Minimal System Application Notes
1. Introduction to the GR5xx Minimum System
GR551x power supply introduction
GR5551x series chips are powered by external power supply through pin VBATL/VBAT_RF, the power supply range is from 2.2 V to 3.8 V.
GR5525 Power Supply Introduction
GR5525 series chips are powered by external power supply via pin VBATL/VBAT_RF, and the power supply range is from 2.4 V to 3.8 V.
Introduction to GR533x Power Supplies
GR533x series chips are powered by external power supply through pin VBATL/VBAT_RF, and the power supply range is 2.0 V to 3.63 V. The GR533x series chips support SYSTEMATIC power supply.
GR533x supports both SYSLDO and DCDC power supply modes.
GR5526 Power Supply Introduction
GR5526 series chips are powered by external power supply through pin VBATL/VBAT_RF, and the power supply range is 2.4 V to 4.35 V. The GR533x supports SYSLDO and DCDC power supply modes.
The GR5xx series chips are recommended to be powered by a separate LDO/DCDC.
GR5xx series chips do not support slow charging of external batteries, and need to use a charger with path management or external circuitry to realize charging path management.
GR5xx series chip power-up timing is when CHIP_EN reaches 1 V after power-up, VBATL needs to be higher than its operating voltage, and VDDIO must not be powered up before VBATL.
GR5xx series power supply PIN pin introduction
VSW: DC-DC switching power supply output pin.
VREG: Feedback pin for DC-DC switching power supply output voltage.
On-chip DC-DC converter to power the RF analog module with the chip Core LDO. The system turns off this power supply during sleep to save power consumption.
VDD_VCO: Internal VCO power supply pin, powered by on-chip DC-DC, connected via external alignment, some chips don’t have this pin, it is enclosed inside the chip with VDD-RF.
VDD_AMS: internal analog power supply pin, powered by on-chip DC-DC, connected by external wiring, some chips don’t have this pin, it is enclosed with VDD-RF inside the chip.
VDD_RF: Power supply pin for internal RF part, powered by on-chip DC-DC, connected by external wiring.
VDD_DIGCORE_1V: Power supply for digital core logic, it is the output pin of Digital LDO, powered by on-chip DC-DC, the system will turn off this power supply during sleep to save power consumption.
VDDIO0: IO0 voltage domain power supply input pin, internal Flash power supply pin, can be powered by VIO_LDO_OUT or external regulator, the chip without this PIN pin, its on-chip and VIO_LDO_OUT internal connection.
VDDIO1: IO1 voltage domain supply input pin, can be powered by VIO_LDO_OUT or external regulator.
VIO_LDO_OUT: IO LDO output pin, supplying power to the internal Flash, or can be externally connected to supply power to VDDIO1.
VBATT_RF: RF power supply input pin, connected to VBATL pin.
GR5xx clock introduction
The system clock source of GR5xx series chips is generated by an external 32 MHz crystal oscillator with a load capacitance of 6 pF to 8 pF, and an internal load capacitor is integrated in the chip.
The RTC clock source of the GR5xx series is generated by an external 32.768 kHz crystal, and the load capacitance of the 32.768 kHz crystal must be 6 pF to 9 pF, and the internal load capacitor is integrated.
GR5xx burn-in interface introduction
The mass production burn-in interfaces of GR5xx series chips are SWDCLK, SWDIO, CLK_TRIM (any GPIO except MSIO), GND, VBAT.
If there is an external watchdog chip, you need to reserve the watchdog enable signal or feed dog signal in the burn-in interface.
For GR531x series chips, if you need to burn eFuse information, you need one more MSIO7.
2. GR5xx Minimum System Application Notes
GR551x VDDIO Voltage Notes
GR551x VDDIO1 can be used with 1.8 V to 3.3 V voltage input. When externally inputting the VDDIO1 voltage, be careful not to exceed the input voltage of the power supply Vbatl.
GR551x Because VDDIO0 is required to supply power to Flash, the VDDIO0 voltage differs for each model, as listed below:
GR5515IGND, GR5515RGBD, GR5515GGBD, GR5513BEND can only use 1.8 V voltage input.
GR5515I0ND can only use 3.3 V voltage input.
GR5515IENDU, GR5515I0NDA, GR5513BENDU can use 1.8 V to 3.3 V voltage input.
When externally inputting the VDDIO0 voltage, be careful not to exceed the input voltage of the power supply Vbatl.
GR533x Power Supply Application Notes
Peripheral BOM when GR533x uses only SYSLDO power supply can directly remove the 9.1 nH and 2.2 μH inductor materials connected to VSW pin.
GR533x can only use SYSLDO power supply mode when using HPA.
There are two GR533x IO_LDOs: ANA_IO_LDO and STB_IO_LDO. ANA_IO_LDO has a maximum drive capability of 30 mA, and STB_IO_LDO has a maximum drive capability of 1 mA. switching to STB_IO_LDO at sleep time helps to reduce sleep power consumption, but there are peripheral devices that require the IO_LDO power supply, so be careful! whether the STB_IO_LDO bandwidth capacity meets the peripheral demand.
When the GR533x is working as a Slave, do not disconnect the input power supply from the chip VBATL power supply when CHIP_EN is pulled low, otherwise the I/O status of the GR533x may get out of control and be forced to output a high level.
GR5526 power supply application notes
VDDIO1 supplies power to the internal PSRAM, the corresponding voltages are different for different models as listed below:
GR5526VGBIP, GR5526RGNIP can only use 1.8 V voltage input.
GR5526VGBI and GR5526RGNI can use 1.8 V to 3.3 V voltage input.
VDDIO0 voltage supply requirements
1.8 V to 3.3 V voltage input can be used. Be careful not to exceed the input voltage of the power supply Vbatl when externally inputting the VDDIO0 voltage.
GR5525 Power Supply Application Precautions
GR5525 series chips are recommended to connect a TVS tube (recommended: µClamp03301ZA) in parallel with the VBATL pin for improving the EOS capability of the system.
When GR5525 is working as a Slave, do not disconnect the input power supply from the VBATL power supply of the chip when CHIP_EN is pulled low, otherwise the I/O state of GR5525 may get out of control and be forced to output a high level.
Other points to be added