Typically a small SMD chip like the 8002B to drive the internal speaker.
The analog audio output from the Si4735 is too weak to drive a speaker directly.
is configured with a very high gain (around 77) to reach audible levels, which can introduce a slight background hiss at zero volume Known Hardware Components Component Type Part Number/Detail Main DSP IC SiLabs Si4735-D60 Multi-band receiver heart Powering speaker/headphones Li-ion battery charging Protection IC Battery overcharge protection 2200uF Capacitor (C98) Maintains clock during battery swap
To solve this, the designers included a secondary, dedicated VHF receiver IC (frequently the or a highly integrated equivalent clone). xhdata d-808 schematic
It supports FM (with RDS), LW, MW, and SW.
Longwave (LW) and Mediumwave (MW/AM) signals route through an internal high-permeability ferrite rod antenna wrapped with fine Litz wire. LNA (Low Noise Amplifier) Stage
: Contains the Si4735 DSP chip and front-end filtering. Notably, newer versions (released around late 2022) feature a major revision of this board with fewer filtering components and a USB-C port instead of the original micro-USB. Charging Circuit : Managed by a charging IC (U2) and protected by a (IC2) paired with an 82015A MOSFET (IC1) to prevent overcharging the 18650 Li-ion battery. MCU Backup Typically a small SMD chip like the 8002B
If you frequently use long wire antennas, soldering a pair of ultra-fast switching diodes (like the 1N4148) in parallel-inverse configuration across the antenna jack to ground can shield the internal schematic architecture from static electricity shocks. Finding and Reading the Schematic
For hobbyists looking to squeeze every ounce of performance out of the D-808, the schematic highlights several mod-friendly areas:
If you're simply looking to learn how to use the device, the user manual and guides available online should suffice. It supports FM (with RDS), LW, MW, and SW
An unbranded or proprietary 8-bit/32-bit MCU acts as the brain of the unit.
When examining a schematic, it is vital to know which version you own. Around 2023, XHDATA released a "New Version" (often identified by a USB-C port) with significant internal changes: