Features

2.7-V and 5-V performance LMV321, LMV358, LMV324, and LMV324S have single, double and four-way low-pressure these devices are the most expensive-effective solutions without cross-handed distortion, which is suitable for effective solution Low -voltage applications are convenient, save space, and low cost.

Low power currents are specifically low-

-40 ° C to 125 ° C work (2.7 V to 5.5 V) Rail-rail calculation of large device

Low low Power shutdown mode (LMV324S) output swing.

-LMV321: 130 μA Typical voltage (2.7 V to 5 V) runs, with performance

—LMV358: 210 μA typical specifications conform to or exceed LM358 and

LM324 equipment, work The voltage from 5 V to 30 V. Use-LMV324: 410 μA Typical packaging size is less than

—LMV324S: 410 μA typical DBV (SOT-23) packaging. These devices

The rail output of various applications can be used.

ESD protection exceeds JESD 22

-2000-V human model

--1000-V charging device model

Application

desktop computer

HVAC: HVAC

motor control: AC response

Paper Electric

Portable media player

Power: Telecom DC/DC module: Numbers

Professional audio mixed

Refrigerator

Washing machine: High -end and low -end

Absolutely largest maximum The rated value

beyond the free air temperature range (unless there is another instructions) (1)

(1) the stress that exceeds the absolute maximum rated value may be possible. Causes permanent damage to the device. These are the functional operations of the equipment under these conditions or under any other conditions. The conditions of the device are not implicit. Long -term exposure may affect the reliability of the device under absolute maximum rated conditions.

(2) All voltage values u200bu200b(except for the differential voltage and VCC specified for measuring iOS) are related to the network GND.

(3) Differential voltage is in+relative to IN-.

(4) The short circuit from output to VCC may cause overheating and eventually cause damage.

Electric characteristics: VCC+u003d 2.7 V vcc+u003d 2.7 V, TA u003d 25 ° C (unless there is another instructions)

(1) Typical values u200bu200bindicate possible parameter nominal determined during the characteristic value. value. The typical value depends on the application and configuration and may change over time. The typical value of production materials cannot be guaranteed.

Electric characteristics: In the prescribed free air temperature, VCC+u003d 5 vcc+u003d 5 V (Unless otherwise explained)

(1) For for I temperature (LMV321, LMV358, LMV324, LMV321idck), full range TA u003d -40 ° C to 125 ° C, (LMV324S) is -40 ° C to 85 ° C, and -40 ° CQ temperature is 125 ° C.

(2) Typical values u200bu200bindicate the possible parameter nominal value determined when the character is. The typical value depends on the application and configuration and may change over time. The typical value of production materials cannot be guaranteed.

Typical features

Detailed description

Overview

LMV321, LMV358, LMV324 and LMV324S equipment are single, double and four low -pressure (2.7 volts to 5.5 volts) with orbit output swinging amplifiers. LMV324S device, it is a standard variant LMV324 device, including a power -saving shutdown function, when the amplifier does not need. Channel 1 and channel 2 are closed together, and channel 3 and channel 4 are also closed. The output was pulled down at the stop. LMV321, LMV358, LMV324, and LMV324S devices are the most cost -effective application solutions where low voltage operation, space saving and low cost. These amplifiers are specially designed for low -voltage (2.7 V to 5 V) operations, and the performance specifications meet or exceed LM358 and LM324 to work between 5V and 30V. The additional characteristics of the LMV3XX device are co-mode input voltage range, including ground, 1-MHz unit gain bandwidth and 1-V/μS conversion rate. The LMV321 device has super small packaging, which is about half of the DBV size (SOT-23) packaging. This encapsulation saves the space of the printing circuit board and makes small portable design into possible electronic devices. It also allows designers to place the device in a place closer to the source of the signal to reduce noise pickup and improve signal integrity.

Function description

Working voltage

LMV321, LMV358, LMV324, LMV324SThe equipment has been completely specified and ensured that from 2.7 V to 5 V. In addition, many specifications are suitable for -40 ° C to 125 ° C. The parameters are shown in the working voltage or temperature as a typical characteristic diagram.

Unit's gain bandwidth

The unit gain bandwidth is a amplifier with a unit gain. The frequency of working without unit gain can cause the signal to be seriously distorted. LMV321, LMV358, LMV324, and LMV324S have a 1M -meter unit gain bandwidth.

Conversion rate

The conversion rate refers to the input of the amplifier. The conversion rate of LMV321, LMV358, LMV324, and LMV324S devices is 1 V/μs.

Equipment function mode

When the power supply is connected, LMV321, LMV358, LMV324, LMV324S device is powered on. This LMV324S device is a variant of the standard LMV324 device. Including the power -saving shutdown function, when no amplifier is required, the power supply of each channel can be reduced to a maximum of 5 μA. Each device can run as a single power computing amplifier or dual -power amplifier, depending on the application.

Typical application

Some applications require differential signals. Figure 46 shows a simple circuit that converts a single -end input on a single 2.7 V power supply, and the differential output of 0.5 to 2 V is ± 1.5 V. The output range is intentionally limited to maximize linearity. The circuit consists of two amplifiers. A amplifier acts as a buffer, generating a voltage, vout+. The second amplifier inputs and adds a reference voltage to generate Vout -. Vout+and VOUT-range from 0.5 to 2 V. Value VDiff is Vout+and VOUT-. This LMV358 is used to build this circuit.

Typical application (continued)

Design requirements

The design requirements are as follows: Power supply voltage: 2.7 v reference Voltage: 2.5 V input: 0.5 to 2 V output tricks: ± 1.5 v

Detailed design program

The circuit in FIG. 46 uses a single -end input signal VIN, and generates two output signals VOUT+ And VOUT -use two amplifiers and a reference voltage VREF. VOUT+is the output of the first amplifier, the buffer version of the input signal, VIN (see equations 1). Water-is the output VREF of the second amplifier used to add bias voltage to the vehicle recognition number (VIN), and feedback to increase the inverse gain. VOUT's transmission function-is Formula 2. Vout+u003d Vehicle recognition number

Differential output signal VDIFF is the difference between two single -end output signals VOUT+and between and between. Formula 3 shows the transmission function of the VDiff. The conditions transfer functions of R1 u003d R2 and R3 u003d R4 are simplified into equation 6. With this configuration, the maximum input signal is equal to the reference voltage and the maximum output of each amplifier is equal to VREF. Differential output range is 2 × VREF. In addition, the co -mode voltage is half of VREF (see equations 7).

The amplifier selection

The linearity within the input range is the key to good DC accuracy. The restriction of the input range and output swing of the co -mode determines the linear. Generally speaking, a amplifier with rail -orbit input and output swing is needed. Bandwidth is a key issue of this design. Because the bandwidth of the LMV358 is 1 MM, this circuit can only process signals with a frequency of less than 1MHz.

Selection of passive components

Because of the transmission function of VOUT-seriously depends on the resistor (R1, R2, R3, and R4), use low resistance to maximize improvement of performance and reducing errors to tolerances to the tolerance to the tolerance of errors. Essence This design uses the resistance value of 36 kΩ, and the measurement tolerance is within 2%. If the noise of the system is a key parameter, users can choose smaller resistance (6 kΩ or lower) to keep the entire system low noise. This ensures that the noise from the resistor is lower than the noise of the amplifier.

Layout

Layout Guide

In order to obtain the best operating performance of the device, please use good PCB layout practice, including:

Noise can pass through the entire throughout The power pins of the circuit spread to the analog circuit and the operation amplifier. The barrier capacitance is used to reduce the local power supply of the coupling noise simulation circuit by providing low impedance.

-Colin the low ESR and 0.1-μF ceramic side electric container between each power supply foot and ground, and place it as close to the device as possible. A single bypass capacitor from V+to the ground is suitable for a single

supply application.

Circuit simulation and the individual grounding of the digital part are one of the simplest and most effective ways of noise suppression methods. A layer or multi -layer on the multi -layer printing circuit board is usually used for ground layers. The floor helps to distribute heat and reduce the noise of electromagnetic interference. Ensure that the numbers are separated in physical and simulate the ground, and pay attention to the flow of ground current. For details, see

Circuit layout technology (Sloa089).

In order to reduce parasitic coupling, the input trajectory should stay away from the power supply or output trajectory as much as possible. If it is impossible to separate them, it is best to be perpendicular to parallel to the noisy trajectory.

The external components are as close to the device as possible. Keep RF and RG close to the reversal input minimum inputChemical parasites, as shown in the layout example.

The length of the input record should be as short as possible.Always remember that the input trajectory is the sensitive part of the circuit.

Considering a driver's low impedance protection ring around the key line.The protective ring can significantly reduce the leakage current of different potentials nearby.