What this 600-ohm common-mode choke does on a signal line
The TDK ACM2520-601-2P-T is a 2-line signal line EMI filter in the ACM series, delivering 600 Ohms of common-mode impedance at 100 MHz. That impedance knocks down conducted noise on differential signal pairs — think USB, HDMI, or LVDS lines — without loading the signal itself, because common-mode chokes pass the differential signal and block the noise that rides on both lines equally. The 20 VDC rating means it handles the typical USB VBUS or low-voltage power rail without breakdown.
Obsolete — sourcing through independent channels
TDK has marked the ACM2520-601-2P-T as obsolete. No official successor is listed, which means the part is no longer manufactured and is not being replaced with a direct pin-compatible drop-in from TDK. For existing designs that already use this filter, the only supply route is through independent distribution or surplus inventory. If you are maintaining a BOM that calls out this specific TDK order code, the procurement path is a quote request rather than a shelf-pick.
The 0.098" x 0.079" body fits standard pick-and-place reflow assembly, and the 4-pad layout is common for common-mode filters in this size class — the two outer pads are the input/output pair for each line, with the inner pads typically grounded or left as NC. Operating temperature range is -25°C to +85°C, which covers most indoor and commercial equipment but not extended industrial or automotive under-hood environments. If your board sees sustained temperatures above 85°C, this part is not the fit.