CD4043 Quad NOR R-S Latch Tristate

Contents hide

The CD4043 IC consists of four R-S latches, made by using the NOR logical gate. There is a common 3-STATE ENABLE input for all four latches. A logic “1” on the ENABLE input connects the latch states to the Q outputs. A logic “0” on the ENABLE input disconnects the latch states from the Q outputs resulting in an open circuit condition on the Q output. The 3-STATE feature allows the common bussing of the outputs. The IC has many features such as high noise immunity, ESD barring, and excellent thermal overload protection.

What is R-S Latch?

An SR latch or an SR Flip-Flop is a combinational logic circuit, that has two inputs S and R, and two outputs Q and Q’. The state of this latch is determined by the condition of output Q. If output Q is 1 (High) the latch is said to be SET and if Q is 0 (Low) the latch is said to be RESET. An SR Latch or Flip flop can be designed either by two cross-coupled NAND gates or two-cross coupled NOR gates.

CD4043 Key Features

Wide supply voltage range: 3V to 15V
Low power: 100 nW (typ.)
High noise immunity: 0.45 VDD (typ.)
Separate SET and RESET inputs for each latch
NOR and NAND configuration
3-STATE output with common output enable

CD4043 Pinout

Pin No	Pin Name	Description
1	Q4	output of latch 4
2	Q1	output of latch 1
3	R1	reset input latch 1
4	S1	set input latch 1
5	ENB	enable pin
6	S2	set input latch 2
7	R2	reset input latch 2
8	VSS	source supply
9	Q2	output of latch 2
10	Q3	output of latch 3
11	R3	reset input latch 3
12	S3	set input latch 3
13	NC	no connection
14	S4	set input latch 4
15	R4	reset input latch 4
16	VDD	Drain supply