Features

Excellent sound quality

Ultra -low noise: 1.5NV/√Hz

Super Low distortion: 0.00003%at 1kHz

High conversion rate: 20V/μs

Broadband: 35MHz (G u003d+1)

Gao Kaihuan gain: 120db

Uniform gain stable

Low static current: Every 2.6MA channel

orbit; Rail output

Wide power supply range: ± 2.25V to ± 18V

provides double and four -heavy versions

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123] Professional audio equipment

Broadcast and studio equipment

simulation and digital mixer

high -end high -end A/V receiver

High -end Blu -ray #8482; Player

Explanation

OPA1602 and OPA1604 bipolar input computing amplifier realizes very low 2.5NV// √Hz noise density, ultra -low distortion at 1kHz is 0.00003%. OPA1602 and OPA1604 series operations amplifiers provide rail -to -rail output width within 600 millivolves at 2K this increases the net air and maximizes the dynamic range. These devices also have high output driving capabilities of ± 30mA.

These devices work within a very wide power supply range from ± 2.25V to ± 18V, and the power supply current of each channel is only 2.6mA. OPA1602 and OPA1604 are stable in unit gains and provide good dynamic performance under extensive load conditions.

These devices also have completely independent circuits to achieve the lowest string disturbances and are not affected by interaction between channels, even if they are driving or overloaded.

The temperature range of OPA1602 and OPA1604 is -40 ° C to+85 ° C.

Typical features TA u003d+25 ° C, vs u003d ± 15V, RL u003d 2kΩ, unless there are other descriptions.

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Application information

OPA1602 and OPA1604 are the unit gain stable, and the accuracy double and the four transport amplifiers are very low noise. Applying noise or high impedance power supply requires decoupled capacitors near the device pins. In most cases, 0.1 μF capacitors are enough. Figure 31 shows the simplified schematic diagram of OPA160X (showing a channel).

Working voltage

OPA160X series operational amplifier can work within the range of ± 2.25V to ± 18V, while maintaining excellent performance. The OPA160X series can be+4.5V between the power supply, and the voltage between the power supply is+36V. However, some applications do not require the same positive and negative output voltage. For the OPA160X series, the power supply voltage does not need to be equal. For example, the positive power supply can be set to+25V, and the negative power supply is set to -5V.

In all cases, the co -mode voltage must be kept within the specified range. In addition, the key parameters are guaranteed within the specified temperature range from TA u003d -40 ° C to+85 ° C. The typical feature shows the parameters that significantly changes with the working voltage or temperature.

Input protection

The input terminals of OPA1602 and OPA1604 are protected by back -to -back binary pipes to prevent too high motion voltage, as shown in Figure 32. In most circuit applications, there are no consequences of input protection circuits. However, in a low -gain or G u003d+1 circuit, because the output of the amplifier cannot respond enough to the input, the rapidly inclined input signal can make these diode move forward. This effect is a typical feature shown in Figure 17. If the input signal is fast enough to generate this positive bias condition, the input signal current must be limited to 10mA or below. If the input signal current has no inherent limit, you can use the input series resistor (RI) and/or feedback resistor (RF) to limit the signal input current. The resistor reduces the low noise performance of OPA160X and is checked in the noise performance part below. Figure 32 shows the configuration example when using a current limit input and feedback resistance.

Noise performance

FIG. 33 shows changes in the power supply source resistance of the unit gain configuration (no feedback resistance network, so there is no additional noise contribution). Total circuit noise.

OPA160X (GBW u003d 35MHz, G u003d+1) is displayed, and the general circuit noise is calculated. The computing amplifier itself provides voltage noise components and current noise components. Voltage noise is usually modified as a part of the bias voltage. The current noise is modeled to the time variable in the input bias current, and the voltage component of the noise is generated with the source resistance reaction. Therefore, the minimum noise of a given applicationSound calculation amplifier depends on source impedance. For low -source impedance, current noise can be ignored, and voltage noise usually dominates. The low -voltage noise of the OPA160X series computing amplifier makes it a better choice for low source impedance less than 1K

Formula in FIG. 33 shows the calculation of the general circuit noise. These parameters are as follows:

EN u003d voltage noise

in u003d current Noise

RS u003d source impedance

k u003d Bolitzman constant u003d 1.38 × 10–23 j/k

#8226 ; T u003d Temperature, Unit: Kaishi (K)

Basic noise calculation

The design of the low noise computing amplifier circuit needs to consider various possibilities carefully Noise factor: noise from signal source, noise generated in the computing amplifier, and noise from feedback network resistors. The total noise of the circuit is a square root and combination of all noise components.

The resistance part of the source impedance generates the heat noise of proportion to the square root of the resistance. Figure 33 depicts this equation. This source of impedance is usually fixed; therefore, the choice of op amp and feedback resistance to minimize their contribution to their total noise.

FIG. 34 illustrates the configuration of the inverter and non -inverter computing amplifier circuit. In the configuration of the gains, the feedback network resistance will also produce noise. The current noise of the amplifier and the feedback resistor reaction to generate additional noise components. The feedback resistance value can usually be selected so that these noise sources can be ignored. The total noise equation of the two structures is given.

Total harmonic distortion measurement

OPA160X series operational amplifier has excellent distortion characteristics. In the audio frequency range of 20Hz to 20kHz, THD+noise is less than 0.00008%(g u003d+1, VO u003d 3VRMS, BW u003d 80kHz) (see Figure 7).

The distortion generated by the OPA160X series operational amplifier is lower than the measurement limit of many commercial distortion analyzers. However, special test circuits (as shown in Figure 35) can be used to expand the measurement capabilities.

The operational amplifier distortion can be considered as an internal error source, and you can refer to the input. FIG. 35 shows the circuit that causes the increasing increasing distortion of the computing amplifier (the distortion gain coefficient on various signal gain, please refer to the form in Figure 35). The addition of R3's non -easy amplifier configuration for other standards can change the feedback coefficient or noise gain of the circuit. The closed -loop gain is unchanged, but the feedback that can be used for error correction is reduced by the distorted gain factors, thereby increasing the same amountEssence Note that the input signal and load of the application to the computing amplifier are the same as the traditional feedback without R3. The R3 value should be kept smaller to minimize its impact on distortion measurement.

The effectiveness of this technology can be verified by repeated measurement under high gain and/or high frequency, where the distortion is within the measurement capacity range of the test equipment. The measurement of this data table uses the dual distortion/noise analyzer of the audio precision system, which greatly simplifies repeated measurement. However, the measurement technology can be executed by manual distortion measuring instruments.

Capacity load

The dynamic characteristics of OPA1602 and OPA1604 have been optimized for common gains, loads and operations. Degree and may cause peak or oscillation. Therefore, the heavier capacitance load must be isolated from the output. The easiest way to achieve this isolation is to connect a small resistance (eg, RS is equal to 50Ω) at the output end.

This small series resistance can also prevent excessive power consumption, if the output of the device is shorter. Figure 19 shows the relationship diagram of the small signal super -adjustment and capacitance load of several RS values. For more information about analysis technology and application circuit, please refer to the application announcement AB-028 (Literature Number: SBOA015, you can download it from the Ti website).

Power loss

OPA1602 and OPA1604 series operational amplifiers can drive 2K load, and the power supply voltage is as high as ± 18V. When working at high power, internal power consumption increases voltage. Compared with traditional materials, the lead frame structure adopted by the OPA160X series computing amplifier improves the heat dissipation performance. The layout of the circuit board also helps reduce the temperature rise to the maximum extent. Wide copper traces help heat dissipation as an extra radiator. By welding the device to the circuit board instead of using the socket, the temperature can be further raised to the lowest.

Excessive electrical stress

Designers often ask the capacity of computing amplifiers to withstand excessive electrical stability. These problems are often concentrated on the device input, but may involve the power supply voltage pins and even output pins. Each different pins function has the electrical stability limit determined by the voltage breakdown characteristics of a specific semiconductor manufacturing process and a specific circuit connected to the pin. In addition, internal electrostatic discharge (ESD) is protected in these circuits to prevent an ESD incident that occurs before and in the process of product assembly.

The ESD event will generate a high -voltage pulse with a short duration. When it discharge through semiconductor devices, the pulse is converted into a pulse with short duration and large current. Design an ESD protection circuit to prevent damage to the core circuit. The energy absorbed by the protective circuit was subsequently lost in the form of heat.

When one ESD voltage is magnified in two or moreWhen the instrument is formed, the current flows through one or more to the diode. According to the path of the current, the absorption device may be activated. When a fast ESD voltage pulse is cited through the power, the absorption device inside the OPA160X will be triggered. ESD pulse triggers once, quickly trigger a safe level.

When the operational amplifier is connected to the circuit shown in Figure 36, the ESD protection component will maintain a non -activity state and will not participate in the operation of the application circuit. However, when the external voltage exceeds the operating voltage range of the given pin, this may occur. If this happens, there are risks that some internal ESD protection circuits may be biased and transmitted. Any current is generated by guiding the diode path, rarely involved an absorption device.

FIG. 36 describes a specific example, where the input voltage vin exceeds 500 millivolttoons (+vs) or more. Most of the situations in the circuit depends on the power characteristics. If+vs can absorb the current, the upper input turns to one in the diode to guide and guide to+VS. Excessive current levels flow with VIN. Therefore, the data table specifications are recommended to limit the input current to 10mA.

If the power supply cannot absorb the current, VIN can start to provide the current to the computing amplifier, and then take over as a positive power supply voltage source. The risk in this case is that the voltage may rise to the level that exceeds the absolute maximum rated value of the operation amplifier. In extreme but rare cases, the absorption device will be triggered when+vs and -vs. If this incident occurs, the DC path is established between+VS and -VS power. The power consumption of the absorption device is quickly exceeded, and the extreme internal heating will destroy the operational amplifier.

Another common problem is that when the power+vs and/or -vs are 0V, if the input signal is applied to the input terminal, what will happen when the amplifier will happen. Similarly, this depends on the power characteristics of the level at the level of 0V or lower than the amplitude of the input signal. If the power supply is displayed as high impedance, the power supply current of the computing amplifier can be provided by the input source through the current control. This state is not a normal partial pressure state; the amplifier is likely to not work properly. If the power impedance is low, the current to the diode may become quite high. The current level depends on the capacity of the input source transmission current and any resistance in the input path.

If the power absorption current is uncertain, you can add an external Qina diode to the power pins, as shown in Figure 36.

Qina voltage must be selected so that the diode will not be turned on under normal circumstances. However, its Qina voltage should be low enough to turn the Qina diode at the level of the power pins began to rise to the level of the safe working power supply voltage level.

Application circuit

Figure 37Show an additional application idea.