Features 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 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. 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.

Datasheets

Title		Size	Date	Other Language
	LF198 Monolithic Sample and Hold Circuit	520 Kbytes	23-Aug-00	日本語

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LF198AH/NOPB LF198AH RoHS Status	TO-99	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 387	$9.60 each at 1K+ pcs	box of 500

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LF198H-MLS	NONE	NONE	08 Sep 1998
LF198H-SMD	NONE	NONE	08 Sep 1999
LF198WG-MLS	JL198SGA	NATIONAL SEMICONDUCTOR	03 Dec 2008
LF198WG/883	LF198H/883	NATIONAL SEMICONDUCTOR	01 Dec 2009

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LF198.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LF198 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LF198AH/NOPB LF198AH	969.917 971.007	TO-99	8	1 1	NA NA	Detail	N/A	N/A	NSZXYTTE# LF198AH

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LF198.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LF198 is located at RoHS Status.

CAD Symbols and Models N/A

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LF198AH	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.

For more information on Reliability Metrics, please click here.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LF198.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LF198 is located at RoHS Status.

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LF198H-MLS	NONE	NONE	08 Sep 1998
LF198H-SMD	NONE	NONE	08 Sep 1999
LF198WG-MLS	JL198SGA	NATIONAL SEMICONDUCTOR	03 Dec 2008
LF198WG/883	LF198H/883	NATIONAL SEMICONDUCTOR	01 Dec 2009