Features

Unit gain bandwidth: 250 mHz

Broadband width: 100 MHz GBW

High conversion rate: 150 v/μs

Low noise: 6.5 nv √Hz

rail o high output current: gt; 100 ma

Outstanding video performance:

-Stinarity gain: 0.02%, phase difference: 0.09 °

-0.1-DB gain flat: 40 mHz

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123] Low input bias current: 3 PA

Static current: 4.9 ma

heat shutdown

#8226 ; Power supply range: 2.5 V to 5.5 v

size and power board #8482; packaging micro

Application

Video processing [ 123]

Ultrasonic

Optical network, adjustable laser

Optical diode cross -blocking large device

#8226 Affiliate

High -speed Points

Model (A/D) Input buffer

Digital modulus output amplifier

barcode scanner

Communication

Instructions

OPA354 series high -speed voltage feedback CMOS operations The amplifier is designed for the application of videos and other broadband. They are stable in unit gain and can drive large current output. Differential gain is 0.02%, and the differential phase is 0.09 °. The static current of each channel is only 4.9 mAh.

The OPA354 series operations amplifier can run on a single power or dual power supply of up to 2.5V (± 1.25V) and up to 5.5V (± 2.75V). The input range of the co -model exceeds the range of power. The output width is within the range of 100 millivolves and supports wide dynamic range.

For applications that require 100 mA -continuous output current, the single and dual 8 -needle HSOP provides PowerPad versions.

A single version (OPA354) canUse in SOP POWERPAD packaging. The dual version (OPA2354) is encapsulated with micro 8 -needle VSSOP and 8 -needle HSOP PowerPad. The four -dollar version (OPA4354) offers 14 -stitches TSSOP and 14 -pin SOIC packaging.

The characteristic of the multi -channel version is a completely independent circuit to reduce the string disturbance and avoid interaction. All prescribed temperature range is -40 ° C to 125 ° C.

Equipment information

(1), please refer to the appointment appendix at the end of the data table.

Simplified schematic diagram

Typical features

Unless otherwise explained, it is in TA u003d 25 ° C, vs u003d 5 v, G, G, G u003d+1, RF u003d 0Ω, RL u003d 1 KΩ, and connected to VS/2.

Detailed description

Overview

OPA354 is a CMOS, I/O, high -speed, voltage feedback computing amplifier, designed for video, high -speed and other applications. It has a single, double or four -way computing amplifier.

The amplifier has a conversion rate of 100MHz gain bandwidth and 150V/μs, but it is stable in unit gain and can be used as a voltage follower of+1V/V.

Figure Figure

Feature description Work voltage

OPA354's power range is 2.7 V to 5.5 V ( ± 1.35 v to ± 2.75 V). However, the range of power voltage is 2.5 V to 5.5 V (± 1.25 V to ± 2.75 V). The power supply voltage higher than 7.5 V (absolute maximum value) will permanently damage the amplifier.

See the typical feature of this data table with the parameters of the power supply voltage or temperature change.

Rail -to -rail input

OPA354 regulations input a co -mode voltage range exceeded 100 millivol to the power rail. As shown in the functional frame diagram, this extension range is realized by parallel parallel parallel parallel parallel parallel parallel parallel parallel parallel parallel. The N-channel is effective for the input voltage near the track, usually higher than the positive power supply (V+) -1.2 V to 100 MV, and input from 100 MV below the negative power to approximately (V+ 1.2 V) input, and input, The P channel is in the open state. There is a small transition zone, usually (V+) -1.5 V to (V+)-0.9 V, the two voltage pairs are open. The 600 MV transition area can change ± 500 mv with the process. Therefore, in the low-end, the range of the transition zone (both input levels open) is (V+)-2 V to (V+)-1.5 V, and high-end (V+)-0.9 V to (V+)-0.4 V.

Dual -folding the common source code of the common source of the two input pairs adds a differential signal to the AB output stage.

The output of the rail

AB output level adopts a common source transistor to achieve rail transfers. For high impedance loads ( gt; 200Ω), the output voltage swing is usually 100 MV. When the load is 10Ω, it can achieve useful output swing while maintaining a high -opening gain. See the typical characteristic curve, the output voltage swing and output current (Figure 20 and Figure 22).

Output drive

OPA354 output level can provide a continuous output current of ± 100 mAh, but it provides about 2.7V output swing on the 5V power supply, as shown in Figure 30. In order to obtain the maximum reliability, TI does not recommend running continuous DC currents with more than ± 100 mA. Reference typical characteristic curve, output voltage swing and output current (Figure 20 and Figure 22). For continuous output currents greater than ± 100 mA, OPA354 can run parallel, as shown in Figure 31.

OPA354 provides a peak current of up to 200 mA, corresponding to a typical short -circuit current. Therefore, a hot shutdown circuit is provided to protect OPA354 from the impact of dangerous high knot temperature. At 160 ° C, the protective circuit is closed. When the knot temperature is cooled to less than 140 ° C, normal work is returned.

Video

OPA354 output level that can drive the standard to connect 75Ω video cables, as shown in Figure 32 as shown in Figure 32 Essence It will not display the capacitance load to the driver by the reverse end transmission line. The correct rear -end 75Ω cable does not display as a capacitor; it only provides a 150Ω resistor load to the OPA354 output terminal.

OPA354 can be used as a amplifier of the RGB graphics signal. The voltage of the signal under the flat video is zero, and the coupling signal is passed and communicated. See Figure 33.

(1), the source video signal offset is 300 MV from the ground to adapt to the capacity of the ground.

Drive Mo Digital Converter

OPA354 series operational amplifier provides a stable time of 60 nan seconds to 0.01%, making it a driver medium -to -high -speed collectionA good choice of A/D converter and reference circuit. While providing signal gain, the OPA354 series provides an effective method for input capacitors in the input capacitance of A/D converter and the charge generated by it. For applications that need high DC accuracy, it is recommended to use the OPA350 series.

FIG. 34 shows OPA354 of the driver A/D converter. In the case of OPA354 in a inverted configuration, the capacitors on the feedback can be used to filter high -frequency noise in the filter signal.

Capacity load and stability

OPA354 series operational amplifier can drive various capacitance loads. However, under certain conditions, all operational amplifiers may become unstable. The configuration, gain, and load value of the operation amplifier are only a few factors to consider when determining the stability. The computing amplifier of the unit gain structure is most likely to be affected by the capacitor load. The capacitance load reacts with the device output resistance and any additional load resistance. A pole is generated in the small signal response to reduce the phase margin. For details, please refer to the typical characteristic curve, and the frequency response of various CL (Figure 13).

OPA354 topology enhances its ability to drive capacitance loads. At the unit gain, these computing amplifiers perform well with large capacitor loads. For detailed information, please refer to the typical characteristic curve, recommended RS and capacitance load (Figure 14) and frequency response and capacitance load (Figure 15).

In the unit gain configuration, a method of improving the capacitor load drive is to connect a resistor from 10Ω to 20Ω at the output end, as shown in Figure 35. This configuration can significantly reduce the bell phenomenon when the large capacitance load is shown in the typical characteristic curve, and the frequency response and capacitance load (Figure 15). However, if there is a resistor load and a capacitor load, RS will generate a divisioner. This voltage division introduces DC errors at the output end and slightly reduces the output swing. This error may be irrelevant. For example, when RL u003d 10kΩ and RS u003d 20Ω, the output error is about 0.2%.

Broadband span jouction

Broadband width, low input bias current, low input voltage and current noise make OPA354 an ideal broadband for low -voltage single power supply applications Optical diode interoperability. Low -voltage noise is important because the optical diode capacitance increases the effective noise gain of the circuit at high frequency.

As shown in Figure 36, the key element of cross -resistance design is the expected diode capacitance [including the parasitic input co -mode and differential input capacitance of the OPA354 (2+2) PF] (RF) and OPA354 gain bandwidth (GBW) (GBW) (typical value is 100 MHz). After setting these three variables, you can set the feedback capacitor value (CF) to control the frequency response.

In order to obtain the largest flat second -order Bartworth frequency response, the setting of the feedback pole must be shown as equal form 1:

Typical typical The parasitic capacitance of the surface sticker is about 0.2 PF, which must be deducted from the calculated feedback capacitor value. Bandwidth is calculated by Formula 2:

For higher cross-resistance bandwidth, you can use high-speed CMOS OPA355 (200-MHz GBW) or OPA655 (400-MHz GBW).

Equipment function mode

After connecting the power supply, the OPAX354 series device is powered on. According to the application, these devices can be operated as a single power computing amplifier or dual -power amplifier. When the voltage difference is 5.V, and the voltage is set at least 5 V+5.V, the voltage can also be set to 5.V.

Application and implementation

Note: The information in the following application chapters is not part of the TI component specification, TI does not guarantee its accuracy or integrity. TI's customers are responsible for determining the applicability of the component. Customers should verify and test their design implementation to confirm the system function.

Application information

OPAX354 series device is a CMOS, I/O, high -speed, voltage feedback computing amplifier, designed for video, high -speed and other applications. OPAX354 series equipment has single, double or four -way op amp. The amplifier has a conversion rate of 100 MMS gain bandwidth and 150 volt/microsecond, but its unit is stable and can work as a voltage follower of 1 volt/volt.

Typical application

Width -increase bandwidth, low input bias current, low input voltage and current noise make the OPAX354 series devices the ideal broad band optoelectronic diode cross -blocking major. Low -voltage noise is important because the optical diode capacitance increases the effective noise gain of the circuit at high frequency. As shown in Figure 37, the key elements of cross -resistance design are the expected diode capacitors, including parasitic input co -mode and differential mode input capacitors; the expected cross -resistance gain; and the gain bandwidth (GBW) of the OPAX354 series device (20 MHz). By setting up these three variables, you can set the feedback capacitor value to control the frequency response. The feedback capacitance includes a strange capacitor. For a typical surface -sticker resistor, the messy capacitance is 0.2 PF.

Design requirements

For the example of this design, the parameters listed in Table 1 are used as the input parameter.

C (F) is optional to prevent the peak of gain. C (F) includes bandal capacitors of R (F).

Detailed design program

In order to obtain the largest flat second -order Bartvos frequency response, the feedback pole of the use of equation 3 sets up.

Calculate the bandwidth with formula 4.

Optimized cross -resistant circuit

In order to obtain the best performance, the component must be selected according to the following guidelines:

Select R (F) to create the total gain required. Lower R (F) values u200bu200bare used to increase gains after increasing the gain after cross -resistant amplifier. The noise generated by R (F) increases with the square root of R (F), while the signal increases linearly. Therefore, when all required gains are placed in cross -resistance, the signal -to -noise ratio increases.

2. The minimum optical diode capacitance and strange capacitance of the conjugate (inverter input). This capacitor causes the voltage noise of the operation amplifier to be amplified (high frequency release). The use of low noise voltage sources reverse bias photoelectric diode can significantly reduce the capacitance. The smaller photoelectric diode has lower capacitors. Use optical devices to concentrate light on a small photoelectric diode.

3. Noise increases with the increase of bandwidth. Limit the circuit bandwidth within the required range. Use a capacitor on R (F) to limit the bandwidth, even if it does not require stability.

4. The leakage of the circuit board will reduce the performance of the well -designed amplifier. Clean the circuit board carefully. Surrounding and knots and the protection trajectory of the circuit board driven by the same voltage can help control the leakage.

Application curve

Power suggestion

The working voltage range of the OPAX354 series equipment is 2.5 V to 5.5 V (± 1.25 to ± 2.75 V); many specifications are suitable for -40 ° C to 125 ° C. Parameters related to working voltage or temperature show a significant difference, these parameters show typical features.

Put the 0.1-μF bypass electric container near the power pins to reduce the coupling error of noise or high impedance power supply. For more information on the side electric container placement, please refer to the layout guidance policy.

Layout

layout guide

OPA354 must adopt a good high -frequency printing circuit board (PCB) layout technology. A large amount of ground layers, short and direct signal trajectories, and the appropriate bypass electric container located in the V+pin to ensure clean and stable operation. Large -area copper also provides a method of calorie during normal runtime.

TI is not recommended to use any high -speed amplifier socket.

10NF ceramic side electric container is the minimum recommendation value; when driving a low resistance load, 1-μF or larger electric container is added in parallelbenefit. Providing sufficient bypass capacitors is essential for achieving very low harmonic and distortion of interoperability.

layout example

Power consumption

Power consumption depends on the power supply voltage, signal and load conditions. For DC signals, power consumption is equal to the output current multiplication of the voltage on the electrical output transistor and the product of the VO. By using the required as much as possible to ensure the required output voltage, the power consumption can be minimized.

For the resistance load, the maximum power consumption occurs at the DC output voltage of half of the power supply voltage. The loss of the exchange signal is lower. AB-039 power amplifier TressandPower Handling Limits explained how to calculate or measure the power consumption under abnormal signals and loads.

Any trend of starting the heat protection circuit indicates that the power consumption is too large or the heat sink is insufficient. For reliable operation, the knot temperature must be limited to a maximum of 150 ° C. In order to estimate the safety of the full design, the ambient temperature should be increased until the heat protection is triggered at 160 ° C. Thermal protection should be triggered above the maximum expected environmental conditions above the application.

PowerPad thermal enhancement package

In addition to the conventional 5-pin SOT-23 and 9-shot VSSOP packaging, the single and dual versions of OPA354 are also equipped with 8-pin SOIC POWERPAD packaging. The 98 -pin SO with PowerPad is a standard size 8 -needle SOIC packaging. The naked lead frame at the bottom of the packaging can be directly welded to the PCB to generate extremely low thermal resistance. This direct connection greatly enhances the power consumption capacity of OPA354 and eliminates the bulky radiator and plugs used in hot packaging. This package can easily install the standard PCB assembly technology.

Note

Since the 8 -pin HSOP PowerPad is compatible with the pins of the standard 8 -pin SOIC packaging, OPA354 and OPA2354 can directly replace the computing amplifier in the existing socket. Always welding PowerPad to PCB, even low -power applications. This configuration provides the necessary thermal connection and mechanical connection between the lead framework and PCB.

The design of PowerPad packaging makes the lead frame mold pad (or hot pad) exposed to the bottom of the IC, as shown in Figure 40. This exposed mold provides a very low thermal resistance (RθJC) path between the mold and the outside. The thermal pad at the bottom of the IC can be welded directly to the PCB and uses PCB as a heat sink. In addition, the electroplated hole (over -perforated) provides a low thermal heating runner on the back of the PCB.

PowerPad assembly process

The power board must be connected to the most negative power supply voltage of the device. It is grounded in the application of a single power supply. In the sub -power supply application, it is V ground.

Prepare PCB with the top etching pattern, as shown in Figure 41. According to the specific assembly process requirements, the specific ground design may be different. The leading wire must be etched, and the hot pad must also be etched.

Place a recommended number of electroplating pores (or heating holes) in the hot pad area. The diameter of these holes must be 13 dense ear (.013 inches). They remain very small, so that during the return welding, it is not a problem with the welded core of the hole. TI recommends that there are at least 5 holes in the 8 -needle HSOP POWERPAD packaging, as shown in Figure 41.

TI recommendation, but not required, set a small amount of extra holes under the package and outside the hot pad area. These holes provide additional thermal channels between copper thermal pads and ground floors. They may be bigger because they are not in areas that need welding, so core suction is not a problem. This technology is shown in Figure 41.

Connect all holes (including holes within the hot pad pad area and outside the pad area) to the internal ground plane or other internal copper planes (for the application of single power supply), and connect to V above (above (above ((above ((above ((above ((above ((above (above (above ((above ((up to V above (above (above (above ((above ((above ((above ((upstream For split power applications).

When arranging these holes, do not use a typical web or SPOKE VIA connection method, as shown in Figure 42. The network connection has a high thermal resistance connection, which helps to slow the heat transfer during the welding process. This function makes welding more easily with holes connecting ground plane. However, in this application, low thermal resistance is the most effective heat transfer requirement. Therefore, the holes under the PowerPad component must be connected to the internal ground layer and a complete connection around the entire electroplated hole.

The welding mask at the top must be exposed to the pad connection and the heat pad area. The hot pad area must show 13 dense ears. The large holes outside the thermal pad can be covered with welding molding.

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

With these preparation steps, PowerPad IC can simply place it in place, and complete the welding back welding operation like any standard surface paste element. Such preparation and processing will make the parts correctly installed.