The EL5164 , EL5165 , EL5364 and amplifiers with current feedback feature a high bandwidth of 600MHz. This makes these amplifiers ideal for today's high-speed video and surveillance applications. With only 5mA supply current and the ability to run from a single supply voltage of 5V to 12V , the amplifier is also ideal for handheld, portable or battery powered devices. The EL5164 also integrates an enable and disable function to reduce the current to 100µA typical per supply current amplifier. Leaving the CE pin floating or bringing it to a low logic level will enable the amplifier. The EL5165 is available in 5 Ld SOT-23 and 5 Ld SC-70 packages, the EL5164 is available in 6 Ld SOT-23 and existing industry standard 8 Ld SOIC packages, and the EL5364 is available in 16 Ld SOIC and 16 Ld SOIC packages Ld's QSOP package. All operate over an industrial temperature range of -40°C to +85°C.

Features

-3dB bandwidth of 600MHz

4700V/µs slew rate

5mA supply current

Single and dual power supply, 5V to 12V supply span

Quick enable/disable (EL5164 and EL5364 only)

Available in SOT-23 package

Dual (EL5264 and EL5265) and triple (EL5362 and EL5363) are also available

High-speed, 1GHz products available (EL5166 and EL5167)

300MHz product available (EL5162 series)

Lead-free available (RoHS compliant)

Product Description

The EL5164, EL5165, and EL5364 op amps with current feedback provide a wide -3dB bandwidth to 600MHz, and a low supply current of 5mA per amplifier. The EL5164, EL5165, and EL5364 operate with supply voltages from a single 5V to 10V, and they are also capable of swinging the output within 1V on either supply. Because of their current feedback topology, the EL5164, EL5165, and EL5364 do not have the normal gain bandwidth product associated with voltage feedback op amps. Instead, its -3dB bandwidth increases in order to maintain a relatively constant closed-loop gain. This combination of high bandwidth and low power consumption, coupled with aggressive pricing makes the EL5164, EL5165, and EL5364 an ideal choice for many low power/high bandwidth applications such as portable, handheld or battery powered devices. For different bandwidth requirements, consider the EL5166 and EL5167 with an 8.5mA supply current at 1GHz or the EL5162 and EL5163 with 300MHz on a 1.5mA supply current. Versions include single, dual and triple amplifier packages in 5 Ld SOT-23, 16 Ld QSOP package, and 8 Ld SOIC or 16 Ld SOIC outline.

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. For good AC performance, parasitic capacitance should be kept to a minimum, especially at the inverting input. Even in the case of a ground plane structure, it should be removed from the adjacent inverting input to minimize any stray area capacitance at that node. Carbon or metal film resistors are slightly less acceptable than metal film resistors for peaking and inductance due to the additional series bandwidth. The use of sockets, especially for SO encapsulation, should be avoided as much as possible. Sockets add parasitic inductance and capacitance, which will cause additional peaking and overshoot.

Disable/Power Down

The EL5164 amplifier can be disabled to put its output in a high impedance state. When disabled, the amplifier's supply current is reduced to <150µA. When the EL5164 is disabled, its CE pin is pulled up to 1V within the positive supply. Similarly, the amplifier is powered by floating or pulling its CE active pin at least 3V below the positive supply. For ±5V supplies, this means that an EL5164 amplifier will be enabled when CE is 2V or lower, and disabled when CE is above 4V. Although the logic levels are not standard TTL, this choice of logic voltage allows the EL5164 to be CE enabled by tying it to ground, even in 5V single-supply applications. The CE pin can be driven from the CMOS output. When the amplifier is off, if the positive input is driven beyond ±2V with respect to the negative input, the device can become active and output a signal. The input diode clamp network e1 and D2, shown in the figure below, can be used to keep the device disabled while a larger input signal is present.

capacitor at the inverting input

High-speed voltage or current feedback amplifiers from any manufacturer can suffer from stray capacitance at the inverting input. For inverting gain, this parasitic capacitance has little effect because the inverting input is on virtual ground, but for non-inverting gain, this capacitance (together with the feedback and gain resistors) creates a pole in the amplifier's feedback path. Such poles, if low enough, have the same destabilizing effect in frequency as the forward open-loop response is zero. Using large-value feedback and gain resistors exacerbates this problem by further reducing the pole frequency (increasing possible oscillations). The EL5164, EL5165, and EL5364 have been optimized with a 510Ω feedback resistor. With the high bandwidth of these amplifiers, these resistor values can cause stability problems when combined with parasitic capacitances, thus a ground plane is not recommended around the inverting input pin of the amplifier.

Feedback resistor value

The EL5164, EL5165 and EL5364 have been designed and specified with an R of approximately 412Ω at a gain of +2. The value of this feedback resistor gives a -3dB bandwidth of 300MHz with 2dB of peak shaving at V=2. With AV=-2, the RF300Ω provides a bandwidth of 275MHz with a peak of 1dB. Since the EL5164, EL5165, and EL5364 have current feedback amplifiers, it is also possible to change the value of RF to get more bandwidth. As can be seen the frequency curve responds to various ?F and RG, bandwidth and peak value can be easily modified by changing the value of the feedback resistor. Since the EL5164, EL5165, and EL5364 have current feedback amplifiers, their gain-bandwidth product is not a constant different closed-loop gain. This feature actually allows the EL5164, EL5165, EL5364 and EL5164 to maintain about the same -3dB bandwidth. As the gain increases, the bandwidth decreases slightly, but increases steadily. Due to improved loop stability and increased closed-loop gain, it is possible to reduce this value of RF below the specified 160Ω and still retain stability, resulting in only a slight reduction in bandwidth with increased closed-loop gain.