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EL2176, EL2276
Data Sheet December 1995, Rev. B FN7054
70MHz/1mA Current Mode Feedback Amp w/Disable
The EL2176/EL2276 are single/dual current-feedback operational amplifiers which achieve a -3dB bandwidth of 70MHz at a gain of +1 while consuming only 1mA 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 EL2176/EL2276 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 EL2276 can output 55mA while swinging to 4V on 5V supplies. The EL2176 can output 100mA with similar output swings. These attributes make the EL2176/EL2276 excellent choices for low power and/or low voltage cabledriver, HDSL, or RGB applications. For Single, Dual and Quad applications without disable, consider the EL2170 (8-Pin Single), EL2270 (8-Pin Dual) or EL2470 (14-Pin Quad). For higher bandwidth applications where low power is still a concern, consider the EL2180/EL2186 family which also comes in similar Single, Dual and Quad configurations. The EL2180/EL2186 family provides a -3dB bandwidth of 250MHz while consuming 3mA of supply current per amplifier.
Features
* Single (EL2176) and dual (EL2276) topologies * 1mA supply current (per amplifier) * 70MHz -3dB bandwidth * Low cost * Fast disable * Powers down to 0mA * Single- and dual-supply operation down to 1.5V * 0.15%/0.15 diff. gain/diff. phase into 150 * 800V/s slew rate * Large output drive current: 100mA (EL2176) 55mA (EL2276) * Also available without disable in single (EL2170), dual (EL2270) and quad (EL2470) * Higher speed EL2180/EL2186 family also available (3mA/ 250MHz) in single, dual and quad
Applications
* Low power/battery applications * HDSL amplifiers * Video amplifiers
Ordering Information
PART NUMBER EL2176CN EL2176CS EL2276CN EL2276CS TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C PACKAGE 8-Pin PDIP 8-Pin SOIC 14-Pin PDIP 14-Pin SOIC PKG. NO. MDP0031 MDP0027 MDP0031 MDP0027
* Cable drivers * RGB amplifiers * Test equipment amplifiers * Current to voltage converters
Pinouts
EL2176 (8-PIN SO, PDIP) TOP VIEW EL2276 (14-PIN SO, PDIP) TOP VIEW
Manufactured under U.S. Patent No. 5,352,989, 5,351,012, 5,418,495
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright (c) Intersil Americas Inc. 2003. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc. All other trademarks mentioned are the property of their respective owners.
EL2176, EL2276
Absolute Maximum Ratings (TA = 25C)
Voltage between VS+ and VS- . . . . . . . . . . . . . . . . . . . . . . . . +12.6V Common-Mode Input Voltage . . . . . . . . . . . . . . . . . . . . . VS- to VS+ Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6V Current into +IN or -IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.5mA Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . See Curves Operating Ambient Temperature Range . . . . . . . . . .-40C to +85C Operating Junction Temperature Plastic Packages . . . . . . . . . 150C Output Current (EL2176) . . . . . . . . . . . . . . . . . . . . . . . . . . . 120mA Output Current (EL2276) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60mA Storage Temperature Range . . . . . . . . . . . . . . . . . .-65C to +150C
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical 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 Specifications
PARAMETER VOS TCVOS dVOS +IIN d+IIN -IIN d-IIN CMRR -ICMR PSRR -IPSR ROL +RIN +CIN CMIR VO
VS = 5V, RL = 150, ENABLE = 0V, TA = 25C unless otherwise specified. CONDITIONS MIN TYP 2.5 Measured from TMIN to TMAX EL2276 only 5 0.5 0.5 EL2276 only 20 4 EL2276 only VCM = 3.5 V VCM = 3.5V VS is moved from 4V to 6V VS is moved from 4V to 6V VOUT = 2.5V VCM = 3.5V 150 1 60 45 1.5 50 4 70 0.5 400 4 1.2 3.5 VS = 5 VS = +5 Single-Supply, High VS = +5 Single-Supply, Low 3.5 4.0 4.0 4.0 0.3 80 50 100 55 1 0 4.4 45 85 -0.04 -53 4.5 2.0 2 20 5 10 15 5 MAX 15 UNITS mV V/C mV A nA A A dB A/V dB A/V k M pF V V V V mA mA mA A pF k A A V V
DESCRIPTION Input Offset Voltage Average Input Offset Voltage Drift VOS Matching + Input Current +IIN Matching - Input Current -IIN Matching Common Mode Rejection Ratio - Input Current Common Mode Rejection Power Supply Rejection Ratio - Input Current Power Supply Rejection Transimpedance + Input Resistance + Input Capacitance Common Mode Input Range Output Voltage Swing
IO
Output Current
EL2176 only EL2276 only, per Amplifier
IS IS(DIS) COUT(DIS) REN IIH IIL VDIS VEN
Supply Current Supply Current (Disabled) Output Capacitance (Disabled) Enable Pin Input Resistance Logic "1" Input Current Logic "0" Input Current Minimum Voltage at ENABLE to Disable Maximum Voltage at ENABLE to Enable
ENABLE = 2.0V, per Amplifier ENABLE = 4.5V ENABLE = 4.5V Measured at ENABLE = 2.0V, 4.5V Measured at ENABLE, ENABLE = 4.5V Measured at ENABLE, ENABLE = 0V
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EL2176, EL2276
AC Electrical Specifications
PARAMETER -3dB BW -3dB BW SR tR, tF tPD OS ts dG dP dG dP tON tOFF CS NOTES: 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. -3dB Bandwidth -3dB Bandwidth Slew Rate Rise and Fall Time Propagation Delay Overshoot 0.1% Settling Differential Gain Differential Phase Differential Gain Differential Phase Turn-On Time Turn-Off Time Channel Separation VS = 5V, RF = RG = 1.0k, RL = 150, ENABLE = 0V, TA = 25C unless otherwise specified. CONDITIONS AV = +1 AV = +2 VOUT = 2.5V, AV = +2 VOUT = 500mV VOUT = 50mV VOUT = 500mV VOUT = 2.5V, AV = -1 AV = +2, RL = 150 (Note 1) AV = +2, RL = 150 (Note 1) AV = +1, RL = 500 (Note 1) AV = +1, RL = 500 (Note 1) AV = +2, VIN = +1V, RL = 150 (Note 2) AV = +2, VIN = +1V, RL = 150 (Note 2) EL2276 only, f = 5MHz 400 MIN TYP 70 60 800 4.5 4.5 3.0 40 0.15 0.15 0.02 0.01 40 1500 85 100 2000 MAX UNITS MHz MHz V/s ns ns % ns % % ns ns dB
DESCRIPTION
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EL2176, EL2276 Test Circuit (per Amplifier)
Simplified Schematic (per Amplifier)
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EL2176, EL2276 Typical Performance Curves
Non-Inverting Frequency Response (Gain) Non-Inverting Frequency Response (Phase) Frequency Response for Various RF and RG
Inverting Frequency Response (Gain)
Inverting Frequency Response (Phase)
Frequency Response for Various RL and CL
Transimpedance (ROL)
PSRR and CMRR
Frequency Response for Various CIN-
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EL2176, EL2276 Typical Performance Curves (Continued)
Voltage and Current Noise vs Frequency 2nd and 3rd Harmonic Distortion vs Frequency Output Voltage vs Frequency
-3dB Bandwidth and Peaking vs Supply Voltage for Various Non-Inverting Gains
-3dB Bandwidth and Peaking vs Supply Voltage for Various Inverting Gains
Output Voltage Swing vs Supply Voltage
Supply Current vs Supply Voltage
Common-Mode Input Range vs Supply Voltage
Slew Rate vs Supply Voltage
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EL2176, EL2276 Typical Performance Curves (Continued)
Input Bias Current vs Die Temperature Short-Circuit Current vs Die Temperature Transimpedance (ROL) vs Die Temperature
-3dB Bandwidth and Peaking vs Die Temperature for Various Non-Inverting Gains
-3dB Bandwidth and Peaking vs Die Temperature for Various Inverting Gains
Input Offset Voltage vs Die Temperature
Supply Current vs Die Temperature
Input Voltage Range vs Die Temperature
Slew Rate vs Die Temperature
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EL2176, EL2276 Typical Performance Curves (Continued)
Differential Gain and Phase vs DC Input Voltage at 3.58MHz/AV = +2 Differential Gain and Phase vs DC Input Offset at 3.58MHz/AV = +1 Settling Time vs Settling Accuracy
Small-Signal Step Response
Large-Signal Step Response
8-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature
8-Pin SO Maximum Power Dissipation vs Ambient Temperature
14-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature
14-Pin SO Maximum Power Dissipation vs Ambient Temperature
Channel Separation vs Frequency (EL2276)
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EL2176, EL2276 Applications Information
Product Description
The EL2176/EL2276 are current-feedback operational amplifiers that offer a wide -3dB bandwidth of 70MHz, a low supply current of 1mA per amplifier and the ability to disable to 0mA. Both products also feature high output current drive. The EL2176 can output 100mA, while the EL2276 can output 55mA per amplifier. The EL2176/EL2276 work with supply voltages ranging from a single 3V to 6V, and they are also capable of swinging to with in 1V of either supply on the input and the output. Because of their current-feedback topology, the EL2176/EL2276 do not have the normal gainbandwidth 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 EL2176/EL2276 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 EL2170 (8-Pin Single), EL2270 (8-Pin Dual) and EL2470 (14-Pin Quad). If more AC performance is required, refer to the EL2180/EL2186 family which provides Singles, Duals, and Quads with 250MHz of bandwidth while consuming 3mA of supply current per amplifier.
Disable/Power-Down
The EL2176/EL2276 amplifiers can be disabled, placing their output in a high-impedance state. When disabled, each amplifier's supply current is reduced to 0mA. Each EL2176/EL2276 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 EL2176/EL2276 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 EL2176/EL2276 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 EL2176 at 5V, if ENABLE is tied to -5V (rather than ground) the supply current will increase about 15% to 1.15mA.
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 EL2176/EL2276 have been specially designed to reduce power dissipation in the feedback network by using large 1.0k 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 EL2176/EL2276 remain very stable. For less experienced users, this feature makes the EL2176/EL2276 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 EL2176/EL2276 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 EL2176/EL2276. 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
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 4.7F tantalum capacitor in parallel with a 0.1F 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.
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EL2176, EL2276
Response for Various RF and RG, and Frequency Response for Various CIN-. output transistors (to reduce variations in output impedance). These currents were typically in excess of the entire 1mA supply current of each EL2176/EL2276 amplifier! Special circuitry has been incorporated in the EL2176/EL2276 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 150 at a gain of +2. Video Performance has also been measured with a 500 load at a gain of +1. Under these conditions, the EL2176/EL2276 have dG and dP specifications of 0.01% and 0.02 respectively while driving 500 at AV = +1.
Feedback Resistor Values
The EL2176/EL2276 have been designed and specified at gains of +1 and +2 with RF = 1.0k. This value of feedback resistor gives 70MHz of -3dB bandwidth at AV = +1 with about 1.5dB of peaking, and 60MHz of -3dB bandwidth at AV = +2 with about 0.5dB of peaking. Since the EL2176/EL2276 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 EL2176 is a current-feedback amplifier, the gain-bandwidth product is not a constant for different closedloop gains. This feature actually allows the EL2176/EL2276 to maintain about the same -3dB 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 1.0k and still retain stability, resulting in only a slight loss of bandwidth with increased closed-loop gain.
Output Drive Capability
In spite of its low 1mA of supply current, the EL2176 is capable of providing a minimum of 80mA of output current. Similarly, each amplifier of the EL2276 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 EL2176 is capable of driving 50 loads to 4V, making it an excellent choice for driving isolation transformers in telecommunications applications. Similarly, the 50mA minimum output drive of each EL2276 amplifier allows swings of 2.5V into 50 loads.
Supply Voltage Range and Single-Supply Operation
The EL2176/EL2276 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 EL2176/EL2276 will operate on dual supplies ranging from 1.5V to 6V. With a single-supply, the EL2176 will operate from +3V to +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 EL2176/EL2276 have an input voltage range that extends to within 1V of either supply. So, for example, on a single +5V supply, the EL2176/EL2276 have an input range which spans from 1V to 4V. The output range of the EL2176/EL2276 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.
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 EL2176/EL2276 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 5 and 50) 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 EL2176/EL2276 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.
Power Dissipation
With the high output drive capability of the EL2176/EL2276, it is possible to exceed the 150C Absolute Maximum junction temperature under certain very high load current conditions. Generally speaking, when RL falls below about 25, it is important to calculate the maximum junction temperatu re (TJmax) for the application to determine if power-supply voltages, load conditions, or package type need to be modified for the EL2176/EL2276 to remain in the
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 150, because of the change in output current with DC level. Until the EL2176/EL2276, good Differential Gain could only be achieved by running high idle currents through the
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EL2176, EL2276
safe operating area. These parameters are calculated as follows: TJMAX = TMAX + (JA * n * PDMAX) [1] where: TMAX=Maximum Ambient Temperature JA =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: PDMAX = (2 * VS * ISMAX) + (VS - VOUTMAX) * (VOUTMAX/RL)) [2] where: VS=Supply Voltage ISMAX=Maximum Supply Current of 1 Amplifier VOUTMAX=Max. Output Voltage of the Application RL=Load Resistance
Typical Application Circuits
LOW POWER MULTIPLEXER WITH SINGLE-ENDED TTL INPUT
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EL2176, EL2276 Typical Application Circuits
(Continued)
INVERTING 200mA OUTPUT CURRENT DISTRIBUTION AMPLIFIER
FAST-SETTLING PRECISION AMPLIFIER
DIFFERENTIAL LINE-DRIVER/RECEIVER
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EL2176, EL2276 EL2176/EL2276 Macromodel
* Revision A, March 1995 * AC characteristics used Rf=Rg=1K,RL=150 * Connections: +input * | -input * | | +Vsupply * | | | -Vsupply * | | | | output * ||||| .subckt EL2176/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 * * 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
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EL2176, EL2276
vxx 23 0 0V e4 24 0 3 0 1.0 e5 25 0 7 0 1.0 e6 26 0 4 0 -1.0 r9 24 23 0.316K 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=1.3v n=4) .ends
EL2176/EL2276 Macromodel (Continued)
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