DATASHEET

ESIGNS
R NEW D NT
O
F
D
E
E
ND
C OM M E
PL ACEM r a t
NO T R E
DED RE
N
te
E
n
e
M
C
M
O
port
NO REC
ical Sup rsil.com/tsc
n
h
c
e
T
r
te
Data
Sheet
May 6, 2005
ct ou
r www.in
conta
ERSIL o
T
N
-I
8
8
1-8
70MHz/1mA Current Mode Feedback Amp
w/Disable
The EL2276 is a dual current-feedback operational amplifier
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. The EL2276
also includes 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. These attributes make the EL2276
excellent choice for low power and/or low voltage cabledriver, HDSL, or RGB applications.
EL2276
FN7054.1
Features
• Dual topology
• 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/µs slew rate
• Large output drive current: 55mA
• Pb-Free available (RoHS compliant)
Ordering Information
PART NUMBER
PACKAGE
TAPE & REEL PKG. DWG. #
Applications
EL2276CS
14-Pin SOIC
-
MDP0027
• Low power/battery applications
EL2276CS-T7
14-Pin SOIC
7”
MDP0027
• HDSL amplifiers
EL2276CS-T13
14-Pin SOIC
13”
MDP0027
• Video amplifiers
EL2276CSZ
(See Note)
14-Pin SOIC
(Pb-free)
-
MDP0027
• Cable drivers
EL2276CSZ-T7
(See Note)
14-Pin SOIC
(Pb-free)
7”
MDP0027
EL2276CSZ-T13
(See Note)
14-Pin SOIC
(Pb-free)
13”
• RGB amplifiers
• Test equipment amplifiers
MDP0027
NOTE: Intersil Pb-free products employ special Pb-free material sets;
molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and 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-020.
• Current to voltage converters
Pinout
EL2276
(14-PIN SO)
TOP VIEW
Manufactured under U.S. Patent No. 5,352,989, 5,351,012,
5,418,495
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 1995, 2003, 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
EL2276
Absolute Maximum Ratings (TA = 25°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
Operating Junction Temperature Plastic Packages . . . . . . . . . 150°C
Output Current (EL2276) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°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 = 150, ENABLE = 0V, TA = 25°C unless otherwise specified.
DESCRIPTION
VOS
Input Offset Voltage
TCVOS
Average Input Offset Voltage Drift
dVOS
CONDITIONS
MIN
Measured from TMIN to TMAX
TYP
MAX
UNITS
2.5
15
mV
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
CMRR
Common Mode Rejection Ratio
VCM = ±3.5 V
-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
k
+RIN
+ Input Resistance
VCM = ±3.5V
1
4
M
+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
45
µA
nA
15
µA
1.5
µA
50
dB
4
60
5
10
70
0.5
µA/V
dB
5
µA/V
IO
Output Current
Per Amplifier
IS
Supply Current
ENABLE = 2.0V, per Amplifier
1
2
mA
IS(DIS)
Supply Current (Disabled)
ENABLE = 4.5V
0
20
µA
COUT(DIS)
Output Capacitance (Disabled)
ENABLE = 4.5V
4.4
pF
REN
Enable Pin Input Resistance
Measured at ENABLE = 2.0V, 4.5V
85
k
IIH
Logic “1” Input Current
Measured at ENABLE, ENABLE = 4.5V
-0.04
µA
IIL
Logic “0” Input Current
Measured at ENABLE, ENABLE = 0V
-53
µA
VDIS
Minimum Voltage at ENABLE to Disable
VEN
Maximum Voltage at ENABLE to Enable
2
50
45
4.5
V
2.0
V
EL2276
AC Electrical Specifications
PARAMETER
VS = ±5V, RF = RG = 1.0k, RL = 150, ENABLE = 0V, TA = 25°C unless otherwise specified.
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNITS
-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 = ±50mV
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 = 150 (Note 1)
0.15
%
dP
Differential Phase
AV = +2, RL = 150(Note 1)
0.15
°
dG
Differential Gain
AV = +1, RL = 500 (Note 1)
0.02
%
dP
Differential Phase
AV = +1, RL = 500 (Note 1)
0.01
°
tON
Turn-On Time
AV = +2, VIN = +1V, RL = 150(Note 2)
40
100
ns
tOFF
Turn-Off Time
AV = +2, VIN = +1V, RL = 150 (Note 2)
1500
2000
ns
CS
Channel Separation
f = 5MHz
400
85
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.
3
dB
EL2276
Test Circuit (per Amplifier)
Simplified Schematic (per Amplifier)
4
EL2276
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-
EL2276
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
Output Voltage
vs Frequency
Output Voltage Swing
vs Supply Voltage
Slew Rate vs
Supply Voltage
EL2276
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
EL2276
Typical Performance Curves (Continued)
Differential Gain and
Phase vs DC Input Voltage
at 3.58MHz/AV = +2
Small-Signal Step Response
14-Pin SO
Maximum Power Dissipation
vs Ambient Temperature
8
Settling Time vs
Settling Accuracy
Differential Gain and
Phase vs DC Input Offset
at 3.58MHz/AV = +1
Large-Signal Step Response
Channel Separation
vs Frequency
EL2276
Applications Information
Product Description
The EL2276 is a current-feedback operational amplifier that
offers a wide -3dB bandwidth of 70MHz, a low supply current
of 1mA per amplifier and the ability to disable to 0mA. This
product also features high output current drive. The EL2276
can output 55mA per amplifier. The EL2276 works with
supply voltages ranging from a single 3V to ±6V, and it is
also capable of swinging to with in 1V of either supply on the
input and the output. Because of its current-feedback
topology, the EL2276 does not have the normal gainbandwidth product associated with voltage-feedback
operational amplifier. 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 EL2276 the ideal choice for
many low-power/high-bandwidth applications such as
portable computing, HDSL, and video processing.
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.
Disable/Power-Down
The EL2276 amplifier can be disabled, placing its output in a
high-impedance state. When disabled, the amplifier's supply
current is reduced to 0mA. The EL2276 amplifier 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 ±5V supplies, this means that an 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
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 EL2276 at ±5V, if ENABLE is tied to -5V
(rather than ground) the supply current will increase about
15% to 2.3mA.
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 EL2276 has 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 this
amplifier, 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 EL2276
remains very stable. For less experienced users, this feature
makes the 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 EL2276
has less bandwidth than expected. In this case, the inverting
input may have less parasitic capacitance than expected by
the internal compensation circuitry of the 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 Response for Various RF and
RG, and Frequency Response for Various CIN-.
9
EL2276
Feedback Resistor Values
The EL2276 has 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 EL2276 is 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 EL2276 is a current-feedback amplifier, the
gain-bandwidth product is not a constant for different closedloop gains. This feature actually allows the 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.
Supply Voltage Range and Single-Supply
Operation
The EL2276 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 EL2276 will
operate on dual supplies ranging from ±1.5V to ±6V.
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
EL2276 has an input voltage range that extends to within 1V
of either supply. So, for example, on a single +5V supply, the
EL2276 has an input range which spans from 1V to 4V. The
output range of the 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.
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 EL2276, 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 in excess of the entire 1mA
supply current of the EL2276 amplifier! Special circuitry has
been incorporated in the EL2276 to reduce the variation of
output impedance with current output. This results in dG and
10
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 EL2276 has
dG and dP specifications of 0.01% and 0.02° respectively
while driving 500 at AV = +1.
Output Drive Capability
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. The ±50mA minimum output drive of each EL2276
amplifier allows swings of ±2.5V into 50 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 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 EL2276 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 EL2276, 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 25, 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 EL2276 to remain in the safe operating area.
These parameters are calculated as follows:
TJMAX = TMAX + (JA * n * PDMAX)
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
EL2276
PDMAX for each amplifier can be calculated as follows:
PDMAX = (2 * VS * ISMAX) + (VS - VOUTMAX) *
(VOUTMAX/RL))
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
11
EL2276
Typical Application Circuits
(Continued)
EL2276
EL2276
INVERTING 200mA OUTPUT CURRENT DISTRIBUTION
AMPLIFIER
FAST-SETTLING PRECISION AMPLIFIER
DIFFERENTIAL LINE-DRIVER/RECEIVER
12
EL2276
EL2276 Macromodel
* Revision A, March 1995
* AC characteristics used Rf = Rg = 1k, RL = 150
* Connections:
+input
*
|
-input
*
|
|
+Vsupply
*
|
|
|
-Vsupply
*
|
|
|
|
output
*
|
|
|
|
|
.subckt EL2276/el 1 14 11 4 13
*
* Input Stage
*
e1 10 0 1 0 1.0
vis 10 9 0V
h2 9 12 vxx 1.0
r1 14 110 165
l1 110 12 25nH
iinp 1 0 0.5uA
iinm 14 0 4uA
r12 1 0 4Meg
*
* Slew Rate Limiting
*
h1 130 0 vis 600
r2 130 140 1K
d1 140 0 dclamp
d2 0 140 dclamp
*
* High Frequency Pole
*
e2 30 0 140 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 11 18 20 qn
q3 11 19 21 qn
q4 4 20 22 qp
r7 21 13 4
r8 22 13 4
ios1 11 19 0.4mA
ios2 20 4 0.4mA
*
* Supply Current
*
ips 11 4 1nA
*
* Error Terms
*
13
EL2276
ivos 0 23 2mA
vxx 23 0 0V
e4 24 0 1 0 1.0
e5 25 0 11 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
EL2276 Macromodel (Continued)
11
1
13
14
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
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.
For information regarding Intersil Corporation and its products, see www.intersil.com
14
Similar pages