Datasheet LT1077 (Analog Devices) - 9

LT1077
W U TYPICAL PERFOR A CE CHARACTERISTICS Common Mode Rejection Ratio Power Supply Rejection Ratio vs Frequency vs Frequency
120 120 TA = 25°C 100 100 POSITIVE SUPPLY VS = ±15V 80 80 VS = 5V, 0V 60 60 NEGATIVE SUPPLY 40 40 20 20 VS = ± 2.5V + 1VP-P SINE WAVE COMMON MODE REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) TA = 25°C 0 0 10 100 1k 10k 100k 1M 0.1 1 10 100 1k 10k 100k FREQUENCY (Hz) FREQUENCY (Hz) LT1077 • TPC28 LT1077 • TPC29
U U W U APPLICATIO S I FOR ATIO
The LT1077 is fully specified with V+ = 5V, V– = 0V, The LT1077 replaces and upgrades such micropower op VCM = 0.1V. This set of operating conditions appears to be amps as the OP-20, LM4250, and OP-90, provided that the the most representative for battery powered micropower external nulling circuitry (and set resistor in the case of the circuits. Offset voltage is internally trimmed to a minimum LM4250) are removed. Since the offset voltage of the value at these supply voltages. When 9V or 3V batteries, LT1077 is extremely low, nulling will be unnecessary in or ±2.5V dual supplies are used, bias and offset current most applications. changes will be minimal. Offset voltage changes will be just a few microvolts as given by the PSRR and CMRR
Single Supply Operation
specifications. For example, if PSRR = 114dB ( = 2µV/V), The LT1077 is fully specified for single supply operation, at 9V the offset voltage change will be 8µV. Similarly, (i.e., when the negative supply is 0V). Input common VS ±2.5V, VCM = 0 is equivalent to a common mode voltage mode range goes below ground and the output swings change of 2.4V or a VOS change of 7µV if within a few millivolts of ground while sinking current. All CMRR = 110dB (3µV/V). competing micropower op amps either cannot swing to A full set of specifications is also provided at ±15V supply within 600mV of ground (OP-20, OP-220, OP-420) or voltages for comparison with other devices and for need a pull-down resistor connected to the output to completeness. swing to ground (OP-90, OP-290, OP-490, HA5141/42/ 44). This difference is critical because in many applica- The LT1077 is pin compatible to, and directly replaces, tions these competing devices cannot be operated as such precision op amps as the OP-07, OP-77, AD7O7 and micropower op amps and swing to ground simultaneously. LT1001 with 30 to 60 times savings in supply current. The LT1077 is also a direct plug-in replacement for LT1012 Consider the difference amplifiers shown in Typical and OP-97 devices with 10 times lower dissipation. Applications as an example. When the common mode Compatibility includes externally nulling the offset signal is high and the output low, the amplifier has to sink voltage, as all of the devices above are trimmed with current. In the gain of 10 circuit, the competing devices a potentiometer between Pins 1 and 8 and the wiper require a 30k pull-down resistor at the output to handle the tied to V+. specified signals. (The LT1077 does not need pull-down 1077fa 9