250MHz/3mA Current Mode Feedback Amp w/Disable Features General Description • Single (EL2186C) and dual (EL2286C) topologies • 3mA supply current (per amplifier) • 250MHz -3dB bandwidth • Low cost • Fast disable • Powers down to 0mA • Single- and dual-supply operation down to ±1.5V • 0.05%/0.05° diff. gain/diff. phase into 150Ω • 1200V/µs slew rate • Large output drive current: 100mA (EL2186C) 55mA (EL2286C) • Also available without disable in single (EL2180C), dual (EL2280C) and quad (EL2480C) • Lower power EL2170C/EL2176C family also available (1 mA/ 70MHz) in single, dual and quad The EL2186C/EL2286C are single/dual current-feedback operational amplifiers which achieve a -3dB bandwidth of 250MHz at a gain of +1 while consuming only 3mA of supply current per amplifier. They will operate with dual supplies ranging from ±1.5V to ±6V, or from single supplies ranging from +3V to +12V. The EL2186C/EL2286C also include a disable/power-down feature which reduces current consumption to 0mA while placing the amplifier output in a high impedance state. In spite of its low supply current, the EL2286C can output 55mA while swinging to ±4V on ±5V supplies. The EL2186C can output 100mA with similar output swings. These attributes make the EL2186C/EL2286C excellent choices for low power and/or low voltage cable-driver, HDSL, or RGB applications. EL2186C, EL2286C EL2186C, EL2286C For Single, Dual and Quad applications without disable, consider the EL2180C (8-Pin Single), EL2280C (8-Pin Dual) or EL2480C (14-Pin Quad). For lower power applications where speed is still a concern, consider the EL2170C/El2176C family which also comes in similar Single, Dual and Quad configurations. The EL2170C/EL2176C family provides a -3dB bandwidth of 70MHz while consuming 1mA of supply current per amplifier. Applications • • • • • • • Low power/battery applications HDSL amplifiers Video amplifiers Cable drivers RGB amplifiers Test equipment amplifiers Current to voltage converters Connection Diagrams EL2186C SO, P-DIP EL2286C SO, P-DIP Ordering Information Temp. Range Package Outline # -40°C to +85°C 8-Pin PDIP MDP0031 EL2186CS -40°C to +85°C 8-Pin SOIC MDP0027 EL2286CN -40°C to +85°C 14-Pin PDIP MDP0031 EL2286CS -40°C to +85°C 14-Pin SOIC MDP0027 Manufactured under U.S. Patent No. 5,418,495 Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a “controlled document”. Current revisions, if any, to these specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation. © 2001 Elantec Semiconductor, Inc. September 26, 2001 Part No. EL2186CN EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Absolute Maximum Ratings (T Voltage between V S+ and VSCommon-Mode Input Voltage Differential Input Voltage Current into +IN or -IN Internal Power Dissipation Operating Ambient A = 25°C) +12.6V VS- to VS+ ±6V ±7.5mA See Curves Temperature Range Operating Junction Temperature Plastic Packages Output Current (EL2186C) Output Current (EL2286C) Storage Temperature Range -40°C to +85°C 150°C ±120mA ±60mA -65°C to +150°C Important Note: All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA. DC Electrical Characteristics VS = ±5V, RL = 150Ω, ENABLE = 0V, TA = 25°C unless otherwise specified Parameter Description Conditions Min Typ Max 2.5 15 Unit VOS Input Offset Voltage TCVOS Average Input Offset Voltage Drift Measured from TMIN to TMAX dVOS VOS Matching EL2286C only +IIN + Input Current d+IIN + IIN Matching -IIN - Input Current d-IIN -IIN Matching EL2286C only CMRR Common Mode Rejection Ratio VCM = ±3.5V -ICMR - Input Current Common Mode Rejection VCM = ±3.5V PSRR Power Supply Rejection Ratio VS is moved from ±4V to ±6V -IPSR - Input Current Power Supply Rejection VS is moved from ±4V to ±6V ROL Transimpedance VOUT = ±2.5V 120 300 kΩ +RIN + Input Resistance VCM = ±3.5V 0.5 2 MΩ +CIN + Input Capacitance 1.2 pF CMIR Common Mode Input Range ±3.5 ±4.0 V VO Output Voltage Swing ±3.5 ±4.0 V VS = +5 Single-Supply, High 4.0 V VS = +5 Single-Supply, Low 0.3 V mA 5 0.5 1.5 EL2286C only mV 15 µA 40 µA 20 16 nA 2 45 VS = ±5 IO Output Current IOUT, OFF Output Current Disable VOUT ±2V, AV = +1@25°C IS Supply Current ENABLE = 2.0V, per Amplifier 60 µA 50 5 dB 30 µA/V 15 µA/V 70 1 EL2186C only 80 100 EL2286C only, per Amplifier 50 55 mV µV/°C dB mA 10 µA 3 6 mA 50 µA IS(DIS) Supply Current (Disabled) ENABLE = 4.5V 0 COUT(DIS) Output Capacitance (Disabled) ENABLE = 4.5V 4.4 pF REN Enable Pin Input Resistance Measured at ENABLE = 2.0V, 4.5V 85 kΩ -0.04 µA -53 µA IIH Logic “1” Input Current Measured at ENABLE, ENABLE = 4.5V IIL Logic “0” Input Current Measured at ENABLE, ENABLE = 0V VDIS Minimum Voltage at ENABLE to Disable VEN Maximum Voltage at ENABLE to Enable 45 4.5 V 2.0 2 V AC Electrical Characteristics VS = ±5V, RF = RG = 750Ω, RL = 150Ω, ENABLE = 0V, TA = 25°C unless otherwise specified Parameter Description Conditions Min Typ Max Unit -3dB BW -3dB Bandwidth AV = +1 250 MHz -3dB BW -3dB Bandwidth AV = +2 180 MHz 0.1dB BW 0.1dB Bandwidth AV = +2 50 MHz SR Slew Rate VOUT = ±2.5V, AV = +2 1200 V/µs tr, tf Rise and Fall Time VOUT = ±500 mV 1.5 ns tpd Propagation Delay VOUT = ±500 mV 1.5 ns OS Overshoot VOUT = ±500 mV 3.0 % ts 0.1% Settling VOUT = ±2.5V, AV = -1 15 ns dG Differential Gain AV = +2, RL = 150Ω  0.05 % dP Differential Phase AV = +2, RL = 150Ω  0.05 dG Differential Gain AV = +1, RL = 500Ω  0.01 dP Differential Phase AV = +1, RL = 500Ω  0.01 tON Turn-On Time AV = +2, V IN = +1V, RL = 150Ω  40 100 tOFF Turn-Off Time AV = +2, V IN = +1V, RL = 150Ω  1500 2000 CS Channel Separation EL2286C only, f = 5MHz 600 85 1. DC offset from 0V to 0.714V, AC amplitude 286mVP-P, f = 3.58MHz. 2. Measured from the application of the logic signal until the output voltage is at the 50% point between initial and final values. Test Circuit (per Amplifier) 3 % ° ns ns dB EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Simplified Schematic (per Amplifier) 4 Typical Performance Curves Non-Inverting Frequency Response (Gain) Inverting Frequency Response (Gain) Transimpedance (ROL) vs Frequency Non-Inverting Frequency Response (Phase) Inverting Frequency Response (Phase) PSRR and CMRR vs Frequency 5 Frequency Response for Various RF and RG Frequency Response for Various RL and CL Frequency Response for Various CIN- EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Voltage and Current Noise vs Frequency -3dB Bandwidth and Peaking vs Supply Voltage for Various Non-Inverting Gains Supply Current vs Supply Voltage 2nd and 3rd Harmonic Distortion vs Frequency -3dB Bandwidth and Peaking vs Supply Voltage for Various Inverting Gains Common-Mode Input Range vs Supply Voltage 6 Output Voltage Swing vs Frequency Output Voltage Swing vs Supply Voltage Slew Rate vs Supply Voltage Input Bias Current vs Die Temperature -3dB Bandwidth and Peaking vs Die Temperature for Various Non-Inverting Gains Supply Current vs Die Temperature Short-Circuit Current vs Die Temperature Transimpedance (ROL) vs Die Temperature -3dB Bandwidth vs Die Temperature for Various Inverting Gains Input Offset Voltage vs Die Temperature Input Voltage Range vs Die Temperature Slew Rate vs Die Temperature 7 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Differential Gain and Phase vs DC Input Voltage at 3.58MHz Differential Gain and Phase vs DC Input Voltage at 3.58MHz Settling Time vs Settling Accuracy Large-Signal Step Response Small-Signal Step Response 8-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 8-Lead SO Maximum Power Dissipation vs Ambient Temperature 8 14-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 14-Lead SO Maximum Power Dissipation vs Ambient Temperature 9 Channel Separation vs Frequency (EL2286) EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Applications Information Product Description 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. The EL2186C/EL2286C 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 EL2186C can output 100mA, while the EL2286C can output 55mA per amplifier. The EL2186C/EL2286C 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 currentfeedback topology, the EL2186C/EL2286C 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 EL2186C/EL2286C the ideal choice for many low-power/high-bandwidth applications such as portable computing, HDSL, and video processing. Disable/Power-Down The EL2186C/EL2286C amplifiers can be disabled, placing their output in a high-impedance state. When disabled, each amplifier's supply current is reduced to 0mA. Each EL2186C/EL2286C 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 EL2186C/EL2286C 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 EL2186C/EL2286C 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. For Single, Dual and Quad applications without disable, consider the EL2180C (8-Pin Single), EL2280C (8-Pin Dual) and EL2480C (14-Pin Quad). If lower power is required, refer to the EL2170C/EL2176C family which provides Singles, Duals, and Quads with 70MHz of bandwidth while consuming 1mA of supply current per amplifier. When enabled, supply current does vary somewhat with the voltage applied at ENABLE. For example, with the supply voltages of the EL2186C at ±5V, if ENABLE is tied to -5V (rather than ground) the supply current will increase about 15% to 3.45mA. 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. 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 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 same destabilizing effect as a zero in the forward openloop response. The use of large value feedback and gain 10 resistors further exacerbates the problem by further lowering the pole frequency. loop gain. However, as closed-loop gain is increased, bandwidth decreases slightly while stability increases. The EL2186C/EL2286C have been specially designed to reduce power dissipation in the feedback network by using large 750Ω 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 EL2186C/EL2286C remain very stable. For less experienced users, this feature makes the EL2186C/EL2286C much more forgiving, and therefore easier to use than other products not incorporating this proprietary circuitry. Since the loop stability is improving with higher closedloop gains, it becomes possible to reduce the value of RF below the specified 750Ω and still retain stability, resulting in only a slight loss of bandwidth with increased closed-loop gain. Supply Voltage Range and Single-Supply Operation The EL2186C/EL2286C have been designed to operate with supply voltages having a span of greater than 3V, and less than 12V. In practical terms, this means that the EL2186C/EL2286C will operate on dual supplies ranging from ±1.5V to ±6V. With a single-supply, the EL2176C will operate from +3V to +12V. The experienced user with a large amount of PC board layout experience may find in rare cases that the EL2186C/EL2286C have less bandwidth than expected. In this case, the inverting input may have less parasitic capacitance than expected As supply voltages continue to decrease, it becomes necessary to provide input and output voltage ranges that can get as close as possible to the supply voltages. The EL2186C/EL2286C have an input voltage range that extends to within 1V of either supply. So, for example, on a single +5V supply, the EL2186C/EL2286C have an input range which spans from 1V to 4V. The output range of the EL2186C/EL2286C is also quite large, extending to within 1V of the supply rail. On a ±5V supply, the output is therefore capable of swinging from 4V to +4V. Single-supply output range is even larger because of the increased negative swing due to the external pull-down resistor to ground. On a single +5V supply, output voltage range is about 0.3V to 4V. by the internal compensation circuitry of the EL2186C/EL2286C. 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-. Feedback Resistor Values The EL2186C/EL2286C have been designed and specified at gains of +1 and +2 with RF = 750Ω. This value of feedback resistor gives 250MHz of -3dB bandwidth at AV = +1 with about 2.5dB of peaking, and 180MHz of 3dB bandwidth at AV = +2 with about 0.1dB of peaking. Since the EL2186C/EL2286C are current-feedback amplifiers, it is also possible to change the value of R F to get more bandwidth. As seen in the curve of Frequency Response For Various RF and RG, bandwidth and peaking can be easily modified by varying the value of the feedback resistor. Video Performance For good video performance, an amplifier is required to maintain the same output impedance and the same frequency response as DC levels are changed at the output. This is especially difficult when driving a standard video load of 150Ω, because of the change in output current with DC level. Until the EL2186C/EL2286C, good Differential Gain could only be achieved by running high idle currents through the output transistors (to reduce variations in output impedance). These currents were typically comparable to the entire 3mA supply current of each EL2186C/EL2286C amplifier! Special circuitry has been incorporated in the EL2186C/EL2286C to reduce the variation of output impedance with current Because the EL2186C/EL2286C are current-feedback amplifiers, their gain-bandwidth product is not a constant for different closed-loop gains. This feature actually allows the EL2186C/EL2286C to maintain about the same -3dB bandwidth, regardless of closed- 11 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Power Dissipation output. This results in dG and dP specifications of 0.05% and 0.05° while driving 150Ω at a gain of +2. With the high output drive capability of the EL2186C/EL2286C, it is possible to exceed the 150°C Absolute Maximum junction temperature under certain very high load current conditions. Generally speaking, when RL falls below about 25Ω, it is important to calculate the maximum junction temperature (TJmax) for the application to determine if power-supply voltages, load conditions, or package type need to be modified for the EL2186C/EL2286C to remain in the safe operating area. These parameters are calculated as follows: Video Performance has also been measured with a 500Ω load at a gain of +1. Under these conditions, the EL2186C/EL2286C have dG and dP specifications of 0.01% and 0.01° respectively while driving 500Ω at AV = +1. Output Drive Capability In spite of its low 3mA of supply current, the EL2186C is capable of providing a minimum of ±80mA of output current. Similarly, each amplifier of the EL2286C is capable of providing a minimum of ±50mA. These output drive levels are unprecedented in amplifiers running at these supply currents. With a minimum ±80mA of output drive, the EL2186C is capable of driving 50Ω loads to ±4V, making it an excellent choice for driving isolation transformers in telecommunications applications. Similarly, the ±50mA minimum output drive of each EL2286C amplifier allows swings of ±2.5V into 50Ω loads. TJMAX = TMAX + (θJA * n * PDMAX)  where: TMAX=Maximum Ambient Temperature θJA=Thermal Resistance of the Package n=Number of Amplifiers in the Package PDMAX=Maximum Power Dissipation of Each Amplifier in the Package. PDMAX for each amplifier can be calculated as follows: Driving Cables and Capacitive Loads PD MAX = (2 * V S * I SMAX ) + (V S - V OUTMAX ) * (VOUTMAX/RL)  When used as a cable driver, double termination is always recommended for reflection-free performance. For those applications, the back-termination series resistor will decouple the EL2186C/EL2286C from the cable and allow extensive capacitive drive. However, other applications may have high capacitive loads without a back-termination resistor. In these applications, a small where: VS=Supply Voltage ISMAX=Maximum Supply Current of 1 Amplifier VOUTMAX=Max. Output Voltage of the Application RL=Load Resistance series resistor (usually between 5Ω and 50Ω) can be placed in series with the output to eliminate most peaking. The gain resistor (RG) can then be chosen to make up for any gain loss which may be created by this additional resistor at the output. In many cases it is also possible to simply increase the value of the feedback resistor (RF) to reduce the peaking. Current Limiting The EL2186C/EL2286C have no internal current-limiting circuitry. If any output is shorted, it is possible to exceed the Absolute Maximum Ratings for output current or power dissipation, potentially resulting in the destruction of the device. 12 Typical Application Circuits Low Power Multiplexer with Single-Ended TTL Input 13 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable Inverting 200mA Output Current Distribution Amplifier 50 50 50 50 Differential Line-Driver/Receiver 14 Fast-Settling Precision Amplifier 15 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C/EL2286C Macromodel * EL2186 Macromodel * Revision A, March 1995 * AC characteristics used: Rf = Rg = 750 ohms * Connections: +input * | -input * | | +Vsupply * | | | -Vsupply * | | | | output * | | | | | .subckt EL2186/e. 2 7 4 6 * * Input Stage * e1 10 0 3 0 1.0 vis 10 9 0V h2 9 12 vxx 1.0 r1 2 11 400 l1 11 12 25nH iinp 3 0 1.5uA iinm 2 0 3uA r12 3 0 2Meg * * Slew Rate Limiting * h1 13 0 vis 600 r2 13 14 1K d1 14 0 dclamp d2 0 14 dclamp * * High Frequency Pole * e2 30 0 14 0 0.00166666666 l3 30 17 150nH c5 17 0 0.8pF r5 17 0 165 * * Transimpedance Stage * g1 0 18 17 0 1.0 rol 18 0 450K cdp 18 0 0.675pF * * Output Stage * q1 4 18 19 qp q2 7 18 20 qn q3 7 19 21 qn q4 4 20 22 qp r7 21 6 4 r8 22 6 4 ios1 7 19 1mA ios2 20 4 1mA * * Supply Current ips 7 4 0.2mA * * Error Terms * ivos 0 23 0.2mA vxx 23 0 0V e4 24 0 3 0 1.0 e5 25 0 7 0 1.0 16 e6 26 0 4 0 -1.0 r9 24 23 316 r10 25 23 3.2K r11 26 23 3.2K * * Models * .model qn npn(is=5e-15 bf=200 tf=0.01nS) *.model qp pnp(is=5e-15 bf=200 tf=0.01nS) .model dclamp d(is=1e-30 ibv=0.266 + bv=0.71v n=4) .ends 17 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable EL2186C/EL2286C Macromodel 18 EL2186C, EL2286C EL2186C, EL2286C 250MHz/3mA Current Mode Feedback Amp w/Disable General Disclaimer Specifications contained in this data sheet are in effect as of the publication date shown. Elantec, Inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. Elantec, Inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. September 26, 2001 WARNING - Life Support Policy Elantec, Inc. products are not authorized for and should not be used within Life Support Systems without the specific written consent of Elantec, Inc. Life Support systems are equipment intended to support or sustain life and whose failure to perform when properly used in accordance with instructions provided can be reasonably expected to result in significant personal injury or death. Users contemplating application of Elantec, Inc. Products in Life Support Systems are requested to contact Elantec, Inc. factory headquarters to establish suitable terms & conditions for these applications. Elantec, Inc.’s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages. Elantec Semiconductor, Inc. 675 Trade Zone Blvd. Milpitas, CA 95035 Telephone: (408) 945-1323 (888) ELANTEC Fax: (408) 945-9305 European Office: +44-118-977-6020 Japan Technical Center: +81-45-682-5820 19 Printed in U.S.A.