AD9853 is a programmable digital QPSK/16-QAM modulator from Analog Devices. It has a frequency range of 5 MHz-42 MHz/5 MHz-65 MHz, 165 MHz internal reference clock capability, and built-in programmable pulse-shaping FIR filters and programmable interpolation filters.
This document describes the AD9853 programmable digital modulator, covering its features, applications, and general description. It explains the integrated DDS, DAC, digital filters and Reed‑Solomon FEC functions that form a complete modulator solution for HFC, WLAN and MMDS networks.
The manual includes detailed specifications, pin‑function tables, control‑register assignments, typical performance plots, ordering information and ESD handling guidelines, enabling designers to configure and operate the device correctly.
| Resolution | 10 Bits |
|---|---|
| Full‑Scale Output Current | 5‑20 mA |
| Gain Error | ±10 % FS |
| Output Offset Temperature Coefficient | 50 nA/°C |
| SFDR at 42 MHz | 48‑50 dBc |
The device is specified to operate over the extended industrial temperature range of –40 °C to +85 °C.
With a +3.3 V supply the reference clock can be 7 MHz to 21 MHz when 6× REFCLK is enabled, and 42 MHz to 126 MHz when disabled.
The pulse‑shaping FIR filter provides 41 taps with 10‑bit coefficients that are fully programmable via the control bus.
The serial control bus can operate up to 25 MHz.