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CMT2218-2219 User Guide for Schematic and PCB Layout Design
Overview
This document provides the schematic and PCB layout design guidelines for users engaging in the development based on the
CMT2218B/2219B receiver chip, which is part of the CMOSTEK NextGenRF
users to quickly achieve target performance objectives such as improving sensitivity, reducing power consumption and system
cost, improving anti-interference ability.
The product models covered in this document are shown in the table below.
Product Model
Frequency Range
CMT2218B
127 - 1020 MHz
CMT2219B
127 - 1020 MHz
©
Copyright
By CMOSTEK
Table 1. Product Models Covered in This Document
Modulation Method
FSK
(G)FSK/OOK
Rev 0.8 | 1/12
TM
product family. The document aims for guiding
Chip Function
Configuration Method
Receiving
Programming
Receiving
Register
AN160
AN160
Package
QFN16
QFN16
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Table of Contents
Related Manuals for CMOSTEK CMT2218-2219
Summary of Contents for CMOSTEK CMT2218-2219
- Page 1 AN160 AN160 CMT2218-2219 User Guide for Schematic and PCB Layout Design Overview This document provides the schematic and PCB layout design guidelines for users engaging in the development based on the CMT2218B/2219B receiver chip, which is part of the CMOSTEK NextGenRF product family.
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Page 2: Table Of Contents
Power and Ground Design ....................... 8 4.1 Power Filter Circuit Design ..........................8 4.2 Ground Plane Design ............................8 Sensitivity Optimization ........................9 Test Circuit Design ........................... 9 Design Checklist ..........................10 Revise History ..........................11 Contacts ............................12 Rev 0.8 | 2/12 www.cmostek.com... -
Page 3: Rf Input Matching
RF Input Matching The matching network achieves high receiving sensitivity performance through the impedance matching between the antenna and chip RF input. The LNA of the CMOSTEK NextGenRF CMT2218B/2219B is a differential port, using L1 and BALUN network (L2, C2, L3 and C3) to achieve the impedance matching between the single-ended antenna and differential LNA. In general, a parallel resonant filter network composed of L4 and C4 along with the input end of antenna can filter out the interference to the receiver caused by complex electromagnetic environment. - Page 4 ± 5%, 0603 multilayer chip inductor EPSON ± 20 ppm, SMD32*25 mm CMT2218B/2219B, ultra-low power CMOSTEK sub-1 GHz RF receiver Note： [1]. Only applications of CMT2218B require the pull up resistor R1 on SDIO port. In practical applications, due to factors such as product structure and physical space, the resistance of a user antenna is often not 50 Ω.
- Page 5 AN160 Figure 2. Matching Network Layout Design Reference Rev 0.8 | 5/12 www.cmostek.com...
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Page 6: Crystal Circuit Design
This refers to all frequency accuracy tolerances, including (1) initial tolerance (2) crystal loading tolerance (3) aging tolerance and (4) temperature variation tolerance. The acceptable crystal tolerance depends on factors such as RF frequency, channel spacing, bandwidth settings. [3]. This parameter is related much to the crystal used. Rev 0.8 | 6/12 www.cmostek.com... -
Page 7: Digital Signal Design
CMT2218B needs an external pull-up resistor, however it's not needed in the CMT2219B. Please use the programming tool provided by CMOSTEK to configure the CMT2218B. The CMT2219B provides a 4-wire series port mechanism using CSB, FCSB, SCLK and SDIO. Please be noted that PIN12 is FCSB pin in CMT2219B, however it is unused NC pin in CMT2218B. -
Page 8: Power And Ground Design
The GPIO1 pin of CMT2218B is fixed as Data Out output, the GPIO2 pin is fixed as Rx Active output and the GPIO3 pin output type is configurable. Please refer to CMOSTEK RFPDK for more details. Moreover, please be noted the following wiring considerations. -
Page 9: Sensitivity Optimization
CSB, SCLK, SDIO, VDD and GND should be reserved in users' applications to support the functions described below. When using CMT2218B, reserve test points of CSB, SCLK, SDIO, VDD, GND to accomplish the following two functions. 1. Update the chip's function via programming during production. 2. Read and get the chip configuration. Rev 0.8 | 9/12 www.cmostek.com... -
Page 10: Design Checklist
On the PCB edges, whether as many as possible vias with no more than λ/10 in size are placed to reduce the □ higher harmonic emissions from the PCB edges Test Circuit Design □ Whether test points for programming are reserved in the PCB design. Rev 0.8 | 10/12 www.cmostek.com... -
Page 11: Revise History
AN160 8 Revise History Table 5. Revise History Records Version No. Chapter Description Date Initial version 2017-09-15 In Table 2, correct some component description and values Section 1 2020-12-07 (translation error). Rev 0.8 | 11/12 www.cmostek.com... -
Page 12: Contacts
The material contained herein is the exclusive property of CMOSTEK and shall not be distributed, reproduced, or disclosed in whole or in part without prior written permission of CMOSTEK. CMOSTEK products are not authorized for use as critical components in life support devices or systems without express written approval of CMOSTEK.
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