The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. The 74LS279 offers 4 basic S-R flip-flop latches in one 16-pin, 300-mil package. Under conventional operation, the S-R inputs are normally held high. When the S input is pulsed low, the output will be set high. When R I pulsed low, the Q output will be reset low.
- Four Individual and Independent Set-Reset Latches
- Inputs Voltage Level Triggered
- Fast Propagation Times
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
|Supply Voltage||4.75 – 5.25Vdc|
|Maximum Clock Frequency||40Mhz|
|Power Dissipation||2mW/gate @100kHz|
|Minimum Output Current||8mA|
|Fan Out (TTL Loads)||20|
74LS279 Pinout Diagram
74LS279 Pin Description
|Pin No||Pin Name||Description|
|2||S1||Set Pin 1 Of Latch 1|
|3||S2||Set Pin 2 Of Latch 1|
|4||Q||Output Of Latch 1|
|6||S1||Set Pin 1 Of Latch 2|
|7||Q||Output Of Latch 2|
|9||Q||Output Of Latch 3|
|10||R’||Reset Pin(Active Low)|
|11||S’2||Set Pin(Active Low) of Latch 3|
|12||S’1||Set Pin(Active Low) of Latch 3|
|13||Q||Output Of Latch 4|
|14||R’||Reset Pin(Active Low)|
|15||S’1||Set Pin(Active Low) of Latch 4|
- As the latch is a single-bit storage element, it may be used as a storage device in power gating circuits and clock.
- They may be used as pulse latches where they perform the same behavior as flip-flops by pulsing the clock very quickly.
74LS279 Alternative Equivalent
Download the 74LS279 Quad Set-Reset Latches Datasheet from the link given below.