General description

lm6181 current feedback amplifier provides an unparalleled combination bandwidth, conversion rate and output current. The amplifier can directly drive up to 100 PF capacitor loads without oscillation, 10V signal input 50 or 75 The temperature range of the coaxial cable system on the back of the entire industrial system. This represents a thorough enhancement of the output driving capacity of 8 -pin DIP high -speed amplifier to make it an ideal choice for video applications. Based on the domestic advanced high -speed VIP #8482; II (vertical integrated PNP) process, LM6181 uses current feedback, and the bandwidth provided will not change significantly with gain; AV 1 is 100 MHz, AV #8722 ; 10 o'clock is 60 MHz. The conversion rate is 2000V/μs, and the second harmonic distortion is 5010 MMS DBC and 50 -nan seconds (0.1%) stable time LM6181 dynamic performance makes it an ideal choice for data collection. application.

Features

(Unless otherwise explained, it is typical)

conversion rate: 2000V/μs

Settling time (0.1%): 50ns [50ns [ 123]

Power range: ± 5V and ± 15V

Low difference gain and phase error: 0.05%, 0.04 ;

High output driver: ± 10V enter 100 #8486 N guarantee bandwidth and conversion rate

Performance is better than EL2020, OP160, AD844, LT1223 and HA5004

Coaxial cable drive

Video amplifier

flash memory ADC buffer

High -frequency filter

Scanner and imaging system

Absolutely maximum rated value (Note 1)

] Power supply voltage ± 18V

Differential input voltage ± 6V

Input voltage ± power voltage

Input current 15 mAh

Welding welding Information

Double -column direct -inserted component (n)

Welding (10 seconds) 260 ; c

Small shape packaging (M)

Qi Phase (60 seconds) 215 ; C

Infrared (15 seconds) 220 ; c

Output short circuit (Note 7)

Storage temperature range #872222 ; 65 ; C≤tj≤+150 ; C

The highest knot temperature 150 ; c

ESD rated value (Note 2) ± 3000V

Retime -up value

Power supply The voltage range is 7V to 32V

Concluding temperature range (Note 3)

lm6181am 55 ; c≤tj ≤+125 ; C

lm6181ai, Lm6181i 40 ; C ≤TJ≤+85 ; C

Thermal resistance (θja, θjc)

8 -needle DIP (n) 102 ; C/W. , 42 ; C/W

8-needle SO (M-8) 153 ; C/W, 42 ; C/W

16-pin SO (M) 70 #730; C/W, 38 ; C/W

± 15V DC electricity characteristics

The following technical specifications are suitable for power supply voltage ± 15V, RF 820 and RL 1 k unless there is another instructions. The thickness limit value is suitable for extreme temperature; all other limit value TJ 25 ; c

± 15V AC electrical characteristics

The technical specifications below are applicable to applicable In the power supply voltage ± 15V, RF 820 , RL 1 K unless there is another explanation. Rich body restrictions are suitable for extreme temperature; all other extreme TJ 25 ; C.

± 5V AC electrical characteristics

The following technical specifications are suitable for power supply voltage ± 5V, RF 820 and RL 1 K #8486 ;,Unless otherwise indicated. Other limit temperature TJ 25 ° C; suitable for all extreme temperatures.

Note 1: Absolute maximum rated value indicates the limit value that may be damaged by the device. The working rated value indicates that the expected state function of the device is normal, but under these conditions, the equipment parameters may not be guaranteed. Please refer to electrical characteristics on the specifications and test conditions of the guarantee.

Note 2: Human model 100 pf and 1.5 k .

Note 3: The typical connection point and environment thermal resistance of the molded plastic impregnation (n) packaged directly welded to the PC board is 102 ; At 16 o'clock, the connection with the S.O. surface installation (m) installation (m) and the environmental thermal resistance with the PC board are 70 ; C/W in total2 -inch 21 ounces of copper traces. 16 stitches S.O. (M) components must be connected to V to work normally. The typical direct welding to the S.O. (M-8) packaging and environmental thermal resistance on the PC board is 153 ; C/W.

Note 4: Typical values represent the most likely parameter specifications.

Note 5: All limits guaranteed under room temperature (standard surface) or extreme operating temperature (thick body).

Note 6: From the+25%of the output waveform to+75%measurement.

Note 7: Continuous short -circuit operations at a higher environmental temperature may cause more than a maximum allowed temperature of 150 ° C. In the long run, the output current exceeding ± 130 mA may adversely affect reliability.

Note 8: See the military temperature range parameters for Rets6181X.

Typical performance characteristics TA 25 ; C, unless there is another instructions

]

Typical application

current feedback topology

For traditional voltage feedback amplifier small signal bandwidth and expected gain to inverse ratio, according to the concept of gain bandwidth. On the contrary, the current feedback amplifier topology, such as LM6181, surpasses this limit and provides signal bandwidth that is relatively independent of a closed -loop gain. Figures 1A and Figure 1b illustrate the consequences of the pulse guarantee of the closed -loop gain 1 and 5 indicate that the bandwidth of the two is very similar to the configuration.

The closed -loop band width of LM6181 depends on the feedback resistance, RF. Therefore, RS instead of RF must be as shown in the figure, which can be adjusted according to the required closed -loop gain [ 123]

Power sources and layout

Consider matters

The basic requirement of high -speed amplifier design is the appropriate bypass of the power supply. It is important to maintain a low -oriented low -impedance to the ground at the pins of the amplifier to ensure the preservation transient signal of the high -speed amplifier. 10 μF 0 0 and 0.1 μF ceramics are recommended to equip capacitors for each power pin. The barrier capacitors should be as close as possible as possible (0.5 or smaller as possible. Feedback resistance selection: RF selects feedback resistance RF, which is compensated LM6181. For general applications LM6181 Value will provide good results for most applications, but adjusting it may be a little small. For example, considering the closed -loop gain of the two different configurations of the pulse, the feedback resistance is 820 It is 1640 . Figure 3A andFigure 3b shows that the effect of a closed-loop gain of RF is increasing when it is maintained unchanged-reduced bandwidth. Correspondingly, a larger feedback resistance can be used to reduce the speed of time domain response at LM6181 (see 3 DB bandwidth VS RF typical curve). Instead, the feedback resistance value is less than 820 CAN is used to compensate for the high -closed ring gain, due to the second order effect. For example, Figure 4 shows that the RF is reduced to 500 the small signal response in the configuration amplifier is 25.

Precautions for conversion rate

The conversion rate of current feedback amplifier is different from traditional voltage feedback amplifiers. The performance of the conversion rate of the voltage feedback amplifier or the performance of the non -linear amplifier depends on the first -level tail current charging of the compensation capacitor. Instead, the conversion rate of current feedback amplifier is whether it is fixed. The transient current of the inverter input terminal determines the conversion rate of inverter and non -inverter gain. The conversion rate input stage limit for non -reversing structure is also determined. Therefore, different circuit topology of rotation will generate different rates.

Driving capacitance load

LM6181 can drive larger capacitor load than many current feedback amplifiers. Although LM6181 can directly drive up to 100 PF voltage without oscillation, the resulting response will be a function of feedback resistance. Figure 5 shows the pulse response of the small signal LM6181 when driving the 50 PF load. The ringtone lasted about 70 nan seconds. Realizing pulse feedback resistance can reduce the increase of bell (see RF and RS recommended by typical curves or can be isolate using resistors (usually 10 –51 effect). However, any method will cause the system to reduce the system Bandwidth. Figure 6 illustrates the use of 47 isolation resistor.

Capacity feedback

For voltage feedback for voltage feedback As far as the amplifier is concerned, the feedback parallel small lead compensation capacitor resistance, RF. This compensation can equally reduce the peak reaction of the amplifier amplifier in the frequency domain. In order to limit the bandwidth of the current feedback amplifier, do not use the capacitor on RF. The dynamic impedance of the capacitor in the feedback circuit reduces the stability of the amplifier. On the contrary, the reduction of the peak is shown in the figure. The frequency response and bandwidth limit can be completed by adding the RC circuit.

Typical Performance

Features

When the output or input voltage range of the high -speed AM amplifier is exceeded, the amplifier must be recovered from the drive state. The input voltage of 12 and 12 is explained in the closed -loop mode. The opening circuit in FIG. 8 allows ± 0.5V to enterThe linear input range of the large device has generated drive response.The typical positive and negative driver recovery time shown in FIG.Output to overspeed.Figure 11 shows the typical recovery time of the linear output value of 30ns.The co -mode input of the circuit in Figure 10 is caused by a 5V pulse, and its typical recovery time is 310 NS as shown in Figure 12.LM6181 power supply voltage is ± 5 volts.