the RF subsystem can be either digital through Jedec Standard (JESD) digital sample interfacing or analog through a baseband or IF connection. We discuss both options here. The JESD204 standards define high-speed serialized data interfaces used for communication of digital radio samples and control data among the logic devices (the 5G modem) Chapter 4 Hardware architecture choices implemented on FPGAs or ASICs or Application Specific Standard Products (ASSPs) and external data converters (DAC/ADC). It is the Serial (SerDes) based evolution of the JESD207 parallel data converter interface that was in use in the early 2000s. Multiple versions of the standard have been developed since 2006 with JESD204b (2011) being the most recent one, supporting up to 12.5 Gbps per serial lane. JESD204 incorporates embedded clocking through use of 8b10b encoding, removing the need for an external clock interface. Synchronization between the baseband ASIC and the data converter is achieved by using an external synchronization signal (SYNC or SYSREF) to achieve deterministic performance (defined and aligned latency). A high level partitioning example is shown in Fig. 4-22 below. Most standalone data converters from vendors like Analog Devices and Texas Instruments support the JESD interface, but it is also used to interface to integrated RFICs. What we mean with integrated RFICs are devices that include the data converters in addition to baseband RF conversion as well as (optional) support for some of the digital processing components such as DPD. The challenge with any digital interface, JESD included, is the required bandwidth as the system scales up with regards to antenna count and RF bandwidth. Consider a 100 MHz 5G/ NR system with a 14-bit (nominal) data conversion requirement and 4 antennas. Given a 122.88 MHz sample rate, we have 4 (antenna) X 122.88 (MSPS) X 2 (I, Q) X 14 (bit) = 14 Gbps. Even though JESD204b supports multiple speed grades (grade 1: < 3.125 Gbps; grade 2: 6.375 Gbps; grade 3: 12.5 Gbps), multiple lanes are 