EL2420CS - Intersil Corporation

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 .

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 0Ω 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 V/µs slew rate

•Drives 150Ω 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

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 Ω, 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 IµA

OS Input Offset Current 0.3 1.0 IµA

TCIOS Average Offset Current Drift [1] -1 -3 V nA/°C

AVOL Open Loop Gain VOUT=..5, 2.5, RL= 1KΩ160 250 I V/V

VOUT=..5, 2.5, RL= 150KΩ160 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

OUT Output Voltage Swing RFB = RG = 1K, RL = 150Ω2.8 3.2 V

ISC Output Short Circuit Current Output to Ground [2] 75 125 ImA

SSupply Current No Load (per channel) VIN = 0V 2.0 2.4 3.0 ImA

IN Input Resistance Differential 150 VKΩ

Common Mode 1.5 VMΩ

IN Input Capacitance AV = +1 @ 10 MHz 1 VpF

OUT Output Resistance 0.150 V Ω

PSOR Power Supply Operating Range Single Supply 4 6 VV

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 = 150Ω

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%

PD Propagation Delay 3.5 Vns

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( ° )

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

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

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 1250Ω 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 Ω b ac k ma tc hi ng

resistor dr iv ing a t erm inat ed 75Ω 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 250Ω resistor to ground directly at the amplifier

output. Then if the 75Ω 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

75Ω back matching resistor to a cable and a 75Ω load to

ground a t t he en d of t he cab le pr ovi de a 15 0 Ω 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 250Ω 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.

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

RIS

V IN

RIL

4.7K

RB +

-AMP

0.1 µF

68K

0.32 VB

–V1

5 V

0.64 VB

250

RPD

V AMP V OUT

RCL

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

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 36Ω, 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 75Ω 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 KΩ 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 KΩ 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

EL2420C

Quad, Low Cost, Gain of 1, Video Op Amp

EL2420C

–Video

1 V

RIS

V IN

RIL

200K

-AMP

47 µF

12K

–V1

5 V

2.1VB

250

RPD

V AMP V OUT

RCL

1 V

Figure 4.

PNP

1.4VB

0.1 µF

4.7K

47 µF

Clamp

Option

2N3904

EL2420C

Quad, Low Cost, Gain of 1, Video Op Amp

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.