General Description
The RDA1845 is a single-chip transceiver for Walkie Talkie with fully integrated synthesizer, IF
selectivity and base-band signal processing. The transceiver uses the CMOS process, support
digital volume control and require the least external component. The package size is 6X6mm
and is completely adjustment-free.The RDA1845 has a powerful low-IF digital audio processor, this make it have optimum sound quality with varying reception conditions.
The RDA1845 can be tuned to the worldwide frequency band for Walkie Talkie

Features
1. CMOS single-chip fully-integrated transceiver
2. Support worldwide frequency band
  300Mhz-500 MHz
12.5Khz,25Khz channels
3. Digital low-IF tuner
 Image-reject down-converter
 High performance A/D converter
 IF selectivity performed internally
4. Fully integrated digital frequency synthesizer
 fully integrated on-chip RF and IF VCO
 fully integrated on-chip loop filter
5. Auto DC offset calibration
6. Digital auto frequency control (AFC)
7. Digital auto gain control (AGC)
8. Support multi-reference clocks
 12.8/25.6Mhz
 13/26Mhz
9. Selectable pre/de-emphasis
10. Support CTCSS and CDCSS
11. Receive signal strength indicator (RSSI)
12. Provide programmable VOX and Squelch indicator
13. Analog and digital volume control
14. Reference clock drift compensation
15. 3-wire serial control bus interface
16. Directly support 32Ω resistance loading
17. Integrated LDO regulator
 2.7 to 3.3 V operation voltage
18. 6X6mm 40 pin QFN package

Applications
1. Cellular handsets
2. Family radio services
3. Walkie Talkies