General description

lmv358 /324 is the dual and four product computing amplifiers version of the low voltage (2.7–5.5V) version, LM358/324, and currently run at 5-30V. LMV321 is a single version. LMV321/358/324 is the most cost -effective solution for applications that require low voltage operation, save space and low prices. The specifications they provide have reached or exceeded the familiar LM358/324. LMV321/358/324 has orbid -orbit output swing capacity and input co -mode voltage range includes ground. They all have an excellent speed and power ratio. Under low power currents, they can reach a transition rate of 1 million bandwidth and 1 volt/microsecond. LMV321 can be used to save space SC70-5 , which is about half of SOT33-5. The small package saves the space on the PC board and supports portable electronic devices. It also allows designers to close the device near the signal source to reduce noise pickup and increase signal integrity. These chips are the national advanced sub -grid BICMOS process. LMV321/358/324 has bipolar input and output levels, improving noise performance and higher output current drivers.

Features

(for V+ 5V and V- 0V, unless there are other instructions, it is typical value)

Guarantee 2.7V and 5V performance

[

123] Unprepared distortion

saving space package SC70-5 2.0x2.1x1.0 mm

Industrial temperature. The temperature range -40 ° C to+85 ° C

The width of the gain band is 1MHz

Low power current

-LMV321 130 Wei'an

-LMV358 210 Wei'an

-LMV324 410 Wei An

at 10kΩV+-10mv time-orbit output voltage-65 millivoltage

VCM-0.2V to V+-0.8 Fu

Application

Affective filter

General low -voltage application

General Portable Equipment

Absolutely maximum rated value (Note 1 1 )

ESD tolerance (Note 2)

Machine model 100V

Human model

lmv358/324 2000 volts

lmv321 900 volts

Differential input voltage ± power voltage

Power supply voltage (V+-伏-) 5.5 volts

output V+short circuit (Note 3)

Output to V-Short-circuit (Note 4)

Welding information

Infrared or convection (20 seconds) 235 degrees Celsius

Storage temperature. Temperature range -65 degrees Celsius to 150 degrees Celsius

Jacking temperature (Note 5) 150 ℉

working rated value (Note 1)

Power supply voltage 2.7V to 5.5V [123 [123 ]

Temperature range

LMV321, LMV358, LMV324 40 ° C to+85 ° C

Thermal resistance (Note 10)

5 Needle SC70-5 478 ° C/W

5-needle SOT2 3-5 265 ° C/W

8-needle SOIC 190∏c/W

8-needle MSOP 235 # C/W

14 -needle SOIC 145∏C/W

14 -needle TSSOP 155 ° C/W

2.7V DC Phaksday

Unless another There are regulations, otherwise, all limits of T J 25 ° C, V+ 2.7V, V- 0V, VCM 1.0V, VO V+/2 and RL GT; 1MΩ.

5V AC electrical characteristics

Unless there are other regulations, it is guaranteed to guarantee t J 25 ℃, V+ 5V, V- 0V, VCM 2.0V , VO V, all limits+/2 and r gt; 1MΩ. Black body restrictions are suitable for extreme temperatures.

Note 1: Absolute maximum rated value indicates the limit that the device may be damaged. The work rated value indicates the state of the device to play the function, but does not guarantee specific performance. For guarantee specifications and test conditions, see electrical characteristics.

Note 2: Human model, 1.5kΩ connects 100pf. Machine model, 0Ω with 200pf series.

Note 3: Short -circuit output to V+will adversely affect reliability.

Note 4: The short circuit to V-will adversely affect the reliability.

Note 5: The maximum power consumption is the functions of TJ (MAX), θJa, and TA. The maximum allowable power consumption at any ambient temperature is pd (TJ (MAX) – TA)/θJa. All numbers are suitable for packaging directly welded to the PC board.

Note 6: Typical values represent the most likely parameter model.

Note 7: All limits are guaranteed by testing or statistical analysis.

Note 8: RL connected V-output voltage 0.5V ≤VO ≤ 4.5V.

Note9: As a 3V step input voltage follower connection. The specified number is the slower in the positive and negative conversion rate.

Note 10: All numbers are typical numbers, which are suitable for packaging directly welded to the PC board in static air.

Typical performance characteristics, unless there are other regulations, vs +5V, single power supply, TA 25 degrees Celsius.

Application description

1.0 lmv321/358/324 : LMV321/358/324 Packaged small footprints save space on the printing circuit board, and enable small -scale electronic products, such as mobile phone, telephone or other portable systems. Low -key LMV321/358/324 can be used for PCMCIA three types.

Signal integrity

Signal can be at the signal source and amplifier. By using a smaller amplifier bag, LMV321/358/324 can close the signal source, reduce noise pickup, and improve signal integrity. The simplified circuit board layout will help you avoid the layout of your PC board. This means that no additional components (such as capacitors and resistors) are filtered to eliminate the long traces of this computer.

Low power supply

These devices will help you extend the battery life to the greatest extent. They are the ideal choice of battery power supply system. Low power voltage NATIONAL provides 2.7V and 5V guarantee performance. This guarantees the operation of the entire battery.

Rail -to -rail transition

Rail output width provides the maximum possible dynamic range at the output end. This is particularly important when working at low power voltage. The input includes the grounding permit directly near the grounding operation. Differential input voltage may be greater than V+, without damaged equipment. Protection should be provided to prevent the input voltage negative voltage of more than -0.3V (at 25 degrees Celsius). An input clamping diode, its integrated circuit input end has a resistor to use the terminal. Easy -to -use and cross -distorted LMV321/358/324 provides similar specifications to FA Miliar LM324. In addition, the new LMV321/358/324 effectively eliminates the output cross distortion. The range of the range 1 and the photos in Figure 2 compares

LMV324 and LM324 in the voltage follower configuration, v S ± 2.5V, and RL ( 2kΩ) to GND. It has obviously cross -distorting has eliminated in the new LMV324.

2.0 capacity load tolerance

lmv321/358/324 can directly drive the unit gain 200pf without oscillation. Unit gainThe follower is the most sensitive configuration of the capacitor load. Direct capacitor loading reduces the phase of the amplifier. The combination of the amplifier output impedance and the capacitor causes phase lag. This can cause the underwriting pulse response or oscillation. Open a heavier capacitance load to use the circuit in Figure 3.

Application instructions (continued)

In FIG. 3, the isolation resistance RISO and the load capacitor CL form a pole Systems of badness. The ideal performance depends on the value of RISO. The larger the Riso resistance, the larger the VOUT. Figure 4 is a waveform of the output Figure 3 using 620Ω to represent RISO, and 510pf represents CL.

The circuit in FIG. 5 is improvement of the circuit in the figure. 3 is provided with DC accuracy and communication stability. If there is a load resistor in Figure 3, the output is the voltage divided by RISO and the load resistance. Instead, in Figure 5, RF uses the feedback technology to connect the vehicle identification number (VIN) to the RL to provide DC accuracy. Be careful due to the input bias current LMV321/358/324. CF and RISO are used to offset the input of phase heavy loss caused by feeding the high -frequency component of the output signal to the reverse of the amplifier, thereby maintaining the phase margin in the entire feedback loop. By increasing the value of C F, the capacitance driver can be increased. This will slow down the pulse response.

3.0 input bias current eliminates

LMV321/358/324 series with bipolar input level. The typical input bias current of this LMV321/358/324 is 15NA and 5V supply. Therefore, the 100kΩ input resistance will cause the error voltage of 1.5MV. By balancing the two reverse resistance values and non -inverse inputs, the input bias current of the amplifier will be reduced. The circuit in FIG. 6 indicates how to eliminate the error caused by the input bias current.

4.0 Typical single -power application circuit

4.1 Differential amplifier

Differential amplifier allows two volts to reduce, or serve as one as one In special circumstances, the two inputs of the signal are allowed to be shared by two inputs. Differential to single -end conversion or rejection of co -mode signals.

4.2 Instrument circuit

The input impedance of the previous differential amplifier was set on the grounds of the resistance R1, R2, R3, and R4 settings. To eliminate low input impedance problems, one method is to use the voltage follower in each input, as shown in the following two instrument amplifiers.

Application for instructions (continued)

4.2.1 Three -handed instrument amplifier

Four Road LMV324 can be used to build a three -computing amplifier instrument instrumentThe table is shown in Figure 8.

The first level of the instrument amplifier is the differential input, the differential output amplifier, and two voltage followers. These two voltage followers ensure that the input impedance exceeds 100 mΩ. The gain of the instrument amplifier is set by the ratio of R2/R1. R3 should equal R1 and R4 equals R2. The matching of R3 to R1 and R4 to R2 affects CMRR. For a good CMRR temperature, low drifting resistors should be used. Small R4 adds a fine -tuning tank that is equivalent to twice the difference between R2 and R4 to allow the best to adjust CMRR.

4.2.2 dual operation amplifier amplifier amplifier

The dual -transportation instrument amplifier can also be used to make high input impedance DC splitter (Figure 9). Like the three op amp circuits, this instrument amplifier requires accurate resistance to match to obtain a good co -mode suppression ratio. R4 should equal R1, R3 should equal to R2.

4.3 Single power supply inverter amplifier

It may be negative in the input signal to enter the amplifier. Because the amplifier works in a single power supply voltage, the amplifier of the R3 and R4 is used to make the amplifier bias, so that the input signal is in the input co -mode voltage range of the input signal in the amplifier. This capacitor C1 is placed between the reverse input and resistance R1 to prevent the DC signal of entering the communication signal source. The value of the R1 and C1 affects the deeper frequency FC

1/2πR1C1. Therefore, the output signal is concentrated near the middle power supply (if the voltage provides V+/2 input at the non -reversal). The output can swing to two orbit to maximize the signal -to -noise ratio in the low pressure system.

4.4 Active filter

4.4.1 Simple low -pass active filter

Simple low -pass filter shown 11 shown. Its low frequency gain (ω → 0) is defined by -R3/R1. This allows low -frequency gains other than the unit. This filter has -20db/Decade attenuation after the angle frequency FC. The selection of R2 should be equal to the parallel combination of R1 and R3, which is to minimize errors caused by bias current. The response of the frequency filter is shown in Figure 12.

Note that the single transport calculating amplifier has the active filter to require low -quality factor Q (≤10), low frequency ( lt; 5 kHz), low gain ( lt; 10 ), Or the multiplier of gain by Q (≤100). The operating amplifier should have an open loop voltage gain at least 50 times more frequency than the filter at this time. In addition, the selected shipping should have the rotation rate that meets the following requirements: the rotation rate ≥0.5 x (ωhvopp) x 10-6 V/microsecond is the highest frequency of interest, VOPP is the output peak room roomVoltage.

4.4.2 Sallen key second -order source low -pass filter

The icon is the second -order source low -pass filter of the Sallen key in FIG. 13.The DC gain of the filter is expressed

The following paragraph explains how to be R1, R2, R3, R4, C1, and C 2.For example, as the Alps, Q and F C.The standard form of the second -order low -pass filter is

Q: Magnetic quality factor

ωc: angle frequency

type (2)Comparison of formula (3)

In order to reduce the calculations required in the design of the filter, it is convenient to introduce standardization and design parameters in the component.In order to standardize, let the ωc ωn 1rad/s, and C1 C2 CN 1F, and replace these values to formula (4) and formula (5).From the equation (4), we get