LF398 - Monolithic Sample and Hold Circuit
Datasheet Packaging Samples & Pricing Reliability Application Notes Knowledge Base

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

 

General 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. More...


ParametersValues
Temperature Min 0 deg C
Temperature Max 70 deg C
Offset Voltage max, 25C 3, 10 mV

Additional Resources

Application Notes



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LF198/LF298/LF398, LF198A/LF398A Monolithic Sample-and-Hold Circuits 520
Kbytes		 23-Aug-00 Download
LF198/LF298/LF398, LF198A/LF398A Monolithic Sample-and-Hold Circuits (Japanese)
 532 Kbytes   Download

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Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
Format
TypePinsSpec.MSL
Rating		Peak
Reflow		RoHS
Report		CAD
Symbols		WeeksQtyQty$US each
LF398MSOIC NARROW14NOPB
STD		1
1		260
235		RoHS N/A Full productionN/A
Samples
Buy Now 		1K+$0.67rail
of
55		NSUZXYTTE#
LF398M
12 weeks2000
LF398MXSOIC NARROW14NOPB
STD		1
1		260
235		RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.67reel
of
2500		NSUZXYTTE#
LF398M
12 weeks20000
LF398ANMDIP8NOPB
STD		1
1		NA
NA		RoHS N/A Full productionN/A
 
Buy Now 		1K+$1.42rail
of
40		NSUZXYTTE#
LF
398AN
6 weeks2000
LF398NMDIP8NOPB
STD		1
1		NA
NA		RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.63rail
of
40		NSUZXYTTE#
LF
398N
8 weeks1000
LF398HTO-998NOPB
STD		1
1		NA
NA		RoHS N/A Full productionN/A
 
Buy Now 		1K+$4.21box
of
500		NSZXYTTE# LF398H
6 weeks1000
LF398 MDCUnpackaged DieCustomN/A
  CALLtray
of
N/A		-
6 weeksN/A

Obsolete Versions

Obsolete PartAlternate Part or SupplierSourceLast Time Buy Date
LF398AH
LF198AH
NATIONAL SEMICONDUCTOR
03 Dec 2008

General 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.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LF398 MDCBIFET0128750010650004302196657
LF398 MWCBIFET0128750010650004302196657
LF398AHBIFET0128750010650004302196657
LF398ANBIFET0128750010650004302196657
LF398HBIFET0128750010650004302196657
LF398MBIFET0128750010650004302196657
LF398MXBIFET0128750010650004302196657
LF398NBIFET0128750010650004302196657

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.


Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-298: Application Note 298 Isolation Techniques for Signal Conditioning 379
Kbytes		 2-Oct-02 Download
AN-775: Specifications and Architectures of Sample-and-Hold Amplifiers 111
Kbytes		 5-Aug-95 Download
AN-775 (Japanese): Specifications and Architectures of Sample-and-Hold Amplifiers
 251 Kbytes   Download
AN-266: Application Note 266 Circuit Applications of Sample-Hold Amplifiers 508
Kbytes		 2-Oct-02 Download
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 Download
AN-301: Application Note 301 Signal Conditioning for Sophisticated Transducers 579
Kbytes		 2-Oct-02 Download
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 Download
AN-294: Application Note 294 Special Sample and Hold Techniques 233
Kbytes		 4-Oct-04 Download

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More Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-292: Application Note 292 Applications of the LM3524 Pulse-Width-Modulator 239
Kbytes		 3-Oct-02 Download

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[Information as of 8-Nov-2009]