Medium Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 20
Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors; Procedure
Aircraft X checked on frequency expecting an ILS for RY36 as advertised on the ATIS. Due to weather observed on final to RY36 I offered the ILS RY13 as an alternative. The pilot said sounds like a good idea and that he was getting set up for RY13 instead. I then descended him to what I thought was 3000 (the MVA) as I have done for years in that area. The Low Altitude alert went off somewhere around 2600-2500 MSL. I advised the pilot of his altitude and he said I told him to descend to 2000. At this point he was entering a lower MVA area of 2100. I told him to just maintain 2000 and he simultaneously reported the airport was in sight anyway. I asked if he would like a visual approach clearance instead. He did; and I cleared him for the visual approach for RY13. He landed without incident.Aircraft X had his company Aircraft Y about 5 miles in trail inbound also. I advised the aircraft of similar sounding call signs. I don't know if it was the [number]'s in the call signs that were on my mind or not; but after I listened to the tape; I indeed did say to descend to 2000; not 3000 as I thought I had. I've descended aircraft in this area probably a couple thousand times in my career and this is the first time 2000 ever came out. I didn't catch the read back of 2000 either. I was expecting 3000. Recommend closer attention to read back and not what I expect to hear.
Approach Controller reported issuing an altitude below the Minimum Vectoring Altitude; triggering a Low Altitude Alert.