250 MHz Triple Current Feedback Amp w/Disable Features General Description # Triple amplifier topology # 3 mA supply current (per amplifier) # 250 MHz b 3 dB bandwidth # Low cost # Fast disable # Powers down to 0 mA # Single- and dual-supply operation down to g 1.5V # 0.05%/0.05§ Diff. gain/Diff. phase into 150X # 1200V/ms slew rate # Large output drive current: 55 mA # Available in single (EL2186C) and dual (EL2286C) form # Non-power down versions available in single, dual, and quad (EL2180C, EL2280C, EL2480C) # Lower power EL2170C/EL2176C family also available (1 mA/70 MHz) in single, dual and quad. The EL2386C is a triple current-feedback operational amplifier which achieves a b 3 dB bandwidth of 250 MHz at a gain of a 1 while consuming only 3 mA of supply current per amplifier. It will operate with dual supplies ranging from g 1.5V to g 6V, or from single supplies ranging from a 3V to a 12V. The EL2386C also includes a disable/power-down feature which reduces current consumption to 0 mA while placing the amplifier output in a high impedance state. In spite of its low supply current, the EL2386C can output 55 mA while swinging to g 4V on g 5V supplies. These attributes make the EL2386C an excellent choice for low power and/or low voltage cable-driver, HDSL, or RGB applications. For Single and Dual applications, consider the EL2186C/ EL2286C. For Single, Dual and Quad applications without disable, consider the EL2180C, EL2280C, or EL2480C, all in industry standard pin outs. The EL2180C also is available in the tiny SOT-23 package, which is 28% the size of an SO8 package. 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 b 3 dB bandwidth of 70 MHz while consuming 1 mA of supply current per amplifier. Connection Diagram EL2386C SO, P-DIP Applications # # # # # # # # # EL2386C EL2386C Low power/battery applications HDSL amplifiers Video amplifiers Cable drivers RGB amplifiers Test equipment amplifiers Current to voltage converters Multiplexing Video broadcast equipment Part No. Temp. Range Package Outline Ý EL2386CN b 40§ C to a 85§ C 16-Pin PDIP MDP0031 2386-1 Top View EL2386CS b 40§ C to a 85§ C 16-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. © 1996 Elantec, Inc. June 1996 Rev A Ordering Information EL2386C 250 MHz Triple Current Feedback Amp w/Disable Absolute Maximum Ratings (TA e 25§ C) Voltage between VS a and VSb Common-Mode Input Voltage Differential Input Voltage Current into a IN or bIN Internal Power Dissipation a 12.6V VSb to VS a g 6V g 7.5 mA See Curves b 40§ C to a 85§ C Operating Ambient Temperature Range Operating Junction Temperature Output Current Storage Temperature Range 150§ C g 60 mA b 65§ C to a 150§ C Important Note: All parameters having Min/Max specifications are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality inspection. Elantec performs most electrical tests using modern high-speed automatic test equipment, specifically the LTX77 Series system. Unless otherwise noted, all tests are pulsed tests, therefore TJ e TC e TA. Test Level I II III IV V Test Procedure 100% production tested and QA sample tested per QA test plan QCX0002. 100% production tested at TA e 25§ C and QA sample tested at TA e 25§ C , TMAX and TMIN per QA test plan QCX0002. QA sample tested per QA test plan QCX0002. Parameter is guaranteed (but not tested) by Design and Characterization Data. Parameter is typical value at TA e 25§ C for information purposes only. DC Electrical Characteristics VS e g 5V, RL e 150X, ENABLE e 0V, TA e 25§ C unless otherwise specified Description Conditions Min Typ Max 2.5 15 Test Level Units VOS Input Offset Voltage TCVOS Average Input Offset Voltage Drift dVOS VOS Matching 0.5 a IIN a Input Current 1.5 d a IIN a IIN Matching 20 b IIN b Input Current 16 I mA dbIIN b IIN Matching 2 V mA CMRR Common Mode Rejection Ratio VCM e g 3.5V 45 50 I dB b ICMR b Input Current Common Mode Rejection VCM e g 3.5V I mA/V PSRR Power Supply Rejection Ratio VS e g 4V to g 6V 60 70 b IPSR b Input Current Power Supply Rejection VS e g 4V to g 6V ROL Transimpedance VOUT e g 2.5V 120 300 I kX a RIN a Input Resistance VCM e g 3.5V 0.5 2 I MX a CIN a Input Capacitance 1.2 V pF CMIR Common Mode Input Range g 3.5 g 4.0 I V VO Output Voltage Swing g 3.5 g 4.0 I V VS e a 5V Single-Supply, High 4.0 V V VS e a 5V Single-Supply, Low 0.3 V V 55 I mA IO Measured from TMIN to TMAX VS e g 5V Output Current 5 5 1 50 2 15 40 30 15 I mV V mV/§ C V mV I mA V nA I dB I mA/V TD is 3.9in Parameter EL2386C 250 MHz Triple Current Feedback Amp w/Disable VS e g 5V, RL e 150 X, ENABLE e 0V, TA e 25§ C unless otherwise specified Parameter Description Ð Contd. Conditions Min ENABLE e 2.0V Typ Max Test Level Units 3 6 I mA 50 I mA V pF IS Supply CurrentÐEnabled (per amplifier) IS(DIS) Supply CurrentÐDisabled (per amplifier) ENABLE e 4.5V 0 COUT(DIS) Output CapacitanceÐDisabled ENABLE e 4.5V 4.4 RIN-EN ENABLE Pin Input Resistance ENABLE e 2.0V to 4.5V IIH-EN ENABLE Pin Input CurrentÐHigh ENABLE e 4.5V IIL-EN ENABLE Pin Input CurrentÐLow ENABLE e 0V VDIS Minimum Voltage at ENABLE to Disable VEN Maximum Voltage at ENABLE to Enable 45 85 I kX b 0.04 V mA b 53 V mA I V I V 4.5 2.0 TD is 1.8in DC Electrical Characteristics AC Electrical Characteristics Parameter BW Description Min Typ Max Test Level Units AV e a 1 250 V MHz AV e a 2 180 V MHz g 0.1 dB Bandwidth AV e a 2 50 V MHz SR Slew Rate VOUT e g 2.5V, Measured at g 1.25V 1200 IV V/ms tR, tF Rise and Fall Time VOUT e g 500 mV 1.5 V ns tPD Propagation Delay VOUT e g 500 mV 1.5 V ns OS Overshoot VOUT e g 500 mV 3.0 V % tS 0.1% Settling VOUT e g 2.5V, AV e b1 15 V ns dG Differential Gain (Note 1) AV e a 2, RL e 150X 0.05 V % dP Differential Phase (Note 1) AV e a 2, RL e 150X, 0.05 V § dG Differential Gain (Note 1) AV e a 1, RL e 500X 0.01 V % dP Differential Phase (Note 1) AV e a 1, RL e 500X 0.01 V § tON Turn-On Time (Note 2) AV e a 2, VIN e a 1V, RL e 150X 40 100 I ns tOFF Turn-Off Time (Note 2) AV e a 2, VIN e a 1V, RL e 150X 800 2000 I ns Channel Separation f e 5 MHz 85 V dB BW CS b 3 dB Bandwidth Conditions 600 Note 1: DC offset from 0V to 0.714V, AC amplitude 286 mVp-p, f e 3.58 MHz. Note 2: Measured from the application of the logic signal until the output voltage is at the 50% point between initial and final values. 3 TD is 3.1in VS e g 5V, RF e RG e 750 X, RL e 150X, ENABLE e 0V, TA e 25§ C unless otherwise specified. EL2386C 250 MHz Triple Current Feedback Amp w/Disable Test Circuit (per Amplifier) 2386-2 Simplified Schematic (per Amplifier) 2386-3 4 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Typical Performance Curves Ð Contd. Non-Inverting Frequency Response (Gain) Non-Inverting Frequency Response (Phase) 2386-4 Inverting Frequency Response (Gain) Frequency Response for Various RF and RG 2386-5 Inverting Frequency Response (Phase) 2386-7 Transimpedance (ROL) vs Frequency 2386-6 Frequency Response for Various RL and CL 2386-8 PSRR and CMRR vs Frequency 2386-9 Frequency Response for Various CIN b 2386-10 2386-11 5 2386-12 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Typical Performance Curves Ð Contd. Voltage and Current Noise vs Frequency 2nd and 3rd Harmonic Distortion vs Frequency 2386 – 14 2386 – 13 b 3 dB Bandwidth and Peaking vs Supply Voltage for Various Non-Inverting Gains b 3 dB Bandwidth and Peaking vs Supply Voltage for Various Inverting Gains 2386 – 16 Supply Current vs Supply Voltage Output Voltage Swing vs Frequency 2386 – 15 Output Voltage Swing vs Supply Voltage 2386 – 17 Common-Mode Input Range vs Supply Voltage 2386 – 19 2386 – 20 6 2386 – 18 Slew Rate vs Supply Voltage 2386 – 21 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Typical Performance Curves Ð Contd. Input Bias Current vs Die Temperature Short-Circuit Current vs Die Temperature 2386-23 2386-22 b 3 dB Bandwidth and Peaking vs Die Temperature for Various Non-Inverting Gains Transimpedance (ROL) vs Die Temperature b 3 dB Bandwidth vs Die Temperature for Various Inverting Gains 2386-24 Input Offset Voltage vs Die Temperature 2386-25 2386-27 2386-26 Supply Current vs Die Temperature Input Voltage Range vs Die Temperature 2386-28 Slew Rate vs Die Temperature 2386-29 7 2386-30 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Typical Performance Curves Ð Contd. Differential Gain and Phase vs DC Input Voltage at 3.58 MHz Differential Gain and Phase vs DC Input Voltage at 3.58 MHz Settling Time vs Settling Accuracy 2386-32 2386-31 2386-33 Small-Signal Step Response Large-Signal Step Response 2386-34 16-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 2386-35 16-Lead SO Maximum Power Dissipation vs Ambient Temperature 2386-36 Channel to Channel Isolation vs Frequency 2386-37 2386-38 8 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Applications Information nected to the ground plane, a single 4.7 mF tantalum capacitor in parallel with a 0.1 mF ceramic capacitor across pins 14 and 3 will suffice. Product Description The EL2386C is a current-feedback operational amplifier that offers a wide b 3 dB bandwidth of 250 MHz, a low supply current of 3 mA per amplifier and the ability to power down to 0 mA. It also features high output current drive. The EL2386C can output 55 mA per amplifier. The EL2386C works with supply voltages ranging from a single 3V to g 6V, and it is also capable of swinging to within 1V of either supply on the input and the output. Because of its current-feedback topology, the EL2386C does not have the normal gain-bandwidth product associated with voltage-feedback operational amplifiers. This allows its b 3 dB 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 EL2386C the ideal choice for many low-power/ high-bandwidth applications such as portable computing, HDSL, and video processing. 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 EL2386C amplifier can be disabled, placing its output in a high-impedance state. When disabled, the supply current is reduced to 0 mA. The EL2386C is disabled when its ENABLE pin is floating or pulled up to within 0.5V of the positive supply. Similarly, the amplifier is enabled by pulling its ENABLE pin at least 3V below the positive supply. For g 5V supplies, this means that an EL2386C 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 EL2386C to be enabled by tying ENABLE to ground, even in a 3V singlesupply applications. The ENABLE pin can be driven from CMOS outputs or open-collector TTL. For Single and Dual applications, consider the EL2186C/EL2286C. For Single, Dual and Quad applications without disable, consider the EL2180C, EL2280C, or EL2480C, all in industry standard pin outs. The EL2180C also is available in the tiny SOT-23 package, which is 28% the size of an SO8 package. 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 with 70 MHz of bandwidth while consuming 1 mA 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 4.7 mF tantalum capacitor in parallel with a 0.1 mF capacitor has been shown to work well when placed at each supply pin. For single supply operation, where pin 3 (VS-) is con- When enabled, supply current does vary somewhat with the voltage applied at ENABLE. For example, with the supply voltages of the EL2186C at g 5V, if ENABLE is tied to b 5V (rather than ground) the supply current will increase about 15% to 3.45 mA. 9 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Applications Information Ð Contd. creased, bandwidth decreases slightly while stability increases. Since the loop stability is improving with higher closed-loop gains, it becomes possible to reduce the value of RF below the specified 750X and still retain stability, resulting in only a slight loss of bandwidth with increased closed-loop gain. 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. Supply Voltage Range and SingleSupply Operation The EL2386C has 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 EL2386C will operate on dual supplies ranging from g 1.5V to g 6V. With a single-supply, the EL2386C will operate from a 3V to a 12V. The experienced user with a large amount of PC board layout experience may find in rare cases that the EL2386C has less bandwidth than expected. In this case, the inverting input may have less parasitic capacitance than expected. The reduction of feedback resistor values (or the addition of a very small amount of external capacitance at the inverting input, e. g. 0.5 pF) will increase bandwidth as desired. Please see the curves for Frequency Response for Various RF and RG, and Frequency Response for Various CIN-. 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 EL2386C has an input voltage range that extends to within 1V of either supply. So, for example, on a single a 5V supply, the EL2386C has an input range which spans from 1V to 4V. The output range of the EL2386C is also quite large, extending to within 1V of the supply rail. On a g 5V supply, the output is therefore capable of swinging from b 4V to a 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 a 5V supply, output voltage range is about 0.3V to 4V. Feedback Resistor Values The EL2386C has been designed and specified at gains of a 1 and a 2 with RF e 750X. This value of feedback resistor gives 250 MHz of b 3 dB bandwidth at AV e a 1 with about 2.5 dB of peaking, and 180 MHz of b 3 dB bandwidth at AV e a 2 with about 0.1 dB of peaking. Since the EL2386C is a current-feedback amplifier, it is also possible to change the value of RF 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 150X, because of the change in output current with DC level. Until the EL2386C, 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 3 mA supply current of each EL2386C amplifier! Spe- Because the EL2386C is a current-feedback amplifier, its gain-bandwidth product is not a constant for different closed-loop gains. This feature actually allows the EL2386C to maintain about the same b 3 dB bandwidth, regardless of closedloop gain. However, as closed-loop gain is in- 10 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Applications Information Ð Contd. cial circuitry has been incorporated in the EL2386C to reduce the variation of output impedance with current output. This results in dG and dP specifications of 0.05% and 0.05§ while driving 150X at a gain of a 2. drive. However, other applications may have high capacitive loads without a back-termination resistor. In these applications, a small series resistor (usually between 5X and 50X) 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. Video Performance has also been measured with a 500X load at a gain of a 1. Under these conditions, the EL2386C has dG and dP specifications of 0.01% and 0.01§ respectively while driving 500X at AV e a 1. For complete curves, see the Differential Gain and Differential Phase vs Input Voltage curves. Current Limiting The EL2386C has no internal current-limiting circuitry. If an output is shorted indefinitely, the power dissipation could easily increase such that the part will be destroyed. Maximum reliability is maintained if the output current never exceeds g 60 mA. A heat sink may be required to keep the junction temperature below absolute maximum when an output is shorted indefinitely. Output Drive Capability In spite of its low 3 mA of supply current per amplifier, the EL2386C is capable of providing a minimum of g 50 mA of output current. This output drive level is unprecedented in amplifiers running at these supply currents. With a minimum g 50 mA of output drive, the EL2386C is capable of driving 50X loads to g 2.5V, making it an excellent choice for driving multiple video loads in RGB applications. Multiplexing with the EL2386C The ENABLE pins on the EL2386C allow for multiplexing applications. Figure 1 shows an EL2386C with all 3 outputs tied together, driving a back terminated 75X video load. Three sine waves of varying amplitudes and frequencies are applied to the three inputs, while a 1 of 3 decoder selects one amplifier to be on at any given time. Figure 2 shows the resulting output wave form at Driving Cables and Capacitive Loads 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 EL2386C from the cable and allow extensive capacitive 2386-39 Figure 1 11 EL2386C 250 MHz Triple Current Feedback Amp w/Disable Applications Information Ð Contd. These parameters are calculated as follows: TJMAX e TMAX a (iJA * n * PDMAX) [1] where: TMAX e Maximum Ambient Temperature iJA e Thermal Resistance of the Package n e Number of Amplifiers in the Package PDMAX e Maximum Power Dissipation of Each Amplifier in the Package. PDMAX for each amplifier can be calculated as follows: 2386-40 Figure 2 PDMAX e (2 * VS * ISMAX) a (VS –VOUTMAX) * (VOUTMAX/RL) VOUT. Switching is complete in about 100 ns. Notice the outputs are tied directly together. Decoupling resistors at each output are not required or advised when multiplexing. where: VS e Supply Voltage ISMAX e Maximum Supply Current of 1 Amplifier VOUTMAX e Max. Output Voltage of the Application RL e Load Resistance Power Dissipation With the high output drive capability of the EL2386C, 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 25X, 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 EL2386C to remain in the safe operating area. 12 [2] EL2386C EL2386C Macromodel * 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 e6 26 0 4 0 b1.0 r9 24 23 316 r10 25 23 3.2K r11 26 23 3.2K * * Models * .model qn npn(is e 5eb15 bf e 200 tf e 0.1nS) .model qp pnp(is e 5eb15 bf e 200 tf e 0.1nS) .model dclamp d(is e 1eb30 ibv e 0.266 a bv e 0.71v n e 4) .ends * EL2386C Macromodel * Revision A, July 1996 * AC characteristics used: Rf e Rg e 750 ohms * Pin numbers reflect a standard single opamp a input * Connections: b input * l a Vsupply * l l b Vsupply * l l l * output l l l l * l l l l l .subckt EL2386/EL 3 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 1.5mA iinm 2 0 3mA 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 * 13 TD is 5.1in TD is 4.8in TAB WIDE 250 MHz Triple Current Feedback Amp w/Disable EL2386C 250 MHz Triple Current Feedback Amp w/Disable EL2386C Macromodel Ð Contd. 2386-41 14 15 BLANK EL2386C EL2386C 250 MHz Triple Current 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. June 1996 Rev A WARNING Ð 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, Inc. 1996 Tarob Court Milpitas, CA 95035 Telephone: (408) 945-1323 (800) 333-6314 Fax: (408) 945-9305 European Office: 44-71-482-4596 16 Printed in U.S.A.