MAX77651EWVT datasheet(39/82 Pages) MAXIM

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Global Resources

The global resources encompass a set of circuits that

serve the entire device and ensure safe, consistent, and

reliable operation.

Features and Benefits

● Voltage Monitors

• SYS POR (power-on-reset) comparator generates

a reset signal upon power-up

• SYS undervoltage ensures repeatable behavior when

power is applied to and removed from the device

• SYS overvoltage monitor inhibits operation with

overvoltage power sources to ensure reliability in

faulty environments

● Thermal Monitors

• 165°C junction temperature shutdown

● Manual Reset

• 8s or 16s period

● Wakeup Events

• Charger insertion (with 120ms debounce)

• nEN input assertion

● Interrupt Handler

• Interrupt output (nIRQ)

• All interrupts are maskable

● Push-button/Slide-Switch Onkey (nEN)

• Configurable push-button/slide-switch functionality

• 100μs or 30ms debounce timer interfaces directly

with mechanical switches

● On/Off Controller

• Startup/shut-down sequencing

• Programable sequencing delay

● PWR_HLD, GPIO, RST Digital I/Os

Voltage Monitors

The device monitors the system voltage (VSYS) to ensure

proper operation using three comparators (POR, UVLO,

and OVLO). These comparators include hysteresis to

prevent their outputs from toggling between states during

noisy system transitions.

SYS POR Comparator

The SYS POR comparator monitors VSYS and generates

a power-on reset signal (POR). When VSYS is below

VPOR, the device is held in reset (SYSRST = 1). When

VSYS rises above VPOR, internal signals and on-chip

memory stabilize and the device is released from reset

(SYSRST = 0).

SYS Undervoltage Lockout Comparator

The SYS undervoltage lockout (UVLO) comparator moni-

tors VSYS and generates a SYSUVLO signal when the

VSYS falls below UVLO threshold. The SYSUVLO signal

is provided to the top-level digital controller. See Figure 4

and Table 2 for additional information regarding the UVLO

comparator:

● When the device is in the STANDBY state, the UVLO

comparator is disabled.

● When transitioning out of the STANDBY state, the

UVLO comparator is enabled allowing the device to

check for sufficient input voltage. If the device has

sufficient input voltage, it can transition to the on

state; if there is insufficient input voltage, the device

transitions back to the STANDBY state.

SYS Overvoltage Lockout Comparator

The device is rated for 5.5V maximum operating voltage

(VSYS) with an absolute maximum input voltage of 6.0V.

An overvoltage lockout monitor increases the robustness

of the device by inhibiting operation when the supply volt-

age is greater than VSYSOVLO. See Figure 4 and Table 2

for additional information regarding the OVLO comparator:

● When the device is in the STANDBY state, the OVLO

comparator is disabled.

nEN Enable Input

nEN is an active-low internally debounced digital input

that typically comes from the system’s on key. The

debounce time is programmable with DBEN_nEN. The

primary purpose of this input is to generate a wake-up

signal for the PMIC that turns on the regulators. Maskable

rising/falling interrupts are available for nEN (nEN_R and

nEN_F) for alternate functionality. nEN requires an exter-

nal pullup resistor (10kΩ to 100kΩ) to SYS.

The nEN input can be configured to work either with a

push-button (nEN_MODE = 0) or a slide-switch (nEN_

MODE = 1). See Figure 2 for more information. In both

push-button mode and slide-switch mode, the on/off con-

troller looks for a falling edge on the nEN input to initiate

a power-up sequence.

nEN Manual Reset

nEN works as a manual reset input when the on/off con-

troller is in the on via on/off controller state. The manual

reset function is useful for forcing a power-down in case

the communication with the processor fails. When nEN is

configured for a push-button mode and the input is assert-

ed (nEN = low) for an extended period (tMRST), the on/off

controller initiates a power-down sequence and goes to

standby mode. When nEN is configured for a slide-switch

mode and the input is deasserted (nEN = high) for an

extended period (tMRST), the on/off controller initiates a

power-down sequence and goes to standby mode.

A dedicated internal oscillator is used to create the 30ms

(tDBNC_nEN) and 16s (tMRST) timers for nEN. Whenever

the device is actively counting either of these times, the

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MAX77650/MAX77651

Ultra-Low Power PMIC with 3-Output SIMO

and Power Path Charger for Small Li+

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