Page 1
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Features
• 400MHz gain-bandwidth product
• Gain-of-2 stable
• Ultra low video distortion =
0.01%/0.015° @NTSC/PAL
• Conventional voltage-feedback
topology
• Low offset voltage = 200µV
• Low bias current = 2µA
• Low offset current = 0.1µA
• Output current = 50mA over
temperature
• Fast settling = 13ns to 0.1%
• Low distortion = -55dB HD2, ------
-70dB HD3 @20MHz, 2VPP, AV =
+2
Applications
• High resolution video
• Active filters/integrators
• High-speed signal processing
• ADC/DAC buffers
• Pulse/RF amplifiers
• Pin diode receivers
• Log amplifiers
• Photo multiplier amplifiers
• High speed sample-and-holds
General Description
The EL2074C is a precision voltage-feedback amplifier featuring a
400MHz gain-bandwidth product, fast settling time, excellent differential gain and differential phase performance, and a minimum of
50mA output current drive over temperature.
The EL2074C is gain-of-2 stable with a -3dB bandwidth of 400MHz
at AV = +2. It has a very low 200µV of input offset voltage, only 2µA
of input bias current, and a fully symmetrical differential input. Like
all voltage-feedback operational amplifiers, the EL2074C allows the
use of reactive or non-linear components in the feedback loop. This
combination of speed and versatility makes the EL2074C the ideal
choice for all op-amp applications at a noise gain of 2 or greater
requiring high speed and precision, including active filters, integrators, sample-and-holds, and log amps. The low distortion, high output
current, and fast settling makes the EL2074C an ideal amplifier for
signal-processing and digitizing systems.
Connection Diagram
Ordering Information
1
Part No. Package Tape & Reel Outline #
EL2074CN 8-Pin PDIP - MDP0031
EL2074CS 8-Pin SO - MDP0027
EL2074CS-T7 8-Pin SO 7” MDP0027
EL2074CS-T13 8-Pin SO 13” MDP0027
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.
© 2001 Elantec Semiconductor, Inc.
NC
2
IN-
3
IN+
4
V-
(8-Pin SO & 8-Pin PDIP)
-
+
EL2074C
8
NC
7
V+
6
OUT
5
NC
September 26, 2001
Page 2
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Absolute Maximum Ratings (T
Supply Voltage (VS) ±7V
Output Current Output is short-circuit protected to ground, however,
maximum reliability is obtained if I
Common-Mode Input ±V
Differential Input Voltage 5V
Thermal Resistance (PDIP) θ
does not exceed 70mA.
OUT
= 25°C)
A
= 95°C/W
JA
Thermal Resistance (SO) θ
Operating Temperature 0°C to +75°C
Junction Temperature 175°C
S
Storage Temperature -60°C to +150°C
Note: See EL2071/EL2171 for Thermal Impedance curves
= 175°C/W
JA
Important Note:
All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are at the
specified temperature and are pulsed tests, therefore: TJ = TC = TA.
Open Loop DC Electrical Characteristics
VS = ±5V, R
V
TCV
I
B
I
OS
PSRR Power Supply Rejection Ratio
CMRR Common Mode Rejection Ratio
I
S
RIN (diff) R
CIN (diff) CIN (Differential) Open-Loop 25°C 1 pF
RIN (cm) R
CIN (cm) CIN (Common-Mode) 25°C 1 pF
R
CMIR Common-Mode Input
I
OUT
V
V
V
A
A
eN@ > 1MHz Noise Voltage 1MHz to 100MHz 25°C 2.3 nV/√Hz
iN@ > 100kHz Noise Current 100kHz to 100MHz 25°C 3.2 pA/√Hz
= 100Ω, unless otherwise specified.
L
Parameter Description Test Conditions Temp Min Typ Max Unit
OS
OS
Input Offset Voltage VCM = 0V 25°C 0.2 1.5 mV
T
Average Offset
, T
MIN
[1]
MAX
All 8 µV/°C
3 mV
Voltage Drift
Input Bias Current VCM = 0V All 2 6 µA
Input Offset Current VCM = 0V 25°C 0.1 1 µA
T
, T
MIN
[2]
[3]
MAX
All 60 80 dB
All 65 90 dB
2 µA
Supply Current - Quiescent No Load 25°C 21 25 mA
T
OUT
, T
MIN
(Differential) Open-Loop 25°C 15 kΩ
IN
(Common-Mode) 25°C 1 MΩ
IN
MAX
Output Resistance 25°C 20 mΩ
25 mA
25°C ±3 ±3.5 V
Range
T
MIN
, T
MAX
±2.5 V
Output Current All 50 70 mA
OUT
100 Output Voltage Swing 100Ω All ±3 ±3.6 V
OUT
50 Output Voltage Swing 50Ω All ±2.5 ±3.4 V
OUT
100 Open-Loop Gain 100Ω 25°C 500 1000 V/V
VOL
50 Open-Loop Gain 50Ω 25°C 400 800 V/V
VOL
1. Measured from T
Output Voltage Swing No Load All ±3.5 ±4 V
T
MIN
, T
MIN
MAX
T
, T
MIN
MAX
, T
MAX
400 V/V
300 V/V
2. ±VCC = ±4.5V to 5.5V
3. ±VIN = ±2.5V, V
OUT
= 0V
2
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EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
Closed Loop AC Electrical Characteristics
VS = ±5V, AV = +2, RF = R
Parameter Description Test Conditions Temp Min Typ Max Unit
SSBW -3dB Bandwidth AV = -1 25°C 400 MHz
GBWP Gain-Bandwidth Product AV = +10 25°C 400 MHz
LSBWa -3dB Bandwidth V
LSBWb -3dB Bandwidth V
GFPL Peaking (<50MHz) V
GFPH Peaking (>50MHz) V
GFR Rolloff (<100MHz) V
LPD Linear Phase Deviation (<100MHz) V
PM Phase Margin AV = +2 25°C 50 °
tr1, tf1 Rise Time, Fall Time 0.4V Step, AV = +2 25°C 1.8 ns
tr2, tf2 Rise Time, Fall Time 5V Step, AV = +2 25°C 8 ns
ts1 Settling to 0.1% (AV = -1) 2V Step 25°C 13 ns
ts2 Settling to 0.01% (AV = -1) 2V Step 25°C 25 ns
OS Overshoot 2V Step 25°C 5 %
SR Slew Rate 2V Step All 275 400 V/µs
[2]
Distortion
HD2a 2nd Harmonic Distortion @ 10MHz, AV = +2 25°C -65 -55 dBc
HD2c 2nd Harmonic Distortion @ 20MHz, AV = +2 25°C -55 -45 dBc
HD3a 3rd Harmonic Distortion @ 10MHz, AV = +2 25°C -72 -60 dBc
HD3c 3rd Harmonic Distortion @ 20MHz, AV = +2 25°C -70 -60 dBc
Video Performance
dG Differential Gain NTSC 25°C 0.01 0.05 %
dP Differential Phase NTSC 25°C 0.015 0.05 °
dG Differential Gain 30MHz 25°C 0.1 %
dP Differential Phase 30MHz 25°C 0.1 °
VBW ±0.1 dB Bandwidth Flatness 25°C 25 50 MHz
1. Large-signal bandwidth calculated using LSBW = Slew Rate / 2π V
2. All distortion measurements are made with V
3. Video performance measured at AV = +2 with 2 times normal video level across R
terminated 50Ω load, i.e., 0–100 IRE, 40IREpp giving a 1VPP video signal across the 50Ω load. For other values of R
= 250Ω, C
G
(V
= 0.4VPP) AV = +2 25°C 250 400 MHz
OUT
= 3pF, R
F
= 100Ω unless otherwise specified.
L
T
MIN
, T
MAX
250 MHz
AV = +5 25°C 100 MHz
AV = +10 25°C 40 MHz
[1]
= 2V
OUT
PP
[1]
= 5V
OUT
PP
= 0.4V
OUT
OUT
OUT
OUT
[3]
= 2VPP, R
OUT
= 0.4V
= 0.4V
= 0.4V
= 100Ω
L
PP
PP
PP
PP
PEAK
All 43 63 MHz
All 17 25 MHz
25°C 0 1 dB
T
MIN
, T
MAX
1 dB
25°C 0 2 dB
T
MIN
, T
MAX
2 dB
25°C 0.1 0.5 dB
T
MIN
, T
MAX
0.5 dB
All 1 1.8 °
T
, T
MIN
MAX
T
, T
MIN
MAX
= 100Ω. This corresponds to standard video levels across a back-
L
, see curves
L
-45 dBc
-60 dBc
EL2074C
pp
pp
pp
pp
3
Page 4
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Typical Performance Curves
Non-Inverting Frequency
Response
Open Loop Gain and Phase Output Voltage Swing vs
PSRR, CMRR, and Closed-Loop
RO vs Frequency
Inverting Frequency Response Frequency Response for Various
Frequency
2nd and 3rd Harmonic
Distortion vs Frequency
RLs
Equivalent Input Noise
2-Tone, 3rd Order
Intermodulation Intercept
4
Page 5
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Series Resistor and Resulting
Bandwidth vs Capacitive Load
Common-Mode Rejection Ratio vs
Input Common-Mode Voltage
Bias and Offset Current vs
Temperature
Settling Time vs
Output Voltage Change
Bias and Offset Current vs
Input Common-Mode Voltage
Offset Voltage vs Temperature A
Settling Time vs
Closed-Loop Gain
Supply Current
vs Temperature
, PSRR, and CMRR vs
VOL
Temperature
5
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EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Small Signal Transient Response Large Signal Transient Response
Differential Gain and Phase vs DC
Input Offset at 3.58MHz
Differential Gain and
Phase vs Number of
150Ω Loads at 3.58MHz
Differential Gain and Phase vs DC
Input Offset at 4.43MHz
Differential Gain and
Phase vs Number of
150Ω Loads at 4.43MHz
Differential Gain and Phase vs DC
Input Offset at 30MHz
Differential Gain and
Phase vs Number of
150Ω Loads at 30MHz
6
Page 7
Equivalent Circuit
EL2074C
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
Burn-In Circuit
All Packages Use The Same Schematic
7
Page 8
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
Applications Information
Product Description
The EL2074C is a wideband monolithic operational
amplifier built on a high-speed complementary bipolar
process. The EL2074C uses a classical voltage-feedback
topology which allows it to be used in a variety of appli-
cations requiring a noise gain ≥2 where current-feedback
amplifiers are not appropriate because of restrictions
placed upon the feedback element used with the amplifier. The conventional topology of the EL2074C allows,
for example, a capacitor to be placed in the feedback
path, making it an excellent choice for applications such
as active filters, sample-and-holds, or integrators. Similarly, because of the ability to use diodes in the feedback
network, the EL2074C is an excellent choice for applications such as log amplifiers.
The EL2074C also has excellent DC specifications:
200µV, VOS, 2µA IB, 0.1µA IOS, and 90dB of CMRR.
These specifications allow the EL2074C to be used in
DC-sensitive applications such as difference amplifiers.
Furthermore, the current noise of the EL2074C is only
3.2pA/√Hz, making it an excellent choice for high-sen-
sitivity transimpedance amplifier configurations.
Gain-Bandwidth Product
The EL2074C has a gain-bandwidth product of
400MHz. For gains greater than 8, its closed-loop -3dB
bandwidth is approximately equal to the gain-bandwidth
product divided by the noise gain of the circuit. For
gains less than 8, higher-order poles in the amplifier's
transfer function contribute to even higher closed loop
bandwidths. For example, the EL2074C has a -3dB
bandwidth of 400MHz at a gain of +2, dropping to
200MHz at a gain of +4. It is important to note that the
EL2074C has been designed so that this “extra” bandwidth in low-gain applications does not come at the
expense of stability. As seen in the typical performance
curves, the EL2074C in a gain of +2 only exhibits 1dB
of peaking with a 100Ω load.
Parasitic Capacitances and Stability
When used in positive-gain configurations, the
EL2074C can be quite sensitive to parasitic capacitances
at the inverting input, especially with values ≥250Ω for
the gain resistor. The problem stems from the feedback
and gain resistance in conjunction with the approximately 3pF of board-related parasitic capacitance from
the inverting input to ground. Assuming a gain-of-2 configuration with RF = R
at 424MHz, which is equivalent to a zero in the forward
path at the same frequency. This zero reduces stability
by reducing the effective phase-margin from about 50°
to about 30°.
A common solution to this problem is to add an additional capacitor from the inverting input to the output.
This capacitor, in conjunction with the parasitic capacitance, maintains a constant voltage-divider between the
output and the inverting input. This technique is used for
AC testing of the EL2074. A 3pF capacitor is placed in
parallel with the feedback resistor for all AC tests. When
this capacitor is used, it is also possible to increase the
resistance values of the feedback and gain resistors without loss of stability, resulting in less loading of the
EL2074C from the feedback network.
= 250Ω, a feedback pole occurs
G
Video Performance
An industry-standard method of measuring the video
distortion of a component such as the EL2074C is to
measure the amount of differential gain (dG) and differential phase (dP) that it introduces. To make these
measurements, a 0.286VPP (40 IRE) signal is applied to
the device with 0V DC offset (0 IRE) at either 3.58MHz
for NTSC, 4.43MHz for PAL, or 30MHz for HDTV. A
second measurement is then made at 0.714V DC offset
(100 IRE). Differential gain is a measure of the change
in amplitude of the sine wave, and is measured in percent. Differential phase is a measure of the change in
phase, and is measured in degrees.
For signal transmission and distribution, a back-termi-
nated cable (75Ω in series at the drive end, and 75Ω to
ground at the receiving end) is preferred since the
impedance match at both ends will absorb any reflections. However, when double termination is used, the
received signal is halved; therefore a gain of 2 configuration is typically used to compensate for the
attenuation.
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Page 9
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
The EL2074C has been designed to be among the best
video amplifiers in the marketplace today. It has been
thoroughly characterized for video performance in the
topology described above, and the results have been
included as minimum dG and dP specifications and as
typical performance curves. In a gain of +2, driving
150Ω, with standard video test levels at the input, the
EL2074C exhibits dG and dP of only 0.01% and 0.015°
at NTSC and PAL. Because dG and dP vary with different DC offsets, the superior video performance of the
EL2074C has been characterized over the entire DC offset range from -0.714V to +0.714V. For more
information, refer to the curves of dG and dP vs DC
Input Offset.
The excellent output drive capability of the EL2074C
allows it to drive up to 4 back-terminated loads with
excellent video performance. With 4 150Ω loads, dG
and dP are only 0.15% and 0.08° at NTSC and PAL. For
more information, refer to the curves for Video Perfor-
mance vs Number of 150Ω Loads.
Output Drive Capability
The EL2074C has been optimized to drive 50Ω and 75Ω
loads. It can easily drive 6V
output drive capability makes the EL2074C an ideal
choice for RF, IF and video applications. Furthermore,
the current drive of the EL2074C remains a minimum of
50mA at low temperatures. The EL2074C is currentlimited at the output, allowing it to withstand momentary shorts to ground. However, power dissipation with
the output shorted can be in excess of the power-dissipation capabilities of the package.
into a 50Ω load. This high
PP
Capacitive Loads
Although the EL2074C has been optimized to drive
resistive loads as low as 50Ω, capacitive loads will
decrease the amplifier's phase margin which may result
in peaking, overshoot, and possible oscillation. For optimum AC performance, capacitive loads should be
reduced as much as possible or isolated via a series output resistor. Coax lines can be driven, as long as they are
terminated with their characteristic impedance. When
properly terminated, the capacitance of coaxial cable
will not add to the capacitive load seen by the amplifier.
Capacitive loads greater than 10pF should be buffered
with a series resistor (Rs) to isolate the load capacitance
from the amplifier output. A curve of recommended Rs
vs Cload has been included for reference. Values of Rs
were chosen to maximize resulting bandwidth without
peaking.
Printed-Circuit Layout
As with any high-frequency device, good PCB layout is
necessary for optimum performance. Ground-plane construction is highly recommended, as is good power
supply bypassing. A 1µF–10µF tantalum capacitor is
recommended in parallel with a 0.01 µF ceramic capacitor. All lead lengths should be as short as possible, and
all bypass capacitors should be as close to the device
pins as possible. Parasitic capacitances should be kept to
an absolute minimum at both inputs and at the output.
Resistor values should be kept under 1000Ω to 2000Ω
because of the RC time constants associated with the
parasitic capacitance. Metal-film and carbon resistors
are both acceptable, use of wire-wound resistors is not
recommended because of parasitic inductance. Similarly, capacitors should be low-inductance for best
performance. If possible, solder the EL2074C directly to
the PC board without a socket. Even high quality sockets
add parasitic capacitance and inductance which can
potentially degrade performance. Because of the degradation of AC performance due to parasitics, the use of
surface-mount components (resistors, capacitors, etc.) is
also recommended.
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Page 10
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
EL2074C Macromodel
*
* Connections: input
* | -input
* | | +Vsupply
* | | | -Vsupply
* | | | | output
* | | | | |
.subckt M2074 3 2 7 4 6
*
*Input Stage
*
ie 37 4 1 mA
r6 36 37 125
r7 38 37 125
rc1 7 30 200
rc2 7 39 200
q1 30 3 36 qn
q2 39 2 38 qna
ediff 33 0 39 30 1
rdiff 33 0 1 Meg
*
* Compensation Section
*
ga 0 34 33 0 2m
rh 34 0 500K
ch 34 0 0.8 pF
rc 34 40 50
cc 40 0 0.05 pF
*
* Poles
*
ep 41 0 40 0 1
rpa 41 42 150
cpa 42 0 0.5 pF
rpb 42 43 50
cpb 43 0 0.5 pF
*
* Output Stage
*
ios1 7 50 3.0 mA
ios2 51 4 3.0 mA
q3 4 43 50 qp
q4 7 43 51 qn
q5 7 50 52 qn
q6 4 51 53 qp
ros1 52 6 2
ros2 6 53 2
*
Power Supply Current
*
ips 7 4 11.4 mA
*
Models
*
.model qna npn(is800e-18 bf170 tf0.2 ns)
.model qn npn(is810e-18 bf200 tf0.2 ns)
.model qp pnp(is800e-18 bf200 tf0.2 ns)
.ends
10
Page 11
EL2074C Macromodel
EL2074C
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
11
Page 12
EL2074C
400MHz GBWP Gain-of-2 Stable Operational Amplifier
EL2074C
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
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 sup-
Elantec Semiconductor, Inc.
675 Trade Zone Blvd.
Milpitas, CA 95035
Telephone: (408) 945-1323
(888) ELANTEC
Fax: (408) 945-9305
European Office: +44-118-977-6020
Japan Technical Center: +81-45-682-5820
port 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.
September 26, 2001
12
Printed in U.S.A.
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