70 MHz/1 mA Current Mode Feedback Amplifiers Features General Description # Single (EL2170C), dual (EL2270C) and quad (EL2470C) topologies # 1 mA supply current (per amplifier) # 70 MHz b 3 dB bandwidth # Tiny SOT23-5 Package (EL2170C) # Low cost # Single- and dual-supply operation down to g 1.5V # 0.15%/0.15§ diff. gain/diff. phase into 150X # 800 V/ms slew rate # Large output drive current: 100 mA (EL2170C) 55 mA (EL2270C) 55 mA (EL2470C) # Also available with disable in single (EL2176C) and dual (EL2276C) # Higher speed EL2180C/EL2186C family also available (3 mA/ 250 MHz) in single, dual and quad The EL2170C/EL2270C/EL2470C are single/dual/quad current-feedback operational amplifiers which achieve a b 3 dB bandwidth of 70 MHz at a gain of a 1 while consuming only 1 mA of supply current per amplifier. They will operate with dual supplies ranging from g 1.5V to g 6V, or from single supplies ranging from a 3V to a 12V. In spite of their low supply current, the EL2270C and the EL2470C can output 55 mA while swinging to g 4V on g 5V supplies. The EL2170C can output 100 mA with similar output swings. These attributes make the EL2170C/EL2270C/EL2470C excellent choices for low power and/or low voltage cable-driver, HDSL, or RGB applications. # # # # # # # For applications where board space is extremely critical, the EL2170C is available in the tiny 5-Lead SOT23 package, which has a footprint 28% the size of an 8-Lead SOIC. The EL2170C/ EL2270C/EL2470C are each also available in industry standard pinouts in PDIP and SOIC packages. For Single and Dual applications with disable, consider the EL2176C (8-Pin Single) or EL2276C (14-Pin Dual). For higher speed applications where power is still a concern, consider the EL2180C/El2186C family which also comes in similar Single, Dual, Triple and Quad configurations. The EL2180C/EL2186C family provides a b 3 dB bandwidth of 250 MHz while consuming 3 mA of supply current per amplifier. Connection Diagrams EL2170C SO, P-DIP Applications Low power/battery applications HDSL amplifiers Video amplifiers Cable drivers RGB amplifiers Test equipment amplifiers Current to voltage converters EL2270C SO, P-DIP 2170 – 1 EL2170C SOT23-5 EL2470C SO, P-DIP Part No. Temp. Range Package Outline Ý MDP0031 EL2170CS b 40§ C to a 85§ C 8-Pin SOIC MDP0027 EL2170CW b 40§ C to a 85§ C 5-Pin SOT23* MDP0038 EL2270CN b 40§ C to a 85§ C 8-Pin PDIP MDP0031 EL2270CS b 40§ C to a 85§ C 8-Pin SOIC MDP0027 EL2470CN b 40§ C to a 85§ C 14-Pin PDIP MDP0031 EL2470CS b 40§ C to a 85§ C 14-Pin SOIC *See Ordering databook. Information 2170 – 46 Top View MDP0027 section of 2170 – 2 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. © 1995 Elantec, Inc. January 1996, Rev. B Ordering Information EL2170CN b 40§ C to a 85§ C 8-Pin PDIP EL2170C/EL2270C/EL2470C EL2170C/EL2270C/EL2470C EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers 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 Operating Ambient Temperature Range Operating Junction Temperature Plastic Packages Output Current (EL2170C) Output Current (EL2270C) Output Current (EL2470C) Storage Temperature Range a 12.6V VSb to VS a g 6V g 7.5 mA See Curves b 40§ C to a 85§ C 150§ C g 120 mA g 60 mA 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. Parameter Description Conditions VOS Input Offset Voltage TCVOS Average Input Offset Voltage Drift Measured from TMIN to TMAX dVOS VOS Matching EL2270C, EL2470C only a IIN a Input Current d a IIN a IIN Matching b IIN b Input Current dbIIN Min Typ Max Test Level Units 2.5 15 I mV V mV/§ C V mV I mA V nA 5 0.5 0.5 5 EL2270C, EL2470C only 20 I mA b IIN Matching EL2270C, EL2470C only 1.5 V mA CMRR Common Mode Rejection Ratio VCM e g 3.5V 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 is moved from g 4V to g 6V I dB b IPSR b Input Current Power Supply Rejection VS is moved from g 4V to g 6V I mA/V ROL Transimpedance VOUT e g 2.5V 150 I kX a RIN a Input Resistance VCM e g 3.5V 1 a CIN a Input Capacitance CMIR Common Mode Input Range 4 45 4 60 2 10 70 0.5 g 3.5 15 400 5 4 I MX 1.2 V pF g 4.0 I V TD is 3.8in DC Electrical Characteristics VS e g 5V, RL e 150X, TA e 25§ C unless otherwise specified EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers DC Electrical Characteristics Ð Contd. Parameter VO Description Output Voltage Swing Conditions VS e g 5 IS Supply Current g 4.0 I V 4.0 V V g 3.5 VS e a 5 Single-Supply, Low Output Current Units Typ VS e a 5 Single-Supply, High IO Test Level Min Max 0.3 V V EL2170C only 80 100 I mA EL2270C only, per Amplifier 50 55 I mA EL2470C only, per Amplifier 50 55 I mA I mA Test Level Units V MHz Per Amplifier 1 2 TD is 1.6in VS e g 5V, RL e 150X, TA e 25§ C unless otherwise specified AC Electrical Characteristics Parameter Description b 3 dB BW b 3 dB Bandwidth Conditions Min AV e a 1 Typ 70 b 3 dB BW b 3 dB Bandwidth AV e a 2 SR Slew Rate VOUT e g 2.5V, AV e a 2 tr, tf Rise and Fall Time tpd OS Max 60 V MHz 800 IV V/ms VOUT e g 500 mV 4.5 V ns Propagation Delay VOUT e g 500 mV 4.5 V ns Overshoot VOUT e g 500 mV 3.0 V % ts 0.1% Settling VOUT e g 2.5V, AV e b1 40 V ns dG Differential Gain AV e a 2, RL e 150X (Note 1) 0.15 V % dP Differential Phase AV e a 2, RL e 150X (Note 1) 0.15 V § dG Differential Gain AV e a 1, RL e 500X (Note 1) 0.02 V % 0.01 V § 85 V dB dP Differential Phase AV e a 1, RL e 500X (Note 1) CS Channel Separation EL2270C, EL2470C only, f e 5 MHz Note 1: DC offset from 0V to 0.714V, AC amplitude 286 mVP-P, f e 3.58 MHz. 3 400 TD is 2.6in VS e g 5V, RF e RG e 1 kX, RL e 150X, TA e 25§ C unless otherwise specified EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Test Circuit (per Amplifier) 2170 – 3 Simplified Schematic (per Amplifer) 2170 – 4 4 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Performance Curves Non-Inverting Frequency Response (Gain) Non-Inverting Frequency Response (Phase) 2170 – 5 Inverting Frequency Response (Gain) 2170 – 7 2170 – 6 Inverting Frequency Response (Phase) 2170 – 8 Transimpedance (ROL) Frequency Response for Various RF and RG Frequency Response for Various RL and CL 2170 – 9 PSRR and CMRR 2170 – 11 2170 – 12 5 2170 – 10 Frequency Response for Various CIN b 2170 – 13 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Performance Curves Ð Contd. Voltage and Current Noise vs Frequency 2nd and 3rd Harmonic Distortion vs Frequency 2170 – 14 2170 – 16 2170 – 15 b 3 dB Bandwith and Peaking b 3 dB Bandwith and Peaking vs Supply Voltage for Various Non-Inverting Gains vs Supply Voltage for Various Inverting Gains Output Voltage Swing vs Supply Voltage 2170 – 18 2170 – 17 Supply Current vs Supply Voltage Output Voltage vs Frequency Common-Mode Input Range vs Supply Voltage 2170 – 20 2170 – 21 6 2170 – 19 Slew Rate vs Supply Voltage 2170 – 22 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Performance Curves Ð Contd. Input Bias Current vs Die Temperature Short-Circuit Current vs Die Temperature 2170 – 23 2170 – 24 b 3 dB Bandwith and Peaking b 3 dB Bandwith and Peaking vs Die Temperature for Various Non-Inverting Gains vs Die Temperature for Various Inverting Gains 2170 – 26 Supply Current vs Die Temperature Transimpedance (ROL) vs Die Temperature 2170 – 25 Input Offset Voltage vs Die Temperature 2170 – 28 2170 – 27 Input Voltage Range vs Die Temperature 2170 – 29 Slew Rate vs Die Temperature 2170 – 30 7 2170 – 31 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Performance Curves Ð Contd. Differential Gain and Phase vs DC Input Voltage at 3.58 MHz/AV e a 2 Differential Gain and Phase vs DC Input Offset at 3.58 MHz/AV e a 1 2170 – 32 Settling Time vs Settling Accuracy 2170 – 33 Small-Signal Step Response 2170 – 34 Large-Signal Step Response 2170 – 35 2170 – 36 8-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 8-Lead SO Maximum Power Dissipation vs Ambient Temperature 2170 – 37 2170 – 38 8 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Performance Curves Ð Contd. 14-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 14-Lead SO Maximum Power Dissipation vs Ambient Temperature 2170 – 39 2170 – 40 5-Lead Plastic SOT23 Maximum Power Dissipation vs Ambient Temperature 2170 – 47 9 Channel Separation vs Frequency 2170 – 41 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Applications Information Power Supply Bypassing and Printed Circuit Board Layout Product Description 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. The EL2170C/EL2270C/EL2470C are currentfeedback operational amplifiers that offer a wide b 3 dB bandwidth of 70 MHz and a low supply current of 1 mA per amplifier. All of these products also feature high output current drive. The EL2170C can output 100 mA, while the EL2270C and the EL2470C can output 55 mA per amplifier. The EL2170C/EL2270C/EL2470C work with supply voltages ranging from a single 3V to g 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 EL2170C/EL2270C/EL2470C do not have the normal gain-bandwidth product associated with voltage-feedback operational amplifiers. This allows their 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 EL2170C/EL2270C/EL2470C 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. For applications where board space is extremely critical, the EL2170C is available in the tiny 5Lead SOT23 package, which has a footprint 28% the size of an 8-Lead SOIC. The EL2170C/ EL2270C/EL2470C are each also available in industry standard pinouts in PDIP and SOIC packages. 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. For Single and Dual applications with disable, consider the EL2176C (8-Pin Single) and EL2276C (14-Pin Dual). If higher speed is required, refer to the EL2180C/EL2186C family which provides Singles, Duals, Triples, and Quads with 250 MHz of bandwidth while consuming 3 mA of supply current per amplifier. 10 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Supply Voltage Range and SingleSupply Operation Applications Information Ð Contd. The experienced user with a large amount of PC board layout experience may find in rare cases that the EL2170C/EL2270C/EL2470C have less bandwidth 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 b . The EL2170C/EL2270C/EL2470C 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 EL2170C/ EL2270C/EL2470C will operate on dual supplies ranging from g 1.5V to g 6V. With a single-supply, the EL2170C/EL2270C/EL2470C will operate from a 3V to a 12V. 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 EL2170C/EL2270C/ EL2470C have an input voltage range that extends to within 1V of either supply. So, for example, on a single a 5V supply, the EL2170C/ EL2270C/EL2470C have an input range which spans from 1V to 4V. The output range of the EL2170C/EL2270C/EL2470C 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 EL2170C/EL2270C/EL2470C have been designed and specified at gains of a 1 and a 2 with RF e 1 kX. This value of feedback resistor gives 70 MHz of b 3 dB bandwidth at AV e a 1 with about 1.5 dB of peaking, and 60 MHz of b 3 dB bandwidth at AV e a 2 with about 0.5 dB of peaking. Since the EL2170C/EL2270C/EL2470C are current-feedback amplifiers, 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. Because the EL2170C/EL2270C/EL2470C are current-feedback amplifiers, their gain-bandwidth product is not a constant for different closed-loop gains. This feature actually allows the EL2170C/EL2270C/EL2470C to maintain about the same b 3 dB bandwidth, regardless of closed-loop gain. However, as closed-loop gain is increased, 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 1 kX and still retain stability, resulting in only a slight loss of bandwidth with increased closed-loop gain. 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 EL2170C/EL2270C/EL2470C, 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 more than the entire 1 mA supply current of each EL2170C/ EL2270C/EL2470C amplifier! Special circuitry has been incorporated in the EL2170C/ EL2270C/EL2470C to reduce the variation of output impedance with current output. This results in dG and dP specifications of 0.15% and 0.15§ while driving 150X at a gain of a 2. 11 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Applications Information Ð Contd. Current Limiting Video Performance has also been measured with a 500X load at a gain of a 1. Under these conditions, the EL2170C/EL2270C/EL2470C have dG and dP specifications of 0.01% and 0.02§ respectively while driving 500 X at AV e a 1. The EL2170C/EL2270C/EL2470C 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. Output Drive Capability Power Dissipation In spite of its low 1 mA of supply current, the EL2170C is capable of providing a minimum of g 80 mA of output current. Similarly, each amplifier of the EL2270C and the EL2470C is capable of providing a minimum of g 50 mA. These output drive levels are unprecedented in amplifiers running at these supply currents. With a minimum g 80 mA of output drive, the EL2170C is capable of driving 50X loads to g 4V, making it an excellent choice for driving isolation transformers in telecommunications applications. Similarly, the g 50 mA minimum output drive of each EL2270C and EL2470C amplifier allows swings of g 2.5V into 50X loads. With the high output drive capability of the EL2170C/EL2270C/EL2470C, 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 EL2170C/EL2270C/EL2470C to remain in the safe operating area. These parameters are calculated as follows:  TJMAX e TMAX a (iJA * n * PDMAX) where: TMAX iJA n 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 EL2170C/ EL2270C/EL2470C 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 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. e Maximum Ambient Temperature e Thermal Resistance of the Package e Number of Amplifiers in the Pack- age PDMAX e Maximum Power Dissipation of Each Amplifier in the Package. PDMAX for each amplifier can be calculated as follows: PDMAX e (2 * VS * ISMAX) a (VS b VOUTMAX) * (VOUTMAX/RL))  where: VS ISMAX e Supply Voltage e Maximum Supply Current of 1 Amplifier VOUTMAX e Max. Output Voltage of the Application e Load Resistance RL 12 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Application Circuits Inverting 200 mA Output Current Distribution Amplifier 2170 – 42 Fast-Settling Precision Amplifier 2170 – 43 13 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers Typical Application Circuits Ð Contd. Differential Line-Driver/Receiver 2170 – 44 14 EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers EL2170C/EL2270C/EL2470C Macromodel * Transimpedance Stage * g1 0 18 17 0 1.0 rol 18 0 400K cdp 18 0 1.9pF * * 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 0.4mA ios2 20 4 0.4mA * * Supply Current * ips 7 4 1nA * * Error Terms * ivos 0 23 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 0.316K r10 25 23 3.2K r11 26 23 3.2K * * Models * .model qn npn(is e 5e-15 bf e 200 tf e 0.01nS) .model qp pnp(is e 5e-15 bf e 200 tf e 0.01nS) .model dclamp d(is e 1e-30 ibv e 0.266 a bv e 1.3v n e 4) .ends 15 TD is 5.2in * Revision A, March 1995 * AC characteristics used Rf e Rg e 1KX, RL e 150X 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 EL2170/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 11 165 l1 11 12 25nH iinp 3 0 0.5uA iinm 2 0 4uA r12 3 0 4Meg * * 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 0.5uH c5 17 0 0.69pF r5 17 0 300 * EL2170C/EL2270C/EL2470C EL2170C/EL2270C/EL2470C 70 MHz/1 mA Current Mode Feedback Amplifiers EL2170C/EL2270C/EL2470C Macromodel Ð Contd. 2170 – 45 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. January 1996, Rev. B 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.