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FPS_EN

OR FPSI

t1–t5: SET BY Mx_STUP_DLY[3:0] AND FPSO_STUP_DLY[3:0] REGISTERS (FACTORY PROGRAMMABLE).

t6–t10: SET BY Mx_SHDN_DLY[3:0] AND FPSO_SHDN_DLY[3:0] REGISTERS.

FPSO

t10

Figure 2. Typical Startup and Shutdown Sequence

Undervoltage Lock-Out (UVLO)

When the VSYS voltage falls below VUVLO_F (typ 2.7V), the MAX77542 disables all individual buck outputs immediately

and resets all buck output-voltage setting registers (Type F). See the Fault Protection section for more information.

A UVLO event forces the device to a dormant state until the VSYS voltage rises above the UVLO rising threshold (typ

2.9V). The UVLO falling threshold is programmable through I2C. If the VSYS voltage drops down to the POR threshold

(typ 1.7V), the VDD supply turns off (all the registers are reset) and the MAX77542 enters shutdown state.

VIO Fault

When the I/O supply falls below VIO_UVLO_F, the I2C buffer is cleared and all MFIO input and output functions are

deactivated. The I2C buffer and the MFIOs remain inactive until the VIO supply goes above VIO_UVLO_R. When

unmasked, the VIO fault event triggers the VIOFLT_I interrupt. See the Register Map section for more details. The VIO

fault condition can initiate a shutdown of all buck outputs immediately when the VIOFLT_SHDN bit is set to 1.

Thermal Warning and Thermal Shutdown (TSHDN)

The MAX77542 has a thermal warning to monitor whether the junction temperature rises above a programmable

threshold temperature. As shown in Figure 3, the device enters thermal shutdown (TSHDN) if the junction temperature

exceeds the TSHDN (approximately +165°C typ). A TSHDN event disables all individual buck outputs immediately and

resets all buck output-voltage setting registers (Type F). See the Fault Protection section for more information. Thermal

monitoring is active whenever any of the following conditions are true:

● One of the buck outputs is enabled.

● The force thermal protection enable bit is set (FTMON_EN = 1).

● Thermal protection is enabled (for any reason) and detects TJ ≥ TWARN_TH[2:0]. (In this case, thermal monitoring

remains active until TJ ≤ TWARN_TH[2:0] - 15°C.)

MAX77542

16VIN/16A, Quad-Phase High-Efficiency Buck

Converter

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DFE252012F-R47M Datasheet(PDF) 36 Page - Analog Devices