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EL2386C
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Features
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 g1 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
General Description
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 g1 5V to g6V 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 g4V on g5V 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
Low power battery applications HDSL amplifiers Video amplifiers Cable drivers RGB amplifiers Test equipment amplifiers Current to voltage converters Multiplexing Video broadcast equipment
Ordering Information
Part No Temp Range Package Outline
2386-1
June 1996 Rev A
EL2386CN b 40 C to a 85 C 16-Pin PDIP MDP0031 EL2386CS b 40 C to a 85 C 16-Pin SOIC MDP0027
Top View
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
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
g6V g7 5 mA See Curves
Operating Ambient Temperature Range Operating Junction Temperature Output Current Storage Temperature Range
b 40 C to a 85 C
150 C
g60 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 g5V RL e 150X ENABLE e 0V TA e 25 C unless otherwise specified Parameter VOS TCVOS dVOS
a IIN
Description Input Offset Voltage Average Input Offset Voltage Drift VOS Matching
a Input Current a IIN Matching b Input Current b IIN Matching
Conditions
Min
Typ 25
Max 15
Test Level I V V
Units mV mV C mV mA nA mA mA dB mA V dB mA V kX MX pF V V TD is 3 9in V V mA
Measured from TMIN to TMAX
5 05 15 20 16 2 40 15
I V I V I
d a IIN
b IIN
dbIIN CMRR
b ICMR
Common Mode Rejection Ratio
b Input Current Common Mode Rejection
VCM e g3 5V VCM e g3 5V VS e g4V to g6V VS e g4V to g6V VOUT e g2 5V VCM e g3 5V
45
50 5 30
I I
PSRR
b IPSR
Power Supply Rejection Ratio
b Input Current Power Supply Rejection
60
70 1 15
I I I V I I V V I
ROL
a RIN a CIN
Transimpedance
a Input Resistance a Input Capacitance
120 05
300 2 12
CMIR VO
Common Mode Input Range Output Voltage Swing VS e g5V VS e a 5V Single-Supply High VS e a 5V Single-Supply Low
g3 5 g3 5
g4 0 g4 0
40 03 50 55
IO
Output Current
2
EL2386C
250 MHz Triple Current Feedback Amp w Disable
DC Electrical Characteristics
VS e g5V RL e 150 X ENABLE e 0V TA e 25 C unless otherwise specified Parameter IS IS(DIS) COUT(DIS) RIN-EN IIH-EN IIL-EN VDIS VEN Description Supply Current Supply Current Enabled (per amplifier) Disabled (per amplifier) Disabled Conditions ENABLE e 2 0V ENABLE e 4 5V ENABLE e 4 5V ENABLE e 2 0V to 4 5V ENABLE e 4 5V ENABLE e 0V 45 20 45
Contd
Min Typ 3 0 44 85
b 0 04 b 53
Max 6 50
Test Level I I V I V V I I
Units mA mA pF kX mA TD is 1 8in TD is 3 1in mA V V
Output Capacitance
ENABLE Pin Input Resistance ENABLE Pin Input Current ENABLE Pin Input Current High Low
Minimum Voltage at ENABLE to Disable Maximum Voltage at ENABLE to Enable
AC Electrical Characteristics
VS e g5V RF e RG e 750 X RL e 150X ENABLE e 0V TA e 25 C unless otherwise specified Parameter BW Description
b 3 dB Bandwidth
Conditions AV e a 1 AV e a 2
Min
Typ 250 180 50
Max
Test Level V V V IV V V V V V V V V
Units MHz MHz MHz V ms ns ns % ns %
BW SR tR tF tPD OS tS dG dP dG dP tON tOFF CS
g 0 1 dB Bandwidth
AV e a 2 VOUT e g2 5V Measured at g1 25V VOUT e g500 mV VOUT e g500 mV VOUT e g500 mV VOUT e g2 5V AV e b1 AV e a 2 RL e 150X AV e a 2 RL e 150X AV e a 1 RL e 500X AV e a 1 RL e 500X AV e a 2 VIN e a 1V RL e 150X AV e a 2 VIN e a 1V RL e 150X f e 5 MHz 600
Slew Rate Rise and Fall Time Propagation Delay Overshoot 0 1% Settling Differential Gain (Note 1) Differential Phase (Note 1) Differential Gain (Note 1) Differential Phase (Note 1) Turn-On Time (Note 2) Turn-Off Time (Note 2) Channel Separation
1200 15 15 30 15 0 05 0 05 0 01 0 01 40 800 85 100 2000
%
I I V
ns ns dB
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
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
Non-Inverting Frequency Response (Gain)
Contd
Non-Inverting Frequency Response (Phase) Frequency Response for Various RF and RG
2386-4
2386-5
2386-6
Inverting Frequency Response (Gain)
Inverting Frequency Response (Phase)
Frequency Response for Various RL and CL
2386-7
2386-8
2386-9
Transimpedance (ROL) vs Frequency
PSRR and CMRR vs Frequency
Frequency Response for Various CIN b
2386-10 2386-11 2386-12
5
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Typical Performance Curves
Voltage and Current Noise vs Frequency
Contd
2nd and 3rd Harmonic Distortion vs Frequency Output Voltage Swing vs Frequency
2386 - 13
2386 - 14
2386 - 15
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
Output Voltage Swing vs Supply Voltage
2386 - 16
2386 - 17
2386 - 18
Supply Current vs Supply Voltage
Common-Mode Input Range vs Supply Voltage
Slew Rate vs Supply Voltage
2386 - 19
2386 - 20
2386 - 21
6
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Typical Performance Curves
Input Bias Current vs Die Temperature
Contd
Short-Circuit Current vs Die Temperature Transimpedance (ROL) vs Die Temperature
2386-22
2386-23
2386-24
b 3 dB Bandwidth and Peaking vs Die Temperature for Various Non-Inverting Gains
b 3 dB Bandwidth vs Die Temperature for Various Inverting Gains
Input Offset Voltage vs Die Temperature
2386-25 2386-27 2386-26
Supply Current vs Die Temperature
Input Voltage Range vs Die Temperature
Slew Rate vs Die Temperature
2386-28
2386-29
2386-30
7
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Typical Performance Curves
Differential Gain and Phase vs DC Input Voltage at 3 58 MHz
Contd
Settling Time vs Settling Accuracy
Differential Gain and Phase vs DC Input Voltage at 3 58 MHz
2386-31
2386-32 2386-33
Small-Signal Step Response
Large-Signal Step Response
2386-34
2386-35
16-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature
16-Lead SO Maximum Power Dissipation vs Ambient Temperature
Channel to Channel Isolation vs Frequency
2386-36
2386-37 2386-38
8
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Applications Information
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 g6V 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 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 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 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 g5V 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 When enabled supply current does vary somewhat with the voltage applied at ENABLE For example with the supply voltages of the EL2186C at g5V if ENABLE is tied to b 5V (rather than ground) the supply current will increase about 15% to 3 45 mA
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-
9
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Applications Information
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 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-
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 g1 5V to g6V With a single-supply the EL2386C 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 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 g5V 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 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-
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-
10
EL2386C
250 MHz Triple Current Feedback Amp w Disable
Applications Information
Contd 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
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 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 g60 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 g50 mA of output current This output drive level is unprecedented in amplifiers running at these supply currents With a minimum g50 mA of output drive the EL2386C is capable of driving 50X loads to g2 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
Contd These parameters are calculated as follows TJMAX e TMAX a (iJA n PDMAX) 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
2386-40
1
Figure 2
PDMAX for each amplifier can be calculated as follows PDMAX e (2 VS ISMAX) a (VS -VOUTMAX) (VOUTMAX RL) 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 2
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
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
EL2386C
250 MHz Triple Current Feedback Amp w Disable
EL2386C Macromodel
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 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 TD is 5 1in 4 8in TD is
TAB WIDE
l
l
l
l
l
subckt EL2386 EL 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
3
2
7
4
6
e2 30 0 14 0 0 00166666666 l3 30 17 150nH c5 17 0 0 8pF r5 17 0 165
13
EL2386C
250 MHz Triple Current Feedback Amp w Disable
EL2386C Macromodel
Contd
2386-41
14
BLANK
15
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
WARNING
Life Support Policy
June 1996 Rev A
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
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
Printed in U S A

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