Overview – Typical RF Remote Control PCB Layout
A typical RF remote control’s PCB is comprised of many electronic components, such as SAW resonator which controls the transmitting frequency and encoder IC which encodes the transmitting data. The typical inner photo of RF remote control is listed as follows.
Identify Operating Frequency
There are two types of RF remote controls based on operating frequency controlling circuit, one is the fixed frequency model, while the other one is the adjustable frequency model.
Fixed frequency model usually uses SAW (Surface Acoustic Wave) resonators to stabilize transmitting frequency, and is easier for operating frequency identification, while adjustable frequency model uses LC circuit, center frequency change is done using adjustable capacitor or adjustable inductor, and the operating frequency can be detected by spectrum or oscilloscope.
The following identification manual applies to fixed frequency model which usually used SAW (Surface Acoustic Wave) resonators and has its operating frequency printed on the enclosure of SAW component.
The detailed comparisons between fixed frequency model and adjustable frequency model are listed as follows.
| Type | Freq. Control Component | Major Differences |
|---|---|---|
| Fixed Frequency | SAW filter | Reduced size and weight High reliability and ruggedness No tuning or readjustment required Mass production capable |
| Adjustable Frequency | Adjustable Ceramic Capacitor | Adjustable frequency from 290MHz to 480MHz Frequency deviates after long time using |
NOTE: Fixed frequency model utilizing SAW filter is strongly recommended since it has performance and stability advantages over adjustable frequency model which utilizes adjustable ceramic capacitor or adjustable inductor.
Identify Encoding Type
There are basically three encoding types in RF remote control field, which are fixed code, learning code and rolling code, encoding type is determined by the encoder IC the remote control is using. The detailed comparisons between three encoding types are listed as follows.
| Type | Typical IC | Encoding Method | Security | Price |
|---|---|---|---|---|
| Fixed Code | PT2262 | Manual Encoding, using dip switch or soldering to set address code | Low | Low |
| Learning Code | EV1527 | Automatic Encoding, copying fixed code or learning code remote | Medium | Medium |
| Rolling Code | HCS301 | Automatic Encoding, using algorithm to generate different code every time | High | High |
INFORMATION: Learning code remote control using EV1527 chip is also known as self-learning copy remote, which can copy fixed code or learning code remote controls face to face. Rolling code remote control is usually duplicated using remote control duplicator, the number of rolling code remote control which can be duplicated is also limited.
| Chip Model | Fixed Code | Rolling Code | Learning Code |
|---|---|---|---|
| [2240] PT2240 [2242] PT2242 [2260] PT2260 [2262] PT2262 / M3E / CT5062 [6010] HT6010 / HT6012 / HT6014 / SH312E [H600] HT600 / HT680 / HT6187 / HT6270 / TT13 / PK10T [5026] AX5026 / CT5026 / SMC5026 [5326] AX5326 / AX5326S [8092] TT8092 [4134] MC4134 / MC1450 / SC4134 [918] SMC918 |
X | ||
| HCS301 / HCS300 / HCS200 | X | ||
| EV1527 / FP527 / HT6P20B / HT6P20D | X |
NOTE: The encoder IC listed above are common encoder chips in the market, if you can’t find your chip in the list, you can ask the corresponding manufacturer for detailed information.
Identify Oscillation Resistance
The oscillator resistor value determines the transmitting OSC frequency, a higher oscillator resistor value will result in a lower OSC frequency, thus a longer wavelength, which will make the receiver pickup the signal easier.
Oscillation Resistor Corresponding Sheet – PT2262 / PT2272 / Other Fixed Code IC
| PT2262 | PT2260 | SC2260 | CS5211 | PT2272 / SC2272 / CS5212 |
|---|---|---|---|---|
| 4.7 M | 1.2 M | 12.0 M | 4.3 M | 820 K* |
| 3.3 M | X | 9.1 M | 3.0 M | 680 K* |
| 2.2 M | X | 6.2 M | 2.0 M | 390 K* |
| 1.5 M | X | 4.3 M | 1.4 M | 270 K* |
| 1.2 M | X | 3.3 M | 1.1 M | 200 K** |
NOTE: * – Operates when PT2272 Vcc is 5V to 15V ** – Operates when PT2272 Vcc is 3V to 15V, which means when PT2272 supply voltage is lower than 5V, you need to use a lower oscillator resistor value for both PT2262 and PT2272.
Oscillation Resistor Correspondence – EV1527 / Other Learning Code IC
EV1527 chip is a learning code IC which is widely used in self-learning copy remote or universal RF remote control duplicator. Self-learning copy remote can duplicate a fixed code or learning code RF remote control face-to-face (e.g. Garage Door Opener Remote Control), making it very popular in today’s market.
The typical oscillator resistor value of EV1527 chip is 300 K, 330 K, 360 K, 390 K and 430 K. Commonly an EV1527 chip with 300 K oscillator resistor can pair with PT2262 chip with oscillator resistor values ranging from 1.5 M to 4.7 M. That explains why self-learning copy remote can copy most fixed code and learning code RF remote controls in the market, regardless of the oscillator resistor they are using.