Features

● 1.2A output current

12VP-P output voltage

● [ 123] Width power range: Single power supply:+7V to+15V

dual power supply: ± 3.5V to ± 7.5V

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Complete protection: heat shutdown

adjustable current limit

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Output Disable control

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17MHz gain bandwidth product

50V/μs conversion rate

● 1MHz full power bandwidth

● Thermal enhancement HTSSOP-20 power board component

Application ]

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Driving valve of the storage device

● Power supply

Test equipment [123 ]

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TEC driver

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Laser diode driver Explanation

OPA561 is a low -cost, large current operations The amplifier can drive up to 1.2A pulse to no merit. This single -chip integrated circuit provides high reliability in high -required line carrier communication, laser diode drives and motor control applications. The high conversion rate provides a full power bandwidth and good linearity of 1MHz.

OPA561 can be powered by a single power supply from the range of 7V to 15V or the dual power supply from ± 3.5V to ± 7.5V to achieve design flexibility. In the operation of a single power supply, the input co -mode range extends below the ground. At the maximum output current, the wide output swing provides the ability to 12VP-P, nominal 15V power.

OPA561 has internal protection to prevent overheating and current overload. In addition, the design of OPA561 provides an accurate, user selection, current restrictions. Using a low -power resistor/potentiometer or DAC (digital modular converter), the current can be adjusted from 0.2A to 1.2A. The high -speed characteristics of the current control loop can provide accuracy even under pulse load conditions.

Enable/status (E/S) pin executes two functions: you can monitor it,To determine whether the device is in a hot shutdown state (low activation state), you can also force the low level to disable the output and disconnect the load.

OPA561 has a micro htssop-20 powerpad #63722; power package. This surface paste and packaging are enhanced and have very low thermal resistance. In the extended industrial temperature range 40C to+125C specified operation.

Note: Needle 1, 10 and 11-20 are not connected .powerPad must be connected to V .

Typical features

tcase u003d+25 ° C, vs u003d 15V, E/S enable, unless there is another instructions.

Application information

FIG connect. However, OPA561 can be used for almost any operational amplifier configuration.

The power terminal should be bypass with low series resistance resistance. It is recommended to use parallel technology of and ceramics. The power terminal should have low series impedance.

Power supply OPA561 can work at a single power supply (+7V to+15V) or dual power supply (± 3.5V to ± 7.5V), performance, performance, performance Excellent. The power supply voltage does not need to be equal. For example, the positive power supply can be set to 10V, the negative power supply is set to -5V, and vice versa. Without the entire working voltage range, most behaviors remain unchanged. The typical feature shows the parameters of significant changes with the working voltage.

adjustable current

By controlling the input of ILIM, the accurate and user -defined current limit of OPA561 can be set from 0.2A to 1.2A. Unlike other designs to use the power resistance string transmission current path, OPA561 internal induction load. In this way, the current limit can be set with a low -power element. In contrast, other designs require one or two expensive power resistors to process all output currents (1.2A in this example).

Flow limit accuracy

Independent circuit monitoring positive and negative current. Each output is compared with a single internal benchmark set by an external current limit resistor (or voltage). OPA561 uses patented circuit technology to achieve accurate and stable current restrictions. The output current limits the accuracy of the 1A current limit of 5%. Due to the internal matching restrictions, positive and negative current restrictions may be slightly different. However, these values u200bu200bare usually within 10%of each other.

Set the current limit

Opening ILIM may be damagedBad parts. Connecting ILIM directly set the maximum output current limit on V programming setting, usually 1.2A. According to equivalent 1, the easiest way to adjust the current limit (ILIM) is to use a resistor or potential connected to the resistor between ILIM pins and V

] This external resistance determines a small internal current to set the expected output current limit. Alternatively, the output current limit can be set by applying a voltage to the ILIM foot. Figure 2 shows a simplified schematic diagram of the OPA561 current limit.

Enable/status (E/S) pin

ENable/Status pin provides two unique features: 1) reduce the output through mandatory pins to reduce the output Disable; 2) Realize the heat shutdown instructions by monitoring the voltage level of the pin. One or two of these functions can be used on the same device. For normal operations (output enable), E/S's injection must be pulled up (at least higher than V ) 2V. Small value capacitors connected between E/S pins and V may be suitable for noise applications. For permanently enable OPA561, the E/S pins can be connected to V+through 402K #8486; upper pull -up resistor.

Output disabled

Tentile injection is related to the negative electrode power supply (V-). Therefore, in the single power supply and dual power application, the shutdown operation is slightly different.

In single power operation, V usually equal to public ground. Therefore, the stop logic signal is the same potential as the shutdown pins of OPA561. Just connect the logic of OPA56 together. The voltage level lt; 0.8V shutdown. OPA561 is enabled at the logic level gt; 2V.

In dual power operation, logical pins still refer to logic ground. However, the shutdown of OPA561 still refers to V . In order to close OPA561, the voltage level of the logical signal needs to be shifted with optocoupler, as shown in Figure 3.

To stop the output, the E/S tactor is low, not higher than V 0.8V. This function can be used to save electricity during idle. The typical time of turning off the output is 50ns. To return the output to the enable state, the E/S should be pulled to at least higher than V 2.0 V. Usually, the output is enabled within 3 μs. It should be noted that the E/S pins (output enabled) will not be disabled in internal heat shutdown.

Make sure that the compatibility of the microcontroller

Not all micro -controllers output the same logical state after power -on or reset. For example, the 8051 microcontroller outputs high levels on its port, while other models are low after resetPower supply.

In the configuration (a) shown in FIG. 3, the shutdown signal was applied to the cathode side of the optoelectronics diode in the optical coupling. High -logic electricity is activated by OPA561, and low -logical electricity is turned off of OPA561. In the configuration (B) of FIG. 3, the logic signal is applied to the anode side, the high level is closed, and the OPA561 is closed, and the low level makes the operational amplifier work.

Overcurrent logo

OPA561 has an overcurrent state logo (CLS, pin 9), you can monitor the logo to check whether the load exceeds the current limit. Output signals of overcurrent restrictions are compatible with standard logic. CLS signal reference v . The voltage level is lower than (v )+0.8V means normal work, higher than (v )+2 indicates that OPA561 is in a current limit. As long as the output of OPA561 is within the current limit, the logo is high. At a very low signal frequency, it is usually lt; 1kHz, and monitor the upper limit of the current (source pole current) and the lower limit of the current (sinking current). At the frequency gt; 1kHz, due to the internal circuit limit, the output signal of the current limit of the current limit is delayed and shortened. The signal of the lower limit of the current is not affected by this behavior. With the further increase of the signal frequency, the output current on the pin 9 is only the lower limit of the current (trap current).

Output level compensation

The common complicated load impedance in the application of power computing amplifier can lead to the output level instability. For normal operations, compensation circuits are usually not required. However, if you plan to drive the OPA561 to the current limit, the R/C network (buffer) may be required. When a large -driven capacitance load ( gt; 1000pf) or perceptual load (a load separated by a motor, a load that is separated from the long cable to the amplifier), the buffer circuit can also improve the stability. Usually, 3 #8486; to 10 #8486; with 0.01 μF to 0.1 μF. Some loads may require some changes in the circuit value.

Output protection

No merit and electric potential generated load can return the load current to the amplifier, causing the output voltage to exceed the power supply voltage. From the output to the clamping diode of the power supply, this damage can be avoided, as shown in Figure 4. It is recommended to use the continuous rated value of 3A or larger Schottky rectifier diode.

Thermal protection

OPA561 has armal sensing circuit, which helps protect the amplifier without exceeding the temperature limit. The power consumed in OPA561 will cause the knot temperature to rise. When the mold temperature reaches about 160 ° C, the internal heat turnover circuit is closed and the output is turned off when the mold cools to 140 ° C. According to the load and signal conditions, the thermal protection circuit can be turned on and closed. This limits the loss of the amplifier, but it may have adverse effects on the load. Any trend to start the heat protection circuit indicates that the power consumption is too large orInsufficient heat dissipation films. For reliable, long -term, and continuous operation, the highest knot temperature should be limited to+125 ° C. It is estimated that the safety balance of the complete design (including the radiator) should be estimated, please increase the ambient temperature until trigger heating protection. Use the load and signal conditions in the worst case. In order to obtain good long -term reliability, thermal protection should be triggered at the maximum expected environmental conditions above the application. This will generate+125 ° C knot temperature under the maximum expected environmental conditions.

The internal protection circuit design of OPA561 is used to prevent overload; it is not to replace proper heat dissipation. Continuously run OPA561 to enter the hot stop pile will reduce reliability. You can monitor the E/S pins to determine whether to stop. During normal work, the voltage on E/S is usually higher than (V )+2V. During the shutdown, the voltage dropped to less than (V )+0.8V.

Power loss

Power consumption depends on power, signals and load conditions. For DC signals, the power consumption is equal to the output current multiplication to the voltage of the voltage of the transistor of the transistor. The loss of the exchange signal is lower.

The area of u200bu200bheat dissipation tablets

The relationship between thermal resistance and power consumption can be expressed as:

tj u003d knot temperature (° C)

] TA u003d ambient temperature (° C)

θja u003d connected to environmental thermal resistance (° C/w)

pd u003d power consumption (w)

In order to properly determine The required heat sink area shall calculate the required power consumption, and consider the relationship between power consumption and thermal resistance to minimize the shutdown conditions and allow appropriate long -term operation (the knot temperature is+125 ° C). Once the heat dissipation area is selected, the load conditions should be tested in the worst case to ensure proper heat protection.

For applications with limited plate size, refer to Figure 5 to understand the approximate thermal resistance of the area of u200bu200bthe radiator. Increased the area of u200bu200bthe heat sink exceeded 2 inches, and the heat resistance was almost improved. In order to achieve 32 ° C/W specified in the electrical characteristics, 9 -inch copper planes are used. According to the ambient temperature and power, HTP-HTP is suitable for continuous work from 2W to 20W. In applications with low switching duty, such as remote meters, it can achieve higher power levels.

Installation of the amplifier

What is PowerPad?

OPA561 uses HTSSOP-20 power board packaging, which is a standard-enhanced standard size IC packaging, which aims to eliminate bulky heat sinks and plugs used in traditional thermal packaging. This package can easily install the use of standard printing circuit board assembly technology, and can delete and replace the standard maintenance program using standards.

The design of PowerPad packaging makes the lead frameThe shelf frame (or thermal pad) is exposed to the bottom of the IC, as shown in Figure 6. This provides a very low thermal resistance (JC) path between the mold and the outside of the packaging. The thermal pad at the bottom of the IC must be welded directly to the PCB and uses PCB as a heat sink. In addition, by using the heating holes, the hot pad can be directly connected to a special heat sink structure with a floor floor or designed as a PCB.

It is recommended that PowerPad is always welded to PCB, even if it is a low -power application. It provides necessary connections between the lead framework and PCB. The power board should be connected to the most negative power supply of the device.

PowerPad assembly process

1. Prepare PCB with top etching patterns, as shown in Figure 7. Both wires and thermal pads should be etched.

2. Place the recommended number of holes (or heating holes) in the hot pad area. The diameter of these holes should be 13 dense ears. They remain very small, so that during the return welding, it is not a problem with the welded core of the hole. HTSSOP-20 PowerPad is a recommended number of holes encapsulated, as shown in Figure 7.

3. Suggestion (but not required) Put a small amount of holes under the package and outside the hot pad area. These holes provide additional thermal channels between the copper ground and the horizon, with a diameter of 25 dense ears. They may be bigger because they are not in areas that need welding, so core suction is not a problem. As shown in Figure 7.

4. Connect all holes (including holes in the hot pads area and outside the pad area) to internal ground planes or other internal copper planes.

5. When connecting these holes to the ground plane, do not use a typical abdomen or wheel spoke connection method, see Figure 8. The network connection has a high thermal resistance connection, which helps to slow the heat transfer during the welding process. This makes it easier to weld the pores with a plane connection. However, in this application, low thermal resistance is the most effective heat transfer requirement. Therefore, the holes under the PowerPad component should be connected to the internal ground plane and a complete connection around the entire electroplated hole.

6. The welding mask at the top should expose the packaging terminal and thermal pad pile area. The hot pad area should be exposed with 13 dense ears. The 25 dense ear holes outside the thermal pads are covered with welding mask.

7. Apply welding paste on the exposed hot pad area and all packaging terminals.

8. With these preparation steps, PowerPad IC can simply place in place and complete welding back welding operations like any standard surface paste element. This will cause the parts to be installed correctly.

layout guide

OPA561 is a high -speed power amplifier, which requires appropriate layout to get the best performance.Figure 9 shows an example of the correct layout.

The power cord should be as short as possible. This will maintain low tostes and minimum resistance. It is recommended that the minimum wire thickness of the power cord is No. 18. The length of the wire should be less than 8 inches.

Appropriate power sources and low ESR capacitors are the key to achieving good performance. The parallel combination of small ceramics (about 100NF) and larger (47μF) non -ceramic roadside electric containers will provide low impedance within a wider frequency range. The barrier capacitor should be as close to the power pins of OPA561 as possible.

PCB lines with high current, if the power pins from output to load or from power connectors to OPA561 should be kept as wide and short as possible. This will keep low toxin and resistance to minimize.

The eight holes on the landing pattern of OPA561 are used to connect the power plate of OPA561 to the heat -pass hole in the radiator area on the printing circuit board. The other four larger holes further strengthened the heat conduction of the heat dissipation area area. The minimum resistance loss of all high -resistant currents is the smallest. Please note that the negative power supply ( v) pins on OPA561 are connected through the power board. This provides the maximum trace line width for the positive power supply (+v).

Application circuit

The high output current and low power supply of OPA561 make it an ideal choice for driving laser diode and thermoelectric refrigerator. Figure 10 shows OPA561 configured to be a laser diode drive.

The programmable power supply

FIG Power solution. The solution has low-voltage operation, small packaging (DAC7513 in SOT23-8, Ref3030 in SOT23-3), and low cost (less than $ 10 in complete solutions).

Power line communication modem

OPA561 is very suitable for AC power cords that drive low -speed communication applications. It provides a reliable and reliable solution, which is better than a separate power transistor circuit. Advantages include:

1. Complete integration solution

2. Integrated shutdown circuit used to send and receive switching

3, heat shutdown

4 , Adjustable flow limit

5. Close signs

6. Energy saving

7. Limited power board component

] Typical land, such a system consists of a microcontroller, a modem IC and a power cord interface circuit. Half -workThe power line communication system is shown in Figure 12.

It uses a synchronous FSK modem, which can transmit data rates of 600 and 1200 Potter, and support two different FSK channels in the range of 60kHz to 80kHz.Use MSP430 and other microcontroller to control the modem chip.

OPA561 analog interface circuit Drive the FSK modem signal on the AC power line.It filters from ST7536 to send signals (ATO) to inhibit the second harmonic distortion of the transmitted signal.It also enlarges the ATO signal and provides a very low output impedance required for the proper drive line.At 70kHz, the impedance range of the typical power cord is 1 #8486; to 100 #8486;OPA561 is an ideal choice for this type of load.The transformer provides isolation and additional filtering.CPR currently flows from the transformer 50/60Hz current.The capacitor must be carefully selected to obtain appropriate rated voltage and safety characteristics.

The input signal was enlarged (g u003d 100) and was applied to the modem IC.OPA561 is disabled in the receiving mode to avoid loading the line.