general description the ald2706 is a dual monolithic cmos micropower high slew-rate operational amplifier intended for a broad range of analog applications using 1v to 6v dual power supply systems, as well as +2v to +12v battery operated systems. all device characteristics are specified for +5v single supply or 2.5v dual supply systems. supply current is 80 m a maximum at 5v supply voltage. it is manufactured with advanced linear devices' enhanced a cmos silicon gate cmos process. the ald2706 is designed to offer a trade-off of performance parameters providing a wide range of desired specifications. it offers the popular industry standard pin configuration. the ald2706 has been developed specifically for the +5v single supply or 1v to 6v dual supply user. several important characteristics of the device make application easier to implement at those voltages. first, each operational amplifier can operate with rail to rail input and output voltages. this means the signal input voltage and output voltage can be equal to the positive and negative supply voltages. this feature allows numerous analog serial stages and flexibility in input signal bias levels. secondly, each device was designed to accommodate mixed applications where digital and analog circuits may operate off the same power supply or battery. thirdly, the output stage can typically drive up to 25pf capacitive and 20k w resistive loads. these features, combined with extremely low input currents, high open loop voltage gain of 100v/mv, useful bandwidth of 200khz, a slew rate of 0.1v/ m s, low offset voltage and temperature drift, make the ald2706 a versatile, micropower dual operational amplifier. a typical ald2706 has the capacity to process a 0.998v amplitude analog signal with only 1.000v single supply voltage, while requiring only 0.1pa input bias current. dual ultra micropower rail-to-rail cmos operational amplifier ald2706a/ald2706b ald2706 a dvanced l inear d evices, i nc. features ? typical 20 m a supply current per amplifier ? all parameters specified for +5v single supply or 2.5v dual supply systems ? rail-to-rail input and output voltage ranges ? unity gain stable ? extremely low input bias currents -- 0.1pa ? high source impedance applications ? dual power supply 1.0v to 6.0v ? single power supply +2v to +12v ? high voltage gain ? unity gain bandwidth of 0.2mhz ? slew rate of 0.1v/ m s ? symmetrical output drive applications ? voltage follower/buffer/amplifier ? charge integrator ? photodiode amplifier ? data acquisition systems ? high performance portable instruments ? signal conditioning circuits ? sensor and transducer amplifiers ? low leakage amplifiers ? active filters ? sample/hold amplifier ? picoammeter ? current to voltage converter pin configuration operating temperature range -55 c to +125 c0 c to +70 c0 c to +70 c 8-pin 8-pin 8-pin cerdip small outline plastic dip package (soic) package ald2706a da ald2706a sa ald2706a pa ald2706b da ald2706b sa ald2706b pa ald2706 da ald2706 sa ald2706 pa ordering information * contact factory for industrial temperature range 2 3 4 8 7 5 top view da, pa, sa package v - out a -in a +in a +in b -in b out b v + 6 1 ? 1998 advanced linear devices, inc. 415 tasman drive, sunnyvale, california 94089 -1706 tel: (408) 747-1155 fax: (408) 747-1286 http://www.aldinc.com
ald2706a/ald2706b advanced linear devices 2 ald2706 supply v s 1.0 6.0 1.0 6.0 1.0 6.0 v dual supply voltage v + 2.0 12.0 2.0 12.0 2.0 12.0 v single supply input offset v os 2.0 5.0 10.0 mv r s 100k w voltage 2.8 5.8 11.0 mv 0 c t a +70 c input offset i os 0.1 20 0.1 20 0.1 20 pa t a = 25 c current 200 200 200 pa 0 c t a +70 c input bias i b 0.1 20 0.1 20 0.1 20 pa t a = 25 c current 200 200 200 pa 0 c t a +70 c input voltage v ir -0.3 5.3 -0.3 5.3 -0.3 5.3 v v + = +5 range -2.8 2.8 -2.8 2.8 -2.8 2.8 v v s = 2.5v input resistance r in 10 12 10 12 10 12 w input offset voltage drift tcv os 7710 m v/ cr s 100k w power supply psrr 65 80 65 80 60 80 db r s 100k w rejection ratio 65 80 65 80 60 80 db 0 c t a +70 c common mode cmrr 65 83 65 83 60 83 db r s 100k w rejection ratio 65 83 65 83 60 83 db 0 c t a +70 c large signal a v 10 100 10 100 5 80 v/mv r l = 100k w voltage gain 300 300 300 v/mv r l 3 1m w 10 10 5 v/mv r l = 100k w 0 c t a +70 c output v o low 0.001 0.01 0.001 0.01 0.001 0.01 v r l = 1m w v + = +5v voltage v o high 4.99 4.999 4.99 4.999 4.99 4.999 v 0 c t a +70 c range v o low -2.40 -2.25 -2.40 -2.25 -2.40 -2.25 v r l = 100k w v o high 2.25 2.40 2.25 2.40 2.25 2.40 v 0 c t a +70 c output short circuit current i sc 200 200 200 m a supply current i s 50 80 50 80 50 80 m av in =0v no load power both amplifiers dissipation p d 400 400 400 m wv s = 2.5v operating electrical characteristics t a = 25 c v s = 2.5v unless otherwise specified 2706a 2706b 2706 test parameter symbol min typ max min typ max min typ max unit conditions absolute maximum ratings supply voltage, v + 13.2v differential input voltage range -0.3v to v + +0.3v power dissipation 600 mw operating temperature range pa,sa package 0 c to +70 c da package -55 c to +125 c storage temperature range -65 c to +150 c lead temperature, 10 seconds +260 c
ald2706a/ald2706b advanced linear devices 3 ald2706 v s = 2.5v -55 c t a +125 c unless otherwise specified input offset voltage v os 3.0 6.0 12.0 mv r s 100k w input offset current i os 4.0 4.0 4.0 na input bias current i b 4.0 4.0 4.0 na power supply rejection ratio psrr 60 75 60 75 60 75 db r s 1m w common mode rejection ratio cmrr 60 83 60 83 60 83 db r s 1m w large signal voltage gain a v 10 50 10 50 5 50 v/mv r l = 1m w output voltage v o low -2.40 -2.25 -2.40 -2.25 -2.40 -2.25 v range v o high 2.25 2.40 2.25 2.40 2.25 2.40 v r l = 1m w 2706a da 2706b da 2706 da test parameter symbol min typ max min typ max min typ max unit conditions input capacitance c in 111pf bandwidth b w 200 200 200 khz slew rate s r 0.1 0.1 0.1 v/ m sa v = +1 r l = 100k w rise time t r 1.0 1.0 1.0 m sr l = 100k w overshoot 20 20 20 % r l = 100k w factor c l = 25pf settling 10.0 10.0 10.0 m s 0.1% time t s a v = -1 c l = 25pf r l = 100k w channel separation c s 140 140 140 db a v = 100 power supply rejection ratio psrr 80 80 80 db r s 1m w common mode rejection ratio cmrr 80 80 80 db r s 1m w large signal voltage gain a v 50 50 50 v/mv r l = 1m w output voltage v o low -0.95 -0.9 -.95 -0.9 -0.95 -0.9 v r l = 1m w range v o high 0.9 0.95 0.9 0.95 0.9 0.95 v bandwidth b w 0.2 0.2 0.2 mhz slew rate s r 0.1 0.1 0.1 v/ m sa v =+1 c l = 25pf t a = 25 c v s = 1.0v unless otherwise specified 2706a 2706b 2706 test parameter symbol min typ max min typ max min typ max unit conditions operating electrical characteristics (cont'd) t a = 25 c v s = 2.5v unless otherwise specified 2706a 2706b 2706 test parameter symbol min typ max min typ max min typ max unit conditions
ald2706a/ald2706b advanced linear devices 4 ald2706 design & operating notes: 1. the ald2706 cmos operational amplifier uses a 3 gain stage architecture and an improved frequency compensation scheme to achieve large voltage gain, high output driving capability, and better frequency stability. in a conventional cmos operational amplifier design, compensation is achieved with a pole splitting capacitor together with a nulling resistor. this method is, however, very bias dependent and thus cannot accommodate the large range of supply voltage operation as is required from a stand alone cmos operational amplifier. the ald2706 is internally compensated for unity gain stability using a novel scheme that does not use a nulling resistor. this scheme produces a clean single pole roll off in the gain characteristics while providing for more than 70 degrees of phase margin at the unity gain frequency. 2. the ald2706 has complementary p-channel and n-channel input differential stages connected in parallel to accomplish rail to rail input common mode voltage range. this means that with the ranges of common mode input voltage close to the power supplies, one of the two differential stages is switched off internally. to maintain compatibility with other operational amplifiers, this switching point has been selected to be about 1.5v below the positive supply voltage. since offset voltage trimming on the ald2706 is made when the input voltage is symmetrical to the supply voltages, this internal switching does not affect a large variety of applications such as an inverting amplifier or non- inverting amplifier with a gain larger than 2.5 (5v operation), where the common mode voltage does not make excursions above this switching point. the user should however, be aware that this switching does take place if the operational amplifier is connected as a unity gain buffer and should make provision in his design to allow for input offset voltage variations. 3. the input bias and offset currents are essentially input protection diode reverse bias leakage currents, and are typically less than 1pa at room temperature. this low input bias current assures that the analog signal from the source will not be distorted by input bias currents. normally, this extremely high input impedance of greater than 10 12 w would not be a problem as the source impedance would limit the node impedance. however, for applications where source impedance is very high, it may be necessary to limit noise and hum pickup through proper shielding. 4. the output stage consists of class ab complementary output drivers, capable of driving a low resistance load. the output voltage swing is limited by the drain to source on-resistance of the output transistors as determined by the bias circuitry, and the value of the load resistor. when connected in the voltage follower configuration, the oscillation resistant feature, combined with the rail to rail input and output feature, makes an effective analog signal buffer for medium to high source impedance sensors, transducers, and other circuit networks. 5. the ald2706 operational amplifier has been designed to provide full static discharge protection. internally, the design has been carefully implemented to minimize latch up. however, care must be exercised when handling the device to avoid strong static fields that may degrade a diode junction, causing increased input leakage currents. in using the operational amplifier, the user is advised to power up the circuit before, or simultaneously with, any input voltages applied and to limit input voltages to not exceed 0.3v of the power supply voltage levels. 6. the ald2706, with its micropower operation, offers numerous benefits in reduced power supply requirements, less noise coupling and current spikes, less thermally induced drift, better overall reliability due to lower self heating, and lower input bias current. it requires practically no warm up time as the chip junction heats up to only 0.1 c above ambient temperature under most operating conditions. typical performance characteristics input bias current as a function of ambient temperature ambient temperature ( c) 1000 100 10 0.1 1.0 input bias current (pa) 100 -25 0 75 125 50 25 -50 10000 v s = 2.5v open loop voltage gain as a function of load resistance 10m load resistance ( ) 10k 100k 1m 1000 100 10 1 open loop voltage gain (v/mv) v s = 2.5v t a = 25 c supply current as a function of supply voltage supply voltage (v) 160 120 40 80 0 supply current ( a) 0 1 2 3 4 5 6 t a = -55 c -25 c +25 c +70 c +125 c inputs grounded output unloaded common mode input voltage range as a function of supply voltage supply voltage (v) common mode input voltage range (v) 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 t a = 25 c
ald2706a/ald2706b advanced linear devices 5 ald2706 typical performance characteristics output voltage swing as a function of supply voltage supply voltage (v) 0 1 2 3 4 7 6 5 6 5 4 3 2 1 output voltage swing (v) 25 c t a +125 c r l = 100k input offset voltage as a function of ambient temperature representative units ambient temperature ( c) input offset voltage (mv) -50 -25 0 +25 +50 +75 +100 +125 +4 +5 +3 +1 +2 0 -2 -1 -4 -3 -5 v s = 2.5v input offset voltage as a function of common mode input voltage common mode input voltage (v) -2 -1 0 +1 +3 +2 15 10 5 -5 -10 0 -15 input offset voltage (mv) v s = 2.5v t a = 25 c small - signal transient response 100mv/div 50mv/div 10 s/div v s = 2.5v t a = 25 c r l = 100k c l = 25pf open loop voltage gain as a function of frequency frequency (hz) 1 10 100 1k 10k 1m 10m 100k 120 100 80 60 40 20 0 -20 open loop voltage gain (db) v s = 2.5v t a = 25 c 90 0 45 180 135 phase shift in degrees large - signal transient response v s = 1.0v t a = 25 c r l = 100k c l = 25pf 2v/div 500mv/div 10 s/div large - signal transient response 2v/div 10 s/div 5v/div v s = 2.5v t a = 25 c r l = 100k c l = 25pf open loop voltage gain as a function of supply voltage and temperature supply voltage (v) 1000 100 10 1 open loop voltage gain (v/mv) 0 2 4 6 55 c t a +125 c r l = 100k 8
ald2706a/ald2706b advanced linear devices 6 ald2706 typical applications rail-to-rail voltage follower/buffer high input impedance rail-to-rail precision dc summing amplifier low voltage instrumentation amplifier rail-to-rail window comparator rail-to-rail waveform performance waveforms. upper trace is the output of a wien bridge oscillator. lower trace is the output of rail-to-rail voltage follower. 0v +5v output 0v +5v input photo detector current to voltage converter + - +2.5v -2.5v r f = 5m i photodiode v out = 1 x r f r l = 100k 1/2 ald2706 high impedance non-inverting amplifier + +1v -1v 900k 100k v out v in 1/2 ald2706 - + output 5v 0.1 f * see rail to rail waveform 0 v in 5v v in z in = 10 12 ~ 1/2 ald2706 v- = - 2.5v 10m 10m 10m 10m 10m 10m r in = 10m accuracy limited by resistor tolerances and input offset voltage v+ = +2.5v - + 0.1 f 0.1 f v out v- v out v+ v 1 v 4 v 3 v 2 v out = v 1 + v 2 - v 3 - v 4 r1 50k 100k r3 100k f max = 20khz -40mv v in 40mv 0.1 f 0.1 f v+ v- - + - + r2 100k 100k - r4 500k 0.1 f v+ v+ 1m + 1m v- v- 0.1 f v out 1/2 ald2706 1/2 ald2706 1/2 ald2706 v+ = +1.0v v- = -1.0v v- v out v+ all resistors are 1%. r1 r3 v out = v in ( 1+ 2r2 ) (r4) = 25 v in +5v + - + - v in 100k v ref (high) v ref (low) 3 2 5 6 8 4 1 7 1/4 74 c00 1/2 ald2706 v out v out (low) for v ref (low) < v in < v ref(high) 100k 1/2 ald2706
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