LM193 datasheet(8/15 Pages) ARTSCHIP

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LM193/LM293/LM393/LM2903

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Application Hints

The LM193 series are high gain, wide bandwidth devices which, like most comparators, can easily oscillate if the output lead is inadvertently

allowed to capacitively couple to the inputs via stray capacitance. This shows up only during the output voltage transition intervals as the

comparator change states. Power supply bypassing is not required to solve this problem. Standard PC board layout is helpful as it reduces

stray input-output coupling. Reducing the input resistors to <10kΩ reduces the feedback signal levels and finally, adding even a small amount

(1.0 to 10mV) of positive feedback ( hysteresis ) causes such a rapid transition that oscillations due to stray feedback are not possible. Simply

socketing the IC and attaching resistors to the pins will cause input-output oscillations during the small transition intervals unless hysteresis is

used. If the input signal is a pulse waveform, with relatively fast rise and fall times, hysteresis is not required.

The bias network of the LM193 series establishes a drain current which is independent of the magnitude of the power supply voltage over the

range of from 2.0 VDC to 30 VDC.

It is usually unnecessary to use a bypass capacitor across the power supply line.

The differential input voltage may be larger than V+ without damaging the device (Note 8). Protection should be provided to prevent the input

voltages from going negative more than -0.3VDC (at 25℃). An input clamp diode can be used as shown in the applications section.

The output of the LM193 series is the uncommitted collector of a grounded-emitter NPN output transistor. Many collectors can be tied together

to provide an output OR’ing function. An output pull-up resistor can be connected to any available power supply voltage within the permitted

supply voltage range and there is no restriction on this voltage due to the magnitude of the voltage which is applied to the V+ terminal of the

LM193 package. The output can also be used as a simple SPST switch to ground (when a pull-up resistor is not used). The amount of current

which the output device can sink is limited by the drive available (which is independent of V+) and the ß of this device. When the maximum

current limit is reached (approximately 16mA), the output transistor will come out of saturation and the output voltage will rise very rapidly. The

output saturation voltage is limited by the approximately 60Ω r SAT of the output transistor. The low offset voltage of the output transistor (1.0mV)

allows the output to clamp essentially to ground level for small load currents.

Typical Applications (V

+ =5.0 VDC)

Basic Comparator

00570935

Squarewave Oscillator

00570938

Driving CMOS

00570936

Pulse Generator

00570939

*For large ratios of R1/R2,

D1 can be omitted.

Driving TTL

00570937

Crystal Controlled Oscillator

00570940

LM193 Datasheet(PDF) 8 Page - ARTSCHIP ELECTRONICS CO.,LMITED.