1. Technical Field
The embodiments described herein relate to a semiconductor memory apparatus, and more particularly, to a trimming circuit for a semiconductor memory apparatus.
2. Related Art
In general, since external supply voltages or ground voltages may have instant variations in noise and voltage levels, a circuit in a semiconductor memory apparatus requires voltages having a stable level. Accordingly, the semiconductor memory apparatus generates internal voltages having various levels by using an external supply voltage or a ground voltage.
The semiconductor memory apparatus includes an internal voltage generating circuit to generate internal voltage using external input voltage. If the internal voltage has no desired level, a fuse is cut if the level of the internal voltage is too high or the internal voltage is properly trimmed using a code signal so that the internal voltage can be output at a target level. For example, fuse cutting is performed in a wafer level for trimming. However, when the trimming is required after a package process, the trimming for the internal voltage may not be precisely performed even if a code signal is used since a preset base voltage is primarily trimmed when the trimming operation is performed in a package level. Here, in order to trim the internal voltage more exactly, the trimming process must be performed by taking into consideration the fuse cutting in the wafer level.