Intersil EL2470CS-T13 70mhz/1ma current mode feedback amplifier Datasheet

EL2170, EL2270, EL2470
®
Data Sheet
70MHz/1mA Current Mode Feedback
Amplifiers
The EL2170, EL2270, and EL2470 are
single/dual/quad 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. In spite of their low
supply current, the EL2270 and the EL2470 can output
55mA while swinging to ±4V on ±5V supplies. The EL2170
can output 100mA with similar output swings. These
attributes make the EL2170, EL2270, and EL2470 excellent
choices for low power and/or low voltage cable-driver, HDSL,
or RGB applications.
For applications where board space is extremely critical, the
EL2170 is available in the tiny 5-pin SOT-23 package, which
has a footprint 28% the size of an 8-pin SO. The EL2170,
EL2270, and EL2470 are each also available in industry
standard pinouts in PDIP and SO packages.
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.
November 13, 2002
FN7053
Features
• Single (EL2170), dual (EL2270) & quad (EL2470)
topologies
• 1mA supply current (per amplifier)
• 70MHz -3dB bandwidth
• Tiny SOT23-5 package (EL2170)
• 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 - 100mA (EL2170), 55mA
(EL2270), 55mA (EL2470)
• Also available with disable in single (EL2176) & dual
(EL2276)
• Higher speed EL2180/EL2186 family available
(3mA/250MHz) in single, dual, and quad
Applications
• Low power/battery applications
• HDSL amplifiers
• Video amplifiers
• Cable drivers
• RGB amplifiers
• Test equipment amplifiers
• Current to voltage converters
Ordering Information
PART
NUMBER
PACKAGE
TAPE & REEL
PKG. NO.
EL2170CN
8-Pin PDIP
-
MDP0031
EL2170CS
8-Pin SO
-
MDP0027
EL2170CS-T7
8-Pin SO
7”
MDP0027
EL2170CS-T13
8-Pin SO
13”
MDP0027
EL2170CW-T7
5-Pin SOT-23*
7”
MDP0038
EL2170CW-T3
5-Pin SOT-23*
13”
MDP0038
EL2270CN
8-Pin PDIP
-
MDP0031
EL2270CS
8-Pin SO
-
MDP0027
EL2270CS-T7
8-Pin SO
7”
MDP0027
EL2270CS-T13
8-Pin SO
13”
MDP0027
EL2470CN
14-Pin PDIP
-
MDP0031
EL2470CS
14-Pin SO
-
MDP0027
EL2470CS-T7
14-Pin SO
7”
MDP0027
EL2470CS-T13
14-Pin SO
13”
MDP0027
NOTE: *EL2170CW symbol is .Bxxx where xxx represents date
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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All other trademarks mentioned are the property of their respective owners.
EL2170, EL2270, EL2470
Pinouts
EL2170
(8-PIN SO, PDIP)
TOP VIEW
EL2270
(8-PIN SO, PDIP)
TOP VIEW
EL2170
(5-PIN SOT-23)
TOP VIEW
EL2470
(14-PIN SO, PDIP)
TOP VIEW
2
EL2170, EL2270, EL2470
Absolute Maximum Ratings (TA = 25°C)
Operating Junction Temperature
Plastic Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
Output Current (EL2170) . . . . . . . . . . . . . . . . . . . . . . . . . . . ±120mA
Output Current (EL2270) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Output Current (EL2470) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±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
CONDITIONS
MIN
TYP
MAX
UNIT
2.5
15
mV
VOS
Input Offset Voltage
TCVOS
Average Input Offset Voltage Drift
Measured from TMIN to TMAX
dVOS
VOS Matching
EL2270, EL2470 only
+IIN
+Input Current
d+IIN
+IIN Matching
-IIN
-Input Current
d-IIN
-IIN Matching
EL2270, EL2470 only
CMRR
Common Mode Rejection Ratio
VCM = ±3.5V
-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
IO
EL2270, EL2470 only
PARAMETER
0.5
mV
VS = ±5
5
20
4
Supply Current
AC Electrical Specifications
µV/°C
0.5
Output Current
IS
5
45
nA
15
µA
1.5
µA
50
dB
4
60
µA
10
70
0.5
µA/V
dB
5
µA/V
EL2170 only
80
100
mA
EL2270 only, per amplifier
50
55
mA
EL2470 only, per amplifier
50
55
mA
Per amplifier
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
3
400
EL2170, EL2270, EL2470
AC Electrical Specifications
PARAMETER
VS = ±5V, RF = RG = 1kΩ, RL = 150Ω, TA = 25°C unless otherwise specified (Continued)
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
tPD
Propagation Delay
VOUT = ±500mV
4.5
ns
OS
Overshoot
VOUT = ±500mV
3.0
%
tS
0.1% Settling
VOUT = ±2.5V, AV = -1
40
ns
dG
Differential Gain
AV = 2, RL = 150Ω (Note 1)
0.15
%
dP
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, EL2470 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)
4
EL2170, EL2270, EL2470
Typical Performance Curves
Non-Inverting
Frequency Response (Gain)
Non-Inverting
Frequency Response (Phase)
Inverting Frequency
Response (Gain)
Inverting Frequency
Response (Phase)
Transimpedance (ROL)
5
PSRR and CMRR
Frequency Response for
Various RF and RG
Frequency Response for
Various RL and CL
Frequency Response
for Various CIN-
EL2170, EL2270, EL2470
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
6
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
EL2170, EL2270, EL2470
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
7
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
EL2170, EL2270, EL2470
Typical Performance Curves (Continued)
Differential Gain and
Phase vs DC Input Voltage
at 3.58MHz/AV = +2
Small-Signal Step Response
8-Pin Plastic DIP
Maximum Power Dissipation
vs Ambient Temperature
8
Differential Gain and
Phase vs DC Input Offset
at 3.58MHz/AV = +1
Settling Time vs
Settling Accuracy
Large-Signal Step Response
8-pin SO
Maximum Power Dissipation
vs Ambient Temperature
EL2170, EL2270, EL2470
Typical Performance Curves (Continued)
14-Pin Plastic DIP
Maximum Power Dissipation
vs Ambient Temperature
Channel Separation
vs Frequency
Applications Information
Product Description
The EL2170, EL2270, and EL2470 are current-feedback
operational amplifiers that offer a wide -3dB bandwidth of
70MHz and a low supply current of 1mA per amplifier. All of
these products also feature high output current drive. The
EL2170 can output 100mA, while the EL2270 and the
EL2470 can output 55mA per amplifier. The EL2170,
EL2270, and EL2470 work with supply voltages ranging from
a single 3V to ±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 EL2170,
EL2270, and EL2470 do not have the normal gain-bandwidth
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 EL2170, EL2270, and EL2470
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
EL2170 is available in the tiny 5-pin SOT-23 package, which
has a footprint 28% the size of an 8-pin SO. The EL2170,
9
14-Pin SO
Maximum Power Dissipation
vs Ambient Temperature
5-Pin Plastic SOT-23
Maximum Power Dissipation
vs Ambient Temperature
EL2270, and EL2470 are each also available in industry
standard pinouts in PDIP and SO packages.
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
EL2170, EL2270, EL2470
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.
The experienced user with a large amount of PC board
layout experience may find in rare cases that the EL2170,
EL2270, and EL2470 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. 0.5pF) 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 EL2170, EL2270, and EL2470 have 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 EL2170,
EL2270, and EL2470 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 EL2170, EL2270, and EL2470 are currentfeedback amplifiers, their gain-bandwidth product is not a
constant for different closed-loop gains. This feature actually
allows the EL2170, EL2270, and EL2470 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 EL2170, EL2270, and EL2470 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
10
EL2170, EL2270, and EL2470 will operate on dual supplies
ranging from ±1.5V to ±6V. With a single-supply, the EL2170,
EL2270, and EL2470 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
EL2170, EL2270, and EL2470 have an input voltage range
that extends to within 1V of either supply. So, for example, on
a single +5V supply, the EL2170, EL2270, and EL2470 have
an input range which spans from 1V to 4V. The output range
of the EL2170, EL2270, and EL2470 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.
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 EL2170, EL2270, and EL2470, 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 EL2170, EL2270,
and EL2470 amplifier! Special circuitry has been
incorporated in the EL2170, EL2270, and EL2470 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 EL2170,
EL2270, and EL2470 have 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, the EL2170 is
capable of providing a minimum of ±80mA of output current.
Similarly, each amplifier of the EL2270 and the EL2470 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
EL2170 is capable of driving 50Ω loads to ±4V, making it an
excellent choice for driving isolation transformers in
telecommunications applications. Similarly, the ±50mA
minimum output drive of each EL2270 and EL2470 amplifier
allows swings of ±2.5V into 50Ω loads.
EL2170, EL2270, EL2470
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 EL2170, EL2270, and EL2470 from the cable
and allow extensive capacitive drive. However, other
applications may have high capacitive loads without a backtermination 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 EL2170, EL2270, and EL2470 have no internal currentlimiting 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 EL2170, EL2270,
and EL2470, 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 EL2170, EL2270, and EL2470 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
Typical Application Circuits
INVERTING 200mA OUTPUT CURRENT
DISTRIBUTION AMPLIFIER
11
FAST-SETTLING PRECISION AMPLIFIER
EL2170, EL2270, EL2470
Typical Application Circuits
(Continued)
DIFFERENTIAL LINE-DRIVER/RECEIVER
12
EL2170, EL2270, EL2470
EL2170/EL2270/EL2470 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
13
EL2170, EL2270, EL2470
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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14
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