27 MHz fundamental crystal in the ECX-2236 series
The ECS-270-10-36-JTM-TR: The 27 MHz fundamental-mode crystal drives the master clock reference in microcontrollers, UARTs, and timing-sensitive ASICs — the load capacitance of 10 pF must match the oscillator circuit's feedback network to hit the rated pullability budget. Frequency stability and tolerance are both ±20 ppm total, meaning the crystal holds ±20 kHz around 27 MHz across the operating temperature band of -20°C to 70°C — adequate for UART baud precision at standard data rates but not for precision timekeeping or boundary-scan test fixtures that require tighter calibration.
4-SMD package and ESR at a glance
Equivalent series resistance is 60 Ω maximum at the fundamental mode; higher ESR at higher harmonics limits this part to the fundamental pull-range and makes it unsuitable as a high-Q filter element.
Tape-and-reel and cut-tape packaging are both listed, supporting both high-volume SMT placement and low-volume prototyping runs.