SL6140

The SL6140 is an integrated broadband AGC amplifier, designed on an advanced bipolar process. The amplifier provides over 15dB of linear gain into 50Ω at 400MHz. Gain control is also provided with over 70dB of dynamic range. The SL 6140 offers over 45dB of voltage gain with an RL of 1kΩ.

The SL6140 (Figure 3) is a high gain amplifier with an AGC control capable of reducing the gain of the amplifier by over 70dB. The gain is adjustable by applying a voltage to the AGC input via an external resistor (RAGC), the value of which adjusts the curve of gain reduction versus control voltage (see Figure 4). As the output stage of the amplifier is an open collector the maximum voltage gain is determined by RL. With load resistance of 1kΩ the single ended voltage gain is 45dB and with a load resistance of 50Ω the voltage gain is 15dB (20log10 VOUT/VIN). Another parameter that depends on the load resistance is the bandwidth: 25MHz for RL = 1kΩ, as compared with 400MHz for RL = 50Ω. RL is chosen to give either the required bandwidth or voltage gain for the circuit SL6140.

Figure 7 through to 10 show the typical S parameters for the device SL6140. Figures 11 and 12 show the typical variation in 3rd order intercept performance with AGC.

In any application, the substrate should be connected to the most negative point in the circuit SL6140, usually to the same point as pin 3.