Features Logic inputs on the LF198 are fully differential with low input current, allowing direct connection to TTL, PMOS, and CMOS. Differential threshold is 1.4V. The LF198 will operate from ±5V to ±18V supplies. An "A" version is available with tightened electrical specifications. • Operates from ±5V to ±18V supplies • Less than 10 µs acquisition time • TTL, PMOS, CMOS compatible logic input • 0.5 mV typical hold step at Ch = 0.01 µF • Low input offset • 0.002% gain accuracy • Low output noise in hold mode • Input characteristics do not change during hold mode • High supply rejection ratio in sample or hold • Wide bandwidth • Space qualified, JM38510 Description The LF198/LF298/LF398 are monolithic sample-and-hold circuits which utilize BI-FET technology to obtain ultra-high dc accuracy with fast acquisition of signal and low droop rate. Operating as a unity gain follower, dc gain accuracy is 0.002% typical and acquisition time is as low as 6 µs to 0.01%. A bipolar input stage is used to achieve low offset voltage and wide bandwidth. Input offset adjust is accomplished with a single pin, and does not degrade input offset drift. The wide bandwidth allows the LF198 to be included inside the feedback loop of 1 MHz op amps without having stability problems. Input impedance of 1010Ohm allows high source impedances to be used without degrading accuracy. P-channel junction FET's are combined with bipolar devices in the output amplifier to give droop rates as low as 5 mV/min with a 1 µF hold capacitor. The JFET's have much lower noise than MOS devices used in previous designs and do not exhibit high temperature instabilities. The overall design guarantees no feed-through from input to output in the hold mode, even for input signals equal to the supply voltages.

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Datasheet

Title		Size	Date	Other Language
	LF198/LF298/LF398, LF198A/LF398A Monolithic Sample-and-Hold Circuits	520 Kbytes	23-Aug-00	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-298: Application Note 298 Isolation Techniques for Signal Conditioning	379 Kbytes	2-Oct-02
	AN-775: Specifications and Architectures of Sample-and-Hold Amplifiers	111 Kbytes	5-Aug-95	日本語
	AN-266: Application Note 266 Circuit Applications of Sample-Hold Amplifiers	508 Kbytes	2-Oct-02
	AN-258: Application Note 258 Data Acquisition Using the ADC0816 and ADC0817 8-Bit A/D Converter with On-Chip 16 Channel Multiplexer	683 Kbytes	4-Oct-04
	AN-301: Application Note 301 Signal Conditioning for Sophisticated Transducers	579 Kbytes	2-Oct-02
	AN-247: Application Note 247 Using the ADC0808/ADC0809 8-Bit µP Compatible A/D Converters with 8-Channel Analog Multiplexer	547 Kbytes	3-Oct-02
	AN-294: Application Note 294 Special Sample and Hold Techniques	233 Kbytes	4-Oct-04

More Application Notes

Title		Size	Date	Other Language
	AN-292: Application Note 292 Applications of the LM3524 Pulse-Width-Modulator	239 Kbytes	3-Oct-02

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Standard Pack Size
LF398M/NOPB LF398M RoHS	SOIC NARROW	Full production Lead Time: 12 weeks	Distributor Region Qty ARROW Worldwide 950 AVNET-EM Worldwide 767 DIGIKEY Worldwide 892 FUTURE Worldwide 770 RS COMPONENTS Worldwide 330 TAYLOR Americas 1985	$0.67 each at 1K+ pcs	rail of 55
LF398MX/NOPB LF398MX RoHS	SOIC NARROW	Full production Lead Time: 12 weeks	Distributor Region Qty DIGIKEY Worldwide 0 FUTURE Worldwide 1100 KEIKONG Asia Pacific 60000	$0.67 each at 1K+ pcs	reel of 2500
LF398AN/NOPB LF398AN RoHS	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 40 AVNET-EM Worldwide 13 DIGIKEY Worldwide 95 FARNELL Europe and Asia 605 FUTURE Worldwide 1100 NEWARK Americas 244 RS COMPONENTS Worldwide 84 TAYLOR Americas 1007	$1.42 each at 1K+ pcs	rail of 40
LF398N/NOPB LF398N RoHS	MDIP	Full production Lead Time: 12 weeks	Distributor Region Qty ARROW Worldwide 711 AVNET-EM Worldwide 88 BRITESTONE South Korea 105 DIGIKEY Worldwide 1694 FARNELL Europe and Asia 1122 FUTURE Worldwide 1100 KEIKONG Asia Pacific 29720 NEWARK Americas 48 RS COMPONENTS Worldwide 405 TAYLOR Americas 195	$0.63 each at 1K+ pcs	rail of 40
LF398H/NOPB LF398H RoHS	TO-99	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 488 AVNET-EM Worldwide 563 DIGIKEY Worldwide 37 FARNELL Europe and Asia 436 FUTURE Worldwide 303 RS COMPONENTS Worldwide 234	$4.21 each at 1K+ pcs	box of 500
LF398 MDC RoHS		Custom Lead Time: 6 weeks	Contact your distributor	CALL	tray of N/A

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LF398AH	LF198AH	NATIONAL SEMICONDUCTOR	03 Dec 2008

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LF398 MDC	BIFET	0	12875	0	0	1065000	4	302196657
LF398 MWC	BIFET	0	12875	0	0	1065000	4	302196657
LF398AH	BIFET	0	12875	0	0	1065000	4	302196657
LF398AN	BIFET	0	12875	0	0	1065000	4	302196657
LF398H	BIFET	0	12875	0	0	1065000	4	302196657
LF398M	BIFET	0	12875	0	0	1065000	4	302196657
LF398MX	BIFET	0	12875	0	0	1065000	4	302196657
LF398N	BIFET	0	12875	0	0	1065000	4	302196657

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LF398AH	LF198AH	NATIONAL SEMICONDUCTOR	03 Dec 2008