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
spec ificat ions are maintained at the factory and are available upon your request. We recomme nd checking the revision level befor e finalization of your design documentation .
© 1997 Elantec, Inc.
EL2420C
General Description
The EL2420C operational amplifier, built using Elantec’s comple-
mentary bipolar process, offers unprecedented high frequency
performance at a very low cost. It is suitable for any application, such
as consumer video, where traditional DC performance specifications
are of secondary importance to the high frequency specifications. On a
5V s upply at a gain of +1 th e EL 242 0C wil l dr ive a 15 0 lo ad to +2V,
with a ba ndw id th o f 5 0 MH z. T his de vi ce ach ie ves 0. 1 dB bandwi dth
at 5 MHz.
The recommended power supply voltage is 5V. At zero and 5V sup-
plies, the inputs will o perate to grou nd. When th e outp uts are at 0 V the
amplifier dra ws only 2.4 mA of supply curren t.
Connection Diagram
P-DIP, SO
Features
Optimized for 5V operation
Stable at gain of 1
50 MHz Gain bandwidth pro duct
130 Vs slew rate
Drives 150 load to video levels
Input and outpu ts operate at
negative supply rail
-60 dB isolation at 4.2 MHz
Applications
Consumer video amplifier
Active filters/integrators
Cost sensitive applica tion s
Single supply amplifiers
Ordering Information
Part No Temp. Range Package Outline #
EL2420CN - 40°C to +85°C 14-Lead P-DIP MDP0031
EL2420CS -40°C to +85°C 14-Lead SO MDP0027
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
April 1998 Rev B
2
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
Absolute Maximum Ratings (TA = 25 °C)
Total Supply Voltage 18V
Input Voltage -6VS
Differential Input Voltage 6V
Peak Output Current 75 mA per amplifier
Power Dissipation See Curves
Storage Temperature Range -65°C to +150°C
Operating Temperature Range -40°C to +85°C
1. Measured from TMIN to TMAX.
2. A heat-sink is required to keep junction temperature below absolute maximum when an output is shorted.
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, therefor TJ = TC = TA.
Test Level Test Procedure
I100% production tested and QA sample tested per QA test plan QCX0002.
II 100% production tested at TA = 25°C and QA sample tested at TA = 25°C, TMAX and TMIN per QA test plan QCX0002.
III QA sample tested per QA test plan QCX0002.
IV Parameter is guaranteed (but not tested) by Design and Characterization Data.
VParameter is typical value at TA = 25°C for information purposes only.
DC Characteristics
VS=+5V, RL=1K , VIN=1V, TA=25°C unless otherwise specified.
Parameter Description Conditions Min Typ Max Test
Level Units
VOS Input Offset Voltage -20 10 20 ImV
TCVOS Average Offset Voltage Drift [1] -50 V µV/°C
IBInput Bias Current -15 -7 -3 A
I
OS Input Offset Current 0.3 1.0 A
TCIOS Average Offset Current Drift [1] -1 -3 V nA/°C
AVOL Open Loop Gain VOUT=..5, 2.5, RL= 1K160 250 I V/V
VOUT=..5, 2.5, RL= 150K160 250 V V/V
PSRR Power Supply Rejection Ratio VS = 4.5V to 5.5V 43 50 IdB
CMRR Common Mode Rejection Ratio VCM = 0V to +3.8V 55 65 IdB
CMIR Common Mode Input Range 0.0 3.0 IV
V
OUT Output Voltage Swing RFB = RG = 1K, RL = 1502.8 3.2 V
ISC Output Short Circuit Current Output to Ground [2] 75 125 ImA
I
SSupply Current No Load (per channel) VIN = 0V 2.0 2.4 3.0 ImA
R
IN Input Resistance Differential 150 VK
Common Mode 1.5 VM
C
IN Input Capacitance AV = +1 @ 10 MHz 1 VpF
R
OUT Output Resistance 0.150 V
PSOR Power Supply Operating Range Single Supply 4 6 VV
3
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
1. For VS = 5V, VOUT = 4Vpp. Full power bandwidth is based on slew rate measurement using: FPBW = SR/(2pi*Vpeak)
2. Video performance measured at VS = 5V, AV = +2 with 2 times normal video level across RL = 150
Closed Loop AC Electrical Characteristics
VS=5V, AC Test Figure, TA = 25°C unless otherwise specified
Parameter Description Conditions Min Typ Max Test
Level Units
BW -3dB Bandwidth (VOUT = 0.4 mVp-p)
±0.1 dB Bandwidth (VOUT = 0.4 mVp-p)
AV = +1 100 V MHz
AV = +1 10 V MHz
GBWP Gain Bandwith Product 50 V MHz
PM Phase Margin 55 V( ° )
SR Slew Rate 85 130 V V/µs
FBWP Full Power Bandwidth [1] 811 V MHz
tR, tFRise T ime, Fall T ime 0.1V step 2 Vns
OS Overshoot 0.1V step 15 V%
t
PD Propagation Delay 3.5 Vns
t
SSettling to 0.1% (AV = 1) VS = 5V, 2V Step 80 Vns
dG Differential Gain [2] NTSC/PAL 0.1 V%
dP Differential Phase [2] NTSC/PAL 0.2 V( ° )
e
NInput Noise Voltage 10 KHz 15 V nV/rt(Hz)
iNInput Noise Current 10 KHz 1.5 V nV/rt(Hz)
CS Channel Separation P = 5 MHz 55 VdB
4
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
Typical Performance Curves
Simplified Block Diagram
14-Pin Plastic DIP
Maximum Power Dissipat ion
vs Ambient Temperature
14-Lead SO
Maximum Power Dissipation
vs Ambient Temperature
5
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
Applications Information
Product Description
The EL24 20 C operatio n al am plifier is stable at a gain of
1. It is built on Elantec’s proprietary complimentary
bipolar process. This topology allows it to be used in a
variet y of applicati ons where curren t mode amplifi ers
are not appr opriate beca use of restriction s placed on the
feedback elements. This product is especially designed
for applications where high bandwidth and good video
perf ormance cha racteristi cs are desired but the h igher
cost of more flexible and sophisticated products are
prohibitive.
Power Supplies
The EL2420C is designed to work at a supply voltage
difference of 4.5V to 5.5V. It will work on any combina-
tion of ± supplies. All electrical characteristics are
measure d wi th a 5V supply.
Output Swing vs Load
Please refer to the simplifie d bloc k diagram. Th is ampli-
fier provides an NPN pull-up transistor output and a
passive 1250 pull-down resistor to th e most negative
supply. In a application where the load is connected to
VS the output voltage can swing to within 200 mV of
VS− .
Output Drive Capability
This device does not have short circuit protection. Each
output is capable of than 100 mA into a shorted output.
Care must be used in the design to limit the output cur-
rent with a series resistor.
Single 5 Volt Supply Video Cable Driver
These amp lifiers ma y be used as a direc t coupled video
cable driver with a gain of 2. With a 75 b ac k ma tc hi ng
resistor dr iv ing a t erm inat ed 75 cable th e outp ut at t he
cable load will be original video level (1V NTSC). The
best operating mode is with direct coupling. The input
signal must be offset to keep the entire signal within the
range of the amplifier. The required o ffset voltage can
be set with a resistor divider and a bypass capaci tor in
the video path (Figure 1). The inp ut DC o ffse t shou ld b e
between .3V and .5V . With RA=68K and RB=4.7K the
input offset will be .32V. Since these amplifiers require
a DC load at their outputs it is good design pr actice to
add a 250 resistor to ground directly at the amplifier
output. Then if the 75 cable term inatio n resist or were
inadve rtently rem oved th ere woul d stil l be an ou tput sig -
nal. The values in figure 1 give an output range of 0V to
2.6V
Output capacitive coupling also has some restrictions.
These amplifiers require a DC load at their outputs. A
75 back matching resistor to a cable and a 75 load to
ground a t t he en d of t he cab le pr ovi de a 15 0 DC load.
But output capacitive coupling opens this DC path so an
extra pull down resistor on the amplifier outpu t to ground
is required. Figure 4 shows a 250 resistor. Capacitively
coupling the output will require that we shift the output
offset voltage higher than in the direct coupled case.
Using RA=43K and RB=4.7K will make the quiescent
output offset voltage about 1V. The output dynamic
range will be .6V to 3V.
6
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
Input capacitive coupling will increase the needed
dynamic range of the amplifier. The standard NTSC
video signal is 1V peak to peak plus 143 mV for the
color AC peak. The video signal is made up of the -286
mV sync pulse plus the 714 mV picture signal which
may very from 0V to 714 mV. The video signal average
value for a black p ictur e is about 28 mV ( Figure 2) and
with a white pict ure level is about 583 mV (Figure 3).
This gives a maximum change in average value of about
555 mV. A direct coupled amplifier with an standard
NTSC video signal need s a dynamic range of 1 .143V.
But with input capacitance coupling the dynamic range
requirements are the sum of the 1.143V video plus the
average pi cture value chang e of 0.555V or 1.698VP-P.
At a ga in o f two thi s do ubles to 3. 394V. These ampl ifi-
ers do not have this much dynamic range so a gain of
less than 2 must be used to avoid waveform compression
under all conditions.
+
Video
1 V
75
RIS
V IN
RIL
4.7K
75
RB +
-AMP
1K
RF
1K
RG
0.1 µF
CB
68K
RA
0.32 VB
+
V1
5 V
0.64 VB
250
RPD
V AMP V OUT
75
RCL
75
RO
1 V
Figure 1.
0.714 V
0.0 V
-0.286 V
Ý10
5.1 µs
3.8 µs
1.3 µs
53 µs
0.6 0.867 0.583 V
Gain = 2 1.8 V offset
Amp Out
Volts
0+0.348
1.166 1.8
1.428 2.062
-0.572 +0.062
Figure 2. White Level Video
7
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
Capacitiv el y co up lin g th e inp ut and o u t pu t is wo rse tha n
a capacitor only on the input. Without any special com-
promises you can only take a gain of one. But if the
backmat ch resisto r is redu ced to 36, redu cing t he out -
put range requirement 25% and the output offset is
shifted to 2.1V you can take a gain of 1.5 and have a
standard NTSC 1Vat the 75 load.
A simple transistor, capacitor and resistor sync tip clamp
may be used wh en the in put is already AC couple d to set
the syn c tip to gr ound.This gi ves the in put a fixed DC
level and can be used like a direct coupled input. The
clamp u s es a PNP t r ansistor with the colle ctor at ground
and the base has a 200 K resistor to 5V. The emitter-
connects t o the amplifier input and a capacito r from the
video input. The clamp f unctions as an inverted Beta
current source for input bias current with plus inputs and
a clamp to ground for minus inputs. The RA and RB
resistor s are removed for the clamp option (Figure 4).
Printed Circuit Layou t
The EL2 420C is wel l behav ed, and ea sy to appl y in most
applications. However, a few simple techniques will
help assure rapid, high quality results. 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 bypass-
ing. A 0. 1 µ F cera mic capacit or is reco mmended for
bypassing bo th sup p lie s. Lea d leng ths shou ld b e as short
as possi ble, and bypass capacito rs should be as cl ose to
the device pins as possible. For good AC performance,
parasitic cap acitances should be kept to a minimum at
both inputs and at the output. Resistor values should be
kept under 5 K because of the RC time constants asso-
ciated with the parasitic capacitance. Metal-film and
carbon resisto rs are b oth accept able, u se of wire -wound
resistors is not recommended because of their parasitic
inductance. Similarly, capacitors should be low-induc-
tance for best performance.
0.714 V
0.0 V
-0.286 V
Gain = 2 1.8 V offset
Amp Out
Volts
+1.8
+3.172
+56 mV
+1.172
Figure 3. Black Level Video
53 mV Average BL
+45 mV 0.686 V +28 mV
Average Picture Value Change — 555 mV
8
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
+
Video
1 V
75
RIS
V IN
RIL
200K
75
RC
+
-AMP
1K
RF
2K
RG
47 µF
CI
12K
RA
+
V1
5 V
2.1VB
250
RPD
V AMP V OUT
75
RCL
36
RO
1 V
Figure 4.
PNP
1.4VB
0.1 µF
RB
CB
4.7K
47 µF
CO
Clamp
Option
2N3904
9
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
10
EL2420C
Quad, Low Cost, Gain of 1, Video Op Amp
EL2420C
General Disclaimer
Specifications c ontained in this data sheet ar e in effec t as of the publication date shown. Elantec, Inc. reser ves the ri ght to make changes in the ci r-
cuitry or specif ications contained herein at any time without notice. El antec, Inc. assumes no responsibilit y fo r 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 Sup port systems are equip ment intended t o sup-
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 con-
templa ting applica tion of E lantec, Inc . Products in Life Supp ort
Systems are requested to contact Elantec, Inc. factory headquarters
to establish suitable terms & conditions for these applications. Elan-
tec, Inc.’s warranty is limited to replacement of defective
component s and does no t cover injur y to persons or property or
other consequential damages.
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
April 1998 Rev B
Printed in U.S.A.