How to read and write data to RAM for the MAX20303?

To write data to the RAM: Write(0x31,0x40)) //sets HptRamEn to enable haptic RAM programming mode Write(0x28,0x00) //Write the RAM address for sample 0. Write(0x29,DAT0) //Write MSB of haptic pattern Write(0x2A,DAT1) //Write middle byte of haptic pattern Write(0x2B,DAT2) //Write LSB of haptic pattern *Repeat steps 2-5 to write the consecutive data word. To read data from the RAM: Write(0x33,0x00) // To start a haptic pattern that is stored in RAM, the sample 0 address of the pattern must be written to HptPatRAMAddr (register 0x33) before triggering a vibration Read(0x28,0x00) //Read the RAM address for sample 0. Read(0x29,DAT0) //Read MSB of haptic pattern Read(0x2A,DAT1) //Read middle byte of haptic pattern Read(0x2B,DAT2) //Read LSB of haptic pattern

When does the watchdog timer on the MAX20303 expire?

The Watchdog timer expires after about 700ms.

What is the function of the watchdog timer on the MAX20303?

The watchdog on the MAX20303 is an internal protection to prevent multiple requests (e.g. MPCs controls toggling) from AP that could halt the internal processor.

How long does it take for the MAX20303 to update the HibStat bit?

The HibStat bit in the MODE register (0x06) takes about 250ms to get updated to the current status on the MAX20303.

If the MPC pin of MAX20303 is connected to an external LED, how to control the brightness of the LED?

If the MPC pin is connected to the LED, it can only output high/low, that is LED on/off operation. If you want to adjust the brightness of the LED, need to connect the LED to the LED pins of the chip and adjust it in the register LEDISet [4:0].

What is the time it takes for the MAX20303 to update the HibStat bit?

It will take approximately 250ms for the HibSet bit on the MODE register (0x06) to update.

How to configurethe MAX20303 to store the haptic pattern in the RAM?

The RAM pattern should be loaded when the MAX20303 comes out of Off mode or at boot. To write a pattern to RAM, the user must set HptRamEn(0x31[6]) to high to enable haptic RAM programming mode. In RAMHP mode, the haptic driver runs the vibration pattern beginning at the RAM address stored in HptPatRAMAddr. Execute a write to register 0x28(HptRAMAddr) sets the starting address in RAM of the haptic pattern followed by 3 data bytes HptDataH, HptDataM, and HptDataL It is possible to read back data from RAM. Writing an address to HptRAMAddr, then initiating an I2C read transaction of register 0x29, will allow readback of the three bytes stored in the RAM address.

What is the minimum voltage that can be supplied to CHGIN for the MAX20303?

To charge the battery, the voltage at CHGIN must be greater than Vbat and the undervoltage threshold. The system loads must also be less than the input current limit. Typically to ensure proper operation you should ensure that the charging voltage supplied at CHGIN is greater than the maximum open-circuit voltage of the battery stored in Vbat_reg.

How do you calculate the inductor value for the buck converters in the MAX20303?

These are peak-current mode controlled buck converters, so the inductance is always 2.2µH. More importantly, you have to select the inductor based on its saturation current. We always recommend metal alloy core inductors (NOT ferrite). The reason is that ferrite cores have extremely bad AC losses in the core and we have seen up to 20% efficiency reduction with the use of small ferrite cores vs. small metal alloy cores. That being said, there are very limited options for 2.2µH inductors in cases smaller than 0805. Any inductor selected should have a saturation current >500mA.

MAX20303 Haptic drive enable

MAX20303 has internal frequency generator. Configure steps can be as following: 1. Set the initial frequency guess to the register. 2. Use Auto Tune function to get the resonant frequency. 3. Enable the haptic driver and set the amplitude to control the LRA/EMA.

How to reset I2C bus contention with MAX20303?

The I2C bus of MAX20303 can be reset from the bus contention (SDA is held low) by clock-through method. The procedure is described below: Step 1: Master tries to send a logic high on the SDA line Step 2: Master checks the SNA line. If the SDA is still low, master generates a clock pulse on SCL line. Step 3: Master checks SDA. If SDA is low, repeat Step 2. If SDA is high, go to Step 4 Step 4: Generate a STOP condition

What is SysMinVlt [2:0] register mentioned on page 96 of the Max20303 datasheet. Also, how is it different from BatReg[3:0]?

VSysMinVlt sets the SYS threshold voltage, where the device will start reducing the charge current. The SysMinVlt is used in an event where, the charger is enabled and functioning.

Will the SYS rail be powered by CHGIN if there is no battery connected on the MAX20303?

Yes, the SYS rail will be powered by the CHGIN power source if there is no battery connected to the MAX20303. The voltage level on the SYS rail will be equal to V_BAT_REG + 0.2V. The battery regulation voltage is set by the value in the BatReg register, typically 4.2V or 4.35V on power-up depending on IC version.

What Fuel Gauge does MAX20303 PMIC utilize?

The MAX20303 fuel gauge is based on the MAX17048 stand-alone fuel gauge and simulates the internal, nonlinear dynamics of a Li+ battery to determine its State of Charge (SOC). It does not have Maxim's Mode Gauge m5 EZ Config option.

The data sheet for the MAX20303 shows a capacitor for LDO2OUT of 1 uF, while the data sheet for the evaluation kit has a capacitor of 10 uF. Which is correct?

This is also the case for BK2OUT (10 uF in the datasheet and 22 uF in the EVKIT). The datasheet minimum capacitor values aree the recommend ones by the design team in the pinout description table (also in the typical applications circuit), but the EVKIT ones (placed by the EVKIT team) are the effective values after derating. Ceramic capacitors tend to deviate a lot from the nominal capacitance over voltage especially in small physical size.

What is meant by battery regulation voltage in the MAX20303?

In the datasheet it says it is between 4.05 V to 4.6 V but where and how is it used? Battery Regulaiton (BatReg) is the voltage to which the MAX20303 will charge the battery. So if BatReg is set to 4.20V, the BAT pin will attempt to drive itself to 4.20V when the charger is active. This action charges the battery, but, the voltage measured at BAT will be the battery voltage, not BatReg. When the real battery voltage matches the BatReg value, the charger considers the battery charged and will stop charging or enter maintain charge mode per the charger configuration settings.

MAX20303A has "Hi-Z" for PFN1 and "pulldown" for PFN2. Does it mean that PFN2 already has internal pull-down and for PFN1 I need an external one?

PFN2 has an internal pulldown and PFN1 needs an external connection. Table 1 is only meant to show what connection type makes the PFN_ pin meaningful. So for PwrRstCfg = 0b0100 where the PFN1 and PFN2 functions are active-high, a pulldown connection is required to keep the inputs in a known, inactive state. Table 193 is meant to clarify the device-specific configuration shown in table 192. So for the MAX20303A, Table 192 shows that PFN1 is Hi-Z and PFN2 has a pullup or pulldown connected. You then go to Table 193 to see which resistor is connected to PFN2.

Can Max20303 be used to charge and discharge Lithium ion polymer batteries as well?

The datasheet only mentions Li+. But the MAX20303 supports charging Li Polymer batteries with full-charge voltages between 4.05 and 4.60V (BatReg range).

What will happen if PFN1 is pulled down for more than 10s in the MAX20303?

The MAX20303A/E have PwrRstCfg = 0111. A 10s PFN1 button press should issue a soft reset to the device. The soft reset does not shut off VSYS. It should only reset the values of the registers. A 3s PFN1 press should enable the device.

MAX20303 PMIC - Not using LDO's how do I terminate pins

Question: If I don’t use the LDO's on the MAX20303 how do I terminate the input and output pins? Answer: The LDO inputs should be grounded, and the outputs should be left floating.

Battery Management System

Documents MAX20303AEWN+T: FAQ

MAX20303AEWN+T: FAQ

Partner Forums

Partner Libraries

MAX20303AEWN+T: FAQ