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? 1998 elantec, inc. el5144c, el5146c, el5244c, el5246c, el5444c general description the el5144c series amplifiers are voltage feedback, high speed, rail to rail amplifiers designed to operate on a single +5v supply. they offer unity gain stability with an unloaded ?3db bandwidth of 100 mhz. the input common mode voltage range extends from the nega- tive rail to within 1.5v of the positive rail. driving a 75 ? double terminated coaxial cable, the el5144c series amplifiers drive to within 150 mv of either rail. the 200 v/ sec slew rate and 0.1% / 0.1 differential gain / differential phase makes these parts ideal for com- posite and component video applications. with its voltage feedback architecture, this amplifier can accept reactive feedback networks, allowing them to be used in analog filtering applications these ampli- fiers will source 90 ma and sink 65 ma. the el5146c and el5246c have a power-savings disable feature. applying a standard ttl low logic level to the ce (chip enable) pin reduces the supply current to 2.6 a within 10 nsec. turn on time is 500 nsec, allowing true break-before-make conditions for multiplex- ing applications. allowing the ce pin to float or applying a high logic level will enable the amplifier. for applications where board space is critical, singles are offered in a sot23-5 package, duals in msop-8 and msop-10 packages, and quads in a qsop-16 package. singles, duals and quads are also avail- able in industry standard pinouts in soic and pdip packages. all parts operate over the industrial temperature range of -40 c to +85 c. out gnd v s in- in+ sot23-5 1 2 3 5 4 - + el5144c dual and quad amplifier pin configurations on page 12 pin configurations 1 2 3 4 8 7 6 5 - + in- in+ gnd nc out v s nc ce soic-8, pdip-8 el5146c features rail to rail output swing -3 db bandwidth = 100 mhz single supply +5v operation power down to 2.6 a large input common mode range 0v < v cm < 3.5 v diff gain/phase = 0.1%/0.1 low power 35mw per amplifier space saving sot23-5, msop- 8&10, & qsop-16 packaging applications video amplifier 5 volt analog signal processing multiplexer line driver portable computers high speed communications sample & hold amplifier comparator ordering information part no temp. range package outline # el5144cw -40 c to +85 c 5 pin sot23 mdp0038 el5146cn -40 c to +85 c 8 pin pdip mdp0031 el5146cs -40 c to +85 c 8 pin soic mdp0027 el5244cn -40 c to +85 c 8 pin pdip mdp0031 EL5244CS -40 c to +85 c 8 pin soic mdp0027 el5244cy -40 c to +85 c 8 pin msop mdp0043 el5246cn -40 c to +85 c 14 pin pdip mdp0031 el5246cs -40 c to +85 c 14 pin soic mdp0027 el5246cy -40 c to +85 c 10 pin msop mdp0043 el5444cn -40 c to +85 c 14 pin pdip mdp0031 el5444cs -40 c to +85 c 14 pin soic mdp0027 el5444cu -40 c to +85 c 16 pin qsop mdp0040 0v 5v el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier march 1, 2000
2 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c absolute maximum ratings (t a = 25 c) values beyond absolute maximum ratings can cause the device to be pre- maturely damaged. absolute maximum ratings are stress ratings only and functional device operation is not implied . supply voltage between v s and gnd +6v maximum continuous output current 50ma power dissipation see curves pin voltages gnd - 0.5v to v s +0.5v storage temperature -65 c to +150 c operating temperature -40 c to +85 c lead temperature 260 c important note: all parameters having min/max specifications are guaranteed. typ values are for information purposes only. unless otherwise not ed, all tests are at the specified temperature and are pulsed tests, therefore: t j = t c = t a . electrical characteristics v s =+5v, gnd=0v, t a =25 c, ce = +2v, unless otherwise specified. parameter description conditions min typ max units ac performance dg differential gain error [1] g=2, r l =150 ? to 2.5v, r f =1k ? 0.1 % dp differential phase error [1] g=2, r l =150 ? to 2.5v, r f =1k ? 0.1 deg bw bandwidth -3db, g=1, r l =10k ?, r f =0 100 mhz -3db, g=1, r l =150 ?, r f =0 60 mhz bw1 bandwidth 0.1db, g=1, r l =150 ? to gnd, r f =0 8 mhz gbwp gain bandwidth product 60 mhz sr slew rate g=1, r l =150 ? to gnd, r f =0, v o =0.5v to 3.5v 150 200 v/s ts settling time to 0.1%, v out = 0 to 3v 35 ns dc performance a vol open loop voltage gain r l =no load, v out =0.5v to 3v 54 65 db r l =150 ? to gnd, v out =0.5v to 3v 40 50 db v os offset voltage v cm =1v, sot23-5 and msop packages 25 mv v cm =1v, all other packages 15 mv t c v os input offset voltage temperature coefficient 10 v/ o c i b input bias current v cm =0v & 3.5v 2 100 na input characteristics cmir common mode input range cmrr 47db 0 3.5 v cmrr common mode rejection ratio dc, v cm = 0 to 3.0v 50 60 db dc, v cm = 0 to 3.5v 47 60 db r in input resistance 1.5 g ? c in input capacitance 1.5 pf output characteristics v op positive output voltage swing r l =150 ? to 2.5v [2] 4.70 4.85 v r l =150 ? to gnd [2] 4.20 4.65 v r l =1k ? to 2.5v [2] 4.95 4.97 v v on negative output voltage swing r l =150 ? to 2.5v [2] 0.15 0.30 v r l =150 ? to gnd [2] 0v r l =1k to 2.5v [2] 0.03 0.05 v +i out positive output current r l =10 ? to 2.5v 60 90 120 ma
3 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c -i out negative output current r l =10 ? to 2.5v -50 -65 -80 ma enable (el5146c & el5246c only) t en enable time el5146c, el5246c 500 ns t dis disable time el5146c, el5246c 10 ns i ihce ce pin input high current ce = 5v, el5146c, el5246c 0.003 1 a i ilce ce pin input low current ce = 0v, el5146c, el5246c -1.2 -3 a v ihce ce pin input high voltage for power up el5146c, el5246c 2.0 v v ilce ce pin input low voltage for power down el5146c, el5246c 0.8 v supply is on supply current - enabled (per amplifier) no load, v in = 0v, ce=5v 7 8.8 ma is off supply current - disabled (per amplifier) no load, v in = 0v, ce=0v 2.6 5 a psor power supply operating range 4.75 5.0 5.25 v psrr power supply rejection ratio dc, v s = 4.75v to 5.25v 50 60 db 1. standard ntsc test, ac signal amplitude = 286 mv p-p , f=3.58 mhz, vout is swept from 0.8v to 3.4v, rl is dc coupled 2. r l is total load resistance due to feedback resistor and load resistor electrical characteristics v s =+5v, gnd=0v, t a =25 c, ce = +2v, unless otherwise specified. parameter description conditions min typ max units
4 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c typical performance curves inverting frequency response (gain) v cm = 1.5v, r f = 1k ?, r l = 150 ? 1m 10m 100m -6 -4 -2 0 +2 magnitude (normailzed) (db) frequency (hz) 1 a v = -1 a v = -2 a v = -5.6 inverting frequency response (phase) v cm = 1.5v, r f = 1k ?, r l = 150 ? 1m 10m 100m 0 45 90 135 180 phase ( ) frequency (hz) 2 a v = -1 a v = -2 a v = -5.6 non-inverting frequency response (gain) v cm = 1.5v, r l = 150 ? 1m 10m 100m -8 -6 -4 -2 0 magnitude (normalized) (db) frequency (hz) 19 a v = +1, r f = 0 ? +2 a v = +2, r f = 1k ? a v = +5.6, r f = 1k ? non-inverting frequency response (phase) v cm = 1.5v, r l = 150 ? 1m 10m 100m -180 -135 -90 -45 0 frequency(hz) 15 phase ( ) a v = +2, r f = 1k ? a v = +1, r f = 0 ? a v = +5.6, r f = 1k ? 3db bandwidth vs. die temperature for various gains rl = 10k ? 3db bandwidth (mhz) die temperature ( c) 51 0 30 60 90 120 -55 -15 25 65 145 105 145 150 a v = +1, r f = 0 ? a v = +2, r f = 1k ? a v = +5.6, r f = 1k ? 3db bandwidth vs. die temperature for various gains rl = 150 ? 3db bandwidth (mhz) die temperature ( c) 52 0 20 40 60 80 -55 -15 25 65 145 105 145 100 a v = +1, r f = 0 ? a v = +2, r f = 1k ? a v = +5.6, r f = 1k ?
5 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c group delay vs. frequency 1m 10m 100m group delay (nsec) frequency (hz) 23 0 2 4 6 8 10 a v = +2 r f = 1k ? a v = +1 r f = 0 ? frequency response for various r l v cm = 1.5v, r f = 0 ?, a v = +1 1m 10m 100m -4 -2 0 +2 +4 magnitude (normalized) (db) frequency (hz) 16 r l = 10k ? r l = 520 ? r l = 150 ? r l = 520 ? frequency response for various c l v cm = 1.5v, r l = 150 ?, a v = +1 1m 10m 100m -8 -4 0 +4 +8 magnitude (normalized) (db) frequency (hz) 17 c l = 47pf c l = 22pf c l = 0pf c l = 100pf frequency response for various r f and r g v cm = 1.5v,r l = 150 ?, a v = +2 1m 10m 100m -4 -2 0 +2 magnitude (normalized) (db) frequency (hz) 18 r f = r g = 1k ? r f = r g = 560 ? -6 r f = r g = 2k ? open loop gain and phase vs. frequency 1k 100k 10m gain (db) frequency (hz) 29 0 20 40 60 80 r l = 1k ? gain r l = 150 ? phase 180 135 90 45 0 phase ( ) open loop voltage gain vs. die temperature open loop gain (db) die temperature ( c) 43 30 40 50 60 70 -55 -15 25 65 145 105 145 80 no load r l =150 ?
6 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c output voltage swing vs. frequency for thd < 1% r f = 1k ?, a v = +2 1m 10m 100m output voltage swing (vpp) frequency (hz) 21 0 1 2 3 4 5 r l = 500 ? to 2.5v r l = 150 ? to 2.5v output voltage swing vs. frequency for thd < 0.1% r f = 1k ?, a v = +2 1m 10m 100m output voltage swing (vpp) frequency (hz) 22 0 1 2 3 4 5 r l = 500 ? to 2.5v r l = 150 ? to 2.5v 10k 100k 1m 10m 100m 0.2 200 20 2 closed loop output impedance vs. frequency r f = 0, a v = +1 closed loop (z 0 ) frequency (hz) 26 psrr and cmrr vs. frequency psrr, cmrr (db) frequency (hz) 28 -80 -60 -40 -20 0 +20 1k 10k 100k 1m 10m 100m cmrr -psrr +psrr offset voltage vs. die temperature (6 typical samples) offset voltage (mv) die temperature ( c) 39 -12 -6 0 6 12 -55 -15 25 65 145 105 145 1 10 100 1k 10 1k 100k 10m 10k voltage noise vs. frequency voltage noise (nv/ hz) frequency (hz) 65
7 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c slew rate vs. die temperature slew rate (v/s) die temperature ( c) -55 -15 25 65 145 105 145 200 150 250 48 large signal pulse response (split supplies) v s = 2.5v, r l = 150 ? to 0v, r f = 1k ?, a v = +2 output voltage (v) time (20ns/div) 61 -2 0 +2 large signal pulse response (single supply) v s = +5v, r l = 150 ? to 0v, r f = 1k ?, a v = +2 output voltage (v) time (20ns/div) 62 1 2 3 4 0 small signal pulse response (single supply) v s = +5v, r l = 150 ? to 0v, r f = 1k ?, a v = +2 output voltage (v) time (20ns/div) 63 1.3 1.5 1.7 small signal pulse response (split supply) v s = 2.5v, r l = 150 ? to 0v, r f = 1k ?, a v = +2 output voltage (v) time (20ns/div) 64 -0.2 0 +0.2 70 settling time vs. settling accuracy r l =1k ?, r f = 500 ?, a v = -1, v step = 3v 0.01 0.1 1.0 settling time (nsec) settling accuracy (%) 0 20 40 60 80 100
8 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c 0.5 2.0 3.5 differential gain for r l tied to 0v r f = 1k ?, a v = +2 differential gain (%) v out (v) 32 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? 0.5 2.0 3.5 differential phase for r l tied to 0v r f = 1k ?, a v = +2 differential phase ( ) v out (v) 34 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? 0.25 1.75 3.25 differential phase for r l tied to 0v r f = 0, a v = +1 differential phase ( ) v out (v) 53 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? 0.25 1.75 3.25 differential gain for r l tied to 0v r f = 0, a v = +1 differential gain (%) v out (v) 54 -0.08 -0.04 0 +0.04 +0.08 r l = 150 ? r l = 10k ? 0.5 2.0 3.5 differential gain for r l tied to 2.5v r f = 0, a v = +1 differential gain (%) v out (v) 56 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? 0.5 2.0 3.5 differential phase for r l tied to 2.5v differential phase ( ) v out (v) 55 -.02 -0.1 0 +0.1 +0.2 r l = r l = 0.5 2.0 3.5 differential phase for r l tied to 2.5v r f = 0, a v = +1 differential phase ( ) v out (v) -.02 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ?
9 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c 2nd and 3rd harmonic distortion vs. frequency v out = 0.25v to 2.25v, r l = 100 ? to 0v 1m 10m 100m -75 -65 -55 -45 -35 -25 distortion (dbc) frequency (hz) 5 2nd and 3rd harmonic distortion vs.frequency v out = 0.5v to 2.5v, r l = 100 ? to 0v 1m 10m 100m -75 -65 -55 -45 -35 -25 distortion (dbc) frequency (hz) 6 hd3 hd2 hd3 hd2 2nd and 3rd harmonic distortion vs. frequency v out = 1v to 3v, r l = 100 ? to 0v 1m 10m 100m distortion (dbc) frequency (hz) 7 -75 -65 -55 -45 -35 -25 hd3 hd2 0.5 2.0 3.5 differential gain for r l tied to 2.5v r f = 1k ?, a v = +2 differential gain (%) v out (v) 31 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? 0.5 2.0 3.5 differential phase for r l tied to 2.5v r f = 1k ?, a v = +2 differential phase ( ) v out (v) 33 -0.2 -0.1 0 +0.1 +0.2 r l = 150 ? r l = 10k ? channel to channel crosstalk- duals and quads (worst channel) crosstalk (db) frequency (hz) 27 100k 1m 10m 100m -100 -80 -60 -40 -20 0
10 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c r l =150 ? to 2.5v r l =150 ? to 0v negative output voltage swing vs. die temperature output voltage (v) die temperature ( c) -55 -15 25 65 145 105 145 0.4 0.3 0.1 0 0.2 0.5 41 supply current (per amp) vs. supply voltage supply current (ma) supply voltage (v) 44 0 2 4 6 8 01234 5 output current vs. die temperature r l = 10 ? to 2.5v output current (ma) die temperature ( c) 45 sink source -55 -15 25 65 145 105 145 100 80 40 20 60 120 supply current - on (per amp) vs. die temperature supply current (ma) die temperature ( c) 46 4 5 6 7 8 -55 -15 25 65 145 105 145 9 supply current - off (per amp) vs. die temperature supply current (a) die temperature ( c) -55 -15 25 65 145 105 145 4 3 1 0 2 5 47 positive output voltage swing vs. die temperature rl = 150 ? output voltage (v) die temperature ( c) 69 4.5 4.6 4.7 4.8 4.9 -55 -15 25 65 145 105 145 5.0 r l =150 ? to 0v r l =150 ? to 2.5v
11 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c output voltage from either rail vs. die temperature for various effective r load output voltage (mv) die temperature ( c) 40 effective r load = 150 ? 1 10 100 300 -55 -15 25 65 145 105 145 effective r load = 1k ? effective r load = 5k ? effective r load = r l //r f to v s /2 maximum power dissipation vs. ambient temperature duals ( t jmax = 150c) power dissipation (w) ambient temperature ( c) 66 pdip-14, ja = 87 c/w 0 0.5 1.0 1.5 2.5 2.0 -50 10 40 70 -20 100 soic-14, ja = 120 c/w pdip-8, ja = 107 c/w soic-8, ja = 159 c/w msop-8,10, ja = 206 c/w maximum power dissipation vs. ambient temperature quads ( t jmax = 150 c) power dissipation (w) ambient temperature ( c) 68 pdip-14, ja = 83 c/w 0 0.5 1.0 1.5 2.5 2.0 -50 10 40 70 -20 100 soic-14, ja = 118 c/w qsop-16, ja = 158 c/w maximum power dissipation vs. ambient temperature singles ( t jmax = 150 c) power dissipation (w) ambient temperature ( c) 67 pdip, ja = 110 c/w 0 0.4 0.8 1.2 2.0 1.6 -50 10 40 70 -20 100 soic, ja = 161 c/w sot23-5, ja = 256 c/w 71 10k 100k 1m 10m 100m -120 -100 -80 -60 -40 off isolation - el5146c & el5246c frequency (hz) magnitude (dbc) -20 el 5146cs & el5146cn el5246cs el5246cn
12 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c 1 2 3 4 14 13 12 11 5 6 7 10 9 8 1 2 3 4 16 15 14 13 5 6 7 12 11 10 8 9 1 2 3 4 14 13 12 11 5 6 7 10 9 8 1 2 3 4 6 5 10 9 8 7 - + - + msop-10 el5246c in a - out a v s out b in b - in a + cea gnd ceb in b + - + - + - + - + in d + in d - gnd out d in c - in c + out c gnd in a - in a + v s out a in b + in b - out b v s - + - + - + - + in a - in a + out a in b + in b - out b v s in d + in d - out d in c - in c + out c gnd - + - + nc out a in a - out b nc in b - v s nc cea in a + ceb nc in b + gnd 1 2 3 4 8 7 6 5 - + in b - out b in a - in a + gnd in b + v s out a - + soic-8, pdip-8, msop-8 soic-14, pdip-14 soic-14, pdip-14 qsop-16 el5444c el5444c el5244c el5246c single amplifier pin configurations on page 1 pin configurations
13 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c pin description el5144c (sot23-5) el5146c (so/pdip) el5244c (so/pdip/msop) el5246c (msop) el5246c (so/pdip) el5444c (so/pdip) el5444c (qsop) name function equivalent circuit 57881144,5v s positive power supply 244341112,13gndgr ound or negative power supply 3 3 in+ noninverting input 4 2 in- inverting input (reference circuit 1) 1 6 out amplifier output 31133in a + amplifier a noninverting input (reference circuit 1) 210142 2 in a - amplifier a inverting input (reference circuit 1) 191311out a amplifier a output (reference circuit 2) 55756in b + amplifier b noninverting input (reference circuit 1) 66867in b - amplifier b inverting input (reference circuit 1) 77978out b amplifier b output (reference circuit 2) 10 11 in c + amplifier c noninverting input (reference circuit 1) 910in c - amplifier c inverting input (reference circuit 1) 8 9 out c amplifier c output (reference circuit 2) 12 14 in d + amplifier d noninverting input (reference circuit 1) 13 15 in d - amplifier d inverting input (reference circuit 1) 14 16 out d amplifier d output (reference circuit 2) v s gnd circuit 1 v s gnd circuit 2
14 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c 8 ce enable (enabled when high) 2 3 cea enable amplifier a (enabled when high) (reference circuit 3) 4 5 ceb enable amplifier b (enabled when high) (reference circuit 3) 1,5 2,6, 10,12 nc no connect. not internally connected. pin description el5144c (sot23-5) el5146c (so/pdip) el5244c (so/pdip/msop) el5246c (msop) el5246c (so/pdip) el5444c (so/pdip) el5444c (qsop) name function equivalent circuit circuit 3 + ? v s 1.4v gnd
15 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c description of operation and applications information product description the el5144c series is a family of wide bandwidth, sin- gle supply, low power, rail-to-rail output, voltage feedback operational amplifiers. the family includes single, dual, and quad configurations. the singles and duals are available with a power down pin to reduce power to 2.6a typically. all the amplifiers are inter- nally compensated for closed loop feedback gains of +1 or greater. larger gains are acceptable but bandwidth will be reduced according to the familiar gain-band- width product. connected in voltage follower mode and driving a high impedance load, the el5144c series has a -3db band- width of 100 mhz. driving a 150 ? load, they have a -3db bandwidth of 60 mhz while maintaining a 200 v/ s slew rate. the input common mode voltage range includes ground while the output can swing rail to rail. 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 pin must be well bypassed to reduce the risk of oscillation for normal single supply operation, where the gnd pin is connected to the ground plane, a single 4.7 f tantalum capacitor in parallel with a 0.1 f ceramic capacitor from v s to gnd will suffice. this same capacitor combination should be placed at each supply pin to ground if split supplies are to be used. in this case, the gnd pin becomes the negative supply rail. for good ac performance, parasitic capacitance should be kept to a minimum. use of wire wound resistors should be avoided because of their additional series inductance. use of sockets, particularly for the so pack- age, should be avoided if possible. sockets add parasitic inductance and capacitance that can result in compro- mised performance. input, output, and supply voltage range the el5144c series has been designed to operate with a single supply voltage of 5v. split supplies can be used so long as their total range is 5v. the amplifiers have an input common mode voltage range that includes the negative supply (gnd pin) and extends to within 1.5v of the positive supply (v s pin). they are specified over this range. the output of the el5144c series amplifiers can swing rail to rail. as the load resistance becomes lower in value, the ability to drive close to each rail is reduced. however, even with an effective 150 ? load resistor connected to a voltage halfway between the supply rails, the output will swing to within 150mv of either rail.
16 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c figure 1 shows the output of the el5144c series ampli- fier swinging rail to rail with r f = 1k ? , a v = +2 and r l = 1m ? . figure 2 is with r l = 150 ? . choice of feedback resistor, r f these amplifiers are optimized for applications that require a gain of +1. hence, no feedback resistor is required. however, for gains greater than +1, the feed- back resistor forms a pole with the input capacitance. as this pole becomes larger, phase margin is reduced. this causes ringing in the time domain and peaking in the fre- quency domain. therefore, r f has some maximum value that should not be exceeded for optimum perfor- mance. if a large value of r f must be used, a small capacitor in the few picofarad range in parallel with r f can help to reduce this ringing and peaking at the expense of reducing the bandwidth. as far as the output stage of the amplifier is concerned, r f + r g appear in parallel with r l for gains other than +1. as this combination gets smaller, the bandwidth falls off. consequently, r f also has a minimum value that should not be exceeded for optimum performance. for a v = +1, r f = 0 ? is optimum. for a v = -1 or +2 (noise gain of 2), optimum response is obtained with r f between 300 ? and 1k ? . for a v = -4 or +5 (noise gain of 5), keep r f between 300 ? and 15k ? . video performance for good video signal integrity, an amplifier is required to maintain the same output impedance and the same fre- quency response as dc levels are changed at the output. this can be difficult when driving a standard video load of 150 ? , because of the change in output current with dc level. a look at the differential gain and differen- tial phase curves for various supply and loading conditions will help you obtain optimal performance. curves are provided for a v = +1 and +2, and r l = 150 ? and 10 k ? tied both to ground as well as 2.5v. as with all video amplifiers, there is a common mode sweet spot for optimum differential gain / differential phase. for example, with a v = +2 and r l = 150 ? tied to 2.5v, and the output common mode voltage kept between 0.8v and 3.2v, dg/dp is a very low 0.1% / 0.1 . this condi- tion corresponds to driving an ac-coupled, double terminated 75 ? coaxial cable. with a v = +1, r l = 150 ? tied to ground, and the video level kept between 0.85v and 2.95v, these amplifiers provide dg/dp per- formance of 0.05% / 0.20 . this condition is representative of using the el5144c series amplifier as a buffer driving a dc coupled, double terminated, 75 ? coaxial cable. driving high impedance loads, such as signals on computer video cards, gives similar or better dg/dp performance as driving cables. driving cables and capacitive loads the el5144c series amplifiers can drive 50pf loads in parallel with 150 ? with 4db of peaking and 100pf with 7db of peaking. if less peaking is desired in these appli- cations, a small series resistor (usually between 5 ? and 50 ? ) can be placed in series with the output to eliminate most peaking. however, this will obviously reduce the gain slightly. if your gain is greater than 1, the gain resistor (r g ) can then be chosen to make up for any gain 0v 5v figure 1 0v 5v figure 2
17 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c loss which may be created by this additional resistor at the output. another method of reducing peaking is to add a ? snubber ? circuit at the output. a snubber is a resistor in a series with a capacitor, 150 ? and 100pf being typical values. the advantage of a snubber is that it does not draw dc load current. when used as a cable driver, double termination is always recommended for reflection-free performance. for those applications, the back-termination series resis- tor will de-couple the el5144c series amplifier from the cable and allow extensive capacitive drive. however, other applications may have high capacitive loads with- out a back-termination resistor. again, a small series resistor at the output can reduce peaking. disable / power-down the el5146c and el5246c amplifiers can be disabled, placing its output in a high-impedance state. turn off time is only 10 nsec and turn on time is around 500 nsec. when disabled, the amplifier ? s supply current is reduced to 2.6a typically, thereby effectively eliminating power consumption. the amplifier ? s power down can be controlled by standard ttl or cmos signal levels at the ce pin. the applied logic signal is relative to the gnd pin. letting the ce pin float will enable the amplifier. hence, the 8 pin pdip and soic single amps are pin compatible with standard amplifiers that don ? t have a power down feature. short circuit current limit the el5144c series amplifiers do not have internal short circuit protection circuitry. short circuit current of 90 ma sourcing and 65 ma sinking typically will flow if the output is trying to drive high or low but is shorted to half way between the rails. if an output is shorted indef- initely, the power dissipation could easily increase such that the part will be destroyed. maximum reliability is maintained if the output current never exceeds 50ma. this limit is set by internal metal interconnect limita- tions. obviously, short circuit conditions must not remain or the internal metal connections will be destroyed. power dissipation with the high output drive capability of the el5144c series amplifiers, it is possible to exceed the 150 c absolute maximum junction temperature under certain load current conditions. therefore, it is important to cal- culate the maximum junction temperature for the application to determine if load conditions or package type need to be modified for the amplifier to remain in the safe operating area. the maximum power dissipation allowed in a package is determined according to: where: t jmax = maximum junction temperature t amax = maximum ambient temperature ja = thermal resistance of the package pd max = maximum power dissipation in the package. the maximum power dissipation actually produced by an ic is the total quiescent supply current times the total power supply voltage, plus the power in the ic due to the load, or: where: n = number of amplifiers in the package v s = total supply voltage pd max t jmax t amax ? ja ---------------------------------------------- = pd max nv s i smax v ( s v out ) v out r l --------------- - ? ? + ? ?? ?? ?? ? =
18 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c i smax = maximum supply current per amplifier v out = maximum output voltage of the application r l = load resistance tied to ground if we set the two pd max equations equal to each other, we can solve for r l : assuming worst case conditions of t a = +85 c, vout = v s /2 v, v s = 5.5v, and i smax = 8.8ma per amplifier, below is a table of all packages and the minimum r l allowed. el5144c series comparator application the el5144c series amplifier can be used as a very fast, single supply comparator. most op amps used as a com- parator allow only slow speed operation because of output saturation issues. the el5144c series amplifier doesn ? t suffer from output saturation issues. figure 3 shows the amplifier implemented as a comparator. fig- ure 4 is a graph of propagation delay vs. overdrive as a square wave is presented at the input of the comparator. multiplexing with the el5144c series amplifier besides normal power down usage, the ce (chip enable) pin on the el5146c and el5246c series ampli- fiers also allow for multiplexing applications. figure 5 shows an el5246c with its outputs tied together, driv- ing a back terminated 75 ? video load. a 3 vp-p 10 mhz sine wave is applied at amp a input, and a 2.4 vp-p 5 mhz square wave to amp b. figure 6 shows the select signal that is applied, and the resulting output waveform at v out . observe the break-before-make operation of the multiplexing. amp a is on and v in1 is being passed through to the output of the amplifier. then amp a turns off in about 10 nsec. the output decays to part package minimum r l el5144cw sot23-5 37 el5146cs soic-8 21 el5146cn pdip-8 14 EL5244CS soic-8 48 el5244cn pdip-8 30 el5244cy msop-8 69 el5246cy msop-10 69 el5246cs soic-14 34 el5246cn pdip-14 23 el5444cu qsop-16 139 el5444cs soic-14 85 el5444cn pdip-14 51 r l v out v s v out ) ? ( ? t jmax t amax ? n ? ja ---------------------------------------------- ?? ?? ?? v s i smax ? () ? ---------------------------------------------------------------------------------------------- = 1 2 3 4 8 7 6 5 + ? - + el5146c +5v v in +2.5v v out r l 0.1f propagation delay vs. overdrive for amplifier used as a comparator 0.01 0.1 1.0 10 100 1000 propagation delay(nsec) overdrive (v) 8 negative going signal positive going signal figure 3 figure 4
19 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c ground with an r l c l time constants. 500 nsec later, amp b turns on and v in2 is passed through to the out- put. this break-before-make operation ensures that more than one amplifier isn ? t trying to drive the bus at the same time. notice the outputs are tied directly together. isolation resistors at each output are not necessary. free running oscillator application figure 7 is an el5144c configured as a free running oscillator. to first order, r osc and c osc determine the frequency of oscillation according to: for rail to rail output swings, maximum frequency of oscillation is around 15 mhz. if reduced output swings are acceptable, 25 mhz can be achieved. figure 8 shows the oscillator for r osc = 510 ? , c osc = 240 pf and f osc = 6 mhz. 1 2 3 4 14 13 12 11 5 6 7 10 9 8 - + - + select +5v v out 150 ? v in 1 3v pp 10mhz 0.1f 4.7f v in 2 2.4v pp 5mhz el5246c 0v 5v figure 6 v out select 0v 5v figure 5 f osc 0.72 r osc c ? osc ----------------------------------- - = figure 7 figure 8 5v v out 0v 1 2 3 5 4 - + +5v 470k 470k 0.1f 470k r osc c osc
20 el5144c, el5146c, el5244c, el5246c, el5444c 100 mhz single supply rail to rail amplifier el5144c, el5146c, el5244c, el5246c, el5444c 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- 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- templating 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. elan- tec, inc. ? s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages. elantec semiconductor, inc. 675 trade zone blvd. milpitas, ca 95035 telephone: (408) 945-1323 toll free: 1 - (888) elantec fax: (408) 945-9305 european office: 44-118-977-6020 march 1, 2000 printed in u.s.a. 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 cir- cuitry or specifications contained herein at any time without notice. elantec, inc. assumes no responsibility for the use of an y circuits described herein and makes no representations that they are free from patent infringement. japan tech center: 81-45-682-5820 web site: http://www.elantec.com

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