Integrated circuits, Transistor, Semiconductors Free Datasheet Search and Download Site


MAX6723AUTTED1-T View Datasheet(PDF) - Maxim Integrated

Part NameMAX6723AUTTED1-T MaximIC
Maxim Integrated MaximIC
DescriptionDual/Triple, Ultra-Low-Voltage, SOT23 µP Supervisory Circuits
MAX6723AUTTED1-T Datasheet PDF : 18 Pages
First Prev 11 12 13 14 15 16 17 18
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
The normal watchdog timeout period (1.12s min)
begins after the first transition on WDI before the con-
clusion of the long initial watchdog period (Figure 2).
During the normal operating mode, the supervisor will
issue a reset pulse for the reset timeout period if the µP
does not update the WDI with a valid transition (high-to-
low or low-to-high) within the standard timeout period
(1.12s min).
Leave WDI unconnected to disable the watchdog timer.
The WDI unconnected-state detector uses a small
(200nA typ) current source. Therefore, do not connect
WDI to anything that will source more than 50nA.
Power-Fail Comparator
PFI is the noninverting input to a comparator. If PFI is
less than VPFI (626.5mV), PFO goes low. Common uses
for the power-fail comparator include monitoring prereg-
ulated input of the power supply (such as a battery) or
providing an early power-fail warning so software can
conduct an orderly system shutdown. It can also be
used to monitor supplies other than VCC1 or VCC2 by
setting the power-fail threshold with a resistor-divider, as
shown in Figure 3. PFI is the input to the power-fail com-
parator. The typical comparator delay is 2µs from PFI to
PFO. Connect PFI to ground of VCC1 if unused.
Ensuring a Valid Reset Output
Down to VCC = 0V
The MAX6715A–MAX6729A/MAX6797A are guaranteed
to operate properly down to VCC = 0.8V. In applications
that require valid reset levels down to VCC = 0V, use a
pulldown resistor at RST to ground. The resistor value
used is not critical, but it must be large enough not to
load the reset output when VCC is above the reset thresh-
old. For most applications, 100kis adequate. This con-
figuration does not work for the open-drain outputs of the
MAX6715A/MAX6717A/MAX6719A/MAX6721A/
MAX6723A/MAX6725A/MAX6727A/MAX6728A. For push-
pull, active-high RST output connect the external resistor
as a pullup from RST to VCC1.
A)
VIN
R1
R2
MAX6728A/
MAX6729A/
MAX6797A
PFI
PFO
( ) VTRIP = VPFI
R1 + R2
R2
GND
VTH
VCC
tWDI-NORMAL
1.12s MAX
tWDI-STARTUP
35s MAX
WDI
1.12s MAX
RST
tRP
B)
VCC
R1
R2
MAX6728A/
MAX6729A/
MAX6797A
PFI
PFO
VIN
GND
[ ( ) ] VTRIP = R2
(VPFI)
1+
R1
1
R2
- VCC
R1
VPFI = 626.5mV
Figure 2. Normal Watchdog Startup Sequence
Figure 3. Using Power-Fail Input to Monitor an Additional
Power-Supply a) VIN is Positive b) VIN is Negative
______________________________________________________________________________________ 11
Direct download click here
 
HOME 'MAX6723AUTTED1-T' Search
Share Link : 
한국어     日本語     русский     简体中文     español
@ 2015 - 2018  [ Home  ] [ Privacy Policy ] [ Request Datasheet  ] [ Contact Us ]