MAX814 Maxim, MAX814 Datasheet - Page 9

• Manufacturer Part Number: MAX814
• Description: 1% Accuracy / Low-Power / +3V and +5V P Supervisory Circuits
• Manufacturer: Maxim

Figure 4. MAX814 Block Diagram
Figure 6. MAX816 Block Diagram
RESET IN
V
MR
PFI
CC
1
2
4
MR
PFI
1
6
4
150 A
2
V
CC
150 A
RESET THRESHOLD
1.70V
_______________________________________________________________________________________
±1% Accuracy, Low-Power, +3V and +5V
1.70V
POWER- FAIL THRESHOLD
MAX814
MAX816
3
60mV
3
GND
GENERATOR
GND
GENERATOR
RESET
RESET
8
RESET
7
RESET
6
LOW LINE
5
PFO
8
7
5
RESET
RESET
PFO
µP Supervisory Circuits
A µP’s reset input starts the µP in a known state.
Whenever the µP is in an unknown state, it should be
held in reset. The MAX814/MAX815/MAX816 assert reset
during power-up, power-down, or brownout conditions.
On power-up, once V
anteed logic low of 0.4V or less. As V
stays low. As V
internal timer releases RESET after 200ms. RESET also
pulses low whenever V
old (i.e., brownout condition). If brownout occurs in the
middle of a previously initiated reset, the internal timer
is reset and the output remains low for at least another
140ms after the brownout ends. On power-down, once
V
and is guaranteed to be less than 0.3V until V
below 1V.
The MAX814 and MAX816 also offer active-high RESET
outputs. They are the inverse of the RESET outputs.
Figure 5. MAX815 Block Diagram
CC
WDI
V
falls below the reset threshold, RESET stays low
MR
PFI
CC
6
1
2
4
150 A
WATCHDOG
TRANSITION
DETECTOR
RESET THRESHOLD
CC
rises above the reset threshold, an
CC
CC
POWER-FAIL THRESHOLD
3
reaches 1V, RESET is a guar-
WATCHDOG
GENERATOR
GND
TIMEBASE
dips below the reset thresh-
TIMER
RESET
MAX815
Reset Output
CC
rises, RESET
CC
8
WDO
7
RESET
5
PFO
drops
9