W3
DS100060-B2
www.national.com 20
Page 21
Physical Dimensions inches (millimeters) unless otherwise noted
5-Pin SC70-5 Tape and Reel
Order Number LMV321M7 and LMV321M7X
NS Package Number MAA05A
www.national.com21
Page 22
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
5-Pin SOT23-5 Tape and Reel
Order Number LMV321M5 and LMV321M5X
NS Package Number MA05B
www.national.com 22
Page 23
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number LMV358M and LMV358MX
8-Pin Small Outline
NS Package Number M08A
www.national.com23
Page 24
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number LMV358MM and LMV358MMX
NS Package Number MUA08A
www.national.com 24
8-Pin MSOP
Page 25
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number LMV324M and LMV324MX
14-Pin Small Outline
NS Package Number M14A
www.national.com25
Page 26
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Operational Amplifiers
Order Number LMV324MT and LMV324MTX
14-Pin TSSOP
NS Package Number MTC14
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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
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.
labeling, can be reasonably expected to result in a
significant injury to the user.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
LMV321 Single/ LMV358 Dual/ LMV324 Quad General Purpose, Low Voltage, Rail-to-Rail Output
Email: support@nsc.com
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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