AC164112 is a simple in line voltage clamp necessary when programming and debugging the latest PIC12/PIC16/PIC18 products. The MPLAB ICD 2 provides a 12V supply to Vpp which supports legacy products. This MPLAB ICD 2 Vpp Voltage Limiter clamps this Vpp supply to 8.5V for use with the Microchip products on the latest process technologies released in 2008 or later.