Product Summary

The LF398N is a monolithic sample-and-hold circuit which utilizes 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 of the LF398N allows the LF198 to be included inside the feedback loop of 1 MHz op amps without having stability problems. Input impedance of 1010W allows high source impedances to be used without degrading accuracy. P-channel junction FET 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 have much lower noise than MOS devices used in previous designs and do not exhibit high temperature instabilities. The overall design of the LF398N guarantees no feed-through from input to output in the hold mode, even for input signals equal to the supply voltages.

Parametrics

LF398N absolute maximum ratings: (1)Supply Voltage: ±18V; (2)Power Dissipation (PackageLimitation): 500 mW; (3)Operating Ambient Temperature Range: -55℃ to +125℃; (4)Storage Temperature Range: -65℃ to +150℃; (5)Input Voltage: Equal to Supply Voltage; (6)Logic To Logic Reference Differential Voltage: +7V, 30V; (7)Output Short Circuit Duration: Indefinite.

Features

LF398N features: (1)Operates from ±5V to ±18V supplies; (2)Less tha10 μs acquisitiotime; (3)TTL, PMOS, CMOS compatible logic input; (4)0.5 mV typical hold step at Ch = 0.01 μF; (5)Low input offset; (6)0.002% gaiaccuracy; (7)Low output noise ihold mode; (8)Input characteristics do not change during hold mode; (9)High supply rejectioratio isample or hold; (10)Wide bandwidth; (11)Space qualified, JM38510.

Diagrams

LF398N Functional Diagram

Image Part No Mfg Description Data Sheet Download Pricing
(USD)
Quantity
LF398N
LF398N

National Semiconductor (TI)

Sample & Hold Amplifiers

Data Sheet

0-720: $0.46
720-1000: $0.44
1000-2520: $0.36
2520-5000: $0.34
LF398N/NOPB
LF398N/NOPB

National Semiconductor (TI)

Sample & Hold Amplifiers MONOLITHIC SAMPLE & HOLD CIRCUIT

Data Sheet

0-1: $0.92
1-25: $0.73
25-100: $0.64
100-250: $0.57
LF398N8
LF398N8


IC AMP PREC SAMPLE & HOLD 8-DIP

Data Sheet

0-3850: $1.04
LF398N8#PBF
LF398N8#PBF

Linear Technology

IC AMP PREC SAMPLE & HOLD 8-DIP

Data Sheet

1-800: $1.04