Analog Devices Inc./Maxim Integrated

Metal Can and Ceramic Package Versions of this part are Obsolete: LF198AH, LF198H, LF398AH, LF398H, LF398J8. The LF398AN8 is Obsolete.The LF398 is a precision sample and hold amplifier which uses a combination of bipolar and junction FET transistors to provide precision, high speed, and long hold times. A typical offset voltage of 2mV and gain error of 0.004% allow this sample and hold amplifier to be used in 12-bit systems. Dynamic performance can be optimized by proper selection of the external hold capacitor. Acquisition times can be as low as 4µs for small capacitors while hold step and droop errors can be held below 0.1mV and 30µV/sec respectively when using larger capacitors.The LF398 is fixed at unity gain with 10Ω input impedance independent of sample/hold mode. The logic inputs are high impedence differential to allow easy interfacing to any logic family without ground loop problems. A separate offset adjust pin can be used to zero the offset voltage in either the sample or hold mode. Additionally, the hold capacitor can be driven with an external signal to provide precision level shifting or "differencing" operation. The device will operate over a wide supply voltage range from ±5V to ±18V with very little change in performance, and key parameters are specified over this full supply range.Applications12-Bit Data Acquisition SystemsRamp GeneratorsAnalog SwitchesStaircase GeneratorsSample and Difference Circuits

The H (Metal Can), J (Ceramic), and K (Metal Can) Packages From Analog Devices Are Now ObsoleteThe LM108 series of precision operational amplifiers are particularly well-suited for high source impedance applications requiring low offset and bias currents as well as low power dissipation. Unlike FET input amplifiers, the offset and bias currents of the LM108 do not change significantly with temperature variations. Advanced design, processing and testing techniques make the LM108 a superior choice over previous devices.A photodiode sensor application is shown below. For applications requiring higher performance, see the LT1008, and LT1012.ApplicationsIntegratorsTransducer amplifiersAnalog memoriesLight meters

The H (Metal Can), J (Ceramic), and K (Metal Can) Packages Are Now Obsolete.The LM185-2.5 is a two-terminal band gap reference diode that has been designed for applications which require precision performance with micropower operation. The device provides guaranteed operation specifications at currents as low as 20µA. The nominal voltage is 2.5V with both 1% and 2% tolerances available. Some additional features are: maximum dynamic impedance of 1Ω, low noise and excellent stability over time and temperature. The advanced design, processing and testing techniques make the LM185-2.5 a superior choice over previous designs. A circuit for cold junction compensation of a thermocouple is shown below.For applications requiring guaranteed temperature drift, see the LT1034 data sheet.ApplicationsPortable Meter ReferencesPortable Test InstrumentsBattery-Operated SystemsPanel MetersCurrent Loop Instrumentation