Ultra-Small, Adjustable

Sequencing/Supervisory Circuits

6

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Detailed Description

The MAX6895–MAX6899 is a family of ultra-small, low-

power, sequencing/supervisory circuits. These devices

provide adjustable voltage monitoring for inputs down to

0.5V. They are ideal for use in power-supply sequenc-

ing, reset sequencing, and power-switching applica-

tions. Multiple devices can be cascaded for complex

sequencing applications.

Voltage monitoring is performed through a high-imped-

ance input (IN) with an internally fixed 0.5V threshold.

When the voltage at IN falls below 0.5V or when the

enable input is deasserted (ENABLE = low or ENABLE =

high), the output deasserts (OUT goes low or OUT goes

asserted (ENABLE = high or ENABLE = low), the output

asserts (OUT goes high or OUT goes low) after a capaci-

tor-programmable time delay.

turn the output on or off. After the enable input is assert-

ed, the output turns on with a capacitor-programmable

delay period (A version) or with a 150ns propagation

delay (P version). Tables 1, 2, and 3 detail the output

state depending on the various input and enable condi-

tions.

1.5V to 5.5V. To maintain a 1.8% accurate threshold,

below 1.2V the output state cannot be determined. For

noisy systems, connect a 0.1µF ceramic capacitor from

push-pull active-high output option, a 100kΩ external

pulldown resistor to ground ensures the correct logic

MAX6895

MAX6899

LOGIC

1.0V

250nA

0.5V

IN

OUT

CDELAY

GND

ENABLE (MAX6895)

ENABLE (MAX6899)

IN

ENABLE

OUT

Low

Low

High

Low

Low

Low

High

OUT = high impedance

(MAX6897)

Figure 1. MAX6895/MAX6899 Functional Diagram

Table 1. MAX6895/MAX6897 Output

IN

ENABLE

OUT

Low

OUT = high impedance

(MAX6898)

High

OUT = high impedance

(MAX6898)

Low

Low

High

OUT = high impedance

(MAX6898)

Table 2. MAX6896/MAX6898 Output

IN

ENABLE

OUT

Low

Low

High

Low

Low

High

High

Low

Table 3. MAX6899 Output