The DSC1121AE1-004.0000 is a 4 MHz XO (Standard) oscillator built on a MEMS resonator, delivering a CMOS output across a 2.25V to 3.6V supply range — it runs directly from a 2.5V or 3.3V rail without an extra LDO. Active product status means no end-of-life concern for ongoing production — the MEMS die is a standard Microchip DSC1121 series part with broad availability.
Package and board layout notes
Housed in a 6-VDFN exposed pad package measuring 7.00mm x 5.00mm x 0.90mm, surface-mount soldering requires a thermal pad on the PCB for heat sinking — the exposed pad must be connected to ground for proper thermal and electrical performance. Frequency stability is ±50 ppm, tight enough for UART baud-rate generation and most MCU clock inputs without external trimming.