Lockup Latch: Understanding Its Role and Function in Digital Circuits
Lock-up latches are vital components in scan-based designs, particularly for ensuring hold timing closure during shift modes. They address issues related to clock skew and uncommon clock paths, which can lead to hold failures. By strategically placing lock-up latches between flops with significant clock skews, designers can mitigate the risk of hold violations and improve overall timing closure in scan chains.
What is Lockup Latch?
The lock-up latch is a transparent latch used to avoid large clock skew and mitigate the problem in closing hold timing due to a large uncommon clock path. Lock-up latches are usually inserted at the point where two scan chains are connected.
Advantages of a Lockup Latch
- It prevents data corruption.
- It is power and area efficient.
- The device can handle more on-chip variation easily.
- This is the robust method to deal with hold time constraints during scan shift mode.
Difference between the lockup latch and lockup register.
Lockup registers, on the other hand, let you have skew on both sides. Here some differences are there, Comparing the lockup latch and lockup register, the lockup latch has an optimum solution in terms of power and area because it takes up about half as much space. Timing restrictions at functional frequency are unimportant during a negative lockup latch. This, however, is not for the lockup register. In the design process and timing analysis, the lockup latch, therefore, predominates over the lockup register.
