EL5106 and EL5306 are fixed gain amplifiers with a bandwidth of 350MHz. This makes these amplifiers ideal for today's high-speed video and surveillance applications. They have internal gain setting resistors and are configurable in gain of +1, -1 or 2. With only 1.5mA of supply current and the ability to operate from a single supply voltage from 5V to 12V , these amplifiers are also ideal for handheld, portable or battery powered devices. The EL5106 and EL5306 also contain an enable and disable function to reduce supply current down to 25µA typical per amplifier. Leaving the CE pin floating or bringing it to a low logic level will enable the amplifier. The EL5106 is available in 6 Ld SOT-23 and industry standard 8 Ld SOIC packages and the EL5306 is available in 16 Ld SOIC and 16 Ld QSOP packages. All operate over an industrial temperature range of -40°C +85°C.

Product Description

The EL5106 and EL5306 are fixed gain amplifiers that provide a wide -3dB bandwidth of 350MHz and a low supply current of 1.5mA. They operate with supply voltages ranging from a single 5V to 12V, and they are also capable of swinging to 1.2V on either supply at the output. These high bandwidth and low power consumption combinations make the EL5106 and EL5306 ideal for many low power/high bandwidth applications such as portable, handheld or battery powered devices. For different bandwidths and higher gains, consider using the 1GHz EL5191 with 9mA supply current or the EL5162 with 300MHz on 4mA supply current. Versions include: 5 Ld SOT-23 for single, dual and triple release packages, 16 Ld QSOP package, and 8 Ld SOIC or 16 Ld SOIC profile.

Power Bypass and Printed Circuit Board Layout As with any high frequency device, good printed circuit board layout is necessary for optimum performance. A low impedance ground plane structure is necessary. Surface mount components are recommended, but if leaded components are used, lead lengths should be as short as possible. The power supply pins must be well bypassed to reduce the risk of oscillation. A 4.7µF combined tantalum capacitor in parallel with a 0.01µF capacitor has proven to work well when placed on each power supply pin.

Disable/Power Down

The EL5106 and EL5306 amplifiers can be disabled by placing their outputs in a high impedance state. When disabled, the amplifier's supply current drops to <25µA. When the EL5106 and EL5306 are disabled, their CE pin is pulled to within 1V of the positive supply. Similarly, the positive supply on the amplifier is enabled by floating or pulling the CE pin to at least 3V below. For a ±5V supply, this means that when CE is 2V or less, and disabled the amplifier will be enabled when CE is above 4V. Although this logic level is not standard TTL, this choice of logic voltage allows the EL5106 and the EL5306 to be enabled by tying the CE ground, even in single 5V supply applications. The CE pin can drive CMOS outputs.

Gain setting

Both the EL5106 and EL5306 are built with internal feedback and gain resistors. The internal feedback resistors are of equal value; as a result, the amplifier can be configured for gains of 1, -1 and 2 without any external resistors. Figure 1 shows a 2-configuration gain amplifier. Gain error is within ±2%. Figure 2 shows the configuration of the gain amplifier-1. For a gain of 1, IN+ and IN should be connected together as shown in Figure 3. This configuration avoids the influence of any parasitic capacitance at the IN- pin. Since the internal feedback and gain resistors vary with temperature and process, external resistors should not be used to adjust the gain setting.

Supply Voltage Range, Single Supply Operation The EL5106 and EL5306 have been designed to operate with a supply voltage span greater than or equal to 5V and less than 11V. In practice, this means that the EL5106 and EL5306 will operate on dual supplies from ±2.5V to ±5V. When powered with a single supply, the EL5106 and EL5306 will operate from 5V to 10V. As the supply voltage continues to decrease, it becomes necessary to provide input and output voltage ranges that can be obtained as close to the supply voltage as possible. The EL5106 and EL5306 have an extended input range of 2V at either supply. So, for example, on a ±5V supply, the EL5106 and EL5306 have an input range of ±3V across. The output range is also quite large, extending to the inner 1V rail. On ±5V supplies, the output is therefore able to swing from -4V to +4V. The single-supply output range is due to the larger negative swing due to the addition of an external pull-down resistor to ground. Figure 3 shows an AC-coupled, single-supply circuit configuration with a gain of +2, +5V.

Video performance

For good video performance, the amplifier needs to maintain the same output impedance and at the same frequency response as the DC level is changed at the output. It is especially difficult to find a standard video load of 150Ω because of the variation in output current with the DC level. Previously, good differential gain could only be achieved by running idle current at the output high to the transistor (to reduce skewed output impedance). Special designed circuits have been incorporated in the EL5106 and EL5306 to reduce current output with output impedance changes. This results in a dG and dp specification of 0.02% and 0.04° while driving 150Ω with a gain of 2.