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High-performance FSK Transceiver Module with Silicon Labs Si4438 Chip Version B

FSK Transceiver module with Si4438 chip, low-power, long-distance
  • DL-RTS4438B

  • 433MHz

  • Si4438

  • -20~20dBm

  • -0.3~3V

  • -124dBm

  • 1800m

  • 15*12.5*2mm


High-performance FSK Transceiver Module with Si4438 chip

Module introduction

DL-RTS4438B was designed base on Silicon Labs' Si4438 wireless transceiver chip. It is a compact,low-power, long distance wireless transceiver module. The chip launched by Silicon Labs is mainly set to 433MHz, 470MHz, 510MHz frequency bands of the national networks. The sensitivity can reach -124dbm, the maximum transmission rate can reach 500Kbps, and the output power can range from -20dbm to + 20dbm through the register configuration. The module integrates all RF-related functions. Users do not need to have a deep understanding of RF circuit design; they can use this module to easily develop wireless products with stable performance and high reliability,shortening the product development cycle.The module adopts single-chip architecture, and the periphery adopts high-precision crystal, high-Q Murata inductor, small volume but high-capacity filter capacitor. All SMD components are used, and the interface is encapsulated with standard pitch stamps, which is conducive to the development of compact systems and the application of mass placement.


● 1800 meters transmission distance (1200bps);

● Working frequency 433.92M

● Working voltage: 1.8V-3.6V

● The receiving working current is only 14mA, which is lower than the industry level

● The interface uses an efficient 4-line SPI interface

● Independent 64-byte RX FIFO and TX FIFO

● Support WOR wireless signal wake-up function for portable devices


● Wireless sensor;

● Home automation;

● Automated data collection;

● Industrial remote control, telemetry;

● Data monitoring and transmission;

● Home Appliance Control;

● Security, alarm control;

Download Center

DL-RTS4438B Specification V1.1 do

Technical Parameter

DC characteristics

Description Min. Max.  Unit
Supply voltage 1.8  3.6  V
Working current RX <14mA TX=75mA@20dbm mA
Standby current
<1uA  Micro-ampere
IO port voltage Vss-0.3 Vdd+0.3 V
Working temperature -40  85

DC characteristics of the Module

RF characteristics (Unless otherwise stated, the temperature is 25  ℃, and VCC is 3.3V)

No Characteristics  Index parameter range  Unit

Min. Typi. Max.

Frequency range (customized by


425 433.92 525 MHz
2 Frequency interval
3  Transmit power -20
20 dBm
4 Receive sensitivity
5 Modulation GFSK 2-FSK OOK MSK
6  Transmission rate 1.2
500 Kbps
7 Harmonic power -45 — — -35 dBm
8  Communication distance  1200
1800 M
9 OOK Modulation mode, sensitivity
10 OOK modulation mode, rate 

120 Kbps
11 Standby power consumption 

0.9 MHz
12 Crystal accuracy

High frequency characteristic table of the module

Pins Definition


Pin Name Description Remark
1 VDD Power supply 3.3V  RF VDD
2 TXRAMP Output of external PA, not used
3 GPIO_0 GPIO0 pin directly connected to the chip
4 GPIO_1 GPIO1 pin directly connected to the chip

Configuration register


Interrupt input pin, output low level when interrupt is generated

6 SCLK SCLK input. Provide four-line serial data clock function
7 MISO 0~VDD Digital output
8 MOSI 0~VDD Digital input
9 NSEL Input pin for serial interface select
10 GPIO_2 GPIO2 pin directly connected to the chip
11 GPIO_3 GPIO3 pin directly connected to the chip
12 SDN Turn off input pin, SDN = 0 or 1; Refer to IC specification
15 ANT Antenna interface, 50Ω standard impedanc
14、16 GND Grounding, common ground with the system 13 pins NC



Dreamlnk is a high-tech enterprise specializing in ISM band micropower wireless communication technology, providing different kinds of wireless modules and one-stop IoT solutions, including 433/868/915MHz wireless modules, 2.4G RF Modules, FSK Transceiver Modules, Antennas, Remote Controls, and customized wireless RF solutions. Welcome to inquire!