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CMT2157A

Rev 0.8 | Page 19/31

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Normal Packet

The traditional 1527 packet contains a 32-symbol Sync, a 20-bit Address (Sync ID) and 4-bit Data. CMOSTEK has defined a

1527 Study Packet to support the ID study in 1527 mode. The traditional packet introduced here is called the “Normal Packet”.

Address (Sync ID)

configurable 20 bits

1 bit

Sync

32 symbols

Figure 17. 1527 Normal Packet Structure

Study Packet

The 1527 Study packet contains a 32-symbol Head_S and a 20-bit Address (Sync ID), as shown below.

Head_S

32-symbol

Address (Sync ID)

20 bits

Figure 18. 1527 Study Packet Structure

Bit Format

In 1527 packet, a single bit is constructed by 4 symbols, as shown below. The user can select the desired value of the “Bit

Format” parameter on the RFPDK. Please note that only the Sync ID field and the D0, D1, D2, D3, D4, D5, D6 field have the

unit of “bit”.

1 SYM

3 SYM

Bit 1

Bit 0

Figure 19. 1527 Bit Format Options

5.7.3 2262 Packet Structure

ID Study is not supported in 2262 mode. Only one packet structure is supported.

Table 15. Configurable Parameters in 2262 Packet

Parameter

Descriptions

Default

Mode

Address (Sync ID)

Length

This is the range of the Sync ID Length. The range is from

6 to 11 bits. This parameter also defines the number of

data bits, because the total number of Sync ID and Data

bits is fixed at 12.

8-bit

Basic

Advanced

Address (Sync ID)

Value

The value of each bit of the Sync ID can only be

represented by 0, 1 or f.

00000000

Basic

Advanced

In the traditional 2262 format, 4 OSC clocks (1 OSC clock cycle is notated as 1

) are equal to 1 symbol. By using the

CMOSTEK products, the user does not need to adjust the OSC to define the symbol rate, because the symbol rate is directly

programmed. The Bit Format is fixed at 8 symbols per bit.

Normal Packet

The traditional 2262 packet contains an Address (Sync ID), a Data, and a 32-symbol Sync.

Summary of Contents for CMT2157A

Page 1: ... with embedded data encoder ideally for 240 to 960 MHz wireless applications The device integrates a data encoder that is not only compatible with the most common used encoding format of 1527 and 2262 but also a more efficient flexible and powerful format of 1920 designed by CMOSTEK Up to 7 configurable push buttons are supported in multiple button modes When pairing the device to CMOSTEK receiver...

Page 2: ...chematic Table 1 BOM of 433 92 868 35 MHz Typical Application Designator Descriptions Value Unit Manufacturer 433 92 MHz 868 35 MHz U1 CMT2157A 240 960 MHz G FSK OOK stand alone transmitter with encoder CMOSTEK X1 20 ppm SMD32 25 mm crystal 26 MHz EPSON C0 20 0402 X7R 25 V 0 1 uF Murata GRM15 C1 5 0402 NP0 50 V 82 82 pF Murata GRM15 C2 5 0402 NP0 50 V 9 1 3 9 pF Murata GRM15 L1 5 0603 multi layer ...

Page 3: ... Loop PN Phase Noise ESD Electro Static Discharge RBW Resolution Bandwidth ESR Equivalent Series Resistance RCLK Reference Clock FSK Frequency Shift Keying RF Radio Frequency GFSK Gauss Frequency Shift Keying RFPDK RF Product Development Kit GUI Graphical User Interface RoHS Restriction of Hazardous Substances IC Integrated Circuit Rx Receiving Receiver LDO Low Drop Out SOT Small Outline Transisto...

Page 4: ...erview 12 5 2 Modulation Frequency Deviation and Symbol Rate 12 5 3 Embedded EEPROM and RFPDK 13 5 4 Power Amplifier 15 5 5 PA Ramping 15 5 6 Working States 16 5 7 The Encoder 17 5 7 1 1920 Packet Structure 17 5 7 2 1527 Packet Structure 18 5 7 3 2262 Packet Structure 19 5 8 ID Study 20 5 9 Button Modes 21 5 9 1 Normal 21 5 9 2 Matrix 22 5 9 3 Toggle 23 5 9 4 PWM 23 5 10 LED Driving Capability 24 ...

Page 5: ...l Conditions Min Max Unit Supply Voltage VDD 0 3 3 6 V Interface Voltage VIN 0 3 VDD 0 3 V Junction Temperature TJ 40 125 Storage Temperature TSTG 50 150 Soldering Temperature TSDR Lasts at least 30 seconds 255 ESD Rating Human Body Model HBM 2 2 kV Latch up Current 85 100 100 mA Note 1 Stresses above those listed as absolute maximum ratings may cause permanent damage to the device This is a stres...

Page 6: ...0 dBm 26 7 mA FSK 13 dBm 35 3 mA Sleep Current ISLEEP 20 nA Frequency Tune Time tTUNE 370 us Phase Noise 433 92 MHz PN433 92 100 kHz offset from FRF 80 dBc Hz 600 kHz offset from FRF 96 dBc Hz 1 2 MHz offset from FRF 108 dBc Hz Phase Noise 868 35 MHz PN868 35 100 kHz offset from FRF 74 dBc Hz 600 kHz offset from FRF 90 dBc Hz 1 2 MHz offset from FRF 102 dBc Hz Harmonics Output for 433 92 MHz 4 H24...

Page 7: ... The CMT2157A can directly work with external 26 MHz reference clock input to XTAL pin a coupling capacitor is required with amplitude 0 3 to 0 7 Vpp 2 This is the total tolerance including 1 initial tolerance 2 crystal loading 3 aging and 4 temperature dependence The acceptable crystal tolerance depends on RF frequency and channel spacing bandwidth 3 The required crystal load capacitance is integ...

Page 8: ...in Number Name I O Descriptions 1 LED O LED driver active low 2 VDD I Power supply input 3 GND I Ground 4 RFO O Power amplifier output 5 11 K 7 1 I Push button 7 to 1 12 DATA IO Data pin to access the embedded EEPROM internally pulled up to VDD 13 CLK I Clock pin to access the embedded EEPROM internally pulled up to VDD 14 XTAL I 26 MHz single ended crystal oscillator input or External 26 MHz refe...

Page 9: ...OK Spectrum 50 40 30 20 10 0 10 20 433 62 433 72 433 82 433 92 434 02 434 12 434 22 Power dBm Frequency MHz FSK vs GFSK FSK GFSK 50 40 30 20 10 0 10 433 17 433 37 433 57 433 77 433 97 434 17 434 37 434 57 Power dBm Frequency MHz Spectrum of Various PA Ramping Options 1024 us 512 us 256 us 128 us 64 us 32 us SR 1 2 ksps 2 0 2 4 6 8 10 12 14 16 1 6 1 8 2 2 2 2 4 2 6 2 8 3 3 2 3 4 3 6 3 8 Power dBm S...

Page 10: ...inductance between the ground pour and the GND pins Avoid using long and or thin transmission lines to connect the components Avoid placing the nearby inductors in the same orientation to reduce the coupling between them Place C0 as close to the CMT2157A as possible for better filtering 3 The table below shows the BOM of 433 92 868 35 MHz Low Cost Application For the BOM of more applications pleas...

Page 11: ...g long and or thin transmission lines to connect the components Avoid placing the nearby inductors in the same orientation to reduce the coupling between them Place C0 as close to the CMT2157A as possible for better filtering 3 The table below shows the BOM of 433 92 868 35 MHz FCC ETSI Compliant Application For the BOM of more application please refer to AN111 CMT215x Schematic and PCB Layout Des...

Page 12: ...OR to an internal reference voltage source The calibration can help the chip to finely work under different temperatures and supply voltages The transmission is triggered by pressing the push button s The data is modulated and sent out by a highly efficient PA which output power can be configured from 10 to 13 dBm in 1 dB step size RF Frequency PA output power and other product features can be pro...

Page 13: ...on the RFPDK CMT2157A Interface CMOSTEK USB Programmer CLK DATA RFPDK EEPROM Figure 12 Accessing Embedded EEPROM For more details of the CMOSTEK USB Programmer and the RFPDK please refer to AN113 CMT2150A 2250 1 A One Way RF Link Development Kits User s Guide For the detail of CMT2157A configurations with the RFPDK please refer to AN142 CMT2157A Configuration Guideline Table 10 Configurable Parame...

Page 14: ...in 1920 mode 3 Basic Advanced Number of Packets This defines the minimum number of packet s being transmitted during each button pressing action It also defines the number of packet s being transmitted during each periodic transmission The range is from 1 to 256 1 Advanced Packet Interval This defines the time interval amount two consecutive transmitted packets The unit is in symbol the range is f...

Page 15: ...ifier PA is integrated in the CMT2157A to transmit the modulated signal out Depending on the application the user can design a matching network for the PA to exhibit optimum efficiency at the desired output power for a wide range of antennas such as loop or monopole antenna Typical application schematics and the required BOM are shown in Chapter 4 Typical Application Schematic For the schematic la...

Page 16: ... to the SLEEP state When the device works in the periodic transmission mode the device periodically wakes up from the SLEEP state goes the same sequence performs the transmission and goes back to the SLEEP state All the details of push button s function and periodic transmission can be referred to AN142 CMT2157A Configuration Guideline SLEEP When the CMT2157A is in the SLEEP state all the internal...

Page 17: ...e The following sections only give the abstracts of these formats In the below explanations some elements in the packet are measured in the unit of symbol while some of them are measured in the unit of bit For those which have the unit of bit one bit is constructed encoded by several symbols In the figures SYM represents the word symbol 5 7 1 1920 Packet Structure Two types of packet structures ar...

Page 18: ...he unit of bit 2 SYM 2 SYM 1 SYM 1 SYM Bit 1 Bit 0 1 SYM 1 SYM 3 SYM 3 SYM Bit 1 Bit 0 3 SYM 2 SYM Bit 1 2 SYM 3 SYM Bit 0 2 SYM 1 SYM Bit 1 1 SYM 2 SYM 1 SYM 1 SYM Bit 0 1 SYM 3 SYM 3 Symbols Bit 4 Symbols Bit 5 Symbols Bit 6 Symbols Bit Figure 16 1920 Bit Format Options 5 7 2 1527 Packet Structure Two types of packet structures are supported for 1527 format Normal Packet and Study Packet The fol...

Page 19: ...4 D5 D6 field have the unit of bit 1 SYM 1 SYM 3 SYM 3 SYM Bit 1 Bit 0 Figure 19 1527 Bit Format Options 5 7 3 2262 Packet Structure ID Study is not supported in 2262 mode Only one packet structure is supported Table 15 Configurable Parameters in 2262 Packet Parameter Descriptions Default Mode Address Sync ID Length This is the range of the Sync ID Length The range is from 6 to 11 bits This parame...

Page 20: ... in the different packet formats In 1920 format it is from 1 to 32 bits In 1527 format it is fixed at 20 bits The ID Study is initialized by the CMT2157A It is done by executing the following steps An example of CMT2157A paring with CMT2250 51A is given below 1 Press the Study Button on the CMT2157A and hold it over the time defined by the Study Trigger Time 2 CMT2157A starts to transmit the Study...

Page 21: ... determined by the Sync ID Length The figure below gives an example which 4 push button keys are selected LED VDD GND RFO K7 K6 K5 XTAL CLK K0 K1 K2 K3 K4 D0 D1 D2 D3 NC NC NC NC LED VDD GND RFO CLK XTAL 7 6 5 1 2 3 4 8 9 10 14 13 12 11 Figure 23 Normal Button Mode In normal button mode the number of button s is used to determines the number of data bits in a packet The table below shows when 4 bu...

Page 22: ...user is able to use the 5 buttons K1 B0 K5 B4 to generate different combinations of the data D0 D3 to be transmitted The number of data bits to be transmitted is fixed at 4 The table below shows the matrix For the K1 K5 buttons 1 in the Push Buttons section means the corresponding button s is are pressed down while the 1 in the Data Bits section means a logic 1 to be transmitted Table 17 Mapping f...

Page 23: ...t down again the D1 is set to 0 in the current transmission and so on This is what it means by Toggle See the table below for the examples of toggle button mode Table 18 Examples of the Toggle Button Mode On Off Button s Pressed Button Times D0 D1 D2 D3 Single K1 is On Off Press K4 D1 1st Time 0 1 0 0 Press K4 D1 2nd Time 0 0 0 0 Press K4 D1 3rd Time 0 1 0 0 Press K1 1st Time On 1 1 1 1 Press K1 2...

Page 24: ...otify the user the battery is running out 5 11 Low Battery Detection LBD This defines the Low Battery Detection threshold Once the LBD is enabled the chip will automatically check the battery status before each transmission Once the chip finds that the battery output is less than the detection threshold the LED will flash at least 5 times at the frequency of 6 Hz to notify the user Once the LED fl...

Page 25: ...MT2157A by feeding the clock into the chip via the XTAL pin This further saves the system cost due to the removal of the crystal A coupling capacitor is required if the RCLK is used The recommended amplitude of the RCLK is 0 3 to 0 7 Vpp on the XTAL pin Also the user should set the internal load capacitor CL to its minimum value See Figure 28 for the RCLK circuitry Figure 28 RCLK Circuitry Figure ...

Page 26: ...6 V 40 to 85 1 000 Note 1 E stands for extended industrial product grade which supports the temperature range from 40 to 85 S stands for the package type of SOP14 R stands for the tape and reel package option the minimum order quantity MOQ for this option is 2 500 pcs B stands for the tube package option with the MOQ of 1 000 pcs The default frequency for CMT2157A is 868 35 MHz for the other setti...

Page 27: ... E1 E Figure 29 14 Pin SOP Package Table 20 14 Pin SOP Package Dimensions Symbol Size millimeters Min Typ Max A 1 75 A1 0 05 0 225 A2 1 30 1 40 1 50 A3 0 60 0 65 0 70 b 0 39 0 48 C 0 21 0 26 D 8 45 8 65 8 85 E 5 80 6 00 6 20 E1 3 70 3 90 4 10 e 1 27 BSC h 0 25 0 50 L 0 30 0 60 L1 1 05 BSC θ 0 8 ...

Page 28: ...157A Top Marking Explanation Mark Method Laser Pin 1 Mark Circle s diameter 1 mm Font Size 0 35 mm right justified Line 1 Marking CMT2157A represents part number CMT2157A Line 2 Marking YYWW is the Date code assigned by the assembly house YY represents the last two digits of the mold year and WW represents the workweek is the internal tracking number ...

Page 29: ... network and other application layout design related issues AN142 CMT2157A Configuration Guideline Details of configuring CMT2157A features on the RFPDK AN113 CMT2157A 2250 1 A One Way RF Link Development Kits User s Guide User s Guides for CMT2157A 2250 1 A Development Kits including Evaluation Board and Evaluation Module CMOSTEK USB Programmer and RFPDK AN115 Pairing CMT215x and CMT225x Provide ...

Page 30: ...CMT2157A Rev 0 8 Page 30 31 www cmostek com 10 Document Change List Table 23 Document Change List Rev No Chapter Description of Changes Date 0 8 All Initial released version 2015 02 11 ...

Page 31: ... for inaccuracies and specifications within this document are subject to change without notice 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 wri...

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