Features

Differential or single -ended profit block (adjustable)

-3DB bandwidth, av ± 250MHz

conversion rate 165V/μs

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123] Low power current 13mA Output current ± 20mA

10MHz 40dB at CMRR

lt1193

pin compatibility

Low low Cost

Single 5V operation

Directly drive the cable

output closure

Line receiver

Video signal processing

] Cable drive

Tape and disk driving system

Instructions

LT1187 is a differential amplifier, optimizing the ± 5V voltage or a single 5V power supply, and the gain is ≥2. This multifunctional amplifier has non -promised high input impedance (+) and ( -) inputs, which can be used for differential or single -end configuration. In addition, the second set provides gain adjustment and DC control differentiator. The high conversion rate of LT1187, 165V/μs, wide band width, 50MHz, ± 20mA output current only requires 13mA power supply. The shutdown function can reduce the power consumption of only 15 MW, allowing multiple amplifiers to drive the same cable. LT1187 is a low -power version of the popular LT1193 and provides packaging such as 8 -stitches Minidips. For applications with gain greater than equal to 10, see the LT1189 data table.

Most

Total power supply voltage (V+to V-) 18 volts

Differential input voltage ± 6 volt

Input voltage ±

working temperature range

LT1187 meters –55 ° C to 150 ° C to 150 ° C to 150 ° C

Jiecin (Note 2)

Plastic packaging (CN8, CS8) 150 degrees Celsius

Ceramic packaging (CJ8, MJ8) 175 degrees Celsius

Storage temperature range –65 ° C to 150 ° C

Lead temperature (welding, 10 seconds) 300 degrees Celsius

Electrical characteristics TA 25 ℃ (Note 3)

+ - 5 volt VS ± 5V, VREF 0V, RFB1 900 (from the pin of the pin 6 to 8), RFB2 100 (from 8 to grounding), RL RFB1+RFB2 1K, CL ≤ 10pf, needle feet 5.

Electrical C feature 0 ° C ≤ TA ≤ 70 ° C, (Note 3)

and+ 5V, vs - 0V, vREF 2.5V, RFB1 900 ( From inserting 6 to 8), RFB2 100 (from inserting 8 to VREF), RL RFB1+RFB2 1K, CL ≤ 10pf, pin 5 open roads.

Note 1: A radiator may be needed to maintain the absolute maximum value when the knot temperature is lower than the output continuous short circuit.

Note 2: TJ calculates according to the ambient temperature TA and power consumption

PD according to the following formulas:

LT1187MJ8, LT1187CJ8: TJ TA+(PD × 100 ° C/W/W )

LT1187CN8: TJ TA+(PD × 100 ° C/W)

LT1187CS8: TJ TA+(PD × 150 ° C/W)

Note 3: When specifying RL 1K, the load resistance is RFB1+RFB2, but when the specified RL 300 and then add additional 430 and 430 side by side (RFB1+RFB2) is RL 300 #8486;.

Note 4: VOS measured at the output end (pin 6) is the contribution pair of two input terminals, and it is input reference.

Note 5: Vin Lim is -Vin and+VIN (pin 2 and pin 3), the output can be responded.

Note 6: Measure the conversion rate between ± 0.5V at the output end, and use VIN jump ± 0.75V, AV 3, RL 1K.

Note 7: The full power bandwidth is calculated based on the conversion rate measurement value: FPBW SR/2πvp.

Note 8: Guess of Settling Time Measurement Technology See Setting time Measurement , EDN, September 19, 1985.

Note 9: NTSC (3.58MHz).

] Note 10: AC parameters perform 100%test packaging parts (J8 and N8 suffix) and each batch of SO sample test packaging parts (S8 suffix) on ceramic and plastic impregnation solution.

Note 11: High temperature shutdown See the application part. Do not stop operation above TJ GT; 125 ° C.

ATIO application

The main purpose of the LT1187 is to convert high -speed differential signals to single -end output. The LT1187 video differences have two unbelievable high input impedance (+) and (+) and ((+) and (-)enter. There is also a set of inputs that can be used for reference and feedback. In addition, this set of input provides DC control of gain adjustment and differential amplifiers. The setting of the voltage gain LT1187 is similar to the traditional operational amplifier. The feedback is applied to pin 8 and optimizes 2 or more to gain. The amplifier can operate a single -end operation through (+) or ( -) input to+/Ref (pin 1) one. The voltage gain is set by the resistor: (RFB+RG)/RG. Like a single -end situation, the difference between the differential voltage is set by the external resistor: (RFB+RG)/RG. The maximum value output will be about ± 0.38V.

Power sources

LT1187 is quite tolerant of power bypass. In some applications, the 0.1 μF ceramic disc capacitor is placed at a place 1/2 inches from a distance amplifier. Use multiple bypass containers that require good settlement time. 0.1 μF ceramic discs are recommended to parallel with 4.7 μF. Calculating output offset voltage both input levels help at pin 6. The feedback school makes the input reach the balance by introducing a VOS at the pin 8 to classify. The expression of the complete output offset voltage is: VOUT (VOS+IOS (RS)+IB (RREF)) × (RFB+RG)/RG+IB (RFB) RS represents the input source resistance, usually 75 #8486 ; RREF represents a limited source impedance DC reference voltage. For VREF ground, RREF 0 This iOS is usually a small contributor and expression simplified to: VOUT VOS (RFB+RG)/RG+IB (RFB). If RFB is limited to 1K, the last item of the equation is because the IB is less than 2 μA, so only contributes to only contributions. 2MV.

ATIO U W U application

Low -closed loop gain operation

LT1187 has optimized the closed -loop gain 2 or larger. When the closed -loop gain is 2, the peak response is about 2DB. The peak can pass through the feedback resistor by placing a capacitor (feedback zero). This peak displayed at about 25%.

Extend the input range

Figure 1 shows the simplified schematic diagram of the LT1187. In the normal operation reference pins 1 ground or ground DC offset control voltage and differential signals are used between pin 2 and pin 3. The input linear response is closed until all 345 μA current flows over 1.1K resistors and Q1 (or Q2). Therefore, the maximum input is 380mvp or 760mvp-P. The second difference is running at a slightly larger current for Q3 and Q4, so when the first level input limit, the second level keep prejudice to maintain feedback.Sometimes it is necessary to handle 760mvp-P than the input terminal. The LT1187 input level can be deceived to process up to 1.5VP-P. To do this, it is necessary to get ground needle 3 and apply the differential input signal between the pinna 1 and 2. At this time, the input signal is applied to the 1.1K resistor that spans two series. Because the input signal is applied to two input pairs, the first pair will use the bias current before the second pair, resulting in the amplifier to open the ring. The result of the technology is given in the range of the scope below.

Use the shutdown function

LT1187 has a unique feature, allowing the amplifier Several amplifiers. The amplifier will adjust the needle 5 to V — closed. When closing, the amplifier dissipates 15 mile, while maintaining a real high impedance output state to 20K, connecting with the feedback resistor. For MUX applications, you can configure the reversal, irreversible or differential of the amplifier. When the output is loaded from the feedback of the amplifier, the 1k resistance is loaded, and the amplifier is closed within 600ns. This closure can be Harbin-5V under HC CMOS with a operating voltage of 0V. On the curve, the typical stop power current and temperature of the capacity of the ability to keep off are displayed at 1MHz sinusoidal wave door control, and the performance characteristics of the pins are closed. At a very high evaporation temperature, maintaining the stopping stack is an important pins near the negative electrode power to keep the power current increase.

Send color videos through twisted twisted lines

LT1187 can send and receive color composite video signals exceeding 1,000 feet, and the cost is low. The two -way Video Bus includes the LT1195 computing amplifier and the LT1187 video difference. A pair of LT1195 transferred at 1 is used to generate differential signals of the drive line, which is reverse in its characteristic impedance. The LT1187 twisted pair receiver converts the signal from the differential to a single -end. LT1187's topology provides cable compensation at the feedback node of the amplifier, as shown in the figure. In this case, 1000 -foot twisted wires with 1000PF and 50 can improve the system from 750kHz to 4MHz. This bandwidth is enough to pass the 3.58MHz chroma -pronunciation and 4.5MHz sound auxiliary carrier. Set the resistance RG by reducing the gain, which can compensate at the attenuation in the cable. AT transmission 2. Another pair of LT1195s has dual functions to provide cable terminals through low output impedance, and generate differential signals to transmit 2. The cable terminal consists of 15 and 33 attenuators. The signal of the maximum input LT1187 is 760mvp-P. 3]