MAX6361 データシートの表示（PDF） - Maxim Integrated

部品番号

コンポーネント説明

メーカー

MAX6361

SOT23, Low-Power µP Supervisory Circuits with Battery Backup

Maxim Integrated 

SOT23, Low-Power µP Supervisory Circuits

with Battery Backup

Operating Circuit, the MAX6362 monitors two supply

voltages. To monitor the secondary 5V logic or analog

supply with a 4.60V nominal programmed reset thresh-

old, choose R2 = 100kΩ, and calculate R1 = 273kΩ.

Reset Output

A µP’s reset input starts the µP in a known state. The

MAX6361–MAX6364 µP supervisory circuits assert a

reset to prevent code-execution errors during power-

up, power-down, and brownout conditions. RESET is

guaranteed to be a logic low or high depending on the

device chosen (see Ordering Information). RESET or

RESET asserts when VCC is below the reset threshold

and for at least 150ms (tRP) after VCC rises above the

reset threshold. RESET or RESET also asserts when MR

is low (MAX6361) and when RESET IN is less than

1.235V (MAX6364). The MAX6362 watchdog function

will cause RESET (or RESET) to assert in pulses follow-

ing a watchdog timeout (Figure 1).

Applications Information

Operation Without a Backup

Power Source

The MAX6361–MAX6364 were designed for battery-

backed applications. If a backup battery is not used,

connect VCC to OUT and connect BATT to GND.

Replacing the Backup Battery

If BATT is decoupled with a 0.1µF capacitor to ground,

the backup power source can be removed while VCC

remains valid without danger of triggering a reset pulse.

The device does not enter battery-backup mode when

VCC stays above the reset threshold voltage.

Negative-Going VCC Transients

These supervisors are relatively immune to short-dura-

tion, negative-going VCC transients. Resetting the µP

when VCC experiences only small glitches is usually

not desirable.

The Typical Operating Characteristics section shows a

graph of Maximum Transient Duration vs. Reset

Threshold Overdrive for which reset is not asserted.

The graph was produced using negative-going VCC

pulses, starting at VCC and ending below the reset

threshold by the magnitude indicated (reset threshold

overdrive). The graph shows the maximum pulse width

that a negative-going VCC transient can typically have

without triggering a reset pulse. As the amplitude of the

transient increases (i.e., goes further below the reset

threshold), the maximum allowable pulse width

decreases. Typically, a VCC transient that goes 100mV

below the reset threshold and lasts for 30µs will not

trigger a reset pulse.

A 0.1µF bypass capacitor mounted close to the VCC

pin provides additional transient immunity.

WDI

RESET

tRP

tRP

tWD

tWD

tWD = WATCHDOG TIMEOUT PERIOD

tRP = RESET TIMEOUT PERIOD

Figure 1. MAX6362 Watchdog Timeout Period and Reset Active Time

_______________________________________________________________________________________ 7

Share Link: