LF198   
Monolithic Sample and Hold Circuit 		Click link to Download

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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ParametersValues
Temperature Min -55 deg C
Temperature Max 125 deg C
Offset Voltage max, 25C 2, 5 mV

Part Number(s)
(NSID)		Top ViewAvailabilityCurrent Reported StockBudgetary PricingStandard Pack Size
LF198AH/NOPB
LF198AH

RoHS



TO-99		Full production
Lead Time: 6 weeks

 
DistributorRegionQty
ARROWWorldwide8
AVNET-EMWorldwide112
$9.60 each at 1K+ pcsbox
of
500
5962-8760801GA
(LF198H/883)


TO-99		Full production
Lead Time: 8 weeks

 

Contact your distributor
$14.50 each at 50+ pcstray
of
20
5962-8760801QZA
(LF198WG/883)
Lifetime buy
Lead Time: 28 weeks

 

Contact your distributor
$16.00 each at 50+ pcstray
of
42
JM38510/12501BGA
(JL198BGA)


TO-99		Full production
Lead Time: 14 weeks

 

Contact your distributor
$49.30 each at 50+ pcstray
of
20
JM38510/12501SGA
(JL198SGA)


TO-99		Full production
Lead Time: N/A

 

Contact your distributor
CALLtray
of
20
LF198WG-QMLV

RoHS

Lifetime buy
Lead Time: N/A

 

Contact your distributor
CALLtray
of
N/A

Obsolete Versions
Obsolete PartAlternate Part or SupplierSourceLast 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-QMLV
LF198H/883
NATIONAL SEMICONDUCTOR
01 Dec 2009
LF198WG/883
LF198H/883
NATIONAL SEMICONDUCTOR
01 Dec 2009

Part Number(s)
(NSID)		Top ViewTypePinsMSL RatingPeak ReflowRoHSCAD SymbolsModelsPackage
Marking
Format
LF198AH/NOPB
LF198AH
TO-9981
1		NA
NA		RoHSN/AN/A
NSZXYTTE# LF198AH
5962-8760801GA
(LF198H/883)
TO-998RoHSN/AN/A
NSZSSXXYYA LF198H/883 Q
5962-8760801GA
5962-8760801QZA
(LF198WG/883)
CERPACK14RoHSN/AN/A
NSZSSXXYYA
LF198WG/
883 Q 5962-
8760801QZA
JM38510/12501BGA
(JL198BGA)
TO-998RoHSN/AN/A
NS ZSSXXYYA 27014 Q
JM38510/12501BGA
JM38510/12501SGA
(JL198SGA)
TO-998RoHSN/AN/A
NS ZSSXXYYA 27014 Q
JM38510/12501SGA
LF198WG-QMLV
CERPACK141NARoHSN/AN/A
NSZSSXXYYA
LF198WG-
QV Q 5962-
8760801VZA

Reliability Metrics
Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
JL198BGABIFET0128750010650004302196657
JL198SGABIFET0128750010650004302196657
LF198AHBIFET0128750010650004302196657
LF198H/883BIFET0128750010650004302196657
LF198WG-QMLVBIFET0128750010650004302196657
LF198WG/883BIFET0128750010650004302196657

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.


Obsolete Versions
Obsolete PartAlternate Part or SupplierSourceLast 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-QMLV
LF198H/883
NATIONAL SEMICONDUCTOR
01 Dec 2009
LF198WG/883
LF198H/883
NATIONAL SEMICONDUCTOR
01 Dec 2009

[Information as of 22-Nov-2009]