ISL88031 Intersil Corporation, ISL88031 Datasheet - Page 5

• Manufacturer Part Number: ISL88031
• Description: Quintuple Voltage Monitor
• Manufacturer: Intersil Corporation

Power On Reset (POR)
Applying power to the ISL88031 activates a POR circuit which
makes the reset pin(s) active (i.e. RST goes high while RST
goes low). These signals provide several benefits:
• It prevents the system microprocessor from starting to
• It prevents the processor from operating prior to stabilization
• It ensures that the monitored device is held out of operation
• It allows time for an FPGA to download its configuration prior
The reset signal remains active until V
minimum voltage sense level for time period t
ensures that the supply voltage has stabilized to sufficient
operating levels.
Manual Reset
The manual-reset input (MR) allows the user to trigger a reset
by using a push-button switch or by signaling the input low. The
MR input is an active low debounced input. Reset is asserted if
the MR pin is pulled low to less than 100mV for the minimum
MR pulse width or longer while the push-button is closed. After
MR is released, the reset output remains asserted low for t
(200ms) and then is released.
Figures 2 and 3 illustrate the operation ISL88031’s
operation. Figure 4 shows the ISL88031EVAL, the
evaluation platform for this family of voltage monitors.
Figures 5 and 6 illustrate RST output response times.
operate with insufficient voltage.
of the oscillator.
until internal registers are properly loaded.
to initialization of the circuit.
V2MON
V
RST
DD /
MR
V
1V
TH1 / 2
t
5
POR
DD
FIGURE 2. POWER SUPPLY MONITORING DIAGRAM
rises above the
POR
. This
t
RPD
POR
ISL88031
t
POR
The ISL88031EVAL1 and Applications
The ISL88031EVAL1 supports all variants of the ISL88031
devices, enabling evaluation of basic functional operation
and common application implementations. Figure 4
illustrates the ISL88031EVAL1 in schematic and
photographic forms. The ISL88031EVAL1 has two isolated
circuits, the left circuit is populated with the
ISL88031IU8HFZ (V
V
to customize to provide a specific voltage monitoring solution
with the accompanying loose packed variants.
With adequate bias on the two preset and the three
adjustable monitor inputs the RST output will release to pull
high indicating that all supplies are compliant for a minimum
of t
V2MON nominal thresholds are as previously noted with the
voltage thresholds being monitored by V3MON, V4MON and
V5MON being nominally 1.990V, 1.44V and 0.95V
respectively.
Special Application Considerations
Using good decoupling practices on bias and other
monitoring inputs will prevent transients (i.e. due to switching
noises and short duration droops in the supply voltage) from
causing unwanted resets.
Although the internal ISL88031 threshold references are
guaranteed over the full temp range accuracy errors due to
external component tolerances and distribution looses will
occur. High tolerance resistors and layout for extreme
accuracy and critical performance must be considered.
TH2
POR
= 3.08V). The right circuit is unpopulated for the user
. For the ISL88031EVAL1 as shipped the V
>t
>t
MR
MD
DD
t
POR
V
TH1
= 4.64V, V2MON
March 31, 2006
DD
FN8227.0
and