[Working frequency band]：410~493MHz
[Transmission power]： 37dBm
[Communication distance]：20km
[Receive gain]：15dBm
[Product size]：45*30mm
[Introduction]：E21-400G37S is a pure hardware RF mid-power amplifier (PA) launched by Chengdu Ebyte Company, with a maximum output power of 37dBm, covering a frequency range of 410-493MHz, and a built-in LNA low-noise amplifier in the module, which greatly improves the wireless communication. communication distance.
| PIN | Name | Direction | Usage |
| 1 | GND | Ground wire, connected to reference ground | |
| 2 | +7. 5V | PA drive power VCC1 | |
| 3 | +7. 5V | PA drive power VCC1 | |
| 4 | GND | Ground wire, connected to reference ground | |
| 5 | +5V | Control power supply VCC2 | |
| 6 | GND | Ground wire, connected to reference ground | |
| 7 | TXEN | Input | Enable the transmission mode, effective at high level (support 3. 3V/5V level) |
| 8 | RXEN | Input | Receive mode enable, active at high level (support 3. 3V/5V level) |
| 9 | GND | Ground wire, connected to reference ground | |
| 10 | PIN | Input/Output | Transmission mode: RF signal input/reception mode: RF signal output |
| 11 | POUT | Output/Input | Transmission mode: RF signal output/reception mode: RF signal input |
| 12 | GND | Ground wire, connected to reference ground | |
| 13 | GND | Ground wire, connected to reference ground | |
| 14 | GND | Ground wire, connected to reference ground | |
| 15 | GND | Ground wire, connected to reference ground | |
| 16 | GND | Ground wire, connected to reference ground | |
| 17 | GND | Bottom heat dissipation pad, connecting module GND | |
| Note: 1. TXEN and RXEN cannot be opened at the same time at any time, which may cause direct damage to PA module. 2. The bottom bonding pad is connected to the internal GND, which needs to be coated with silicone grease for heat dissipation or welded to the base plate to enhance heat dissipation. | |||