Datasheet RN4678 (Microchip) - 7

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RN4678 Function Name Description
UART RX Indication Use this pin to enable communication with the UART when the module is in Low-Power mode. When not in Low-Power mode, the module runs on a 16 MHz clock. If Low-Power mode is enabled on the module by using command SO,1, the module runs on a 32 kHz clock thus reducing power consumption. However, in Low-Power mode, the host MCU cannot communicate with the module via the UART since the UART is not operational. If the user intends to provide data or commands via UART in the Low-Power mode, then the UART_RX_IND pin must be pulled low and the user needs to wait for at least five milliseconds before sending the data. Pulling the UART_RX_IND pin low allows the module to operate the 16 MHz clock and to enable UART. Pairing Key Use this pin to force the module to enter Standby mode. The pin must be pulled down for at least 160 ms. Inquiry Control This pin forces the module to enter Inquiry mode (BT Classic). The pin must be pulled low for at least 240 ms for the device to enter Inquiry mode. Profile_IND This pin is used to indicate whether current connection is in BR/EDR (BT Classic), or in Bluetooth Low Energy (BLE). If the Profile_IND pin is high, then the current connection is BR/EDR connection. If low, then the current connection is a BLE connection. This pin is valid only for the Link state.
2.4 Power Tree
Figure 2-1 illustrates the power tree diagram of the RN4678.
FIGURE 2-1: POWER TREE DIAGRAM
BAT_IN 3.3v˜4.2v PMULDO o VCC_RF LDO18_EN 1v8 PMU Logic LDO18 AVDD_SAR VDD_XO SW_BTN LDO33_EN VDD_IO 3v3 LDO33 LED EEPROM  2016-2020 Microchip Technology Inc. DS50002519E-page 7 Document Outline RN4678 Features RF/Analog Data Throughput Operating Conditions MAC/Baseband/Higher Layer Features Applications Description Table of Contents Most Current Data Sheet Errata Customer Notification System 1.0 Device Overview FIGURE 1-1: RN4678 Internal Block Diagram TABLE 1-1: PIN Description FIGURE 1-2: RN4678 PIN DIAGRAM 2.0 Application Information 2.1 Module Configuration 2.2 Flow Control 2.3 Control and Indication I/O Pins 2.4 Power Tree FIGURE 2-1: Power Tree Diagram 2.5 Software Button (SW_BTN) FIGURE 2-2: SW_BTN TIME (HIGH) AT APP MODE(1,2) FIGURE 2-3: SW_BTN TIME (LOW) AT ACCESS STATES(1) FIGURE 2-4: SW_BTN TIME (LOW) AT LINK STATES(1,2) 2.6 WAKE-UP FIGURE 2-5: WAKE-UP TIME(1) 2.7 External Reset FIGURE 2-6: TIMING WAVEFORMS ON RESET (1,2) 2.8 LED Driver FIGURE 2-7: LED Driver 2.9 Host MCU Interface over UART FIGURE 2-8: Power and MCU Interface Example for Rn4678 2.10 Reference Circuit FIGURE 2-9: RN4678 Reference Circuit 3.0 Electrical Characteristics Absolute Maximum Ratings TABLE 3-1: Recommended Operating Conditions TABLE 3-2: 3.3V LDO Electrical Parameters (1,2) TABLE 3-3: PMU LDO(1,2) TABLE 3-4: SAR-ADC AND Battery Voltage Detector TABLE 3-5: Intensity Controllable LED Driver TABLE 3-6: Power Consumption-Classic(1) TABLE 3-7: Power Consumption-Low Energy(1,2) 4.0 Radio Characteristics TABLE 4-1: Transmitter Performance (1,2) TABLE 4-2: Receiver Performance(1) 5.0 Physical Dimensions FIGURE 5-1: RN4678 Module Dimensions FIGURE 5-2: RN4678 Recommended PCB Footprint FIGURE 5-3: RN4678 Host PCB Mounting Suggestion 6.0 Reflow profile FIGURE 6-1: Reflow Profile 7.0 Module Placement FIGURE 7-1: Module Placement Examples TABLE 7-1: Recommended Antenna FIGURE 7-2: Keep Out Area Recommended for Antenna 7.1 RN4678 Ceramic Chip Antenna FIGURE 7-3: RN4678 Antenna Radiation Pattern 8.0 Ordering Information TABLE 8-1: Ordering Information 9.0 Regulatory Approval 9.1 United States 9.2 Canada 9.3 Europe TABLE 9-1: EUROPEAN COMPLIANCE TESTING 9.4 Japan 9.5 Korea 9.6 Taiwan 9.7 China 9.8 Other Regulatory Information Appendix A: Revision History The Microchip WebSite Product Identification System Trademarks Worldwide Sales