PCA9421 datasheet(11/66 Pages) NXP

11 / 66 page

NXP Semiconductors

PCA9421

Power management IC for low-power microcontroller applications

1. ON pin has internal 1 MΩ pullup resistor to either 2.5 V or VIN_AUX depending on VIN_AUX and VIN

voltages:

• When VIN is present (5 V): If VIN_AUX is less than 3.8 V (typical), ON is pulled up to 2.5 V (typical) and if

VIN_AUX is greater than 3.8 V (typical), it is pulled to VIN_AUX.

• When VIN is not present (0 V): ON pin follows VIN_AUX.

Falling edge (filtered after deglitching time, 200 μs typ), active-LOW signal enables the chip and starts the

power-up sequence from STANDBY state. If the device is already in the middle of power-up or power-down

sequence, the falling edge applied on the ON pin is ignored by the chip.

1. Long press (duration time, 4 s, 8 s, 12 s or 16 s, is programmable via I2C, ON_GLT_LONG [1:0]). If the logic

LOW signal is applied continuously over a programmed duration, the chip gets reset and recycles all power

rails to their default values

2. Also, in mode setting 0, 1, 2, or 3, an I2C bit “ON_CFG_x“ (x=0, 1, 2, or 3) is reserved; by setting its value to

either 0 or 1, the user can configure whether a mode setting switches back to Mode Setting 0 or not, upon

a valid falling edge detected from “ON” pin. Refer to ON_CFG_x bit description in the relation registers for

more details.

3. The filtered falling edge on the ON pin resets the bit of EN_MODE_SEL_BY_PIN_X to the default value, 0,

at 22h register. The status of the ON pin is available in reset monitor register (address 0x71, bit [7]).

8.7 Mode setting

When the MCU operates in different modes such as overdrive run mode or low power mode, it may require the

power supply to operate in different settings accordingly (for example, enable/disable of each rail, output voltage

of each rail, etc.) to achieve a better performance and efficiency.

On the PCA9421, there are four modes of registers representing Mode Setting 0/1/2/3 to accommodate

such requirements from MCU, where Mode Setting A is the default mode setting (i.e., the initial mode setting

upon initial power up). Depending on the user’s preference, switching among different mode settings can be

controlled by either the external signal (ON pin), external pins (MODESEL0/1) or I2C.

Within each mode setting, the user can program the follow parameters providing great flexibility to

accommodate different MCU operation modes:

1. Enable/disable of the four output voltage rails

2. Voltage setting of the four output voltage rails

3. Watchdog timer setting

4. Mode control selection (EN_MODE_SEL_BY_PIN_x, x=0, 1, 2, or 3)

EN_MODE_SEL_BY_PIN_x = 0: under current mode setting, mode setting switch is controlled by internal I2C

ignored.

EN_MODE_SEL_BY_PIN_x = 1: under current mode setting, mode setting switch is controlled by signal

applied on external MODESEL0 and/or MODESEL1 pins only, not by internal I2C register bits MODE0_I2C and

MODE1_I2C.

1. Mode setting switches back to Mode Setting A triggered by ON pin falling edge. Refer to register description

for “ON_CFG_x” bit for more details.

In the event of switching from one mode setting (initial mode setting) to another mode setting (target mode

setting):

1. If one output rail remains enabled in both initial mode setting and target mode setting but with different

output voltage in each setting, such voltage transition should happen when the mode setting switch

command (from either internal I2C setting or external signal) is received;

PCA9421

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 1.0 — 16 October 2023

11 / 66

PCA9421 bảng dữ liệu(PDF) 11 Page - NXP Semiconductors

PCA9421 bảng dữ liệu(HTML) 11 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

bảng dữ liệu tải về

Link URL