MAX6303CSA Maxim Integrated Products, MAX6303CSA Datasheet - Page 9

• Manufacturer Part Number: MAX6303CSA
• Description: IC SUPERVISORY CIRC 5V LP 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Simple Reset/Power-On Resetr

Specifications of MAX6303CSA

• Number Of Voltages Monitored: 1
• Output: Push-Pull, Totem Pole
• Reset: Active Low
• Reset Timeout: 2.8 ms Minimum
• Voltage - Threshold: Adjustable/Selectable
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Figure 7. Interfacing to µPs with Bidirectional Reset I/O Pins
Since RESET is open-drain, the MAX6301 interfaces
easily with µPs that have bidirectional reset pins, such
as the Motorola 68HC11 (Figure 7). Connecting RESET
directly to the µP’s reset pin with a single pullup allows
either device to assert reset.
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these supervisors
are relatively immune to short-duration negative-going
transients (glitches). The Maximum Transient Duration vs.
Reset Threshold Overdrive graph in the Typical
Operating Characteristics shows this relationship.
The area below the curves of the graph is the region in
which these devices typically do not generate a reset
pulse. This graph was generated using a negative-
going pulse applied to V
reset threshold (V
nitude indicated (reset-threshold overdrive). As the
magnitude of the transient increases (farther below the
reset threshold), the maximum allowable pulse width
decreases. Typically, a V
below the reset threshold and lasts 50µs or less will not
cause a reset pulse to be issued.
GND
MAX6301
Negative-Going V
RESET
V
RST
CC
_______________________________________________________________________________________
+5V, Low-Power µP Supervisory Circuits
) and ending below it by the mag-
0.1µF
Bidirectional Reset Pins
V
CC
CC
Interfacing to µPs with
IN
, starting above the actual
transient that goes 100mV
4.7kΩ
with Adjustable Reset/Watchdog
CC
RESET
V
Transients
µP
CC
RESET TO
OTHER SYSTEM
COMPONENTS
In extended mode (WDS = V
nally driven through a buffer and series resistor from
the watchdog counter (Figure 8). When WDI is left
unconnected, the watchdog timer is serviced within the
watchdog timeout period by a very brief low-high-low
pulse from the counter chain. For minimum watchdog
input current (minimum overall power consumption),
leave WDI low for the majority of the watchdog timeout
period, pulsing it low-high-low (> 30ns) once within the
period to reset the watchdog timer. If instead WDI is
externally driven high for the majority of the timeout
period, typically 70µA can flow into WDI.
In normal mode (WDS = GND), the internal buffer that
drives WDI is disabled. In this mode, WDI is a standard
CMOS input and leakage current is typically 100pA,
regardless of whether WDI is high or low.
When V
(sourcing) capabilities decline drastically. In the case
of the MAX6303, high-impedance CMOS-logic inputs
connected to RESET can drift to undetermined
voltages. This presents no problem in most applica-
tions, since most µPs and other circuitry do not operate
with V
Figure 8. Watchdog Input Structure
Down to V
WDS
CC
Ensuring a Valid RESET /RESET Output
WDI
CC
below 1V.
falls below 1V, RESET/RESET current sinking
CC
= 0V (MAX6303/MAX6304)
Watchdog Input Current
CC
TO MODE
CONTROL
WATCHDOG
), the WDI input is inter-
TIMER
MAX6301
MAX6302
MAX6303
MAX6304
GENERATOR
Extended Mode
TO RESET
Normal Mode
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