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EL2170C EL2270C EL2470C
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Features
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 g1 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
General Description
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 g1 5V to g6V 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 g4V on g5V 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 EL2270C SO P-DIP
Applications
Low power battery applications HDSL amplifiers Video amplifiers Cable drivers RGB amplifiers Test equipment amplifiers Current to voltage converters
2170 - 1
EL2170C SOT23-5
EL2470C SO P-DIP
January 1996 Rev B
Ordering Information
Part No Temp Range Package Outline MDP0031 MDP0027 MDP0038 MDP0031 MDP0027
2170 - 46
EL2170CN b 40 C to a 85 C 8-Pin PDIP EL2170CS b 40 C to a 85 C 8-Pin SOIC EL2170CW b 40 C to a 85 C 5-Pin SOT23 EL2270CN b 40 C to a 85 C 8-Pin PDIP EL2270CS b 40 C to a 85 C 8-Pin SOIC
EL2470CN b 40 C to a 85 C 14-Pin PDIP MDP0031 EL2470CS b 40 C to a 85 C 14-Pin SOIC MDP0027
Top View
See Ordering databook
Information
section
of
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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
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
a 12 6V VSb to VS a
g6V g7 5 mA See Curves b 40 C to a 85 C
Operating Junction Temperature Plastic Packages Output Current (EL2170C) Output Current (EL2270C) Output Current (EL2470C) Storage Temperature Range
150 C
g120 mA g60 mA 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
Parameter VOS TCVOS dVOS
a IIN
RL e 150X TA e 25 C unless otherwise specified Min Typ 25 Max 15 Test Level I V V 5 I V 15 I V I 10 I I 5 I I I V I Units mV mV C mV mA nA mA mA dB mA V dB mA V kX TD is 3 8in MX pF V
Description Input Offset Voltage Average Input Offset Voltage Drift VOS Matching
a Input Current a IIN Matching b Input Current b IIN Matching
Conditions
Measured from TMIN to TMAX EL2270C EL2470C only
5 05 05
d a IIN
b IIN
EL2270C EL2470C only
20 4
dbIIN CMRR
b ICMR
EL2270C EL2470C only VCM e g3 5V VCM e g3 5V VS is moved from g4V to g6V VS is moved from g4V to g6V VOUT e g2 5V VCM e g3 5V 150 1 60 45
15 50 4 70 05 400 4 12
g3 5 g4 0
Common Mode Rejection Ratio
b Input Current Common Mode Rejection
PSRR
b IPSR
Power Supply Rejection Ratio
b Input Current Power Supply Rejection
ROL
a RIN a CIN
Transimpedance
a Input Resistance a Input Capacitance
CMIR
Common Mode Input Range
2
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
DC Electrical Characteristics
Parameter VO Description Output Voltage Swing
Contd
Conditions Min
g3 5
VS e g5V RL e 150X TA e 25 C unless otherwise specified Typ
g4 0
Max
Test Level I V V I I I
Units V V V mA TD is 1 6in TD is 2 6in mA mA mA
VS e g5 VS e a 5 Single-Supply High VS e a 5 Single-Supply Low
40 03 80 50 50 100 55 55 1 2
IO
Output Current
EL2170C only EL2270C only per Amplifier EL2470C only per Amplifier
IS
Supply Current
Per Amplifier
I
AC Electrical Characteristics
VS e g5V RF e RG e 1 kX RL e 150X TA e 25 C unless otherwise specified Parameter
b 3 dB BW b 3 dB BW
Description
b 3 dB Bandwidth b 3 dB Bandwidth
Conditions AV e a 1 AV e a 2 VOUT e g2 5V AV e a 2 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 (Note 1) AV e a 2 RL e 150X (Note 1) AV e a 1 RL e 500X (Note 1) AV e a 1 RL e 500X (Note 1) EL2270C EL2470C only f e 5 MHz
Min
Typ 70 60
Max
Test Level V V IV V V V V V V V V V
Units MHz MHz V ms ns ns % ns %
SR tr tf tpd OS ts dG dP dG dP CS
Slew Rate Rise and Fall Time Propagation Delay Overshoot 0 1% Settling Differential Gain Differential Phase Differential Gain Differential Phase Channel Separation
400
800 45 45 30 40 0 15 0 15 0 02 0 01 85
%
dB
Note 1 DC offset from 0V to 0 714V AC amplitude 286 mVP-P f e 3 58 MHz
3
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) Frequency Response for Various RF and RG
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Inverting Frequency Response (Gain)
Inverting Frequency Response (Phase)
Frequency Response for Various RL and CL
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Transimpedance (ROL)
PSRR and CMRR
Frequency Response for Various CIN b
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5
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Typical Performance Curves
Voltage and Current Noise vs Frequency
Contd
2nd and 3rd Harmonic Distortion vs Frequency Output Voltage vs Frequency
2170 - 14
2170 - 15
2170 - 16
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
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Supply Current vs Supply Voltage
Common-Mode Input Range vs Supply Voltage
Slew Rate vs Supply Voltage
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6
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Typical Performance Curves
Input Bias Current vs Die Temperature
Contd
Short-Circuit Current vs Die Temperature Transimpedance (ROL) vs Die Temperature
2170 - 23
2170 - 24
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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
Input Offset Voltage vs Die Temperature
2170 - 26
2170 - 27
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Supply Current vs Die Temperature
Input Voltage Range vs Die Temperature
Slew Rate vs Die Temperature
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7
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Typical Performance Curves
Differential Gain and Phase vs DC Input Voltage at 3 58 MHz AV e a 2
Contd
Differential Gain and Phase vs DC Input Offset at 3 58 MHz AV e a 1 Settling Time vs Settling Accuracy
2170 - 32
2170 - 33
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Small-Signal Step Response
Large-Signal Step Response
2170 - 35
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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
14-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature
Contd
14-Lead SO Maximum Power Dissipation vs Ambient Temperature Channel Separation vs Frequency
2170 - 39
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5-Lead Plastic SOT23 Maximum Power Dissipation vs Ambient Temperature
2170 - 47
9
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Applications Information
Product Description
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 g6V 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 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 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
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 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
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
10
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
Applications Information
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
Supply Voltage Range and SingleSupply Operation
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 g1 5V to g6V 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 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 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
Contd
Current Limiting
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
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
Output Drive Capability
In spite of its low 1 mA of supply current the EL2170C is capable of providing a minimum of g80 mA of output current Similarly each amplifier of the EL2270C and the EL2470C is capable of providing a minimum of g50 mA These output drive levels are unprecedented in amplifiers running at these supply currents With a minimum g80 mA of output drive the EL2170C is capable of driving 50X loads to g4V making it an excellent choice for driving isolation transformers in telecommunications applications Similarly the g50 mA minimum output drive of each EL2270C and EL2470C amplifier allows swings of g2 5V into 50X loads
Power Dissipation
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) 1 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)) 2 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
Contd
Differential Line-Driver Receiver
2170 - 44
14
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
EL2170C EL2270C EL2470C Macromodel
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 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
l l l
subckt EL2170 el 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 3
l l l
2
l l l
7
b Vsupply
l l
4
output
l
6
15
TD is 5 2in
EL2170C EL2270C EL2470C
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
EL2170C EL2270C EL2470C Macromodel
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
WARNING
Life Support Policy
January 1996 Rev B
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
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