?2014 advanced linear devices, inc., vers. 2.0 www.aldinc.com 1 of 9 e epad tm ? n a b l e d e precision dual micropower cmos operational amplifier ald2731a/ald2731 a dvanced l inear d evices, i nc. general description the ald2731a/ald2731 is a precision dual low-cost high-slew-rate monolithic cmos micropower operational amplifier intended for a broad range of analog applications using 1v to 5v dual power supply systems, as well as +2v to +10v battery operated systems. all device characteristics are specified for +5v single supply or 2.5v dual supply systems. supply current is 250 a per amplifier maximum at 5v supply voltage. it is manufactured with advanced linear devices' enhanced epad ? silicon gate cmos process. the ald2731a/ald2731 features extremely low input power require- ments, practically removing any leading effects on high source imped- ance signal sources such as cpacitive sensors. these devices do not add any significant errors, regardless of what the souce impedance variations may be, thereby improving overall system precision and accuracy. the device is designed to offer the benefits of cmos technology by providing a wide range of desired specifications. the most important of these specifications is extremely low input bias/offset currents at extremely low input offset voltages. it has been developed specifically for the +5v single supply or 1v to 5v dual supply user and offers the popular industry standard pin configuration of a741 and icl7611 types. several additional important characteristics of the device make applica- tion easier to implement at those voltages. first, the 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. second, the device was designed to accommodate mixed applications where digital and analog circuits may operate off the same power supply or battery. third, the output stage can typically drive up to 50pf capacitive and 10k ? resistive loads. these features, combined with extremely low input currents, high open loop voltage gain of 100v/mv, useful bandwidth of 700khz, a slew rate of 0.7v/ s, low power dissipation of 0.5mw, low offset voltage and temperature drift, make the ald2731a/ald2731 a versatile, micropower operational amplifier. the ald2731a/ald2731, designed and fabricated with silicon gate cmos technology, offers 0.01pa typical input bias current. on chip offset voltage trimming, using epad technology, allows the device to be used without nulling. additionally, robust design and rigorous screening make this device especially suitable for operation in temperature-extreme environments and rugged conditions. features & benefits ? two package versions -- lead-free (rohs compliant) and legacy leaded (tin-lead) ? extremely low input offset voltages -- 0.6mv typical ? extremely low input bias currents -- 0.01pa typical ? all parameters specified for +5v single supply or 2.5v dual supply systems ? rail to rail input and output voltage ranges ? no frequency compensation required -- unity gain stable ? ideal for high source impedance applications ? dual power supplies 1.0v to 5.0v ? single power supply +2.0v to +10.0v ? high voltage gain -- typ. 100v/mv @ 2.5v ? drive as low as 10k ? load ? output short circuit protected ? unity gain bandwidth of 0.7mhz ? slew rate of 0.7v/ s ? micropower symmetrical complementary output drive ? suitable for rugged, temperature-extreme environments applications ? voltage amplifier ? voltage follower/buffer ? 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 * contact factory for leaded (non-rohs) or high temperature versions. ordering information (?l? suffix denotes lead-free (rohs)) operating temperature range 0 c to +70 c0 c to +70 c -55 c to 125 c 8-pin 8-pin 8-pin small outline plastic dip cerdip package (soic) package package ald2731asal ald2731apal ald2731sal ald2731pal ald2731asa ald2731apa ald2731ada ald2731sa ald2731pa ALD2731DA pin configuration top view sal, pal, sa, pa, da packages 1 2 3 4 8 7 6 5 out a -in a +in a v + -in b +in b v - out b
ald2731a/ald2731 advanced linear devices 2 of 9 supply voltage, v + 10.6v differential input voltage range -0.3v to v + +0.3v power dissipation 600mw operating temperature range sal, pal, sa, pa packages 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 caution: esd sensitive device. use static control procedures in esd controlled environment. absolute maximum ratings operating electrical characteristics t a = 25 c v s = 2.5v unless otherwise specified ald2731a ald2731 test parameter symbol min typ max min typ max unit conditions supply voltage v s 1.0 5.0 1.0 5.0 v dual supply v + 2.0 10.0 2.0 10.0 v single supply input offset voltage v os 0.6 1.0 1.0 2.0 mv r s 100k ? input offset current i os 0.01 10 0.01 10 pa t a = 25 c 200 200 pa 0 c t a +70 c input bias current i b 0.01 10 0.01 10 pa t a = 25 c 200 200 pa 0 c t a +70 c input voltage range v ir -0.3 +5.3 -0.3 +5.3 v v + = +5v -2.8 +2.8 -2.8 +2.8 v v s = 2.5v input resistance r in 10 14 10 14 ? input offset voltage drift tcv os 55 v/ cr s 100k ? power supply psrr 85 85 db r s 100k ? rejection ratio 85 85 db 0 c t a +70 c common mode cmrr 85 85 db r s 100k ? rejection ratio 85 85 db 0 c t a +70 c large signal a v 100 100 v/mv r l = 100k ? voltage gain 300 300 v/mv r l = 1m ? output voltage range v o low 0.001 0.01 0.001 0.01 v r l = 1m ? , v + = +5v v o high 4.99 4.999 4.99 4.999 v 0 c t a +70 c v o low -2.48 -2.40 -2.48 -2.40 v r l =100k ? v o high 2.40 2.48 2.40 2.48 v 0 c t a +70 c output short circuit current i sc 11ma supply current i s 240 360 240 360 av in = 0v, no load power dissipation p d 1.8 1.8 mw v s = 2.5v input capacitance c in 1 1 pf bandwidth b w 700 700 khz slew rate s r 0.7 0.7 v/ sa v = +1, r l =100k ?
ald2731a/ald2731 advanced linear devices 3 of 9 operating electrical characteristics (cont'd) ald2731a ald2731 parameter symbol min typ max min typ max unit test conditions input offset voltage v os 2.0 3.0 mv r s 100k ? input offset current i os 2.0 2.0 na input bias current i b 2.0 2.0 na power supply rejection ratio psrr 75 75 db r s 100k ? common mode rejection ratio cmrr 83 83 db r s 100k ? large signal voltage gain a v 50 50 v/mv r l = 100k ? output voltage range v o low -2.47 -2.40 -2.47 -2.40 v r l = 100k ? v o high 2.35 2.45 2.35 2.45 v v s = 2.5v -55 c t a +125 c unless otherwise specified ald2731a ald2731 parameter symbol min typ max min typ max unit test conditions power supply rejection ratio psrr 90 90 db r s 100k ? common mode rejection ratio cmrr 90 90 db r s 100k ? large signal voltage gain a v 250 250 v/mv r l = 100k ? output voltage range v o low -4.98 -4.90 -4.98 -4.90 v r l = 100k ? v o high 4.90 4.98 4.90 4.98 bandwidth b w 1.0 1.0 mhz slew rate s r 1.0 1.0 v/ sa v = +1, c l = 50pf t a = 25 c v s = 5.0v unless otherwise specified ald2731a ald2731 parameter symbol min typ max min typ max unit test conditions rise time t r 0.2 0.2 sr l = 100k ? overshoot factor 20 20 % r l = 100k ? , c l = 50pf settling time t s 10 10 s 0.1%, a v = 100, r l = 100k ? , c l = 50pf channel separation c s 140 140 db a v = 100 t a = 25 c v s = 2.5v unless otherwise specified (cont'd)
ald2731a/ald2731 advanced linear devices 4 of 9 design & operating notes: 1. the ald2731a/ald2731 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 ald2731a/ald2731 is internally compen- sated 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 ald2731a/ald2731 has complementary p-channel and n- channel input differential stages connected in parallel to accomplish rail to rail common mode input voltage ranges. 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 ald2731a/ ald2731 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 below 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 provisions in the 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 0.01pa 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 14 ? 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 ald2731a/ald2731 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 not to exceed 0.3v of the power supply voltage levels. 6. the ald 2731a/ald2731 , 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. 7. the ald 2731a/ald2731 has an internal design architecture that provides robust high temperature operation. contact factory for custom screening versions. typical performance characteristics common mode input voltage range as a function of supply voltage supply voltage (v) common mode input voltage range (v) 5 3 0 1 4 2 0 1 2 3 4 5 6 6 t a = 25 c open loop voltage gain as a function of load resistance load resistance ( ? ) open loop voltage gain (v/mv) 10m 10k 100k 1m 1000 100 10 1 v s = 2.5v t a = 25 c supply current as a function of supply voltage supply voltage (v) supply current ( a) 500 300 0 100 400 200 0 1 2 3 4 5 6 t a = -55 c +25 c +70 c +125 c inputs grounded output unloaded -25 c input bias current as a function of ambient temperature ambient temperature ( c) input bias current (pa) 100 10 1.0 0.01 0.1 1000 +100 -25 0 +75 +125 +50 +25 -50 v s = 2.5v
ald2731a/ald2731 advanced linear devices 5 of 9 typical performance characteristics (cont'd) open loop voltage gain as a function of frequency frequency (hz) open loop voltage gain (db) 90 0 45 180 135 phase shift in degrees 1 10 100 1k 10k 1m 10m 100k 120 100 80 60 40 20 0 -20 v s = 2.5v t a = 25 c large-signal transient response v s = 2.5v t a = 25 c r l = 100k ? c l = 50pf 5v/div 2v/div 5 s/div large-signal transient response v s = 1.0v t a = 25 c r l = 100k ? c l = 50pf 2v/div 500mv/div 5 s/div small-signal transient response v s = 2.5v t a = 25 c r l = 100k ? c l = 50pf 100mv/div 20mv/div 2 s/div open loop voltage gain as a function of supply voltage and temperature supply voltage (v) open loop voltage gain (v/mv) 1000 100 10 1 0 1 2 3 4 5 6 -55 c t a +125 c r l = 100k ? output voltage swing as a function of supply voltage supply voltage (v) output voltage swing (v) 5 3 1 4 2 0 1 2 3 4 5 6 6 -55 c t a +125 c r l = 100k ?
ald2731a/ald2731 advanced linear devices 6 of 9 typical applications low voltage instrumentation amplifier rail-to-rail window comparator 50k 100k 100k f max = 20khz -40mv v in 40mv - + 0.1 f 0.1 f v+ v- - + 100k 100k 1m - 500k 0.1 f v+ v+ 1m + 1m v- v- 0.1 f v out 1m ald1731 1/2 ald2731 gain = 25 v- v out v+ all resistors are 1% v+ = +1.0v v- = -1.0v short circuit input current 1 a 0.1 f 0.1 f v+ v- 1/2 ald2731 +5v + - + - v in 100k v ref (high) v ref (low) 3 2 5 6 8 4 1 7 1/4 74 c00 1/2 ald2731 v out v out (low) for v ref (low) < v in < v ref(high) 100k 1/2 ald2731 rail-to-rail voltage follower/buffer - + output 5v 0.1 f * see rail to rail waveform 0 v in 5v v in z in = 10 12 ? ~ 1/2 ald2731 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 ald2731 high input impedance rail-to-rail precision dc summing amplifier 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 in v+ v- v out v+ v 1 v 4 v 3 v 2 v out = v 1 + v 2 - v 3 - v 4 1/2 ald2731 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 rail-to-rail waveform wien bridge oscillator (rail-to-rail) sine wave generator 10k 10k 10k +2.5v -2.5v .01 f c = .01 f r = 10k - + 1/2 ald2731 f = 1 = 1.6khz 2 rc ~~ v out * see rail to rail waveform
ald2731a/ald2731 advanced linear devices 7 of 9 8 pin plastic soic package millimeters inches min max min max dim a a 1 b c d-8 e e h l s 1.75 0.25 0.45 0.25 5.00 4.05 6.30 0.937 8 0.50 0.053 0.004 0.014 0.007 0.185 0.140 0.224 0.024 0 0.010 0.069 0.010 0.018 0.010 0.196 0.160 0.248 0.037 8 0.020 1.27 bsc 0.050 bsc 1.35 0.10 0.35 0.18 4.69 3.50 5.70 0.60 0 0.25 ? soic-8 package drawing l c h s (45 ) ? e a a 1 b d s (45 ) e
ald2731a/ald2731 advanced linear devices 8 of 9 8 pin plastic dip package millimeters inches min max min max dim a a 1 a 2 b b 1 c d-8 e e 1 e e 1 l s-8 ? 3.81 0.38 1.27 0.89 0.38 0.20 9.40 5.59 7.62 2.29 7.37 2.79 1.02 0 5.08 1.27 2.03 1.65 0.51 0.30 11.68 7.11 8.26 2.79 7.87 3.81 2.03 15 0.105 0.015 0.050 0.035 0.015 0.008 0.370 0.220 0.300 0.090 0.290 0.110 0.040 0 0.200 0.050 0.080 0.065 0.020 0.012 0.460 0.280 0.325 0.110 0.310 0.150 0.080 15 pdip-8 package drawing b 1 s b e e 1 d e a 2 a 1 a l c e 1 ?
ald2731a/ald2731 advanced linear devices 9 of 9 8 pin cerdip package cerdip-8 package drawing a a 1 b b 1 c d-8 e e 1 e e 1 l l 1 l 2 s ? 3.55 1.27 0.97 0.36 0.20 -- 5.59 7.73 3.81 3.18 0.38 -- 0 5.08 2.16 1.65 0.58 0.38 10.29 7.87 8.26 5.08 -- 1.78 2.49 15 millimeters inches min max min max dim 0.140 0.050 0.038 0.014 0.008 -- 0.220 0.290 0.150 0.125 0.015 -- 0 0.200 0.085 0.065 0.023 0.015 0.405 0.310 0.325 0.200 -- 0.070 0.098 15 2.54 bsc 7.62 bsc 0.100 bsc 0.300 bsc e e 1 c e 1 ? s b l d b 1 e a l 2 a 1 l 1
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