MAXQ3120 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAXQ3120

High-Precision ADC Mixed-Signal Microcontroller

Maxim Integrated 

High-Precision ADC

Mixed-Signal Microcontroller

System Timing

The MAXQ3120 generates its internal system clock

from an external high-frequency crystal. Because the

MAXQ3120 includes internal capacitors for this pur-

pose, no external capacitors are required to use the

high-frequency crystal. The MAXQ3120 should not be

driven directly by an external clock source.

A crystal warmup counter enhances operational relia-

bility. Each time the external crystal oscillation must

restart, such as after exiting stop mode, the device initi-

ates a crystal warmup period of 65,536 oscillations.

This allows time for the crystal amplitude and frequency

to stabilize before using it as a clock source.

Power Management

Advanced power-management features minimize power

consumption by dynamically matching the processing

speed of the device to the required performance level.

This means device operation can be slowed and power

consumption minimized during periods of reduced

activity. When more processing power is required, the

microcontroller can increase its operating frequency.

Software-selectable clock-divide operations allow flexi-

bility, selecting whether a system clock cycle is 1, 2, 4,

or 8 oscillator cycles. By performing this function in soft-

ware, a lower power state can be entered without the

cost of additional hardware.

For extremely power-sensitive applications, two addi-

tional low-power modes are available.

• Divide-by-256 power-management mode (PMM)

(PMME = 1, CD1:0 = 00b)

• Stop mode (STOP = 1)

In PMM, one system clock is 256 oscillator cycles, signifi-

cantly reducing power consumption while the microcon-

troller functions at reduced speed. The optional

switchback feature allows enabled interrupt sources,

such as the external interrupts and USARTs, to cause the

processor to quickly exit PMM mode and return to a

faster internal clock rate.

POWER-ON

RESET

STOP

CRYSTAL KILL

HF

CRYSTAL

RESET

XDOG

STARTUP

TIMER

CLK INPUT

XDOG COUNT

XDOG DONE

MAXQ3120

32kHz

CRYSTAL

CLOCK

DIVIDER

REAL-TIME CLOCK

LCD CONTROLLER

RESET DOG

WATCHDOG

TIMER

RWT

RESET

WATCHDOG RESET

WATCHDOG INTERRUPT

ENABLE

CLOCK

GENERATION

STOP

POWER-ON

RESET

SYSTEM CLOCK

INPUT

CRYSTAL

MONITOR

ENABLE

Figure 2. Clock Sources

POWER MONITOR

SELECTOR

DEFAULT

SWB

INTERRUPT/SERIAL PORT

RESET

STOP

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