SDLS201 - DECEMBER 1983 - REVISED MARCH 1988
PRODUCTION DATA documents contain information current as of publicationdate. Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily include testingof all parameters.
The 'S124 features two independent voltage-controlled oscillators (VCO)in a single monolithic chip. The output frequency of each VCO is establishedby an external capacitor in combination with two voltage-sensitive inputs,one for frequency range and one for frequency control. These inputs can beused to vary the output frequency as shown under typical characteristics.These highly stable oscillators can be set to operate at any frequency typicallybetween 0.12 hertz and 85 megahertz. Under the conditions used in Figure 1,the output frequency can be approximated as follows:
These devices can operate from a single 5-volt supply. However, one setof supply-voltage and ground pins (VCC and GND) is provided forthe enable, synchronization-gating, and output sections, and a separate set and is provided for theoscillator and associated frequency-control circuits so that effective isolationcan be accomplished in the system.
The enable input of these devices starts or stops the output pulses whenit is low or high, respectively. The internal oscillator of the 'S124 is startedand stopped by the enable input. The enable input is one standard load; itand the buffered output operate at standard Schottky-clamped TTL levels.
The pulse synchronization-gating section ensures that the first outputpulse is neither clipped nor extended. Duty cycle of the square-wave outputis fixed at approximately 50 percent.
The SN54S124 is characterized for operation over the full military temperaturerange of -55°C to 125°C; the SN74S124 is characterized for operationfrom 0°C to 70°C.
View more information about generic part numbers:SN54S124, SN74S124
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