MAX3318CAP+ Maxim Integrated, MAX3318CAP+ Datasheet - Page 11

• Manufacturer Part Number: MAX3318CAP+
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX3316, MAX3317, MAX3318, MAX3319r

Specifications of MAX3318CAP+

• Data Rate: 460 Kbps
• Operating Supply Voltage: 2.5 V
• Supply Current: 1 mA
• Operating Temperature Range: 0 C to + 70 C
• Function: Transceiver
• Number Of Drivers: 2
• Number Of I/os: 8
• Number Of Receivers: 2
• Propagation Delay Time Ns: 0.175 us
• Shutdown: Yes

released. The manual reset detect function is internally
debounced for the t
can be connected directly to a momentary pushbutton
switch, if desired (Figure 2).
Many microprocessor-based products require manual
reset capability, allowing the operator, a test techni-
cian, or external logic circuitry to initiate a reset while
the monitored supplies remain above their reset thresh-
olds. The MAX6736–MAX6739 have a dedicated
active-low MR input. The RESET is asserted low while
MR is held low and remains asserted for the manual
reset timeout period after MR returns high. The MR
input has an internal 1.5kΩ pullup resistor to V
can be left unconnected if not used. MR can be driven
with CMOS logic levels, open-drain/open-collector out-
puts, or a momentary pushbutton switch to GND to cre-
ate a manual reset function.
The MAX6738/MAX6739 and MAX6740/MAX6743 pro-
vide an additional input to monitor a second or third
system voltage. The threshold voltage at RSTIN is typi-
Figure 2. MAX6740/MAX6741/MAX6742 Manual Reset Timing Diagram
Figure 3. Monitoring an Additional Voltage
PUSHBUTTON
SWITCH
V
EXT_TH
RESET
CLOSED
OPEN
V
GND
CC
1
R1
R2
______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
DEB
Adjustable Input Voltage
BOUNCE
SWITCH
timeout period, so the output
RSTIN
Manual Reset Input
t
DEB
MAX6738
MAX6739
MAX6740
MAX6743
GND
CC
1 and
BOUNCE
SWITCH
t
MRP
cally 488mV. Connect a resistor-divider network to the
circuit as shown in Figure 3 to establish an externally
controlled threshold voltage, V
Low leakage current at RSTIN allows the use of large-
valued resistors, resulting in reduced power consump-
tion of the system.
PFI is the noninverting input to an auxiliary comparator. A
488mV internal reference (V
inverting input of the comparator. If PFI is less than
488mV, PFO is asserted low. PFO deasserts without a
timeout period when PFI rises above the externally set
threshold. Common uses for the power-fail comparator
include monitoring for low battery conditions or a failing
DC-DC converter input voltage (see the Typical
Application Circuits). The asserted PFO output can place
a system in a low-power suspend mode or support an
orderly system shutdown before monitored V
drop below the reset thresholds. Connect PFI to an exter-
nal resistor-divider network as shown in Figure 4 to set
the desired trip threshold. Connect PFI to V
Most microprocessors with bidirectional reset pins can
interface directly to open-drain RESET output options.
Systems simultaneously requiring a push-pull RESET
output and a bidirectional reset interface can be in
logic contention. To prevent contention, connect a
4.7kΩ resistor between RESET and the µP’s reset I/O
port as shown in Figure 5.
Supervisory Circuits
V
EXT_TH
Applications Information
BOUNCE
SWITCH
= 0.488V((R1 + R2) / R2)
Interfacing to the µP with
t
DEB
BOUNCE
SWITCH
Bidirectional Reset Pins
Power-Fail Comparator
TH
EXT_TH
-
PFI
) is connected to the
.
t
MRP
CC
CC
1 if unused.
voltages
11