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
	LF398 Monolithic Sample and Hold Circuit	520 Kbytes	23-Aug-00	日本語

Application Notes

Title		Size	Date	Other Language
	AN-247: Application Note 247 Using the ADC0808/ADC0809 8-Bit MicroP Compatible A/D Converters with 8-Channel Analog Multiplexer	547 Kbytes	3-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-292: Application Note 292 Applications of the LM3524 Pulse-Width-Modulator	239 Kbytes	3-Oct-02
	AN-294: Application Note 294 Special Sample and Hold Techniques	233 Kbytes	4-Oct-04
	AN-298: Application Note 298 Isolation Techniques for Signal Conditioning	379 Kbytes	2-Oct-02
	AN-301: Application Note 301 Signal Conditioning for Sophisticated Transducers	579 Kbytes	2-Oct-02
	AN-775: Application Note 775	111 Kbytes	5-Aug-95	日本語

Other Technical Documents

Title		Type	Date
	Frequency-to-Voltage Converter Uses Sample-and-Hold to Improve Response and Ripple	App Note	2002-10-03

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LF398AN/NOPB LF398AN RoHS Status	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 360 AVNET-EM Worldwide 336 DIGI-KEY Worldwide 200 FARNELL Europe and Asia 623 MOUSER Worldwide 359 NEWARK Americas 128 RS COMPONENTS Worldwide 84 TAYLOR Americas 360	$1.15 each at 1K+ pcs	rail of 40
LF398M/NOPB LF398M RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 655 AVNET-EM Worldwide 512 DIGI-KEY Worldwide 825 FARNELL Europe and Asia 1914 MOUSER Worldwide 593 NEWARK Americas 720 RS COMPONENTS Worldwide 330 TAYLOR Americas 3724	$0.58 each at 1K+ pcs	rail of 55
LF398MX/NOPB LF398MX RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty CEAC Asia Pacific 7500 DIGI-KEY Worldwide 0 RSL MICRO Asia Pacific 30000	$0.58 each at 1K+ pcs	reel of 2500
LF398N/NOPB LF398N RoHS Status	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 933 AVNET-EM Worldwide 221 BRITESTONE South Korea 105 DIGI-KEY Worldwide 405 FARNELL Europe and Asia 768 MOUSER Worldwide 338 NEWARK Americas 50 RS COMPONENTS Worldwide 405 RSL MICRO Asia Pacific 28000 TAYLOR Americas 3688	$0.55 each at 1K+ pcs	rail of 40
LF398H/NOPB LF398H RoHS Status	TO-99	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 400 AVNET-EM Worldwide 474 DIGI-KEY Worldwide 242 MOUSER Worldwide 415 RS COMPONENTS Worldwide 234 TAYLOR Americas 400	$4.21 each at 1K+ pcs	box of 500
LF398 MDC RoHS Status		Custom / Full Production 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

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 LF398.

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 LF398 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
LF398AN/NOPB LF398AN	508.252 510.002	MDIP	8	1 1	NA NA	Detail	N/A	N/A	NSUZXYTTE# LF 398AN
LF398M/NOPB LF398M	129.551 130.001	SOIC NARROW	14	1 1	260 235	Detail	N/A	N/A	NSUZXYTTE# LF398M
LF398MX/NOPB LF398MX	129.551 130.001	SOIC NARROW	14	1 1	260 235	Detail	N/A	N/A	NSUZXYTTE# LF398M
LF398N/NOPB LF398N	508.252 510.002	MDIP	8	1 1	NA NA	Detail	N/A	N/A	NSUZXYTTE# LF 398N
LF398H/NOPB LF398H	969.917 971.007	TO-99	8	1 1	NA NA	Detail	N/A	N/A	NSZXYTTE# LF398H
LF398 MDC	3.128	Unpackaged Die				N/A	-

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 LF398.

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 LF398 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)
LF398 MDC	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.

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 LF398.

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 LF398 is located at RoHS Status.

Obsolete Versions

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