RDA5807 + PAM8406 Battery Mini FM Radio Circuit

Table of Contents

RDA5807 (RDA5807FP) + PAM8406 + ETA9638 battery powered mini FM radio circuit. This project is following the official RDA5807 tutorial in the community step by step. The first module added is the PAM8406 amplifier. For the 8406 amplifier, the official technical data includes a classic circuit, but the standard values for Cin and Rin at the input terminal are not specified, only a formula is provided. Set Cin to 470nF and Rin to 47KΩ. If there is no sound output, consider changing the values of Cin or Rin, Rin must be included.

Schematic RDA5807FP + PAM8406 Battery mini FM radio circuit

Schematic Rda5807 + Eta9638 Battery Mini Fm Radio Circuit — Schematic

The second module is the charging and discharging of 18650 batteries. Here using the ETA9638, which is a commonly used chip in Bluetooth headset boxes. The circuit is completely done according to the official guidance document. In the official guidance, it is specifically emphasized to separate the digital ground and analog ground. Then, the GND at the bottom of the 9638 chip also needs to be soldered. If you do not have a hot air gun, deliberately added extended solder pads at the bottom of the IC, where you can solder tin between the pad and the bottom to heat the bottom first before soldering the pins.

The following is the official information:
Note that this is for a single battery, for a dual battery setup, R1 needs to be doubled. The 10uF capacitor of the battery and the 22uF output capacitor should be placed as close to the IC as possible. The output of this chip is 5V1A (not the battery voltage, there is a boost inside the IC), so added a Schottky diode at the front end of the PMOS tube for voltage drop. A regular diode can also be used, but the voltage drop should be less than the USB voltage (for ease of use with the PMOS tube).

Then another change is to change the official version’s power input to Type-C 6P socket (A USB port is almost obsolete), with 2 resistors connected to the data position to avoid the C-C charging cable from being unable to supply power.

Other small modules, such as adding battery/external power automatic switching (PMOS high position), as well as the circuit diagram of the power automatic switching circuit MOS tube, because there are many capacitors in the load circuit, there may be switching peaks, waiting for verification in the later stage.

Battery External Power Automatic Switching Mosfet Circuit

The antenna can be soldered to any wire, and the charging efficiency and heating will be verified for subsequent use.

Welding difficulty level: beginner friendly, 0805 SMD and through-hole components, wide IC pin pitch, the only difficulty is soldering the GND mesh of 9638 at the bottom (solder pads have been added to reduce difficulty).

Recommended soldering sequence:

Power module area (TYPE-C 6P first, it is recommended to test with a power bank after soldering)
Radio module area
Battery module area,
Amplifier module area,
Battery box last (the battery pins are very small, so it is best to glue or screw the bottom of the battery box).

Firstly, in the case of multiple modules, it is best to have only one GND in per module area. Secondly, analog ground and digital ground should be separated in the circuit, unless necessary. It is not recommended to have large areas of copper coverage, as with high temperatures, a slight scratch can expose the copper, leading to short circuits.

BOM RDA5807 + PAM8406 Battery mini FM radio circuit

Parts	Value	Description	Quantity
Resistors
R1,R2	5.1kΩ (512)	R0805 – SMD resistor	2
R3,R17,R23	1kΩ (102)	R0805 – SMD resistor	3
R12,R13,R22,R24,R25,R26	10kΩ (103)	R0805 – SMD resistor	6
R14,R15	NC	R0805 – SMD resistor	2
R21,R28,R29	47kΩ (473)	R0805 – SMD resistor	3
R30	20kΩ (203)	R0805 – SMD resistor	1
Capacitors
C1,C2	10uF/16V	Electrolytic capacitor	2
C3,C4,C28	100nF	Ceramic capacitor	3
C5	22nF	Ceramic capacitor	1
C6	33pF	Ceramic capacitor	1
C7,C10	470nF	C0805 – SMD capacitor	2
C8,C9	100uF/16V	Electrolytic capacitor	2
C14,C15,C17,C18,C19	1uF	C0805 – SMD capacitor	5
C21,C22	100nF	C0805 – SMD capacitor	2
C24	22uF	C0805 – SMD capacitor	1
C25,C26	10uF	C0805 – SMD capacitor	2
C27	1nF	C0805 – SMD capacitor	1
Semiconductors
D1,D2	1N4148	75V 150mA DO-35 Switching Diode	2
D3,D4	SS34	40V 3A SMA Schottky Diode	2
LED1,LED8	KT-0805B	LED0805 – Blue	2
LED6	KT-0805R	LED0805 – Red	1
LED7,LED9	KT-0805G	LED0805 – Green	2
Q1	S8050	25V 800mA NPN SOT-23 Bipolar (BJT)	1
Q2	FH3415S	20V 4.5A P-Channel SOT-23-3L MOSFET	1
U1	TPXC6219B332MR	300mA Fixed 3.3V Positive SOT-23-5 Voltage Regulator – Linear, Low Drop Out (LDO)	1
U5	PAM8406DR	Dual Channel 5Wx2@2Ω SOIC-16 Audio Amplifier	1
U6	RDA5807FP	SOP-16 Single chip FM broadcast radio tuner	1
U13	ETA9638	ESOP-8 5V/1A Synchronous Boost with 1A Linear Charger for Power Bank	1
Miscellaneous
BT1	BH-18650-A5BJ001	Battery box	1
H5	PZ254V-11-01P	1x1P 2.54mm Pin Header	1
L1	10uH	D2.8xL7mm Color Ring Inductor Brown, black, brown, silver	1
L2	2.2uH (2R2)	SMD,6.6×7.3mm Power Inductor	1
J1,J2	PJ-307C	3.5mm Headphone Jack	2
J3,J5	B-2100S04P-A110	1x4P 2.54mm Pin Header	2
J4	77311-102-03LF	1x3P 2.54mm Pin Header	1
J6,J7	KF301-5.0-2P	1x2P 5mm Screw Terminal Block	2
POW,SEEK+,SEEK-,VOL+,VOL-	TS-1095PD-A9B3-D2	6mm 8mm SPST Tactile Switch	5
SW1	SS-12F44-G5	SPDT Slide Switch	1
TP1	TP1	M3	1
TP2	TP2	M3	1
TP3	TP3	M3	1
TP4	TP4	M3	1
USB1	TYPE-C 6P	5A USB 3.1 6P Type-C SMD USB Connector	1
X1	32.768kHz	DT-26 Crystal Oscillator	1

Download files, links, and notes

Rda5807 + Eta9638 Battery Mini Fm Radio Circuit Pcb 3D — Pcb 3D

Source https://oshwhub.com/smthem/rda5807-diao-pin-shou-yin-ji-dian-chi-chang-xu-hang-ban