MICRF011 Reference Design With Filter Carlos Ribeiro Performance
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Receiver Board
MICRF011 Reference Design With Filter Carlos Ribeiro
Performance Summary
receiver board enables MICRF011 achieve meter open-field range when used with 0dBm transmitter.
Synopsis
receiver reference design intended (Remote Keyless Entry) similar applications. design complete solution incorporating Micrel MICRF011BM receiver, filter microcontroller. This circuit designed operate (bits second) although same board configured higher data-rate applications. information needed make this receiver provided including schematics, bill material layout. frequencies interest presented; 433.92 MHz.
Circuit Description
consists three main parts: Power Supply Receiver Decoder power supply noise regulator that supplies entire circuit. inductors separate analog digital supply voltages isolate noise created decoder from very important provide very clean voltage receiver, capacitors C12, C13, will clean conductive noise supply line.
SW100 SPST volts 4.7uF 4.7uF MIC5205-5.0BM5 +5VDIG PCBCOIL +5VANA
470pF
PCBCOIL
5-volt Power Supply
RX2-xxx Receiver
Qwikradio
Micrel
receiver consists main sections; front-end MICRF011BM receiver. front-end incorporates filter improve selectivity reduce unwanted noise. Inductors capacitors part filter network must used obtain desired filter performance.
Size 23.1 inches ANT1 WHIP ANTENNA 82nH 0603/0805S 5.6pF 0603S
VALUES SHOWN table other frequencies SAW1 B3551 EPCOS OUTPUT
82nH 0603/0805S
Front-End 5.6pF 0603S
1GND
6GND
Receiver FrontEnd
MICRF011BM fully integrated receiver that takes input from filter provides digital output baseband decoder. Inductors match MICRF011BM antenna input Ohms. Matching impedance improves sensitivity.
CON5 VALUES SHOWN MATCHING table other frequencies
jumper OPEN
MICRF011BM SEL0 VSSRF VSSRF VDDRF VDDBB SWEN REFOSC SEL1 CAGC VSSBB VSSBB
(NP)1nF
Front-End 18nH
72nH
0.1uF +5VANA
47nF +5VANA
2.2uF 6.3V
jumper SHORT
4.8970MHz
(NP)MMBT3906LT1 (NP) (NP)
(NP) 1kohm
Pulse
Receiver
(NP)
CON1 (NP) 75kohm
OFFSET
FAST RECOVERY (NP) 0.22uF
RX2-xxx Receiver
Qwikradio
Micrel
Jumper open jumper shorted, this configuration ties SEL1 lets SEL0 float high. This setting corresponds demodulator bandwidth 2500Hz. calculate desired demodulator bandwidth necessary determine shortest pulse width transmitter encoder. this case, have 33/66 scheme 850bps providing minimum pulse width 392us ((1/850)/3).The minimum demodulator bandwidth determined 0.65 392us 1.66 kHz). Looking MICRF011BM data sheet page that filter bandwidth closest greater than, 1.66kHz corresponds SEL0 (open) SEL1 (short ground). next step calculate capacitor (C5). value frequency dependent purpose this example, will consider calculation MHz. need know: period (BP) reference oscillator frequency (REFOSC), (internal resistor value chosen reference oscillator frequency) These 1.18ms, 4.8970 (high-side mixing) 118.1kOhms respectively. calculated from following equation: (4.90 REFOSC [MHz]) 118k. capacitor obtained Rsc, =49.97nF (nearest commercial value 47nF). optimal value dependent transmitter data format being very different from calculated value (values high 2.2uF). example pulse modulation scheme without preamble optimal value will different. software squelch used more precise timing required demodulation, network included create offset demodulator threshold detector. This offset performs squelch will result loss range. calculate reference oscillator frequency need know local oscillator frequency calculated fcarrier 1.064 fcarrier 390, 315MHz 1.064 315MHz 315.86 MHz. reference oscillator frequency determined using: REFOSC 64.5 315.86 64.5 4.8970 MHz. this example using high-side mixing, low-side used MICRF011BM used swept mode, different reference oscillator frequency would required (flo fcarrier 1.064 fcarrier low-side mixing, REFOSC fcarrier 64.25 swept mode). Capacitor placed pads provided case external signal generation used place resonator. using signal generator signal level 500mVp should exceeded. Cagc (C6) capacitor values vary depending application. Practical values vary from 0.1uF 4.7uF. Components placed. They have function charge Cagc much faster needed.
RX2-xxx Receiver
Qwikradio
Micrel
decoder circuit made primarily microcontroller PIC16C54C. more information obtain firmware samples, www.microchip.com.
CON4 +5VDIG +5VPIC PCBCOIL
Decode
PIC16C54C-04SO
1kohm
LEARN
10kohm
0.1uF
1kohm
GREEN
MCLR RTCC
1kohm
YELOW
1kohm
10kohm 10pF OSC1 CLKOUT
(NP)
(NP)
93LC46B 47kohm 1kohm
+5VPIC
0.1uF
LEARN INIT
RX2-xxx Receiver
Qwikradio
Micrel
Layout Considerations
board designed using sided 0.062 inch thick material with ounce copper clad. Four layers shown your reference. They layer, bottom layer, silkscreen top, drilling. layers available gerber format. other layers site shown here useful manufacturing process. They mask paste layers. with design, layout should done with care, taking into consideration sources noise, internal external circuit. Normally, decoder huge internal source noise, that noise could impact receiver sensitivity reducing performance receiver. avoid such problems, ground separated from digital ground through inductor. Also, small portion ground plane place section decoder right oscillator, which possible from receiver section. This ground plane serves trap noise radiated from decoder oscillator. lines separated through inductors, power supply large value decoupling capacitors filter conductive noise. receiver side, avoid running ground traces top. separate vias each ground connection. very important that ground plane solid without traces running bottom. traces close possible ground plane ground trace. outer ground trace receiver section several purposes. First, will provide room metal needed. Second, terminates ground plane bottom third, gives further separation from decoder. mentioned before, decoupling capacitors lines should close possible pins.
Layer
Bottom Layer
Drilling Plot
Silkscreen
Setting Receiver Maximum Data Rate Sweep Mode
RX2-xxx Receiver
Qwikradio
Micrel
Bill Materials (Parts placed shown bill materials) RX2-315
Item Part Number Description Reference ANT1 SAW1
23.1 antenna (9.1 inches) wire volts battery GRM39COG5R6D50 5.6pF 0603 Ceramic capacitor GRM39COG5R6D50 5.6pF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R473K16 47nF 0603 Ceramic capacitor GRM40X5R225K6.3 2.2uF 6.3V 0805 Ceramic capacitor GRM40X7R105K16 0805 Ceramic capacitor GRM39COG100D50 10pF 0603 Ceramic capacitor 0475X 9016 4.7uF Tant Size ,Tantalum capacitor 0475X 9016 4.7uF Tant Size ,Tantalum capacitor GRM39X7R471K50 470pF 0603 Ceramic capacitor SML-LX1206IC-TR LED, 1206, Learn function SML-LX1206GC-TR Green LED, 1206, function SML-LX1206YC-TR Yellow LED, 1206, function SML-LX1206IC-TR LED, 1206, function SML-LX1206GC-TR Green LED, 1206, ON/OFF function LQN21A82NJ04 82nH wire wound 0805 inductor LQN21A82NJ04 82nH wire wound 0805 inductor 0603CS-72NX_BC 72nH wire wound 0603 inductor 0603CS-18NX_BC 18nH wire wound 0603 inductor CRCW06030R0 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603103J 10kohm 0603 resistor CRCW0603103J 10kohm 0603 resistor CRCW0603473J 47kohm 0603 resistor B3551 Filter G105-0513 switch B3F-1022 Switch Momentarily 150g, Learn MICRF011BM QwikRadio Receiver SO14 PIC16C54C-04SO Microcontroller, SO18 93LC46B Memory, MIC5205-5.0BM5 5-volt Voltage Regulator, SOT23 AB-4.8970MHZ-20-D 4.8970 leaded crystal, HC-49 Package
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Industries
Omron Micrel Microchip Microchip Micrel Abracon
RX2-xxx Receiver
Qwikradio
Micrel
Bill Materials (Parts placed shown bill materials) RX2-433
Item Part Number Description Reference ANT1 SAW1
16.8 antenna (6.6 inches) wire volts battery GRM39COG5R6D50 5.6pF 0603 Ceramic capacitor GRM39COG5R6D50 5.6pF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R104K16 0.1uF 0603 Ceramic capacitor GRM39X7R683K16 68nF 0603 Ceramic capacitor GRM40X5R225K6.3 2.2uF 6.3V 0805 Ceramic capacitor GRM40X7R105K16 0805 Ceramic capacitor GRM39COG100D50 10pF 0603 Ceramic capacitor 0475X 9016 4.7uF Tant Size ,Tantalum capacitor 0475X 9016 4.7uF Tant Size ,Tantalum capacitor GRM39X7R471K50 470pF 0603 Ceramic capacitor SML-LX1206IC-TR LED, 1206, Learn function SML-LX1206GC-TR Green LED, 1206, function SML-LX1206YC-TR Yellow LED, 1206, function SML-LX1206IC-TR LED, 1206, function SML-LX1206GC-TR Green LED, 1206, ON/OFF function LQN21A33NJ04 33nH wire wound 0805 inductor LQN21A33NJ04 33nH wire wound 0805 inductor 0603CS-36NX_BC 36nH wire wound 0603 inductor 0603CS-10NX_BC 10nH wire wound 0603 inductor CRCW06030R0 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603102J 1kohm 0603 resistor CRCW0603103J 10kohm 0603 resistor CRCW0603103J 10kohm 0603 resistor CRCW0603473J 47kohm 0603 resistor B3550 433.92 Filter G105-0513 switch B3F-1022 Switch Momentarily 150g, Learn MICRF011BM QwikRadio Receiver SO14 PIC16C54C-04SO Microcontroller, SO18 93LC46B Memory, MIC5205-5.0BM5 5-volt Voltage Regulator, SOT23 AB-6.7458MHZ-20-D 6.7458 leaded crystal, HC-49 Package
MuRata MuRata MuRata MuRata MuRata MuRata MuRata MuRata MuRata Vishay Vishay MuRata Lumex Lumex Lumex Lumex Lumex MuRata MuRata Coilcraft Coilcraft Vishay Vishay Vishay Vishay Vishay Vishay Vishay Vishay Vishay Epcos
Industries
Omron Micrel Microchip Microchip Micrel Abracon
RX2-xxx Receiver
Qwikradio
Micrel
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