DATASHEET

EL2270
®
Data Sheet
July 13, 2004
70MHz/1mA Current Mode Feedback
Amplifiers
Features
The EL2270 is a dual current-feedback
operational amplifiers which achieves
a -3dB bandwidth of 70MHz at a gain
of +1 while consuming only 1mA of supply current per
amplifier. It will operate with dual supplies ranging from
±1.5V to ±6V, or from single supplies ranging from +3V to
+12V. In spite of its low supply current, the EL2270 can
output 55mA while swinging to ±4V on ±5V supplies. These
attributes make the EL2270 an excellent choice for low
power and/or low voltage cable-driver, HDSL, or RGB
applications.
• 1mA supply current (per amplifier)
For applications where board space is extremely critical. The
EL2270 is available in industry standard pinouts in SO
package.
For single and dual applications with disable, consider the
EL2176 (8-pin single) or EL2276 (14-pin dual). For higher
speed applications where power is still a concern, consider
the EL2180/EL2186 family which also comes in similar
single, dual, triple and quad configurations. The
EL2180/EL2186 family provides a -3dB bandwidth of
250MHz while consuming 3mA of supply current per
amplifier.
• Dual topologies
• 70MHz -3dB bandwidth
• Low cost
• Single- and dual-supply operation down to ±1.5V
• 0.15%/0.15° diff. gain/diff. phase into 150Ω
• 800V/µs slew rate
• Large output drive current - 55mA
• Also available with disable in single (EL2176) & dual
(EL2276)
• Higher speed EL2180/EL2186 family available
(3mA/250MHz) in single, dual, and quad
• Pb-free available
Applications
• Low power/battery applications
• HDSL amplifiers
• Video amplifiers
• Cable drivers
• RGB amplifiers
Ordering Information
PART
NUMBER
FN7053.1
• Test equipment amplifiers
PACKAGE
TAPE & REEL PKG. DWG. #
EL2270CS
8-Pin SO
-
MDP0027
EL2270CS-T7
8-Pin SO
7”
MDP0027
EL2270CS-T13
8-Pin SO
13”
MDP0027
EL2270CSZ
(See Note)
8-Pin SO
(Pb-free)
-
MDP0027
EL2270CSZ-T7
(See Note)
8-Pin SO
(Pb-free)
7”
MDP0027
EL2270CSZT13 (See Note)
8-Pin SO
(Pb-free)
13”
MDP0027
• Current to voltage converters
Pinout
EL2270
(8-PIN SO)
TOP VIEW
NOTE: Intersil Pb-free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which is compatible with both SnPb and
Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J Std-020B.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Copyright © 2002 Elantec Semiconductor, Inc. 2002-2004 Intersil Americas Inc. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
All other trademarks mentioned are the property of their respective owners.
EL2270
Absolute Maximum Ratings (TA = 25°C)
Operating Junction Temperature
Plastic Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
Output Current (EL2270) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°C
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 . . . . . . . . . .-40°C to +85°C
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
VS = ±5V, RL = 150Ω, TA = 25°C unless otherwise specified.
DESCRIPTION
VOS
Input Offset Voltage
TCVOS
Average Input Offset Voltage Drift
dVOS
CONDITIONS
MIN
TYP
MAX
UNIT
2.5
15
mV
Measured from TMIN to TMAX
5
µV/°C
VOS Matching
0.5
mV
+IIN
+Input Current
0.5
d+IIN
+IIN Matching
20
-IIN
-Input Current
4
d-IIN
-IIN Matching
1.5
µA
CMRR
Common Mode Rejection Ratio
VCM = ±3.5V
50
dB
-ICMR
-Input Current Common Mode
Rejection
VCM = ±3.5V
PSRR
Power Supply Rejection Ratio
VS is moved from ±4V to ±6V
-IPSR
-Input Current Power Supply
Rejection
VS is moved from ±4V to ±6V
ROL
Transimpedance
VOUT = ±2.5V
150
400
kΩ
+RIN
+Input Resistance
VCM = ±3.5V
1
4
MΩ
+CIN
+Input Capacitance
1.2
pF
CMIR
Common Mode Input Range
±3.5
±4.0
V
VO
Output Voltage Swing
±3.5
±4.0
V
VS = 5 single-supply, high
4.0
V
VS = 5 single-supply, low
0.3
V
55
mA
VS = ±5
IO
Output Current
Per amplifier
IS
Supply Current
Per amplifier
AC Electrical Specifications
PARAMETER
45
4
60
µA
nA
15
10
70
0.5
50
5
µA
µA/V
dB
5
µA/V
1
2
mA
TYP
MAX
UNIT
VS = ±5V, RF = RG = 1kΩ, RL = 150Ω, TA = 25°C unless otherwise specified
DESCRIPTION
CONDITIONS
MIN
-3dB BW
-3dB Bandwidth
AV = 1
70
MHz
-3dB BW
-3dB Bandwidth
AV = 2
60
MHz
SR
Slew Rate
VOUT = ±2.5V, AV = 2
800
V/µs
tR, tF
Rise and Fall Time
VOUT = ±500mV
4.5
ns
tPD
Propagation Delay
VOUT = ±500mV
4.5
ns
OS
Overshoot
VOUT = ±500mV
3.0
%
2
400
EL2270
AC Electrical Specifications
PARAMETER
VS = ±5V, RF = RG = 1kΩ, RL = 150Ω, TA = 25°C unless otherwise specified (Continued)
DESCRIPTION
CONDITIONS
tS
0.1% Settling
VOUT = ±2.5V, AV = -1
dG
Differential Gain
dP
MIN
TYP
MAX
UNIT
40
ns
AV = 2, RL = 150Ω (Note 1)
0.15
%
Differential Phase
AV = 2, RL = 150Ω (Note 1)
0.15
°
dG
Differential Gain
AV = 1, RL = 500Ω (Note 1)
0.02
%
dP
Differential Phase
AV = 1, RL = 500Ω (Note 1)
0.01
°
CS
Channel Separation
EL2270 only, f = 5MHz
85
dB
NOTE:
1. DC offset from 0V to 0.714V, AC amplitude 286mVP-P, f = 3.58MHz.
Test Circuit (per Amplifier)
Simplified Schematic (per Amplifier)
3
EL2270
Typical Performance Curves
Non-Inverting
Frequency Response (Gain)
Non-Inverting
Frequency Response (Phase)
Inverting Frequency
Response (Gain)
Inverting Frequency
Response (Phase)
Transimpedance (ROL)
4
PSRR and CMRR
Frequency Response for
Various RF and RG
Frequency Response for
Various RL and CL
Frequency Response
for Various CIN-
EL2270
Typical Performance Curves (Continued)
Voltage and Current
Noise vs Frequency
-3dB Bandwidth and Peaking
vs Supply Voltage for
Various Non-Inverting Gains
Supply Current vs
Supply Voltage
5
2nd and 3rd Harmonic
Distortion vs Frequency
-3dB Bandwidth and Peaking
vs Supply Voltage for
Various Inverting Gains
Common-Mode Input Range
vs Supply Voltage
FOutput Voltage
vs Frequency
Output Voltage Swing
vs Supply Voltage
Slew Rate vs
Supply Voltage
EL2270
Typical Performance Curves (Continued)
Input Bias Current vs
Die Temperature
-3dB Bandwidth and Peaking
vs Die Temperature for
Various Non-Inverting Gains
Supply Current vs
Die Temperature
6
Short-Circuit Current vs
Die Temperature
-3dB Bandwidth and Peaking
vs Die Temperature for
Various Inverting Gains
Input Voltage Range vs
Die Temperature
Transimpedance (ROL) vs
Die Temperature
Input Offset Voltage vs
Die Temperature
Slew Rate vs
Die Temperature
EL2270
Typical Performance Curves (Continued)
Differential Gain and
Phase vs DC Input Voltage
at 3.58MHz/AV = +2
Small-Signal Step Response
Differential Gain and
Phase vs DC Input Offset
at 3.58MHz/AV = +1
Large-Signal Step Response
2
1.8
1.8
1.6
1.6
1.4
Power Dissipation (W)
Power Dissipation (W)
Channel Separation
vs Frequency
Package Power Dissipation vs Ambient Temperature
JEDEC JESD51-3 Low Effective Thermal Conductivity Test
Board
Package Power Dissipation vs Ambient Temperature
JEDEC JESD51-7 High Effective Thermal Conductivity Test
Board
1.4
1.2
SO8
θJA=110°C/W
1.136W
1
Settling Time vs
Settling Accuracy
0.8
0.6
0.4
1.2
1
SO8
θJA=160°C/W
0.8
781mW
0.6
0.4
0.2
0.2
0
0
0
25
50
75 85 100
Ambient Temperature (°C)
7
125
150
0
25
50
75 85 100
Ambient Temperature (°C)
125
150
EL2270
Applications Information
Product Description
The EL2270 is a current-feedback operational amplifier that
offers a wide -3dB bandwidth of 70MHz and a low supply
current of 1mA per amplifier. This product also features high
output current drive. The EL2270 can output 55mA per
amplifier and works with supply voltages ranging from a
single 3V to ±6V, and is also capable of swinging to within 1V
of either supply on the input and the output. Because of its
current-feedback topology, the EL2270 does not have the
normal gain-bandwidth product associated with voltagefeedback operational amplifiers. This allows its -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 EL2270
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
EL2270 is available in industry standard pinouts in SO
package.
For single and dual applications with disable, consider the
EL2176 (8-pin single) and EL2276 (14-pin dual). If higher
speed is required, refer to the EL2180/EL2186 family which
provides singles, duals, triples, and quads with 250MHz of
bandwidth while consuming 3mA 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 4.7µF tantalum capacitor in parallel with a
0.1µF 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
8
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 EL2270 has
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. 0.5pF) will
increase bandwidth as desired. Please see the curves for
Frequency Response for Various RF and RG, and Frequency
Response for Various CIN-.
Feedback Resistor Values
The EL2270 has been designed and specified at gains of +1
and +2 with RF = 1kΩ. 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 EL2270 is a currentfeedback 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 EL2270 is a current-feedback amplifier, its gainbandwidth product is not a constant for different closed-loop
gains. This feature actually allows the EL2270 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 1kΩ and still retain stability, resulting in only a slight
loss of bandwidth with increased closed-loop gain.
Supply Voltage Range and Single-Supply
Operation
The EL2270 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 EL2270 will
operate on dual supplies ranging from ±1.5V to ±6V. With a
single-supply, the EL2270 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
EL2270 has an input voltage range that extends to within 1V
of either supply. So, for example, on a single +5V supply, the
EL2270 has an input range which spans from 1V to 4V. The
output range of the EL2270 is also quite large, extending to
within 1V of the supply rail. On a ±5V supply, the output is
EL2270
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.
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 150Ω, because of the change in output current with DC
level. Until the EL2270, 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 1mA supply
current of each EL2270 amplifier! Special circuitry has been
incorporated in the EL2270 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 150Ω at a
gain of +2.
Video performance has also been measured with a 500Ω
load at a gain of +1. Under these conditions, the EL2270 has
dG and dP specifications of 0.01% and 0.02° respectively
while driving 500Ω at AV = +1.
Output Drive Capability
In spite of its low 1mA of supply current, each amplifier of the
EL2270 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 ±50mA minimum output drive of each EL2270
amplifier allows swings of ±2.5V into 50Ω loads.
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 EL2270 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 5Ω and
50Ω) 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 EL2270 has 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 EL2270, 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 25Ω, 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 EL2270 to remain in the safe operating area.
These parameters are calculated as follows [1]:
T JMAX = T MAX + ( Θ JA × n × PD MAX )
where:
TMAX = Maximum ambient temperature
θJA = 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 [2]:
V OUTMAX
PD MAX = ( 2 × V S × I SMAX ) + ( V S - V OUTMAX ) × ---------------------------R
L
where:
VS = Supply voltage
ISMAX = Maximum supply current of 1 amplifier
VOUTMAX = Maximum output voltage of the application
RL = Load resistance
9
EL2270
Typical Application Circuits
INVERTING 200mA OUTPUT CURRENT
DISTRIBUTION AMPLIFIER
FAST-SETTLING PRECISION AMPLIFIER
DIFFERENTIAL LINE-DRIVER/RECEIVER
10
EL2270
EL2270 Macromodel
* Revision A, March 1995
* AC characteristics used Rf=Rg=1KΩ,RL=150Ω
* Connections:
+input
*
|
-input
*
|
| +Vsupply
*
|
|
|
-Vsupply
*
|
|
|
| output
*
|
|
|
|
|
.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
*
* 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
11
EL2270
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
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Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
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12
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