Datasheet
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
high). When VIN rises above 0.5V and the enable input is
asserted (ENABLE = high or ENABLE = low), the output
asserts (OUT goes high or OUT goes low) after a capaci-
tor-programmable time delay.
With VIN above 0.5V, the enable input can be used to
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 out-
put state depending on the various input and enable
conditions.
Supply Input (V
CC
)
The device operates with a V
CC
supply voltage from
1.5V to 5.5V. To maintain a 1.8% accurate threshold,
VCC must be above 1.5V. When V
CC
falls below the
UVLO threshold, the output deasserts. When V
CC
falls
below 1.2V the output state cannot be determined. For
noisy systems, connect a 0.1µF ceramic capacitor from
V
CC
to GND as close to the device as possible. For the
push-pull active-high output option, a 100kΩ external
pulldown resistor to ground ensures the correct logic
state for V
CC
down to 0.
Table 3. MAX6899 Output
Table 2. MAX6896/MAX6898 Output
Table 1. MAX6895/MAX6897 Output
Figure 1. MAX6895/MAX6899 Functional Diagram
IN ENABLE OUT
V
IN
< V
TH
Low Low
V
IN
< V
TH
High Low
V
IN
> V
TH
Low High
V
IN
> V
TH
High Low
IN ENABLE OUT
V
IN
< V
TH
Low
OUT = V
CC
(MAX6896)
OUT = high impedance
(MAX6898)
V
IN
< V
TH
High
OUT = V
CC
(MAX6896)
OUT = high impedance
(MAX6898)
V
IN
> V
TH
Low Low
V
IN
> V
TH
High
OUT = V
CC
(MAX6896)
OUT = high impedance
(MAX6898)
IN ENABLE OUT
V
IN
< V
TH
Low Low
V
IN
< V
TH
High Low
V
IN
> V
TH
Low Low
V
IN
> V
TH
High
OUT = V
CC
(MAX6895)
OUT = high
Impedance
(MAX6897)
MAX6895
MAX6899
LOGIC
1.0V
250nA
0.5V
IN
OUT
CDELAY GND
ENABLE (MAX6895)
ENABLE (MAX6899)
V
CC
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Maxim Integrated
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6
MAX6895–MAX6899 Ultra-Small, Adjustable Sequencing/
Supervisory Circuits