Features

● The range of power supply is wide:

± 10V to ± 40V

● High -output load driver:

50ma continuous

123] ● Wide output voltage swing: 1V to orbit

● Complete protection:

- Hot shutdown

- output current limit

● Work temperature Wide range:

-40 ° C to+125 ° C

● Packaging option:

-to 220-7

-DDPACK-7 surface Installation

Application

● Blood battery

● Test equipment

● Audio amplifier

● Sensor driver

[123 ] ● Servo drive

Instructions

OPA452 and OPA453 are low -cost computing amplifiers, with high voltage (80V) and large current capacity (50mA). OPA452 is stable in unit gain, with a width of gain bandwidth of 1.8MHz, while the gain of OPA453 is greater than 5, and the bandwidth is 7.5MHz.

OPA452 and OPA453 have internal protection to prevent overheating and current overload. The power supply can be used from ± 10V to ± 40V. Unlike most other power computing amplifiers, OPA452 and OPA453 ensure the specifications of the entire power supply range.

These laser fine -tuning, single -piece integrated circuit provides excellent low level accuracy and extensive output swing. The special design considerations ensure that the product is easy to use, and there is no problem with the common phase reversal in other amplifiers.

OPA452 and OPA453 have TO220-7 and DDPAK-7 options. They are suitable for the temperature range of -40 ° C to+125 ° C.

Note: Connect to the power of convex ears and V power supply.

Typical features

TJ u003d+25 ° C, vs u003d ± 40V, RL u003d 3.8K

Unless otherwise explained, all temperatures are knot temperature. See the application information section, calculate the knot temperature according to the environmental temperature of a specific configuration.

Application information FIG. 1 shows OPA452 as the basic non -mute amplifier connection. OPA452 can be used for almost any computing amplifier configuration. OPA453 Design is used for configuration with gain greater than equal to 5. The power terminal should be bypassed with 0.1 μF or larger capacitors near the power of the power supply. Ensure that the rated value of the capacitor matches the voltage of the power supply. OPA452 and OPA453 can provide output currents up to 50mA with excellent performance.

current limitation

OPA452 and OPA453 design with internal current limit circuits, which can limit the output current to about 125mA. Under the limitation of typical current and voltage, it changes slightly as the current and temperature change. Current limits, combined with thermal protection circuit to provide protection to prevent most types of overload conditions, including short circuits on the ground.

Heat Protection

OPA452 and OPA453 have a heat clearance circuit, which can protect the amplifier from damage caused by overload. When the knot temperature reaches about 160 ° C, the thermal protection circuit will be disabled and the equipment will cool down. When the knot temperature is cooled to about 140 ° C, the output circuit will be automatically enabled.

The heat clearance function is not used to replace appropriate heat dissipation. The activation of the heat shutdown circuit indicates that the power consumption is too large or the heat sink is insufficient. Continuous operation amplifiers enter the heat shutdown state to reduce reliability.

Monitor the heating shutdown indicator (logo) pin to determine whether to stop. During the normal operation, the current output of the signs pins is usually 50NA. During the shutdown, the current output of the logo pin increased to 140 μA (typical value). This current output allows connecting with external logic. Figure 2 shows two examples of implementing this function.

Power supply

It can work under the condition of 45V to 45V. Without the entire working voltage range, most characteristics remain unchanged. The typical feature shows the parameters of significant changes with the working voltage.

For applications that do not require symmetrical output voltage, the power supply voltage does not require equal. OPA452 and OPA453 can work when the voltage between the power supply is as low as 20V or the voltage between the power supply is as high as 80V. For example, the positive power supply can be set to 70V, and the negative power supply is set to -10V, and vice versa.

DDPAK-7 and TO220 packed the convex ears to the negative electrode power supply (V-) power supply, but these connections are not used in the load. In order to obtain the best thermal performance, the label should be welded directly to the copper area of u200bu200bthe circuit board (see the heat dissipation part).

Power loss

The internal power consumption of these computing amplifiers may be quite large. All specifications of OPA452 and OPA453 may change with warmth. If the device is not heated inside, the knot temperature will be the same as the ambient temperature. However, in practical applications, the device will be spontaneous, and the knot temperature will be significantly higher than the environmental temperatureSpend. The following calculations can be performed to determine that the knot temperature is a function of the ambient temperature and application conditions.

Considering the circuit configuration of OPA452, the load is 600 and the output voltage is 20V. The power supply is ± 40V and the ambient temperature (TA) is 40 ° C. The θJa of the package+radiator is 30 ° C/W.

First, the static heating of the operation amplifier is as follows:

Can calculate the output current (IO):

The power consumption (PD) in the amplifier output transistor can be calculated as:

]

In the formula,

VO u003d output voltage

vs u003d power supply voltage

io u003d output current

rl u003d load resistance

tj u003d knot temperature (° C)

TA u003d ambient temperature (° C)

θja u003d the thermal resistance of air (° C/w) [123 ]

To estimate the safety of the complete design (including the radiator), increase the ambient temperature until the heat protection activation. Use the load and signal conditions in the worst case. In order to obtain good reliability, thermal protection should trigger a temperature above the maximum expected environmental conditions of the application+35 ° C. This ensures that the maximum temperature under the expected environmental conditions is+125 ° C.

The operation of a single power supply (or unbalanced power supply) can generate greater power consumption because a larger voltage can be applied to the electrical output transistor.

By using as low as possible, the power consumption can be minimized. For example, under the 50mA load, the output will swing within the 5.0V range of the power rail. Set the power supply to the maximum output voltage required for the application of 5.0V, which will minimize power consumption.

Security operation area

Safe operating area (SOA curve, Figure 3) shows the allowable range of voltage and current. When the voltage (VS -VO) on the output transistor increases, the safe output current decreases. To learn more about SOA, see the application report sBOA022.

The output short circuit is a very harsh situation for SOA. The short-circuit of the ground forced the entire power supply voltage (V+or V-) through the conductive transistor and generated a typical 125mA output current. For ± 40V power, this will cause 10W internal loss. This far exceeds the actual heat dissipation range, so it is not recommended. If it is not avoided in this area, use a component with a radiator.

Heating

The power consumed in OPA452 or OPA453 will lead to an increase in junction temperature. To ensure reliable operation, the knot temperature should be limited to+125 ° C. Many applications will require a radiator to ensure that it will not exceed the highest work knot temperature. The required heat sink depends on the power and environmental conditions consumed.

In order to heat dissipation, the convex ear of DDPAK is usually welded directly to the copper area of u200bu200bthe circuit board. Increased copper area can improve heat dissipation. Figure 4 shows the change of typical thermal resistance from the connection to the surrounding environment.

According to the situation, additional heat dissipation may be needed. AAVID thermal product company manufacture surface -packed radiator, which is specially designed for these packaging.

The dynamic characteristics of capacitance load

OPA452 and OPA453 have been optimized for common gain, load and operating conditions. The combination of low -closed loop gain and capacitance load will reduce phase margin, and may lead to peak or oscillation of gain. Figure 5 shows a circuit that maintains phase margin under the capacity load. Figure 6 shows the small signal step response of the circuit in Figure 5.

Increase the output current

In the application of the 50mA output current to drive the required load, it can be connected in parallel to two or more. OPA452S or OPA453S to increase the output current, as shown in Figure 7. In fact, any amplifier can be configured in the main amplifier circuit. From the amplifier A2 to the unit gain buffer. Alternatively, you can use an external output transistor to increase the output current. The circuit in FIG. 8 can provide an output current up to 1A. Alternatively, OPA547, OPA548 and OPA549 series power calculation amplifiers should be considered for high output current drivers, and programmable current restrictions and output disable functions.

Input protection

OPA452 and OPA453 have internal clamping diode, which is protected input when encountering voltage exceeding the power rail. However, the input current should be limited to 5mA. In some cases, external series resistors may be needed. Many input signals have inherent current limits, so there may be no restrictions on the resistor. Please consider a large series resistance and input capacitance, which will affect stability.

Use OPA453

OPA453 in low -gain for applications with a signal gain of 5 or higher, but you can use external compensation technology in the inverter configuration to use its height at a lower gain under low gain. The conversion rate. This technology maintains the low noise characteristics of the OPA453 architecture at low frequency. According to the application, it may lead to a small increase in high -frequency noise. This technologyThe stability of the loop gain is good, while providing an easy -to -control second -order low -line frequency response.

Considering the noise gain (non -reversal signal gain) of the circuit 9, low -frequency noise gain (NG1) will be set by a resistor ratio, and high -frequency noise gain (NG2) will be set by a capacitor ratio. The capacitor value sets the transition frequency and high -frequency noise gain. If the noise gain determined by NG2 u003d 1+CS/CF is set to the recommended minimum stable gain value greater than the computing amplifier, and the noise gain set by 1/RFCF is polarized, it will produce a very good control two two Low -pass frequency response.

The values u200bu200bof CS and CF should be selected at the same time, and only two parameters and three equations are required. First, the target value of high -frequency noise gain (NG2) should be greater than the minimum stable gain of OPA453. In the circuit in Figure 9, use the target NG2 of 10. Secondly, the signal gain in FIG. 10 -1 Set low -frequency noise gain to ng1 u003d 1+rf/rg (u003d in this example 2). Use these two gains to learn about the gain bandwidth (GBP) of OPA453 (7.5MHz), and aim at the maximum flat second -order low -pass Bartworth frequency response (Q u003d 0.707), you can find the key frequency in compensation.

For the value in FIG. 9, F -3DB is about 180kHz. This is less than the simply predicted by NG1 with the British pound. The compensation network controls the bandwidth to a lower value, and at the same time provides a good conversion rate at the output end, and has increased the loop gain at the frequency of Ng1 u0026#8226; z0, so it has excellent distortion performance. The capacitance value in FIG. 10 is calculated for ng1 u003d 2 and ng2 u003d 10, and there is no parasitic adjustment.

The actual circuit value can be optimized by checking the small signal steps under the actual load conditions. This OPA453, G u003d -1 Circuit's small signal steps under the 1000pf should be shown in Figure 9. It has good performance and has no oscillation trend. If CS and CF are removed, the circuit will be unstable.