Question

A 4-bit Modulo-6 ripple counter uses J-K flip flop. If the propagation delay of each FF is 50 ns, the maximum clock frequency that can be used is equal to ___MHz.

• A. 5

Answer 1

The correct option is A 5
$T_{clk}\ge n{t}_{pd}$

$f_{clk}\le \frac{1}{T_c}=\frac{1}{n{t}_{pd}}$

n = 4

$t_{pd}=50ns$

$f_{clk}\le \frac{1}{4\times 50\times {10}^{-9}}=5\times {10}^{6}Hz$

$f_{clk\left(max\right)}$ = 5 MHz