Electronic Components Datasheet Search |
|
EL2186CS Datasheet(PDF) 9 Page - Intersil Corporation |
|
EL2186CS Datasheet(HTML) 9 Page - Intersil Corporation |
9 / 14 page 9 Applications Information Product Description The EL2186/EL2286 are current-feedback operational amplifiers that offer a wide -3dB bandwidth of 250MHz, a low supply current of 3mA per amplifier and the ability to disable to 0mA. Both products also feature high output current drive. The EL2186 can output 100mA, while the EL2286 can output 55mA per amplifier. The EL2186/EL2286 work with supply voltages ranging from a single 3V to ±6V, and they are also capable of swinging to within 1V of either supply on the input and the output. Because of their current-feedback topology, the EL2186/EL2286 do not have the normal gain- bandwidth product associated with voltage-feedback operational amplifiers. This allows their -3dB bandwidth to remain relatively constant as closed-loop gain is increased. This combination of high bandwidth and low power, together with aggressive pricing make the EL2186/EL2286 the ideal choice for many low-power/high-bandwidth applications such as portable computing, HDSL, and video processing. For Single, Dual and Quad applications without disable, consider the EL2180 (8-Pin Single), EL2280 (8-Pin Dual) and EL2480 (14-Pin Quad). If lower power is required, refer to the EL2170/EL2176 family which provides Singles, Duals, and Quads with 70MHz of bandwidth while consuming 1mA of supply current per amplifier. Power Supply Bypassing and Printed Circuit Board Layout As with any high-frequency device, good printed circuit board layout is necessary for optimum performance. Ground plane construction is highly recommended. Lead lengths should be as short as possible. The power supply pins must be well bypassed to reduce the risk of oscillation. The combination of a 4.7µF tantalum capacitor in parallel with a 0.1µF capacitor has been shown to work well when placed at each supply pin. For good AC performance, parasitic capacitance should be kept to a minimum especially at the inverting input (see the Capacitance at the Inverting Input section). Ground plane construction should be used, but it should be removed from the area near the inverting input to minimize any stray capacitance at that node. Carbon or Metal-Film resistors are acceptable with the Metal-Film resistors giving slightly less peaking and bandwidth because of their additional series inductance. Use of sockets, particularly for the SO package should be avoided if possible. Sockets add parasitic inductance and capacitance which will result in some additional peaking and overshoot. Disable/Power-Down The EL2186/EL2286 amplifiers can be disabled, placing their output in a high-impedance state. When disabled, each amplifier's supply current is reduced to 0mA. Each EL2186/EL2286 amplifier is disabled when its ENABLE pin is floating or pulled up to within 0.5V of the positive supply. Similarly, each amplifier is enabled by pulling its ENABLE pin at least 3V below the positive supply. For ±5V supplies, this means that an EL2186/EL2286 amplifier will be enabled when ENABLE is at 2V or less, and disabled when ENABLE is above 4.5V. Although the logic levels are not standard TTL, this choice of logic voltages allows the EL2186/EL2286 to be enabled by tying ENABLE to ground, even in +3V single-supply applications. The ENABLE pin can be driven from CMOS outputs or open-collector TTL. When enabled, supply current does vary somewhat with the voltage applied at ENABLE. For example, with the supply voltages of the EL2186 at ±5V, if ENABLE is tied to -5V (rather than ground) the supply current will increase about 15% to 3.45mA. Capacitance at the Inverting Input Any manufacturer's high-speed voltage- or current-feedback amplifier can be affected by stray capacitance at the inverting input. For inverting gains this parasitic capacitance has little effect because the inverting input is a virtual ground, but for non-inverting gains this capacitance (in conjunction with the feedback and gain resistors) creates a pole in the feedback path of the amplifier. This pole, if low enough in frequency, has the same destabilizing effect as a zero in the forward open-loop response. The use of large value feedback and gain resistors further exacerbates the problem by further lowering the pole frequency. The EL2186/EL2286 have been specially designed to reduce power dissipation in the feedback network by using large 750 Ω feedback and gain resistors. With the high bandwidths of these amplifiers, these large resistor values would normally cause stability problems when combined with parasitic capacitance, but by internally canceling the effects of a nominal amount of parasitic capacitance, the EL2186/EL2286 remain very stable. For less experienced users, this feature makes the EL2186/EL2286 much more forgiving, and therefore easier to use than other products not incorporating this proprietary circuitry. The experienced user with a large amount of PC board layout experience may find in rare cases that the EL2186/EL2286 have less bandwidth than expected. In this case, the inverting input may have less parasitic capacitance than expected by the internal compensation circuitry of the EL2186/EL2286. The reduction of feedback resistor values (or the addition of a very small amount of external capacitance at the inverting input, e.g. 0.5pF) will increase bandwidth as desired. Please see the curves for Frequency Response for Various RF and RG, and Frequency Response for Various CIN-. EL2186, EL2286 |
Similar Part No. - EL2186CS |
|
Similar Description - EL2186CS |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |